bv 2010 parts abdem ss&mw full hrch

Pt A, Ch 1, Sec 1

April 2009 Bureau Veritas 27

SECTION 1 GENERAL PRINCIPLES OF CLASSIFICATION

1 Principles of classification

1.1 Purpose of the Rules

1.1.1 The Rules published by the Society give the require-ments for the assignment and the maintenance of classifica-tion for seagoing ships.

Note 1: The general conditions of classification are laid down inthe Marine Division General Conditions.

1.1.2 The application criteria of the different parts of thepresent Rules are the following:

• Part A - Classification and Surveys applies to all ships.

• Part B - Hull and Stability, Part C - Machinery and Sys-tems, Part D - Service Notations apply to seagoing shipswhose hull is of welded steel construction. Where nec-essary, the extent of application is more preciselydefined in each chapter of these parts of the Rules.

• Part E - Additional Class Notations applies, at therequest of the Interested Party, to all ships.

The classification of ships other than those dealt with in theabove-mentioned Parts B, C, D and E is covered by specificRules published by the Society.

1.2 General definitions

1.2.1 The following general definitions are used in theseRules :

• Society means the Classification Society with which theship is classed

• Rules means these Rules for the Classification of Shipsand documents issued by the Society serving the samepurpose

• Surveyor means technical staff acting on behalf of theSociety to perform tasks in relation to classification andsurvey duties

• Survey means an intervention by the Surveyor forassignment or maintenance of class as defined in Part A,Chapter 2, or interventions by the Surveyor within thelimits of the tasks delegated by the Administrations

• Administration means the Government of the Statewhose flag the ship is entitled to fly or the State underwhose authority the ship is operating in the specific case

• Interested Party means a party, other than the Society,having responsibility for the classification of the ship,such as the Owners of a ship and his representatives, orthe Shipbuilder, or the Engine Builder, or the Supplier ofparts to be tested

• Owner means the Registered Owner or the DisponentOwner or the Manager or any other party having theresponsibility to keep the ship seaworthy, having partic-ular regard to the provisions relating to the maintenanceof class laid down in Part A, Chapter 2

• Approval means the review by the Society of documents,procedures or other items related to classification, verify-ing solely their compliance with the relevant Rulesrequirements, or other referentials where requested

• Type approval means an approval process for verifyingcompliance with the Rules of a product, a group ofproducts or a system, and considered by the Society asrepresentative of continuous production

• Essential service is intended to mean a service necessaryfor a ship to proceed at sea, be steered or manoeuvred,or undertake activities connected with its operation, andfor the safety of life, as far as class is concerned.

1.2.2 Definition of date of “contract for construction”:

The date of “contract for construction” of a ship is the dateon which the contract to build the ship is signed betweenthe Owner and the Shipbuilder. This date is normally to bedeclared to the Society by the Interested Party applying forthe assignment of class to a new ship. For ships “contractedfor construction” on or after 1st April 2006, this date and theconstruction numbers (i.e. hull numbers) of all the shipsincluded in the contract, are to be declared to the Societyby the Interested Party applying for the assignment of classto a new ship.

The date of “contract of construction” of a series of ships,including specified optional ships for which the option isultimately exercised, is the date on which the contract tobuild the series is signed between the Owner and the Ship-builder.

For the purpose of this definition, ships built under a singlecontract for construction are considered a “series of ships”if they are built to the same approved plans for classificationpurposes. However, ships within a series may have designalterations from the original design provided:

• Such alterations do not affect matters related to classifi-cation, or

• If the alterations are subject to classification require-ments, these alterations are to comply with the classifi-cation requirements in effect on the date on which thealterations are contracted between the prospectiveOwner and the Shipbuilder or, in the absence of thealteration contract, comply with the classificationrequirements in effect on the date on which the altera-tions are submitted to the Society for approval.

The optional ships will be considered part of the sameseries of ships if the option is exercised not later than 1 yearafter the contract to build the series was signed.

Pt A, Ch 1, Sec 1

28 Bureau Veritas April 2009

If a contract for construction is later amended to includeadditional ships or additional options, the date of “contractfor construction” for such ships is the date on which theamendment to the contract is signed between the Ownerand the Shipbuilder. The amendment to the contract is to beconsidered as a “new contract” to which the above applies.

If a contract for construction is amended to change the shiptype, the date of “contract for construction” of this modifiedship or ships, is the date on which the revised contract ornew contract is signed between the Owner, or Owners, andthe shipbuilder.

1.3 Meaning of classification, scope and limits

1.3.1 The classification process consists of:

• the development of Rules, guidance notes and otherdocuments relevant to the ship, structure, material,equipment, machinery and other items covered by suchdocuments

• the review of plans and calculations and the surveys,checks and tests intended to demonstrate that the shipmeets the Rules (refer to Ch 2, Sec 1)

• the assignment of class (see Ch 2, Sec 1) and issue of aCertificate of Classification, where compliance with theabove Rules is found

• the periodical, occasional and class renewal surveysperformed to record that the ship in service meets theconditions for maintenance of class (see Ch 2, Sec 2).

1.3.2 The Rules, surveys performed, reports, certificatesand other documents issued by the Society, are in no wayintended to replace or alleviate the duties and responsibili-ties of other parties such as Administrations, Designers,Shipbuilders, Manufacturers, Repairers, Suppliers, Contrac-tors or Sub-contractors, actual or prospective Owners orOperators, Charterers, Brokers, Cargo-owners and Under-writers.The activities of such parties which fall outside the scope ofthe classification as set out in the Rules, such as design,engineering, manufacturing, operating alternatives, choiceof type and power of machinery and equipment, numberand qualification of crew or operating personnel, lines ofthe ship, trim, hull vibrations, spare parts including theirnumber, location and fastening arrangements, life-savingappliances, and maintenance equipment, remain thereforethe responsibility of those parties, even if these matters maybe given consideration for classification according to thetype of ship or additional class notation assigned.

1.3.3 Unless otherwise specified, the Rules do not dealwith structures, pressure vessels, machinery and equipmentwhich are not permanently installed and used solely foroperational activities such as dredging or heavy load lifting,workshops or welding equipment, except for their effect onthe classification-related matters, as declared by the Inter-ested Party, such as fire protection and ship’s generalstrength.During periods of construction, modification or repair, theunit is solely under the responsibility of the builder or therepair yard. As an example, the builder or repair yard is to

ensure that the construction, modification or repair activi-ties are compatible with the design strength of the ship andthat no permanent deformations are sustained.Note 1: Refer to [3.3] as regards the Owner’s responsibility formaintenance and operation of the ship in relation to the mainte-nance of class.

1.3.4 The class assigned to a ship by the Society followingits interventions is embodied in a Certificate of Classifica-tion and noted in the Register of ships.

At a certain date the class of a ship is maintained or regularwhen no surveys are overdue, when the conditions for sus-pension of class are not met and when the class is not with-drawn nor suspended. Otherwise the class is irregular.Attention is drawn on the fact that a ship holding a validCertificate of Classification may be in an irregular classposition.

1.4 Request for services

1.4.1 Requests for interventions by the Society, such assuveys during construction, surveys of ships in service, tests,etc., are in principle to be submitted in writing and signedby the Interested Party. Such request implies that the appli-cant will abide by all the relevant requirements of the Rules,including the Marine Division General Conditions.

The Society reserves the right to refuse or withdraw the classof any ship for which any applicable requirement of theRules is not complied with.

1.5 Register of ships

1.5.1 A Register of Ships is published periodically by theSociety. This publication, which is updated by the Society,contains the names of ships which have received the Certif-icate of Classification, as well as particulars of the classassigned and information concerning each ship.

2 Rules

2.1 Effective date

2.1.1 The effective date of entry into force of any amend-ments to the Rules is indicated on the inside front page ofthe Rules or in the relevant Section.

2.1.2 In principle, the applicable Rules for assignment ofclass to a new ship are those in force at the date of contractfor construction.

2.1.3 Special consideration may be given to applying newor modified rule requirements which entered into force sub-sequent to the date of contract for construction, at the dis-cretion of the Society and in the following cases:

• when a justified written request is received from theparty applying for classification

• when the keel is not yet laid and more than one year haselapsed since the contract for construction was signed

• where it is intended to use existing previously approvedplans for a new contract.

Pt A, Ch 1, Sec 1


2.1.4 The above procedures for application of the Rulesare, in principle, also applicable to existing ships in the caseof major conversions and, in the case of alterations, to thealtered parts of the ship.

2.1.5 The rule requirements related to assignment, mainte-nance and withdrawal of the class of ships already in opera-tion, as detailed in Part A, Chapter 2 to Part A, Chapter 5,are applicable from the date of their entry into force.

2.2 Equivalence

2.2.1 The Society may consider the acceptance of alterna-tives to these Rules, provided that they are deemed to beequivalent to the Rules to the satisfaction to the Society.

2.3 Novel features

2.3.1 The Society may consider the classification of shipsbased on or applying novel design principles or features, towhich the Rules are not directly applicable, on the basis ofexperiments, calculations or other supporting informationprovided to the Society. Specific limitations may then beindicated on the Certificate of Classification.

2.4 Disagreement and appeal

2.4.1 Any technical disagreement with the Surveyor in con-nection with the performance of his duties should be raisedby the Interested Party as soon as possible.

The Interested Party may appeal in writing to the Society,which will subsequently consider the matter and announceits decision according to its established procedure.

3 Duties of the Interested Parties

3.1 International and national regulations

3.1.1 The classification of a ship does not relieve the Inter-ested Party from compliance with any requirements issuedby Administrations.

Note 1: Attention is drawn on the prohibition of asbestos on-boardships (new ships, modified parts of existing ships) and otherNational Regulations, as applicable.

3.2 Surveyor’s intervention

3.2.1 Surveyors are to be given free access at all times toships which are classed or being classed, shipyards andworks, to carry out their interventions within the scope ofassignment or maintenance of class, or within the scope ofinterventions carried out on behalf of Administrations,when so delegated.

Free access is also to be given to auditors accompanying theSurveyors of the Society within the scope of the audits asrequired in pursuance of the Society’s internal Quality Sys-tem or as required by external organizations.

3.2.2 Interested Parties are to take the necessary measuresfor the Surveyors’ inspections and testing to be carried outsafely. Interested Parties - irrespective of the nature of theservice provided by the Surveyors of the Society or othersacting on its behalf - assume with respect to such Surveyorsall the responsibility of an employer for his workforce suchas to meet the provisions of applicable legislation. As a rule,the Surveyor is to be constantly accompanied during sur-veys by personnel of the Interested Party.

Interested Parties are to inform promptly the Surveyor ofdefects or problems in relation to class.

Refer also to Ch 2, Sec 2, [2.5] to Ch 2, Sec 2, [2.8].

3.2.3 The Certificate of Classification and/or other docu-ments issued by the Society remain the property of the Soci-ety. All certificates and documents necessary to theSurveyor’s interventions are to be made available by theInterested Party to the Surveyor on request.

3.2.4 During the phases of ship design and construction,due consideration should be given to rule requirements inrespect of all necessary arrangements for access to spacesand structures with a view to carrying out class surveys.Arrangements of a special nature are to be brought to theattention of the Society.

3.3 Operation and maintenance of ships

3.3.1 The classification of a ship is based on the under-standing that the ship is loaded and operated in a propermanner by competent and qualified crew or operating per-sonnel according to the environmental, loading, operatingand other criteria on which classification is based.

In particular, it will be assumed that the draught of the shipin operating conditions will not exceed that correspondingto the freeboard assigned or the maximum approved for theclassification, that the ship will be properly loaded takinginto account both its stability and the stresses imposed onits structures and that cargoes will be properly stowed andsuitably secured and that the speed and course of the shipare adapted to the prevailing sea and weather conditionsaccording to the normal prudent seamanship.

3.3.2 Ships are to be maintained at all times, at the dili-gence of the Owners, in proper condition complying withinternational safety and pollution prevention regulations.

3.3.3 Any document issued by the Society in relation to itsinterventions reflects the condition of the ship as found atthe time and within the scope of the survey. It is the Inter-ested Party’s responsibility to ensure proper maintenance ofthe ship until the next survey required by the Rules. It is theduty of the Interested Party to inform the Surveyor when heboards the ship of any events or circumstances affecting theclass.

Pt A, Ch 1, Sec 1


3.4 Flag and Port State Control inspections

3.4.1 Where defects are found further to an inspection byan Administration in pursuance of Port State Control or sim-ilar programmes, Owners are to:

• immediately report the outcome of this inspection to theSociety, and

• ask the Society to perform an occasional survey in orderto verify that the deficiencies, when related to the classof the ship or to the statutory certificates issued by theSociety on behalf of the flag Administration, are recti-fied and/or the necessary repair work is carried outwithin the due time.

3.5 Use of measuring equipment and of service suppliers

3.5.1 General

Firms providing services on behalf of the Interested Party,such as measurements, tests and servicing of safety systemsand equipment, the results of which may form the basis forthe Surveyor’s decisions, are subject to the acceptance ofthe Society, as deemed necessary.

The equipment used during tests and inspections in work-shops, shipyards and on board ships, the results of whichmay form the basis for the Surveyor’s decisions, is to be cus-tomary for the checks to be performed. Firms are to individ-ually identify and calibrate to a national or internationalstandard each piece of such equipment.

Note 1: Refer to Rule Note NR 533 Approval of Service Suppliers.

3.5.2 Simple measuring equipment

The Surveyor may accept simple measuring equipment (e.g.rulers, tape measures, weld gauges, micrometers) withoutindividual identification or confirmation of calibration, pro-vided it is of standard commercial design, properly main-tained and periodically compared with other similarequipment or test pieces.

3.5.3 Shipboard measuring equipment

The Surveyor may accept measuring equipment fitted onboard a ship (e.g. pressure, temperature or rpm gauges andmeters) and used in examination of shipboard machineryand/or equipment based either on calibration records orcomparison of readings with multiple instruments.

3.6 Spare parts

3.6.1 It is the Owner’s responsibility to decide whether andwhich spare parts are to be carried on board.

3.6.2 As spare parts are outside the scope of classification,the Surveyor will not check that they are kept on board,maintained in a satisfactory condition, or suitably protectedand lashed.However, in the case of repairs or replacement, the spareparts used are to meet the requirements of the Rules as faras practicable; refer to Ch 2, Sec 2, [6.4.2].

4 Application of statutory requirements by the Society

4.1 International and national regulations

4.1.1 Where requirements of International Conventions,such as SOLAS, ILLC, MARPOL, ILO or of IMO AssemblyResolutions, are quoted as excerpts, they are printed initalic type replacing the word “Administration” with “Soci-ety”.These requirements are quoted for ease of reference.

4.1.2 When authorised by the Administration concerned,the Society will act on its behalf within the limits of suchauthorisation. In this respect, the Society will take intoaccount the relevant national requirements, survey the ship,report and issue or contribute to the issue of the corre-sponding certificates.The above surveys do not fall within the scope of the classi-fication of ships, even though their scope may overlap inpart and may be carried out concurrently with surveys forassignment or maintenance of class.

4.1.3 In the case of a discrepancy between the provisionsof the applicable international and national regulations andthose of the Rules, normally, the former take precedence.However, the Society reserves the right to call for the neces-sary adaptation to preserve the intention of the Rules or toapply the provisions of [1.4.1].

4.1.4 In statutory matters, when authorized by the Adminis-tration concerned and acting on its behalf, the Societyapplies the available IACS Unified Interpretations (UIs),unless the Administration provides another interpretation ordecides otherwise.

Pt A, Ch 1, Sec 2

January 2010 Bureau Veritas 31

SECTION 2 CLASSIFICATION NOTATIONS

1 General

1.1 Purpose of the classification notations

1.1.1 The classification notations give the scope according to which the class of the ship has been based and refer to the specific rule requirements which are to be complied with for their assignment. In particular, the classification notations are assigned according to the type, service and navigation of the ship and other criteria which have been provided by the Interested Party, when applying for classification.The Society may change the classification notations at any time, when the information available shows that the requested or already assigned notations are not suitable for the intended service, navigation and any other criteria taken into account for classification.Note 1: Reference should be made to Ch 1, Sec 1, [1.3] on the lim-its of classification and its meaning.

1.1.2 The classification notations assigned to a ship are indicated on the Certificate of Classification, as well as in the Register of Ships published by the Society.

1.1.3 The classification notations assigned to ships and units, other than those covered in Parts B, C, D and E, which are to comply with specific Rules published by the Society are given in Ch 1, App 1.

1.1.4 The classification notations applicable to existing ships conform to the Rules of the Society in force at the date of assignment of class, as indicated in Ch 2, Sec 1. How-ever, the classification notations of existing ships may be updated according to the current Rules, as far as applicable.

1.2 Types of notations assigned

1.2.1 The types of classification notations assigned to a ship are the following:

a) class symbol

b) construction marks

c) service notations with additional service features, as applicable

d) navigation notations

e) operating area notations (optional)

f) additional class notations (optional)The different classification notations and their conditions of assignment are listed in [2] to [6], according to their types.

1.2.2 As an example, the classification notations assigned to a ship may be as follows (the kind of notation shown in brackets does not form part of the classification notation indicated in the Register of Ships and on the Certificate of Classification):

I { HULL [ MACH

(class symbol, construction marks)

Oil tanker-Chemical tanker-ESP-Flash point > 60°C

(service notation and additional service features)

Unrestricted navigation

(navigation notation)

{ SYS

(additional class notation).

2 Class symbol

2.1 General

2.1.1 The class symbol expresses the degree of compliance of the ship with the rule requirements as regards its con-struction and maintenance. There is one class symbol, which is compulsory for every classed ship.

2.1.2 The class symbol I is assigned to ships built in accordance with the requirements of the Rules or other rules recognised as equivalent, and maintained in a condi-tion considered satisfactory by the Society.

The period of class (or interval between class renewal sur-veys) assigned to class symbol I ships is maximum 5 years, see Ch 2, Sec 2, [4].

Note 1: The class symbol I is to be understood as being the highest class granted by the Society.

2.1.3 The class symbol II is assigned to ships which do not meet all requirements for class symbol I, but are deemed acceptable to be entered into the Register of Ships.

The period of class assigned to class symbol II ships is max-imum 3 years, see Ch 2, Sec 2, [4].

2.1.4 Except for special cases, class is assigned to a ship only when the hull, propulsion and auxiliary machinery installations, and equipment providing essential services have all been reviewed in relation to the requirements of the Rules.

3 Construction marks

3.1 General

3.1.1 The construction mark identifies the procedure under which the ship and its main equipment or arrangements have been surveyed for initial assignment of the class. The procedures under which the ship is assigned one of the con-struction marks are detailed in Ch 2, Sec 1.

Pt A, Ch 1, Sec 2

32 Bureau Veritas January 2010

3.1.2 One of the construction marks defined below is assigned separately to the hull of the ship and its append-ages, to the machinery installation, and to some installa-tions for which an additional classification notation (see [6]below) is assigned.The construction mark is placed before the symbol HULLfor the hull, before the symbol MACH for the machinery installations, and before the additional class notation granted, when such a notation is eligible for a construction mark.

If the ship has no machinery installations covered by classi-fication, the symbol MACH is not granted and the construc-tion mark will be only placed before the symbol HULL.Note 1: Ships assigned with the service notation yacht or charter yacht according to the requirements of [4.11.3] and having a length less than 24 m may be assigned the construction mark only placed before the symbol HULL when the machinery installations are not surveyed for classification. No symbol MACH is granted in this case.

3.1.3 The construction marks refer to the original condition of the ship. However, the Society may change the construc-tion mark where the ship is subjected to repairs, conversion or alterations.

3.2 List of construction marks

3.2.1 The mark { is assigned to the relevant part of the ship, when it has been surveyed by the Society during its construction in compliance with the new building proce-dure detailed in Ch 2, Sec 1, [2.1], or when it is changing class from an IACS Society at ship's delivery or when class is being added to an IACS Society's class at ship's delivery in accordance with specific procedures.

3.2.2 The mark [ is assigned to the relevant part of the ship, when the latter is classed after construction in compli-ance with the procedure detailed in Ch 2, Sec 1, [3.2] and it is changing class from an IACS Society at the time of the admission to class.

3.2.3 The mark µ is assigned to the relevant part of the ship, where the procedure for the assignment of classification is other than those detailed in [3.2.1] and [3.2.2], but how-ever deemed acceptable.

4 Service notations and corresponding additional service features

4.1 General

4.1.1 The service notations define the type and/or service of the ship which have been considered for its classifica-tion, according to the request for classification signed by the Interested Party. At least one service notation is to be assigned to every classed ship.Note 1: The service notations applicable to existing ships conform to the Rules of the Society in force at the date of assignment of class. However, the service notations of existing ships may be updated according to the current Rules, as far as applicable, at the request of the Interested Party.

4.1.2 The assignment of any service notation to a new ship is subject to compliance with general rule requirements laid down in Part B and Part C of the Rules and in NR216 Mate-rials and Welding, and, for some service notations, the additional requirements laid down in Part D.

Table 1 : List of service notations and additional service features

Service notationAdditional service feature

Definition in

Reference in NR 467 or to other Rule Notes

Corresponding type of ship according toConventions and/or Codes

Asphalt carrier [4.4.3] Part D, Chapter 7

Barge [4.8.1] Part D, Chapter 19

tug combined Pt D, Ch 14, Sec 3

type of cargo (1)

Bulk carrier [4.4.3] Cargo ship (SOLAS, Reg I/2(g))Bulk carrier (SOLAS, Reg XII/1)

ESP [4.3.2] Part D, Chapter 4 Bulk carrier (SOLAS, Reg IX/1.6, Reg XII/1)

BC-A or BC-B or BC-C (2) Part D, Chapter 4

heavycargo [AREA1, X1 kN/m2 - …] Pt B, Ch 5, Sec 6

nonhomload (3)

CSR Rule Note NR 522

GRAB [X] (4) NR 522, Ch12, Sec1

CPS(WBT) (5) Rule Note NR 530

Cable laying ship [4.7.6] Part D, Chapter 18 Cargo ship (SOLAS, Reg I/2(g))

Chemical tanker [4.4.4] Part D, Chapter 8 Chemical tanker (SOLAS, Reg.II-2/3.11, Reg.VII /8.2)Chemical tanker (MARPOL Annex II, Reg 1/16.1) when noxious liquid substances are loaded

ESP

type of cargo (1)

Pt A, Ch 1, Sec 2


Combination carrier/OBO ESP [4.3.4] Part D, Chapter 6 Combination carrier (SOLAS, Reg II-2/3.14)Tanker (SOLAS, Reg I/2(h))Bulk carrier (SOLAS, Reg IX/1.6, Reg XII/1)Oil tanker - Combination carrier (MARPOL Annex I, Reg I/1.8)

Combination carrier/OOC ESP [4.3.5] Part D, Chapter 6 Combination carrier (SOLAS, Reg II-2/3.14)Tanker (SOLAS, Reg I/2(h))Bulk carrier (SOLAS, Reg IX/1.6, Reg XII/1)Oil tanker - Combination carrier (MARPOL Annex I, Reg I/1.8)

Compressed natural gas carrier [4.11.5] Rule Note NR 517

Container ship [4.2.5] Part D, Chapter 2 Cargo ship (SOLAS, Reg I/2(g))

Crew boat [4.11.4] Rule Note NR 490

Deck ship [4.2.7] (6) Cargo ship (SOLAS, Reg I/2(g))

Dredger [4.6.2] Part D, Chapter 13 Cargo ship (SOLAS, Reg I/2(g))

Escort tug [4.7.2] Part D, Chapter 14 Cargo ship (SOLAS, Reg I/2(g))

barge combined Pt D, Ch 14, Sec 3

Fire-fighting ship [4.7.4] Part D, Chapter 16 Cargo ship (SOLAS, Reg I/2(g))

1, 2 , 3 or E Pt D, Ch 16, Sec 3

water spraying Pt D, Ch 16, Sec 4

Fishing vessel [4.9.1] Part D, Chapter 20 Fishing vessel (SOLAS, Reg I/2(i)). To be noted that SOLAS Convention does not apply to such ships

F Pt D, Ch 20, Sec 6

ED European Directive 97/70/EC as amended

TORRE Torremolinos International Convention for the Safety of Fishing Vessels as amended

Floating dock [4.7.7] Rule Note NR 475

FLS tanker [4.4.6] Part D, Chapter 7 Tanker (SOLAS, Reg I/2(h)) NLS Tanker (MARPOL, Annex II, Reg 1/16.2), when noxious liquid substances are loaded

flash point > 60°C Part D, Chapter 7

type of cargo (1)

General cargo ship [4.2.2] (6) Cargo ship (SOLAS, Reg I/2(g))

equipped for carriage of containers Part D, Chapter 2

heavycargo [AREA1, X1 kN/m2 - …] Pt B, Ch 5, Sec 6

nonhomload (3)

occasional dry bulk cargo IMO Res.MSC 277(85) para. 1.6 and 1.7

Hopper dredgerHopper unit

[4.6.2] Part D, Chapter 13 Cargo ship (SOLAS, Reg I/2(g))

HSC (7) [4.10.1] NR 396 UNITAS High-speed craft (SOLAS, Chapter X), 2000 HSC CodeHSC-CAT A, HSC-CAT B

Launch, Seagoing launch [4.11.2] Part D, Chapter 21 (non-convention ship)

Light ship (7) [4.10.2] see [4.10.2]

Liquefied gas carrier [4.4.5] Part D, Chapter 9 Tanker (SOLAS, Reg I/2(h))Gas carrier (SOLAS, Reg II-1/3.20, Reg II-2/3.25, Reg VII /11.2)

RV Pt D, Ch 9, Sec 1, [5]

STL-SPM Pt D, Ch 9, Sec 1, [6]

Livestock carrier [4.2.6] Part D, Chapter 3 Cargo ship (SOLAS, Reg I/2(g))

Oil recovery ship [4.7.5] Part D, Chapter 17

Oil tanker [4.4.2] Part D, Chapter 7 Tanker (SOLAS, Reg I/2(h))Oil tanker (MARPOL Annex I, Reg I/1.5)ESP Part D, Chapter 7

flash point > 60°C Part D, Chapter 7

asphalt carrier Part D, Chapter 7

CSR Rule Note NR 523

CPS(WBT) (5) Rule Note NR 530


Definition in



Pt A, Ch 1, Sec 2


Ore carrier ESP [4.3.3] Part D, Chapter 5 Cargo ship (SOLAS, Reg I/2(g))Bulk carrier (SOLAS, Reg IX/1.6, Reg XII/1)

Passenger ship [4.5.2] Part D, Chapter 11 Passenger ship (SOLAS, Reg. I/2(f))

≤ 36 passengers

PontoonPontoon - crane

[4.8.2] Part D, Chapter 19

Refrigerated cargo ship [4.2.4] (8) Cargo ship (SOLAS, Reg I/2(g))


Ro-ro cargo ship [4.2.3] Part D, Chapter 1 Cargo ship (SOLAS, Reg I/2(g))


Ro-ro passenger ship [4.5.3] Part D, Chapter 12 Passenger ship (SOLAS, Reg. I/2(f))Ro-ro passenger ship (SOLAS, Reg II-2/3.42) ≤ 36 passengers

Salvage tug [4.7.2] Part D, Chapter 14 Cargo ship (SOLAS, Reg I/2(g))


Special service (7) [4.11.1] a)

(9)

Special service-standby rescue vessel [4.11.1] b)

Rule Note NR 482

number of survivors

ship operation area

Split hopper dredgerSplit hopper unit

[4.6.2] Part D, Chapter 13 Cargo ship (SOLAS, Reg I/2(g))

Supply vessel [4.7.3] Part D, Chapter 15 Cargo ship (SOLAS, Reg I/2(g))

oil product Part D, Chapter 15

LHNS Part D, Chapter 15

WS Part D, Chapter 15

Tanker [4.4.7] Part D, Chapter 10 Cargo ship (SOLAS, Reg I/2(g))

type of cargo (1)

Tug [4.7.2] Part D, Chapter 14 Cargo ship (SOLAS, Reg I/2(g))


Yacht, Charter yacht [4.11.3] Rule Note NR 500

motor or sailing

S (10)

OTHER ADDITIONAL SERVICE FEATURES

no propulsion (11) [4.8.3] Part D, Chapter 19

assisted propulsion [4.8.4]

WAP or EAWP [4.8.5] Rule Note NR 206

dualfuel or gasfuel [4.12.1] Rule Note NR 529

(1) For ships intended to carry only one type of cargo.(2) Additional indications: for BC-A: (holds a, b, .., ... may be empty); for BC-A or BC-B and if x.y ≤ 3 t/m3: (maximum cargo den-

sity x.y t/m3); for BC-A, BC-B or BC-C: (no MP) if applicable. (3) Completed with indication of the different maximum loads allowed in each hold and which holds may be empty, if appropriate.(4) Mandatory as an additional service feature for bulk carriers CSR BC-A or CSR BC-B.(5) Mandatory for ships assigned with additional service feature CSR and contracted for construction on or after 8 December 2006.(6) No additional requirements are specified in Part D for this service notation.(7) The type of service may be specified after the notation.(8) No additional requirements are specified in Part D for this service notation; however requirements of Part E, Chapter 7 for the

assignment of the additional class notation REF-CARGO are to be applied.(9) These ships are considered on a case by case basis by the Society according to their type of service.(10) Corresponding to hull made of steel material as per these Rules (NR 467).(11) Any non-propelled units other than barge or pontoon.


Definition in



Pt A, Ch 1, Sec 2


4.1.3 A ship may be assigned several different service nota-tions. In such case, the specific rule requirements applica-ble to each service notation are to be complied with. However, if there is any conflict in the application of the requirements applicable to different service notations, the Society reserves the right to apply the most appropriate requirements or to refuse the assignment of one of the requested service notations.

4.1.4 A service notation may be completed by one or more additional service features, giving further precision regard-ing the type of service of the ship, for which specific rule requirements are applied.

4.1.5 The different service notations which may be assigned to a ship are listed in [4.2] to [4.11], according to the category to which they belong. These service notations are also listed in alphabetical order in Tab 1, where the cor-respondence between the service notation assigned by the Society and the type of ship defined by the International Conventions is also given for information.

As a rule, all notations in [4.2], [4.3], [4.4] and [4.5] are only to be assigned to self-propelled units.

4.2 Cargo ships

4.2.1 The service notations related to self-propelled ships intended for the carriage of cargo are listed in [4.2.2] to [4.2.6].

4.2.2 General cargo ship, for ships intended to carry gen-eral cargo.

The service notation may be completed by the following additional service feature, as applicable:

• equipped for carriage of containers, where the ship’s fixed arrangements comply with the applicable rule requirements in Part D, Chapter 2

• heavycargo [AREA1, X1 kN/m2 - AREA2, X2 kN/m2 - ...], when the double bottom and/or hatch covers and/or other cargo areas designed to support heavy cargoes fulfil the appropriate rule requirements. The values Xi indicate the maximum allowable local pressures on the various zones AREAi where the cargo is intended to be stowed. The requirements for the assignment of this additional service feature are given in Pt B, Ch 5, Sec 6, [4.1.2]

• nonhomload, when the ship has been designed in such a way that the cargo spaces may be loaded non-homo-geneously, including cases where some holds may be empty, at a draught up to the scantling draught and fulfil the appropriate rule requirements for general strength, and when the corresponding loading conditions are listed in the reviewed loading manual. This notation can be completed with the indication of the different maxi-mum loads allowed in each hold and which holds may be empty, if appropriate.

• occasional dry bulk cargo, for ships the keels of which are laid or which are at a similar stage of construction on or after the 1st July 2010, and which occasionally carry dry cargoes in bulk, as described in IMO Res.MSC 277(85), paragraphs 1.6 and 1.7.

4.2.3 Ro-ro cargo ship, for ships specially intended to carry vehicles, trains or loads on wheeled beds. The additional requirements of Part D, Chapter 1 are applicable to these ships. The service notation may be completed by the addi-tional service feature equipped for carriage of containers, where the ship’s fixed arrangements comply with the appli-cable rule requirements in Part D, Chapter 2.

4.2.4 Refrigerated cargo ship, for ships specially intended to carry refrigerated cargo. No additional requirements are specified in Part D for this service notation; however, the requirements of Part E, Chapter 7 for the assignment of the additional class notation REF-CARGO are to be applied. The service notation may be completed by the additional service feature equipped for carriage of containers, where the ship’s fixed arrangements comply with the applicable rule requirements in Part D, Chapter 2.

4.2.5 Container ship, for ships specially intended to carry containers in holds or on decks. The additional require-ments of Part D, Chapter 2 are applicable to these ships.

4.2.6 Livestock carrier, for ships specially intended to carry livestock. The additional requirements of Part D, Chapter 3are applicable to these ships.

4.2.7 Deck ship, for ships specially intended to carry cargo exclusively on the deck.

Note 1: a ship with the service notation deck ship is usually but not necessarily a self-propelled unit intended for unrestricted navigation.

4.3 Bulk, ore and combination carriers

4.3.1 The service notations related to self-propelled ships specially intended for the carriage of dry cargo in bulk are those listed in [4.3.2] to [4.3.5] or bulk carrier when the ship does not meet the forthcoming conditions.

The service notations described in [4.3.2] to [4.3.5] are always completed by the additional service feature ESP, which means that these ships are submitted to the Enhanced Survey Program as laid down in Ch 4, Sec 2.

Example: ore carrier ESP.

Note 1: Self-propelled ships are ships with mechanical means of propulsion not requiring assistance from another ship during nor-mal operation.

4.3.2 Bulk carrier ESP, for sea going self-propelled ships which are constructed generally with single deck, double bottom, hopper side tanks and topside tanks and with single or double side skin construction in cargo length area and intended primarily to carry dry cargoes in bulk. Typical midship sections are illustrated in Fig 1, or a midship sec-tion deemed equivalent by the Society. The additional requirements of Part D, Chapter 4 are applicable to these ships.

The service notation bulk carrier ESP is always completed by one of the following additional service features, for bulk carriers of length greater than or equal to 150 m contracted for new construction on or after 1 July 2003:

Pt A, Ch 1, Sec 2


• BC-A, for bulk carriers designed to carry dry bulk car-goes of density 1.0 t/m3 and above with specified holds empty at maximum draught in addition to BC-B condi-tions

• BC-B, for bulk carriers designed to carry dry bulk car-goes of density 1.0 t/m3 and above with all cargo holds loaded in addition to BC-C conditions

• BC-C, for bulk carriers designed to carry dry bulk car-goes of density less than 1.0 t/m3.

The additional service feature BC-A is completed with the indication of the allowed combination of specified empty holds, as follows: (holds a, b, .., ... may be empty).

If limitations are to be observed during operation:

• the additional service features BC-A and BC-B are com-pleted, when the maximum cargo density is less than 3.0 t/m3, with the indication of the maximum density of cargo that the ship is allowed to carry, as follows: (maximum cargo density x.y t/m3)

• the additional service features BC-A, BC-B and BC-C are completed by the following indication when the vessel has not been designed for loading and unloading in multiple ports: (no MP).

Examples:

Bulk carrier BC-A (maximum cargo density 2.5 t/m3; holds 2, 4, 6 may be empty) ESP

Bulk carrier BC-B (maximum cargo density 2.5 t/m3; no MP) ESP

Bulk carrier BC-C (no MP) ESP

For ships contracted for new construction before 1 July 2003 or for ships contracted for new construction on or after 1 July 2003 but less than 150 m in length, the service notation bulk carrier ESP may be completed by the addi-tional service features heavycargo or nonhomload defined under [4.2.2].

The service notation bulk carrier ESP is always completed by the additional service feature CSR for bulk carriers of length greater than or equal to 90 m contracted for new construction on or after 1 April 2006.

Figure 1 : Typical midship sections of shipswith service notation bulk carrier ESP

Left: Single side skin construction

Right: Double side skin construction.

Bulk carriers assigned with the additional service feature CSR are to comply with the requirements of the Common Structural Rules for Bulk Carriers (Rule Note NR522). The elements not dealt with in NR522 are to comply with the requirements of Part B, Part C and Part D of the Rules for the Classification of Steel Ships.

Note 1: Hybrid bulk carriers, where at least one cargo hold is con-structed with hopper tank and topside tank, are covered by NR522. The structural strength of members in holds constructed without hopper tank and/or topside tank is to comply with the strength cri-teria defined in NR522.

Bulk carriers assigned with the additional service feature CSR and with holds designed for loading/unloading by grabs having a maximum specific weight up to [x] tons are assigned the notation GRAB [X] according to NR522 (Com-mon Structural Rules for Bulk Carriers), Ch 1, Sec 1, [3.2.1]. The requirements for GRAB [X] notation are given in NR522, Ch 12, Sec 1.

For bulk carriers assigned with the additional service feature CSR, and one of the additional service features BC-A or BC-B, these additional service features are always completed by the additional service feature GRAB [X]. For these ships, the requirements for the GRAB [X] notation are to be complied with for an unladen grab weight X equal to or greater than 20 tons.

For bulk carriers assigned with the additional service feature CSR others than above, the additional class notation GRAB [X] may be assigned on a voluntary basis (refer to[6.13.2], item a)).

Bulk carriers assigned with the additional service feature CSR are to comply with the requirements for maintenance of class, thickness measurements and acceptance criteria given in NR522, Chapter 13.

For bulk carriers assigned with the additional service feature CSR and contracted for construction on or after 8 Decem-ber 2006, this additional service feature is always com-pleted by the additional service feature CPS(WBT) for which the rule requirements of NR530 Coating Performance Standard, applicable to ships complying with the require-ments of the Common Structural Rules for Bulk Carriers or the Common Structural Rules for Double Hull Oil Tankersand related to protective coatings in dedicated seawater ballast tanks of ships of not less than 500 gross tonnage and double-side skin spaces arranged in bulk carriers of length greater than or equal to 150 m, are applied.

Example:

Bulk carrier CSR CPS(WBT) BC-A (maximum cargo density 2.5 t/m3; holds 2, 4, 6 may be empty) ESP GRAB [20]

Note 2: Attention is drawn on the coating condition which is sur-veyed as per the requirements of Ch 4, Sec 2 for ships in service.

4.3.3 Ore carrier ESP, for sea going self-propelled ships which are constructed generally with single deck, two lon-gitudinal bulkheads and a double bottom throughout the cargo length area and intended primarily to carry ore car-goes in the centre holds only. Typical midship sections are illustrated in Fig 2, or a midship section deemed equivalent by the Society. The additional requirements of Part D, Chap-ter 5 are applicable to these ships.

Pt A, Ch 1, Sec 2


Figure 2 : Typical midship sections of shipwith service notation ore carrier ESP

4.3.4 Combination carrier/OBO ESP, for sea going self-propelled ships which are constructed generally with single deck, double bottom, hopper side tanks and topside tanks and with single or double side skin construction in the cargo length area, and intended primarily to carry oil or dry cargoes, including ore, in bulk. Typical midship sections are illustrated in Fig 3, or a midship section deemed equivalent by the Society. The additional requirements of Part D, Chap-ter 6 are applicable to these ships.

Figure 3 : Typical midship sections of shipwith service notation combination carrier/OBO ESP

Left: Single side skin construction

Right: Double side skin construction.

4.3.5 Combination carrier/OOC ESP, for sea going self-propelled ships which are constructed generally with single deck, two longitudinal bulkheads and a double bottom throughout the cargo length area and intended primarily to carry ore cargoes in the centre holds or oil cargoes in centre holds and wing tanks. Typical midship sections are illus-trated in Fig 4, or a midship section deemed equivalent by the Society. The additional requirements of Part D, Chapter 6 are applicable to these ships.

Note 1: “combination carrier” is a general term applied to ships intended for the carriage of both oil and dry cargoes in bulk; these cargoes are not carried simultaneously, with the exception of oily mixture retained in slop tanks.

Figure 4 : Typical midship sections of shipswith service notation combination carrier/OOC ESP

4.4 Ships carrying liquid cargo in bulk

4.4.1 The service notations related to self-propelled ships intended for the carriage of liquid cargo in bulk are listed in[4.4.2] to [4.4.8].

4.4.2 Oil tanker, for sea going self-propelled ships which are constructed generally with integral tanks and intended primarily to carry in bulk crude oil, other oil products, or oil-like substances having any flash point, or liquid at atmospheric pressure and ambient temperature (or thus maintained by heating). This notation may be assigned to tankers of both single and double hull construction, as well as tankers with alternative structural arrangements, e.g. mid-deck designs.

The service notation may be completed by the additional service feature flash point > 60°C, as applicable, where the ship is intended to carry only such type of products, under certain conditions.

The service notation may be completed by the additional service feature asphalt carrier, where the ship is intended to carry such type of products, under certain conditions. The maximum cargo temperature is to be indicated on the Cer-tificate of Classification.

The additional requirements of Part D, Chapter 7 are appli-cable to these ships.

For ships with integral cargo tanks, the service notation oil tanker is always completed by the additional service feature ESP (i.e. oil tanker ESP), which means that these ships are submitted to the Enhanced Survey Program as laid down inCh 4, Sec 3. Typical midship sections are illustrated in Fig 5.

The service notation oil tanker ESP is always completed by the additional service feature CSR for double hull oil tank-ers of length greater than or equal to 150 m and contracted for new construction on or after 1 April 2006.

Oil tankers assigned with the additional service feature CSRare to comply with the requirements of the Common Struc-tural Rules for Double Hull Oil Tankers (Rule Note NR523). The elements not dealt with in NR523 are to comply with the requirements of Part B, Part C and Part D of the Rules for the Classification of Steel Ships.

Pt A, Ch 1, Sec 2


Figure 5 : Typical midship sections of ships with service notation oil tanker ESP

Oil tankers assigned with the additional service feature CSRare to comply with the requirements for ship in operation renewal criteria given in NR523, Section 12, related to the allowable thickness diminution for hull structure.

For oil tankers assigned with the additional service feature CSR and contracted for construction on or after 8 Decem-ber 2006, this additional service feature is always com-pleted by the additional service feature CPS(WBT) for which the rule requirements of NR530 Coating Performance Standard, applicable to ships complying with the require-ments of the Common Structural Rules for Bulk Carriers or the Common Structural Rules for Double Hull Oil Tankersand related to protective coatings in dedicated seawater ballast tanks of ships of not less than 500 gross tonnage and double-side skin spaces arranged in bulk carriers of length greater than or equal to 150 m, are applied.Example:

Oil tanker CSR CPS(WBT) ESPNote 1: Attention is drawn on the coating condition which is sur-veyed as per the requirements of Ch 4, Sec 3 for ships in service.

4.4.3 Asphalt carrier, for sea going self-propelled ships which are constructed with independent (non-integral) cargo tanks, intended to carry only such type of products, under certain conditions. The additional requirements of Part D, Chapter 7 are applicable to these ships.The maximum cargo temperature is to be indicated on the Certificate of Classification.

4.4.4 Chemical tanker, for sea going self-propelled ships which are constructed generally with integral tanks and intended primarily to carry chemicals in bulk. This notation may be assigned to tankers of both single or double hull construction, as well as tankers with alternative structural arrangements. Typical midship sections are illustrated in Fig 6, or a midship section deemed equivalent by the Society. The additional requirements of Part D, Chapter 8 are appli-cable to these ships.

The list of products the ship is allowed to carry is attached to the Certificate of Classification or the Certificate of Fit-ness, where issued by the Society, including, where neces-sary, the maximum allowable specific gravity and/or temperature.

For ships intended to carry only one type of cargo, the serv-ice notation may be completed by the additional service feature indicating the type of product carried.For ships with integral cargo tanks, the service notationchemical tanker is always completed by the additional serv-ice feature ESP (i.e. chemical tanker ESP), which means that these ships are submitted to the Enhanced Survey Pro-gramme as laid down in Ch 4, Sec 4.

4.4.5 Liquefied gas carrier, for ships specially intended to carry liquefied gases or other substances listed in Pt D, Ch 9, Sec 1 of the Rules. The additional requirements of Part D, Chapter 9 are applicable to these ships.The list of products the ship is allowed to carry is attached to the Certificate of Classification or the Certificate of Fit-ness, where issued by the Society, including, where neces-sary, the conditions of transportation (pressure, temperature, filling limits).

The service notation may be completed by the following additional service feature, as applicable:• RV, where the ship is fitted with an installation for

revaporisation of the liquefied natural gas. The require-ments for the assignment of this additional service fea-ture are given in Pt D, Ch 9, Sec 1, [5]

• STL-SPM, where the ship is used as re-gasification termi-nal and fitted forward with equipment for non perma-nent mooring or single buoy. The requirements for the assignment of this additional service feature are given inPt D, Ch 9, Sec 1, [6].

Example:

Liquefied gas carrier RV STL-SPM

Pt A, Ch 1, Sec 2


Figure 6 : Typical midship sections of ships with service notation chemical tanker ESP

4.4.6 FLS tanker, for ships specially intended to carry in bulk flammable liquid products other than those covered by the service notations oil tanker, chemical tanker or lique-fied gas carrier.

The list of products the ship is allowed to carry may be attached to the Certificate of Classification, including, where necessary, the maximum allowable specific gravity and/or temperature.

The service notation may be completed by the additional service feature flash point > 60°C, where the ship is intended to carry only such type of products, under certain conditions.

For ships intended to carry only one type of cargo, the serv-ice notation may be completed by the additional service feature indicating the type of product carried.


4.4.7 Tanker, for ships intended to carry non-flammable liquid cargoes in bulk other than those covered by the serv-ice notations in [4.4.2] to [4.4.6], such as water.

The list of cargoes the ship is allowed to carry may be attached to the Certificate of Classification.

For ships intended to carry only one type of cargo, the serv-ice notation may be completed by the additional service feature indicating the type of product carried, e.g. tanker-water.


4.4.8 Refer also to [4.3.4] and [4.3.5] for combination car-rier intended to carry alternatively oil products and dry cargo in bulk in cargo holds/tanks.

4.5 Ships carrying passengers

4.5.1 The service notations related to ships specially intended for the carriage of passengers are listed in [4.5.2]to [4.5.3].

4.5.2 Passenger ship, for ships intended to carry more than 12 passengers. The additional requirements of Part D, Chap-ter 11 are applicable to these ships.

The service notation may be completed by the additional service feature ≤ 36 passengers, where the ship is intended to carry only such a limited number of passengers.

4.5.3 Ro-ro passenger ship, for ships intended to carry more than 12 passengers and specially equipped to load trains or wheeled vehicles. The additional requirements ofPart D, Chapter 12 are applicable to these ships.

The service notation may be completed by the additional service feature ≤ 36 passengers, where the ship is intended to carry only such a limited number of passengers.

4.6 Ships for dredging activities

4.6.1 The service notations related to ships specially intended for dredging activities are listed in [4.6.2]. The additional requirements of Part D, Chapter 13 are applica-ble to these ships.

4.6.2 The following notations are provided:

a) dredger, for ships specially equipped only for dredging activities (excluding carrying dredged material)

b) hopper dredger, for ships specially equipped for dredg-ing activities and carrying spoils or dredged material

c) hopper unit, for ships specially equipped for carrying spoils or dredged material

d) split hopper unit, for ships specially equipped for carry-ing spoils or dredged material and which open longitu-dinally, around hinges

e) split hopper dredger, for ships specially equipped for dredging and for carrying spoils or dredged material and which open longitudinally, around hinges.

4.6.3 These ships which are likely to operate at sea within specific limits may, under certain conditions, be granted an operating area notation. For the definition of operating area notation, reference should be made to [5.3].

Pt A, Ch 1, Sec 2


4.7 Working ships

4.7.1 The service notations related to ships specially intended for different working services are listed in [4.7.2]to [4.7.6].

4.7.2 The service notations for ships intended to tow and/or push other ships or units are:

a) tug, for ships specially equipped for towing and/or pushing

b) salvage tug, for ships specially equipped for towing and/or pushing having specific equipment for salvage

c) escort tug, for ships specially equipped for towing and/or pushing having specific equipment for escorting ships or units during navigation.


These service notations may be completed by the additional service feature barge combined, when units are designed to be connected with barges and comply with the relevant requirements of Pt D, Ch 14, Sec 3. The barges to which the tug can be connected are specified in an annex to the Cer-tificate of Classification.

4.7.3 The service notation supply vessel is assigned to ships specially intended for the carriage and/or storage of special material and equipment and/or which are used to provide facilities and assistance for the performance of specified activities, such as offshore, research and underwater activi-ties.

The service notation is to be completed by the additional service feature oil product, when the ship is also specially intended to carry oil products having any flash point and having a specified maximum cargo tank capacity.

The service notation is to be completed by the additional service feature LHNS, for ships, other than well stimulation vessels, carrying amounts of hazardous and noxious liquid substances in bulk not exceeding a specified maximum value.

The service notation is to be completed by the additional service feature WS for well stimulation vessels.


4.7.4 The service notation fire-fighting ship is assigned to ships specially intended and equipped for fighting fire. The additional requirements of Part D, Chapter 16 are applica-ble to these ships.

The service notation may be completed by the following additional service features, as applicable:

• 1 or 2 or 3, when the ship complies with the applicable requirements of Pt D, Ch 16, Sec 3

• E, when the characteristics of the water fire-fighting sys-tem are not those required for the assignment of the additional service features 1, 2 or 3, and when the sys-tem is specially considered by the Society

• water spraying, when the ship is fitted with a water-spraying system complying with the applicable require-ments of Pt D, Ch 16, Sec 4, [3].

4.7.5 The service notation oil recovery ship is assigned to ships specially equipped with fixed installations and/or mobile equipment for the removal of oil from the sea sur-face and its retention on board, carriage and subsequent unloading. The additional requirements of Part D, Chapter 17 are applicable to these ships.

4.7.6 The service notation cable laying ship is assigned to ships specially equipped for the carriage and/or laying, hauling and repair of submarine cables. The additional requirements of Part D, Chapter 18 are applicable to these ships.

4.7.7 The service notation floating dock is assigned to floating docks meeting the requirements of Rule Note NR475.

Note 1: The navigation notation sheltered area is assigned to these units. When the dock is intended to be towed, the navigation nota-tion temporary unrestricted navigation is also to be assigned.

4.8 Non-propelled units, units with sail pro-pulsion and other units

4.8.1 Barge

The service notation barge is assigned to non-propelled units intended to carry (dry or liquid) cargo inside holds or tanks. The additional requirements of Part D, Chapter 19 are applicable to these ships.

For ships intended to carry only one type of cargo, the serv-ice notation may be completed by an additional service fea-ture indicating the type of product carried e.g. barge - oil, barge - general cargo.

This service notation may be completed by the additional service feature tug combined when units are designed to be connected with tugs, and comply with the relevant require-ments of Pt D, Ch 14, Sec 3. The tugs to which the barge can be connected are specified in an annex to the Certifi-cate of Classification.

4.8.2 Pontoon

The service notation pontoon is assigned to non-propelled units intended to carry cargo and/or equipment on deck only. When a crane is permanently fitted on board, the crane is to be certified and the service notation pontoon - crane is granted. The additional requirements of Part D, Chapter 19 are applicable to these ships.

4.8.3 Other units

Any non-propelled units other than those covered by the service notations listed above will be assigned the addi-tional service feature no propulsion, to be added to their own service notation, e.g. dredger - no propulsion.

4.8.4 Assisted propulsion units

Any units having a propulsion system not enabling them to proceed at a speed greater than 7 knots, used for short tran-sit voyages, will be assigned the additional service feature assisted propulsion to be added to their own service nota-tion, e.g. dredger - assisted propulsion.

Pt A, Ch 1, Sec 2


4.8.5 Units with a sail propulsion

Ships fitted with a wind propulsion plant meeting the requirements of the Rule Note Classification of wind pro-pulsion plants onboard ships (NR206) may have their serv-ice notation completed by the following additional service feature:

• WAP for an auxiliary wind propulsion

• EAWP for a wind propulsion assisted by auxiliary engine propulsion.

4.9 Fishing vessels

4.9.1 The service notation fishing vessel is assigned to ships specially equipped for catching and storing fish or other liv-ing resources of the sea. The additional requirements of Part D, Chapter 20 are applicable to these ships.

The service notation may be completed by the following additional service feature, as applicable:

• F, when the ship complies with the requirements of Pt D, Ch 20, Sec 6 related to fire prevention, ventilation systems and means of escape

• TORRE, when the Society has verified the compliance with the requirements for construction and equipment of fishing vessels of the Torremolinos International Con-vention for the Safety of Fishing Vessels, as amended

• ED, when the Society has verified the compliance with the requirements for construction and equipment of fishing vessels of the European Directive 97/70/EC, as amended.

Note 1: Units solely dedicated to service in a fishing flotilla by means of cold storage and/or transformation of fish are not covered by the service notation fishing vessel. They will be considered with the service notation special service.

4.10 High Speed Crafts (HSC)

4.10.1 The high speed crafts meeting the requirements of the Rules for the Construction and the Classification of High Speed Craft (NR396 UNITAS) are assigned the following service notations:

• HSC-CAT A (or high speed craft-CAT A) for passenger ships defined as ‘’Category A craft’’ in respect of the IMO International Code of Safety for High Speed Craft

• HSC-CAT B (or high speed craft-CAT B) for passenger ships defined as ‘’Category B craft’’ in respect of the IMO International Code of Safety for High Speed Craft

• HSC (or high speed craft) for ships other than the above; in this case, the type of service may be specified after the notation, i.e. HSC/passenger carrier.

4.10.2 The service notation light ship is assigned to ships meeting the requirements of the Rules for the Construction and the Classification of High Speed Craft (NR396 UNITAS) for the hull requirements (Chapters 3 and 6) and the requirements of the present Rules for the stability ( Part B) and for the machinery installation ( Part C).

The type of service may be specified after the notation, i.e. light ship/fast passenger vessel, light ship/fast cargo vessel.

4.11 Miscellaneous units

4.11.1 Special servicea) General

The service notation special service is assigned to ships which, due to the peculiar characteristics of their activ-ity, are not covered by any of the notations mentioned above. The classification requirements of such units are considered by the Society on a case by case basis.This service notation may apply, for instance, to ships engaged in research, expeditions and survey, ships for training of marine personnel, whale and fish factory ships not engaged in catching, ships processing other living resources of the sea, and other ships with design features and modes of operation which may be referred to the same group of ships.An additional service feature may be specified after the notation (e.g. special service-training, special service-fish factory, special service-standby rescue vessel) to identify the particular service in which the ship is intended to trade. The scope and criteria of classifica-tion of such units are indicated in an annex to the Certif-icate of Classification.

b) Special service - standby rescue vesselShips complying with the requirements of Rule Note NR482 are eligible for the assignment of the service notation special service - standby rescue vessel.This service notation may be completed by the number of survivors that the vessel is intended to carry. Depend-ing on the vessel operation area, the Society may adapt the requirements regarding the survivors accommoda-tion and/or the safety equipment. In such a case, this service notation is to be completed by the number of survivors that the vessel is intended to carry and by the vessel operation area, as for example: special service - standby rescue vessel (150 survivors, Guinea Gulf).

4.11.2 LaunchThe launches or motorboats with a length not exceeding 24m and meeting the requirements of Part D, Chapter 21are assigned the following service notations:• seagoing launch, for units intended for seagoing service,

limited at a wind force not exceeding 6 Beaufort scale• launch, for units intended for operation in ports, road-

steads, bays and generally calm stretches of water, lim-ited at a wind force not exceeding 4 Beaufort scale.

Note 1: Ships that are assigned the service notation launch or sea-going launch are not assigned a navigation notation.

4.11.3 Yacht and charter yachtThe service notation charter yacht is assigned to ships intended for pleasure cruising, engaged in commercial sail-ing and complying with the applicable requirements of Rule Note NR500.

The service notation yacht is assigned to ships intended for pleasure cruising other than charter yacht and complying with the applicable requirements of Rule Note NR500. Ships assigned with the service notation yacht and having a length less than 24 m are not submitted to annual surveys for hull and machinery.

Pt A, Ch 1, Sec 2


The service notation yacht or charter yacht is always com-pleted by one of the following additional service features, as applicable:

• motor for units propelled by propulsion engine

• sailing for units with a sail propulsion, including those assisted by auxiliary propulsion engine.

Examples:

yacht-motor

yacht-sailing

charter yacht-motor

charter yacht-sailing

The service notation yacht or charter yacht is completed by the additional service feature S when the hull is made of steel material.

Example:

yacht-motor-S

When the hull is made of other material, additional service features are to be assigned in accordance with the require-ments of Rule Note NR500.

Ships with service notation yacht or charter yacht are assigned a navigation notation as listed in [5.2], except for the navigation notations summer zone and tropical zonewhich are not assigned.

For high speed motor yachts meeting the requirements of Rule Note NR500, Pt B, Ch 5, Sec 1, [2], the following applies:

• As a rule, the navigation notation assigned to such unit is corresponding to sea areas where the significant wave height H.S. is not to exceed for more then 10 per cent of the year the following values:

- sheltered area: 0,5 m

- coastal area: 2,5 m

- unrestricted navigation: no limitation.

• The table of the speed relative to the sea states, charac-terised by their significant wave height, is annexed to the Certificate of Classification.

4.11.4 Crew boats

The service notation crew boat is assigned to ships less than 500 grt, of length not greater than 45 m, dedicated to trans-port of offshore personnel from harbours to moored offshore installations or ships and meeting the requirements of Rule Note NR490.

Note 1: Ships which do not fulfil the minimum speed criteria in Section 1, [1.1.1] of NR490 will not be assigned the above service notation.

4.11.5 Compressed natural gas carrier

The service notation compressed natural gas carrier is assigned to ships intended to carry compressed natural gas (CNG) meeting the requirements of NR517 Classification of Compressed Natural Gas Carriers.

4.11.6 Other unitsFor ships or other floating units intended to be classed with other service notations, reference is to be made to the spe-cific Rules of the Society, and in particular:

• Rules and Regulations for the Construction and Classifi-cation of Wooden Fishing Vessels (NR219)

• Rules for the Classification of Offshore Units (NR445)

• Rules and Regulations for the Classification of Submers-ibles (NR316).

4.11.7 Inland navigation vesselsFor ships and units intended for navigation in inland waters, reference is to be made to the Rules and Regulations for the Construction and Classification of Inland Navigation Ves-sels (NR217).

4.12 Ships with gas fuelled propulsion

4.12.1 The service notation is completed by one of the fol-lowing additional service features, when the ship complies with the requirements of NR529 Safety Rules for Gas-Fuelled Engine Installations in Ships, for internal combus-tion engines using gas as fuel, as applicable:

• dualfuel for engines using both gas and fuel oil as fuel

• gasfuel for engines using only gas as fuel.

The gas may be either compressed natural gas or liquefied natural gas.

5 Navigation and operating area notations

5.1 Navigation notations

5.1.1 Every classed ship is to be assigned one navigation notation as listed in [5.2], except those with the service notations launch or seagoing launch.

5.1.2 The assignment of a navigation notation, including the reduction of scantlings or specific arrangements for restricted navigation notations, is subject to compliance with the requirements laid down in Part B, Part C and Part Dof the Rules and in NR216 Materials and Welding.

5.1.3 The assignment of a navigation notation does not absolve the Interested Party from compliance with any inter-national and national regulations established by the Admin-istrations for a ship operating in national waters, or a specific area, or a navigation zone. Neither does it waive the requirements in Ch 1, Sec 1, [3.3.1].

5.2 List of navigation notations

5.2.1 The navigation notation unrestricted navigation is assigned to a ship intended to operate in any area and any period of the year.

5.2.2 The navigation notation summer zone is assigned to ships intended to operate only within the geographical lim-its as defined in ILLC 1966 for the Summer zones.

Pt A, Ch 1, Sec 2


5.2.3 The navigation notation tropical zone is assigned to ships intended to operate only within the geographical lim-its as defined in ILLC 1966 for the Tropical zones.

5.2.4 The navigation notation coastal area is assigned to ships intended to operate only within 20 nautical miles from the shore and with a maximum sailing time of six hours from a port of refuge or safe sheltered anchorage.

5.2.5 The navigation notation sheltered area is assigned to ships intended to operate in sheltered waters, i.e. harbours, estuaries, roadsteads, bays, lagoons and generally calm stretches of water and when the wind force does not exceed 6 Beaufort scale.

5.2.6 In specific cases, the designation of the geographical area and/or the most unfavourable sea conditions consid-ered may be added to the navigation notation.

5.2.7 The navigation notation temporary unrestricted navi-gation may be assigned, in addition to the navigation nota-tions defined in [5.2.2], [5.2.3], [5.2.4] or [5.2.5] to service ships for which the period of unrestricted navigation may be chosen to satisfy the conditions defined in an annex to the Certificate of Classification.

When a favourable weather situation is included amongst these conditions, the voyages are to be such as the ship can be put in a port or a sheltered anchorage in about 12 hours from any point of its route.

Note 1: Before any voyage covered by the navigation notation tem-porary unrestricted navigation, the ship is to be submitted to an occasional survey, during which the Surveyor checks that the intended voyage and the ship’s specific condition, if any, comply with the conditions defined in the annex to the Certificate of Classi-fication.

5.2.8 For ships assigned with the service notation:

• HSC-CAT A, HSC-CAT B, or HSC as defined in [4.10.1],

• light ship, as defined in [4.10.2], or

• crew boat, as defined in [4.11.4],

as a rule, one of the following navigation notations is to be assigned to such units and is corresponding to sea areas where the significant wave height H.S. is not to exceed for more than 10 per cent of the year the following values:

• sea area 1: 0,5 m



• sea area 4: no limitation.

The shipyard’s table of the maximum allowed ship speed relative to the sea states, characterised by their significant wave height, is annexed to the Certificate of Classification.

5.3 Operating area notations

5.3.1 The operating area notation expresses the specified area where some service units are likely to operate at sea within specific restrictions which are different from normal navigation conditions.

The operating area notation is, in principle, solely granted to ships for dredging activities.

This operating area notation is indicated after the navigation notation.

Example: unrestricted navigation - “operating area notation”

5.3.2 The following operating area notations may be assigned:

• dredging within 8 miles from shore,

• dredging within 15 miles from shore or within 20 miles from port,

• dredging over 15 miles from shore.

The operating area of the first two categories may be extended respectively over 8 or 15 miles. In that case, the operating area notation is completed by the maximum sig-nificant wave height during service, as follows:

dredging over 8 (or 15) miles from shore with H.S. ≤ ... m.

For ships being assigned the service notation split hopper barge or split hopper dredger, the operating area notation may be completed by the maximum allowable significant height of waves during the service, being indicated between parenthesis, i.e. (H.S. ≤ ... m).

6 Additional class notations

6.1 General

6.1.1 An additional class notation expresses the classifica-tion of additional equipment or specific arrangement, which has been requested by the Interested Party.

6.1.2 The assignment of such an additional class notation is subject to the compliance with additional rule require-ments, which are detailed in Part E of the Rules.

6.1.3 Some additional class notations are assigned a con-struction mark, according to the principles given in [3.1.2]. This is indicated in the definition of the relevant additional class notations.

6.1.4 The different additional class notations which may be assigned to a ship are listed in [6.2] to [6.15], according to the category to which they belong. These additional class notations are also listed in alphabetical order in Tab 2.

6.2 VeriSTAR system

6.2.1 General

VeriSTAR is a system integrating rational analysis at design stage or after construction and possibly with data and records from ships-in-service concerning planned inspec-tion and ship maintenance.

In compliance with [6.1.3], these notations are assigned a construction mark, as defined in [3].

The requirements for the assignment of these notations are given in Part E, Chapter 1.

Pt A, Ch 1, Sec 2


Table 2 : List of additional class notations

Additional class notation Definition in Reference in NR 467 or to other Rule Notes Remarks

ALP, ALM, ALS, [6.12] Rule Note NR 526(Rule Note NR 184)

(1)(for derricks including union purchase use)

(ALP), (ALM), (ALS) [6.12] Rule Note NR 526(Rule Note NR 184)

(1)(for derricks including union purchase use)

AUT-CCS [6.4.3] Pt E, Ch 3, Sec 2 (1)

AUT-IMS [6.4.5] Pt E, Ch 3, Sec 4 (1)

AUT-PORT [6.4.4] Pt E, Ch 3, Sec 3 (1)

AUT-UMS [6.4.2] Pt E, Ch 3, Sec 1 (1)

AVM-APS [6.3.2] Pt E, Ch 2, Sec 1 (1)

AVM-DPS [6.3.3] Pt E, Ch 2, Sec 2 (1)

AVM-IPS [6.3.4] Pt E, Ch 2, Sec 3 (1)

CARGOCONTROL [6.14.9] Pt E, Ch 10, Sec 9

CLEANSHIP (C) [6.8.2] Pt E, Ch 9, Sec 5 Pt E, Ch 9, Sec 2

CLEANSHIP x [6.8.3] Pt E, Ch 9, Sec 2 Pt E, Ch 9, Sec 2

no discharge period x (in days) equals to 1, 2, 3, 4, 5, 6, 7 or 7+

CLEANSHIP SUPER x [6.8.4] Pt E, Ch 9, Sec 3 Pt E, Ch 9, Sec 2


CLEANSHIP x AWTCLEANSHIP SUPER x AWT

[6.8.5] [6.8.3]

Pt E, Ch 9, Sec 4 Pt E, Ch 9, Sec 2


COLD (H tDH, E tDE) [6.14.12] Pt E, Ch 10, Sec 11

COMF+ [6.7.4] Part E, Chapter 6 to be completed by the selected performance indexes (Sound insulation index / Impact index / Emergence / Intermittent noise / Intelligibility)

COMF-NOISE y [6.7.2] Part E, Chapter 6 grade y equals to 1, 2, or 3

COMF-VIB y’ [6.7.3] Part E, Chapter 6 grade y’ equals to 1, 2, 3, 1PK, 2PK or 3PK

COMF-NOISE-Pax yCOMF-NOISE-Crew yCOMF-VIB-Pax y’COMF-VIB-Crew y’

[6.7.5] Part E, Chapter 6 for grades y and y’ see above

COVENT [6.14.8] Pt E, Ch 10, Sec 8

CPS(WBT) [6.15.4] Rule Note NR 530

DYNAPOS SAM [6.14.6] Pt E, Ch 10, Sec 6 (1)

DYNAPOS AM may be completed by R or RS

DYNAPOS AT may be completed by R or RS

DYNAPOS AM/AT may be completed by R or RS

EFP-A, EFP-M, EFP-C, EFP-AMC [6.14.17] Pt E, Ch 10, Sec 15

ERS-HERS-MERS-S

[6.13.2] Rule Note NR 556

ETA [6.15.3] Pt B, Ch 10, Sec 4, [4]

Fatigue PLUSFatigue PLUS DFL xxFatigue PLUS spectral ( )Fatigue PLUS spectral ( ) DFL xx

[6.14.18] Rule Note NR 552 xx in years and xx > 25between brackets: short description of the route or areas encountered by the ship during its service life

FORS [6.14.19] Rule Note NR 553 This notation may be completed by the notation -NS

EWCT [6.14.14] Pt E, Ch 10, Sec 12

GRAB [X] [6.14.2] Rule Note NR 522, Ch 12

Pt A, Ch 1, Sec 2


GRABLOADING [6.14.2] b) Pt E, Ch 10, Sec 2

GREEN PASSPORT [6.14.13] Rule Note NR 528

HVSC [6.14.20] Rule Note NR 557

IATP [6.14.16] Pt E, Ch 10, Sec 14

ICE [6.10.4] Part E, Chapter 8

ICE CLASS IAICE CLASS IA SUPERICE CLASS IBICE CLASS IC

[6.10.2] Part E, Chapter 8

ICE CLASS ID [6.10.4] Part E, Chapter 8

IG [6.15.2] Pt D, Ch 7, Sec 6 and Pt D, Ch 8, Sec 9

INWATERSURVEY [6.14.3] Pt E, Ch 10, Sec 3

LASHING [6.14.5] Pt E, Ch 10, Sec 5

MANOVR [6.14.10] Pt E, Ch 10, Sec 10 IMO Resolution MSC 137(76)

MON-HULL [6.6.2] Pt E, Ch 5, Sec 1

MON-SHAFT [6.6.3] Pt E, Ch 5, Sec 2

POLAR CLASS z [6.11] Rule Note NR 527 z equals to 1, 2, 3, 4, 5, 6 or 7

PROTECTED FO TANK [6.14.15] Pt E, Ch 10, Sec 13

REF-CARGO [6.9.2] Pt E, Ch 7, Sec 2 (1) (2)This notation may be completed by the specific notation -AIRCONT

REF-CONT (A) or REF-CONT (E) [6.9.3] Pt E, Ch 7, Sec 3 (1) (2)The notation REF-CONT (A) may be completed by the specific notation -AIRCONT

REF-STORE [6.9.4] Pt E, Ch 7, Sec 4 (1) (2)

SDS [6.14.11] Pt B, Ch 3, Sec 3

SPM [6.14.4] Pt E, Ch 10, Sec 4

STAR SIS [6.2.8] (1)

STAR-HULL [6.2.5] Pt E, Ch 1, Sec 2 (1)

STAR-MACH [6.2.7] Pt E, Ch 1, Sec 3 (1)

STAR-MACH SIS [6.2.6] Pt E, Ch 1, Sec 3 (1)

STRENGTHBOTTOM [6.14.1] Pt E, Ch 10, Sec 1

SYS [6.5.5] Part E, Chapter 4 (1)This cumulative notation supersedes the notations SYS-NEQ (or SYS-NEQ-1), SYS-COM and SYS-IBS (or SYS-IBS-1), when all are assigned

SYS-COM [6.5.4] Pt E, Ch 4, Sec 3 (1)The notation SYS-COM can only be assigned to ships which are also assigned the notation AUT-IMS

SYS-IBS, SYS-IBS-1 [6.5.3] Pt E, Ch 4, Sec 2 (1)

SYS-NEQ, SYS-NEQ-1 [6.5.2] Pt E, Ch 4, Sec 1 (1)

VCS [6.14.7] Pt E, Ch 10, Sec 7 This notation may be completed by the specific notation -TRANSFER.

VeriSTAR-HULL [6.2.2] Pt E, Ch 1, Sec 2 (1)This notation may be completed by DFL xx years, with 25 ≤ xx ≤ 40

VeriSTAR-HULL SIS [6.2.4] Pt E, Ch 1, Sec 2 (1)This notation may be completed by DFL xx years, with 25 ≤ xx ≤ 40

(1) A construction mark is added to this notation.(2) This notation may be completed by the specific notations -PRECOOLING and/or -QUICKFREEZE (see [6.9.5]).

Additional class notation Definition in Reference in NR 467 or to other Rule Notes Remarks

Pt A, Ch 1, Sec 2


6.2.2 VeriSTAR-HULLThe additional class notation VeriSTAR-HULL is assigned to ships the structural condition of which is checked with 3D FEM calculation programme at design stage or after con-struction, according to the requirements of the Society.

The requirements for the assignment of this notation are given in Pt E, Ch 1, Sec 2.

6.2.3 DFL xx yearsThe additional class notation VeriSTAR-HULL may be com-pleted by DFL xx years, with xx having values between 25 and 40, when a fatigue assessment has been carried out on selected structural details showing that their evaluated design fatigue life is not less than xx years.

The requirements for the assignment of DFL xx years are given in Pt E, Ch 1, Sec 2 and Pt B, Ch 7, Sec 4, as relevant.

The additional class notation VeriSTAR-HULL DFL xx yearsmay be assigned to ships of less than 170 m in length, sub-ject to special consideration by the Society.

6.2.4 VeriSTAR-HULL SISThe additional class notation VeriSTAR-HULL may be com-pleted by SIS for ships the structural condition of which is monitored using computerized survey data.

The requirements for the assignment and maintenance of this notation are given respectively in Pt E, Ch 1, Sec 2 and in Ch 5, Sec 2.

6.2.5 STAR-HULLThe additional class notation STAR-HULL is assigned to ships for which, in addition to the requirements for assign-ment of the additional class notation VeriSTAR-HULL SIS, an Inspection and Maintenance Plan for the hull is imple-mented by the Owner.

6.2.6 STAR-MACH SISThe additional class notation STAR-MACH SIS is assigned to ships on which a Planned Maintenance Survey System for machinery (PMS) is implemented as per the requirements ofCh 2, Sec 2, [4.4]. In addition, the notation STAR-MACH SIS includes a risk analysis update of the ship's machinery and other equipment (navigation instrumentation, anchor-ing and mooring arrangements, ...).

The requirements for the assignment and maintenance of this notation are given respectively in Pt E, Ch 1, Sec 3 and in Ch 5, Sec 2.

6.2.7 STAR-MACH The additional class notation STAR-MACH is assigned to ships subject to compliance with the requirements for the assignment of the notation and for which the requirements for maintenance of the notation given in Ch 5, Sec 2 are not applied.


6.2.8 STAR SISWhen ships are assigned the notations STAR-HULL and STAR-MACH SIS, the two separate notations are superseded by the cumulative additional class notation STAR SIS.

6.3 Availability of machinery (AVM)

6.3.1 GeneralThe notations dealt with under this heading are relevant to systems and/or arrangements enabling the ship to carry on limited operations when single failure affects propulsion or auxiliary machinery or when an external event such as fire or flooding involving machinery spaces affects the availabil-ity of the machinery.



6.3.2 AVM-APS (Alternative propulsion system)The additional class notation AVM-APS is assigned to ships which are fitted with systems and/or arrangements enabling them to maintain operating conditions with some limitations in speed, range and comfort, in the case of single failure of items relative to the propulsion or power generating system.

The limitations in operation and the types of single failure covered by this notation are specified in Pt E, Ch 2, Sec 1, [1.2].

6.3.3 AVM-DPS (Duplicated propulsion system)The additional class notation AVM-DPS is assigned to ships which are fitted with a duplicated propulsion system ena-bling them to maintain operating conditions with some lim-itations in power (but 50% of the main power is to be maintained), speed, range and comfort, in the case of single failure of items relative to the propulsion or power generat-ing system.

The limitations in operation and the types of failure which are covered by this notation are specified in Pt E, Ch 2, Sec 2, [1.2].Note 1: The loss of one compartment due to fire or flooding is not considered as a single failure case.

6.3.4 AVM-IPS (Independent propulsion system)The additional class notation AVM-IPS is assigned to ships which are fitted with an independent propulsion system enabling them to maintain operating conditions with some limitations in power (but 50% of the main power is to be maintained), speed, range and comfort, in the case of single failure of items relative to the propulsion or power generat-ing system.

The limitations in operation and the types of failure which are covered by this notation are specified in Pt E, Ch 2, Sec 3, [1.2].Note 1: The loss of one compartment due to fire or flooding is con-sidered as a single failure case.

6.4 Automated machinery systems (AUT)

6.4.1 GeneralThe notations dealt with under this heading are relevant to automated machinery systems installed on board ships.



Pt A, Ch 1, Sec 2


6.4.2 Unattended machinery space (AUT-UMS)

The additional class notation AUT-UMS is assigned to ships which are fitted with automated installations enabling machinery spaces to remain periodically unattended in all sailing conditions including manoeuvring.

6.4.3 Centralised control station (AUT-CCS)

The additional class notation AUT-CCS is assigned to ships which are fitted with machinery installations operated and monitored from a centralised control station.

6.4.4 Automated operation in port (AUT-PORT)

The additional class notation AUT-PORT is assigned to ships which are fitted with automated installations enabling the ship’s operation in port or at anchor without personnel spe-cially assigned for the watch-keeping of the machinery in service.

6.4.5 Integrated machinery system (AUT-IMS)

The additional class notation AUT-IMS is assigned to ships which are fitted with automated installations enabling machinery spaces to remain periodically unattended in all sailing conditions including manoeuvring, and additionally provided with integrated systems enabling to handle con-trol, safety and monitoring of machinery.

6.5 Integrated ship systems (SYS)

6.5.1 General

The notations dealt with under this heading are relevant to operation of integrated systems regarding navigation, machinery, communication and specific cargo, as applica-ble.



6.5.2 Centralised navigation equipment (SYS-NEQ and SYS-NEQ-1)

The additional class notation SYS-NEQ is assigned to ships which are fitted with a centralised navigation control system so laid out and arranged that it enables normal navigation and manoeuvring operation of the ship by two persons in cooperation.

The additional class notation SYS-NEQ-1 is assigned when, in addition to the above, the installation is so arranged that the navigation and manoeuvring of the ship can be oper-ated under normal conditions by one person, for periodical one man watch. This notation includes specific require-ments for prevention of accidents caused by the operator’s unfitness.

6.5.3 Integrated bridge system (SYS-IBS and SYS-IBS-1)

The additional class notation SYS-IBS is assigned to ships fitted with an integrated bridge system which allows simpli-fied and centralised bridge operation of the main functions of navigation, manoeuvring and communication, as well as monitoring from bridge of other functions related to passage

execution, route control and monitoring and control and monitoring of machinery installation according to Part C, Chapter 3.

The notation SYS-IBS is assigned only to ships which are also assigned the additional class notation SYS-NEQ or SYS-NEQ-1.

The additional class notation SYS-IBS-1 is assigned to ships fitted with an integrated bridge system which allows simpli-fied and centralised bridge operation of the main functions of navigation, manoeuvring and communication, as well as monitoring from bridge of other functions related to passage execution, route control and monitoring and control and monitoring of machinery installation according to Part C, Chapter 3 and Pt E, Ch 3, Sec 1 (AUT-UMS notation).

In addition the following functions may be part of SYS-IBS-1notation:

• external / internal communication system

• monitoring of specific cargo operations

• pollution monitoring

• monitoring of heating, ventilation and air conditioning for passenger ships.

The notation SYS -IBS-1 is assigned only to ships which are also assigned the additional class notation SYS-NEQ-1.

6.5.4 Communication system (SYS-COM)

The additional class notation SYS-COM is assigned to ships which are fitted with a local area network including the alarm, monitoring and control systems and computers used for management operations and external communication devices for reporting ashore navigation, maintenance and operational information.

The notation SYS-COM is assigned only to ships which are also assigned the additional class notation AUT-IMS.

6.5.5 Integrated ship systems notation (SYS)

When ships are assigned the notations SYS-NEQ (or SYS-NEQ-1), SYS-IBS (or SYS-IBS-1) and SYS-COM, the three separate notations are superseded by the cumulative addi-tional class notation SYS.

6.6 Monitoring equipment (MON)

6.6.1 General

The notations dealt with under this heading are relevant to hull and tailshaft monitoring equipment installed on board ships.


6.6.2 Hull stress monitoring (MON-HULL)

The additional class notation MON-HULL is assigned to ships which are fitted with equipment continuously moni-toring ship’s dynamic loads through measurements of motions in waves and stresses/deformations in the hull structure.

Pt A, Ch 1, Sec 2


6.6.3 Tailshaft monitoring system (MON-SHAFT)

The additional class notation MON-SHAFT is assigned to ships which are fitted with a temperature monitoring system for the tailshaft sterntube aft bearing. The assignment of this notation allows the ship to be granted a reduced scope for complete tailshaft surveys, see Ch 2, Sec 2, [5.5.4].

6.7 Comfort on board ships (COMF)

6.7.1 General

The notations dealt with under this heading are relevant to the assessment of comfort on board ships with regard to the noise and/or vibration.

The parameters which are taken into consideration for the evaluation of the comfort such as the level of noise, the level of vibration will be indicated in the relevant annex to the Certificate of Classification.


6.7.2 Comfort with regard to noise (COMF-NOISE)

The additional class notation COMF-NOISE is assigned to ships satisfying levels of noise defined in Part E, Chapter 6. The assessment of noise levels is carried out through meas-urements during harbour and sea trials.

The notation is completed by a grade 1, 2 or 3 which repre-sents the comfort level achieved for the assignment of the notation. The lower grade (1) corresponds to the higher class of comfort.

Example:

COMF-NOISE 2

6.7.3 Comfort with regard to vibration (COMF-VIB)

The additional class notation COMF-VIB is assigned to ships satisfying levels of vibration defined in Part E, Chapter 6. The assessment of vibration is carried out through meas-urements during harbour and sea trials.

The notation is completed by a grade:

• 1, 2 or 3 for an evaluation based on overall frequency criteria, or

• 1PK, 2PK or 3PK for an evaluation based on single amplitude peak criteria.

The grade represents the comfort level achieved for the assignment of the notation. The lower grade (1 or 1PK) cor-responds to the higher class of comfort.

Example:

COMF-VIB 1PK

6.7.4 High comfort level with regard to noise (COMF+)

The additional class notation COMF+ is assigned to yachts satisfying levels of noise defined in Pt E, Ch 6, Sec 5.

The requirements of notations COMF-NOISE have to be ful-filled prior to assigning the notation COMF+.

This notation COMF+ deals with additional criteria in view to evaluate higher standard comfort level than COMF-NOISE. These additional criteria are to be selected among the following performance indexes:

• Sound insulation index

• Impact index

• Emergence

• Intermittent noise

• Intelligibility.

The additional class notation COMF+ is to be completed by the selected performance indexes.

Example:

COMF + /Impact index /Intermittent noise /Intelligibility

This notation is assigned only to ships having the service notation yacht or charter yacht .

Note 1: The additional class notation COMF+ may also be applied to ships assigned with the service notation Passenger ship after spe-cial consideration.

6.7.5 Comfort for passenger and crew areas

The additional class notations COMF-NOISE-Pax, COMF-NOISE-Crew, followed by grade 1, 2 or 3 and COMF-VIB-Pax and COMF-VIB-Crew, followed by grade 1, 2 or 3 or 1PK, 2PK or 3PK are assigned to ships satisfying levels of noise / vibration defined in Part E, Chapter 6, for passenger or crew area, as applicable.

Example:

COMF-VIB-Crew 3

6.8 Pollution prevention

6.8.1 General

The notations dealt with under this heading are assigned to ships fitted with equipment and arrangements enabling them to control and limit the emission of polluting sub-stances in the sea and the air.


6.8.2 Pollution prevention (CLEANSHIP (C))

The additional class notation CLEANSHIP (C) is assigned to ships complying with the requirements given in Pt E, Ch 9, Sec 1, [1.1.1], Pt E, Ch 9, Sec 5 and Pt E, Ch 9, Sec 6.

6.8.3 Pollution prevention (CLEANSHIP)

The additional class notation CLEANSHIP is assigned to ships fitted with equipment and arrangements as given in Pt E, Ch 9, Sec 1, [1.2], Pt E, Ch 9, Sec 2 and Pt E, Ch 9, Sec 6.

6.8.4 Pollution prevention (CLEANSHIP SUPER)

The additional class notation CLEANSHIP SUPER is assigned to ships fitted with equipment and arrangements as given in Pt E, Ch 9, Sec 1, [1.3], Pt E, Ch 9, Sec 3 and Pt E, Ch 9, Sec 6.

Pt A, Ch 1, Sec 2


6.8.5 Advanced Wastewater Treatment (AWT)

The additional class notations CLEANSHIP AWT and CLEANSHIP SUPER AWT are assigned when, in addition to the above, the ship is fitted with an Advanced Wastewater Treatment as given in Pt E, Ch 9, Sec 4.

6.8.6 No discharge period

The additional class notations CLEANSHIP, CLEANSHIP AWT, CLEANSHIP SUPER and CLEANSHIP SUPER AWTare completed by the number of consecutive days the ship is able to operate with the full complement of on-board people, including crew and passengers, without the need for discharging any substances into the sea. This number cannot be less than one day (24 hours). If this period is longer than seven days, notation 7+ is appended to the additional class notation.

Examples:

CLEANSHIP 1

CLEANSHIP SUPER 3

CLEANSHIP 7+ AWT

CLEANSHIP SUPER 7 AWT

6.9 Refrigerating installations

6.9.1 General

The notations dealt with under this heading are relevant to refrigerating installations fitted on board ships, including machinery and storing equipment or arrangements.



6.9.2 Refrigerating installations for cargo (REF-CARGO)

The additional class notation REF-CARGO is assigned to ships fitted with refrigerating plants and holds intended to carry cargoes, with the condition that the number and the power of the refrigerating units are such that the specified temperatures can be maintained with one unit on standby.

The notation -AIRCONT is added when the refrigerating plant is equipped with controlled atmosphere installations.

6.9.3 Refrigerating installations for insulated containers (REF-CONT)

The additional class notation REF-CONT is assigned to ships fitted with refrigerating plants for insulated containers carried in holds of container ships.

The additional class notation REF-CONT is followed by a suffix:

• (A) where the containers are cooled by a permanently installed refrigerating plant designed to supply refriger-ated air to insulated containers carried in holds of con-tainer ships, with the condition that the number and the power of the refrigerating units are such that the specified temperatures can be maintained with one unit on standby

• (E) where the ship is intended only to supply electrical power to self-refrigerated containers.

The notation -AIRCONT is added to the additional class notation REF-CONT (A) when the refrigerating plant is equipped with controlled atmosphere installations.

6.9.4 Refrigerating installations for domestic supplies (REF-STORE)

The additional class notation REF-STORE is assigned to ships fitted with refrigerating plants and spaces exclusively intended for the preservation of ship’s domestic supplies.

6.9.5 The additional class notations REF-CARGO, REF-CONT and REF-STORE may also be completed by the fol-lowing notations:

a) -PRECOOLING when the refrigerating plants are designed to cool down a complete cargo of fruit and/or vegetables to the required temperature of transportation

b) -QUICKFREEZE for the refrigerating plants of fishing vessels and fish factory ships where the design and equipment of such plants have been recognised suitable to permit quick-freezing of fish in specified conditions.

6.10 Navigation in ice

6.10.1 The notations dealt with under [6.10.2] are relevant to ships strengthened for navigation in ice in accordance with the “Finnish-Swedish Ice Class Rules 1985 as amended”.


These requirements reproduce the provisions of the Finnish-Swedish Ice Class Rules cited above.Note 1: These National requirements are applicable for ships trad-ing in the Finnish/Swedish waters and other relevant areas of the Baltic sea during the ice period.

6.10.2 The following additional class notations are assigned:

• ICE CLASS IA SUPER for ships with such structure, engine output and other properties that they are nor-mally capable of navigating in difficult ice conditions without the assistance of icebreakers

• ICE CLASS IA for ships with such structure, engine out-put and other properties that they are capable of navi-gating in difficult ice conditions, with the assistance of icebreakers when necessary

• ICE CLASS IB for ships with such structure, engine out-put and other properties that they are capable of navi-gating in moderate ice conditions, with the assistance of icebreakers when necessary

• ICE CLASS IC for ships with such structure, engine out-put and other properties that they are capable of navi-gating in light ice conditions, with the assistance of icebreakers when necessary.

Pt A, Ch 1, Sec 2


6.10.3 The additional class notation ICE CLASS ID is assigned to ships whose reinforcements for navigation in ice are different from those required for the assignment of the notations defined in [6.10.2] but comply with the specific requirements detailed in Part E, Chapter 8.

6.10.4 The additional class notation ICE is assigned to ships whose reinforcements for navigation in ice are similar but not equivalent to those required for the assignment of the notations defined in [6.10.2] and [6.10.3], when this has been specially considered by the Society.

6.11 Navigation in polar waters

6.11.1 The notations dealt with under [6.11.2] are relevant to ships intended for navigation in ice-infested polar waters, except icebreakers.

The requirements for the assignment of these notations are given in NR527 Rules for the Classification of Polar Class Ships.

Ships complying with the requirements of NR527 and assigned with one of the additional class notations POLAR CLASS are also to comply with the requirements for the assignment of the additional class notation defined in[6.14.12]: COLD (H tDH , E tDE).

Note 1: Icebreaker refers to any ship having an operational profile that includes escort or ice management functions, having powering and dimensions that allow it to undertake operations in ice covered waters.

6.11.2 The following additional class notations are assigned:

• POLAR CLASS 1 for year-round operations in all polar waters

• POLAR CLASS 2 for year-round operations in moderate multi-year ice conditions

• POLAR CLASS 3 for year-round operations in second-year ice which may include multi-year ice conditions

• POLAR CLASS 4 for year-round operations in thick first-year ice which may include old ice inclusions

• POLAR CLASS 5 for year-round operations in medium first-year ice which may include old ice inclusions

• POLAR CLASS 6 for summer/autumn operations in medium first-year ice which may include old ice inclu-sions

• POLAR CLASS 7 for summer/autumn operations in thin first-year ice which may include old ice inclusions.

6.12 Lifting appliances

6.12.1 Ships fitted with lifting appliances meeting the requirements of the Rules for the Classification and the Cer-tification of Cranes onboard Ships and Offshore Units (NR526) may be assigned the following additional class notations:

a) ALP for appliances intended to be used at harbour, for loading or unloading cargoes, equipments, spare parts or consumable

b) ALM for appliances intended to be used in offshore con-ditions for various lifting operations exclusive of the appliances mentioned in item a)

c) ALS for lifting appliances intended to be used at sea for launching and recovering diving devices.

Note 1: Ships fitted with lifting appliances used in harbour or in similar conditions for lifting operations other than ships loading or unloading may be assigned the additional service notation ALP.

6.12.2 The additional class notations (ALP), (ALM), (ALS)may be assigned by the Society in lieu of the notations ALP, ALM, ALS respectively, when the corresponding lifting appliances meet the requirements of specific National Reg-ulations under the conditions defined in NR526.

6.12.3 The additional class notations ALP, ALM, ALS, (ALP), (ALM) or (ALS) are optional. However, the Society may require the compliance of lifting appliances with the assigning conditions of one of the above mentioned addi-tional class notations for the classification of ships, when one or several lifting appliances are of a primary impor-tance for their operation, or when such appliances signifi-cantly influence their structure. As a rule, such is the case for the shear leg pontoons, crane pontoons, crane vessels, supporting ships for diving devices and when the lifting appliances concerned have special high capacities, for example in case of ships specially equipped for handling very heavy loads.

6.12.4 In compliance with [6.1.3], these notations are assigned a construction mark as defined in [3].Note 1: Rules for the Classification and Certification of Lifting Appliances of ships and offshore units (Rule Note NR184) are applicable to derricks including union purchase use.

6.13 Emergency Response Service (ERS)

6.13.1 GeneralThe notations dealt with under this sub-article are related to the provision of technical assistance in case of a maritime accident at sea during the time ERS is contracted by the Owner.

The requirements for the assignment and maintenance of these notations are given in NR556 (Emergency Response Service).

6.13.2 ERS-S (Strength), ERS-M (Mooring) and ERS-H (Hydrodynamic) services

The additional class notation ERS-S is assigned for service aiming at providing information on the remaining capaci-ties and stability of the hull after the failure of the structure.

The additional class notation ERS-M is assigned for service aiming at providing information on the remaining capaci-ties of the mooring system after the failure of one or several mooring lines and the potential failure of an additional mooring line.

The additional class notation ERS-H is assigned for service aiming at providing information on the wave bending moment of the damage ship in the actual environment condition.

Pt A, Ch 1, Sec 2


6.14 Other additional class notations

6.14.1 Strengthened bottom

The additional class notation STRENGTHBOTTOM may be assigned to ships built with specially strengthened bottom structures so as to be able to be loaded and/or unloaded when properly stranded.


6.14.2 Loading by grabs

a) Loading by grabs for bulk carriers subject to NR522 Common Structural Rules for Bulk Carriers

The additional class notation GRAB [X] is assigned to ships with holds designed for loading/unloading by grabs having a maximum specific weight up to [X] tons.

The requirements for the assignment of this notation are given in NR522 Common Structural Rules for Bulk Car-riers.

Note 1: It is reminded that for bulk carriers assigned with the addi-tional service feature CSR, and one of the additional service features BC-A or BC-B, GRAB [X] is assigned as a mandatory additional service feature.

For bulk carriers assigned with the additional service feature CSR others than above, GRAB [X] may be assigned on a volun-tary basis as an additional class notation.

It is to be noted that this additional class notation does not negate the use of heavier grabs, but the owner and operators are to be made aware of the increased risk of local damage and possible early renewal of inner bot-tom plating if heavier grabs are used regularly or occa-sionally to discharge cargo.

b) Loading by grabs for ships other than those subject to NR522 Common Structural Rules for Bulk Carriers

The additional class notation GRABLOADING may be assigned to ships with hold tank tops specially rein-forced for loading/unloading cargoes by means of grabs or buckets.


Note 2: This additional class notation may only be assigned to ships with the service notation general cargo ship (intended to carry dry bulk cargoes), ore carrier, combination car-rier/OBO, combination carrier/OOC or bulk carrier not assigned with the additional service feature CSR.

However, this does not preclude ships not assigned with this notation from being loaded/unloaded with grabs.

6.14.3 In-water survey

The additional class notation INWATERSURVEY may be assigned to ships provided with suitable arrangements to facilitate the in-water surveys as provided in Ch 2, Sec 2, [5.4.5].


6.14.4 Single point mooring

The additional class notation SPM (Single Point Mooring) may be assigned to ships fitted with a specific mooring installation.


These requirements reproduce the provisions of “Recom-mendations for Equipment Employed in the Mooring of Ships at Single Point Mooring” (3rd edition 1993), issued by OCIMF (Oil Companies International Marine Forum).

6.14.5 Container lashing equipment

The additional class notation LASHING may be assigned to ships initially fitted with mobile container lashing equip-ment which has been documented, tested and checked.

This notation is assigned only to ships having the service notation container ship or the additional service feature equipped for carriage of containers.


This equipment, however, will not be verified any longer at the periodical class surveys to which the ship is submitted.

6.14.6 Dynamic positioning

The additional class notation DYNAPOS may be assigned to ships equipped with a dynamic positioning system.

In compliance with [6.1.3], this notation is assigned a con-struction mark, as defined in [3].

The scope of the notation, including the additional keys for the description of capability of the installation and the requirements for assignment, are given in Pt E, Ch 10, Sec 6.

6.14.7 Vapour control system

The additional class notation VCS (Vapour Control System) may be assigned to ships equipped with cargo vapour con-trol systems. The notation -TRANSFER is added to the nota-tion where, in addition, the ship is fitted with specific arrangements for transferring cargo vapours to another ship.

This notation is assigned only to ships having the service notation oil tanker, combination carrier/OBO, combina-tion carrier/OOC, liquefied gas carrier, chemical tanker or FLS tanker.


6.14.8 Cofferdam ventilation

The additional class notation COVENT may be assigned to ships having cofferdams in the cargo area which can be used as ballast tanks and which may be ventilated through a fixed ventilation system.

This notation is assigned only to ships having the service notation bulk carrier, ore carrier, oil tanker, combination carrier/OBO, combination carrier/OOC, liquefied gas car-rier, chemical tanker or FLS tanker.


Pt A, Ch 1, Sec 2


6.14.9 Centralised cargo controlThe additional class notation CARGOCONTROL may be assigned to ships (carrying liquid cargo in bulk) equipped with a centralised system for handling cargo and ballast liq-uids.

In principle, this notation is assigned only to ships having the service notation oil tanker, combination carrier/OBO, combination carrier/OOC, chemical tanker or FLS tanker.


6.14.10 Ship manoeuvrabilityThe additional class notation MANOVR may be assigned to ships complying with the requirements related to manoeu-vring capability defined in Pt E, Ch 10, Sec 10.Note 1: According to Resolution MSC.137(76), these provisions are to be applied to ships of all rudder and propulsion types, of 100 m in length and over, and to chemical tankers and gas carriers regard-less of the length, which were constructed on or after 1 January 2004.

6.14.11 Ship subdivision and damage stabilityThe additional class notation SDS may be assigned to ships for which a damage buoyancy, subdivision and stability file has been examined and found to satisfy the requirements given in Pt B, Ch 3, Sec 3.

An attestation of compliance may be issued to the Interested Party, specifying the rules and criteria considered for the examination of the file.Note 1: As a rule, class assigned to a ship does not cover require-ments applicable to the assignment of the notation SDS.

6.14.12 Ships operating in cold weather conditionsThe additional class notation COLD (H tDH , E tDE) may be assigned to ships intended to operate in cold weather con-ditions and fitted with arrangements for de-icing.

The requirements for the assignment of this notation are given in Pt E, Ch 10, Sec 11, where tDH and tDE are defined, respectively for hull and equipment, by:

tDH : Design temperature, in °C, to be considered for the hull, provided by the ship designer

tDE : Design temperature, in ° C, to be considered for the equipment, provided by the ship designer.

6.14.13 Green passport for ship recyclingThe additional class notation GREEN PASSPORT may be assigned to ships for which requirements intended to facili-tate ship recycling have been applied, encompassing the identification, quantification and localization of materials which may cause harm to the environment and people when the fittings or equipment containing such materials are removed, or when the ship is recycled.

The requirements for the assignment and maintenance of this notation are given in NR528 Green passport.

6.14.14 Efficient washing of cargo tanksThe additional class notation EWCT may be assigned to ships fitted with washing arrangements complying with the requirements given in Pt E, Ch 10, Sec 12.

6.14.15 Protected FO tankThe additional class notation PROTECTED FO TANK may be assigned to ships with an aggregate oil fuel capacity of less than 600 m3, fitted with oil fuel tanks complying with the requirements given in Pt E, Ch 10, Sec 13.

6.14.16 Sealed liquefied natural gas carrierThe additional class notation IATP (increased admissible cargo tank pressure) may only be assigned to ships having the service notation liquefied gas carrier and intended to carry methane (LNG) whose maximum cargo tank design pressure does not exceed 70 kPa and that are designed and built so as to allow the pressure in the tanks to increase above 25 kPa.


6.14.17 Enhanced fire protection for cargo ships and tankers (EFP-AMC)

The additional class notation EFP-A or EFP-M or EFP-C or EFP-AMC may be assigned to ships fitted with enhanced fire safety protection in, respectively, accommodation spaces or machinery spaces or cargo areas or all these spaces and areas.

This notation is assigned only to ships having the service notations as per [4.2] (Cargo ships), or [4.3] (Bulk, ore and combination carriers), or [4.4] (Ships carrying liquid cargo in bulk).

The requirements for the assignment of these notations are given in Pt E, Ch 10, Sec 15.

6.14.18 Design fatigue life for oil tankers subject to NR523 Common Structural Rules for Double Hull Oil tankers

The additional class notations Fatigue PLUS, Fatigue PLUS DFL xx, Fatigue PLUS spectral ( ) and Fatigue PLUS spectral ( ) DFL xx may be assigned to ships for which the Society proposes an extended scope of critical details in addition to the details required to be checked by NR523 Common Structural Rules for Double Hull Oil Tank-ers.

The requirements for the assignment of these notations are given in NR552 Additional Class Notations Fatigue PLUS for Oil Tanker CSR.Note 1: The additional class notations Fatigue PLUS, Fatigue PLUS DFL xx, Fatigue PLUS spectral ( ) and Fatigue PLUS spectral ( ) DFL xx may be assigned only to ships with the service notation oil tanker ESP CSR.

The additional class notation Fatigue PLUS is assigned if all analysed details comply with a design fatigue life equal to 25 years.

The additional class notation Fatigue PLUS DFL xx corre-sponds to the notation Fatigue PLUS with an extended design fatigue life of xx years, with xx above 25.

The additional class notations Fatigue PLUS spectral ( ) and Fatigue PLUS spectral ( ) DFL xx are introduced to consider wave environment areas encountered during trading other than that considered in NR523 Common Structural Rules for Double Hull Oil Tankers (i.e. North Atlantic). The infor-mation between brackets is a short description of the route or areas encountered by the ship during its service life.

Pt A, Ch 1, Sec 2


The additional class notation Fatigue PLUS spectral ( ) is assigned if all analysed details comply with a design fatigue life equal to 25 years.

The additional class notation Fatigue PLUS spectral ( ) DFL xxis assigned if all analysed details comply with a design fatigue life of xx years, with xx above 25.

6.14.19 Fast Oil Recovery System (FORS)The additional class notation FORS may be assigned to ships with oil fuel tanks and cargo tanks, as applicable, fit-ted with two (or more) connectors allowing the recovery of the tank contents as follows:• by injecting sea water through one connector, the tank

contents being recovered through the other one, and• by introducing a submersible pump in the tank through

one of the connectors.

The requirements for the assignment of this notation are given in NR553 Fast Oil Recovery System.

The additional class notation FORS may be completed by the notation -NS when the connectors are intended to be used during the normal service of the ship and, for that pur-pose, comply with the additional requirements given in Article [3] of NR553 Fast Oil Recovery System.

For ships not assigned with the notation -NS, the connectors may be used only to facilitate the recovery of the tank con-tents when the ship is damaged or wrecked.

6.14.20 High-Voltage Shore Connection Systems (HVSC)

The additional class notation HVSC may be assigned to ships fitted with electrical and control engineering arrange-ments allowing operation of services by connection to an external high-voltage electrical power supply in port.

The requirements for the assignment of this notation are given in NR557 High-Voltage Shore Connection Systems.

6.15 System fitted but not required by the Rules

6.15.1 GeneralThe notations dealt with in this sub-article are assigned only when a system is installed on board, although the ship does not meet the conditions under which the Rules request it to be fitted.

6.15.2 Inert gas

The additional class notation IG may be assigned to ships fitted with an inert gas system.

This notation is assigned only to ships having the service notation oil tanker or FLS tanker of less than 20000 tonnes deadweight and to ships having the service notation chemi-cal tanker for which an inert gas system is not required in pursuance of Pt D, Ch 8, Sec 9, [1.3.1].

The requirements for the assignment of this notation are given in Pt D, Ch 7, Sec 6, [5.1.2] for an oil tanker or a FLS tanker and in Pt D, Ch 8, Sec 9, [2.5.3] for a chemical tanker.

6.15.3 Emergency towing arrangement

The additional class notation ETA may be assigned to ships fitted with an emergency towing arrangement.

In principle, this notation is assigned only to ships of less than 20000 tonnes deadweight having the service notation oil tanker, combination carrier/OBO, combination carrier /OOC, liquefied gas carrier, chemical tanker or FLS tanker.

The requirements for the assignment of this notation are given in Pt B, Ch 10, Sec 4, [4].

6.15.4 Coating performance standard

The additional class notation CPS(WBT) may be assigned to ships complying with the requirements of NR530 Coating Performance Standard.

Note 1: For bulk carriers and oil tankers assigned with the addi-tional service feature CSR and contracted for construction on or after 8 December 2006, reference is made to [4.3.2] and [4.4.2] for the mandatory assignment of the additional service feature CPS(WBT).

7 Other notations

7.1

7.1.1 The Society may also define other notations by means of provisional requirements and guidelines, which may then be published in the form of tentative rules.

Pt B, Ch 1, Sec 1


SECTION 1 APPLICATION

1 General

1.1 Structural requirements

1.1.1 Part B of the Rules contains the requirements for determination of the minimum hull scantlings, applicable to all types of seagoing monohull displacement ships of nor-mal form, speed and proportions, made in welded steel construction. These requirements are to be integrated with those specified in Part D, for any individual ship type, and in Part E, as applicable, depending on the additional class notations assigned to the ships.

1.1.2 The requirements of Part B, Part D and Part E apply also to those steel ships in which parts of the hull, e.g. superstructures or movable decks, are built in aluminium alloys.

1.1.3 Ships whose hull materials are different than those given in [1.1.2] and ships with novel features or unusual hull design are to be individually considered by the Society, on the basis of the principles and criteria adopted in the Rules.

1.1.4 The strength of ships constructed and maintained according to the Rules is sufficient for the draught corre-sponding to the assigned freeboard. The scantling draught considered when applying the Rules is to be not less than that corresponding to the assigned freeboard.

1.1.5 Where scantlings are obtained from direct calcula-tion procedures which are different from those specified inPart B, Chapter 7, adequate supporting documentation is to be submitted to the Society, as detailed in Ch 1, Sec 3.

1.2 Limits of application to lifting appli-ances

1.2.1 The fixed parts of lifting appliances, considered as an integral part of the hull, are the structures permanently con-nected by welding to the ship’s hull (for instance crane ped-estals, masts, king posts, derrick heel seatings, etc., excluding cranes, derrick booms, ropes, rigging accessories, and, generally, any dismountable parts). The shrouds of masts embedded in the ship’s structure are considered as fixed parts.

1.2.2 The fixed parts of lifting appliances and their connec-tions to the ship’s structure are covered by the Rules, even when the certification (especially the issuance of the Cargo Gear Register) of lifting appliances is not required.

2 Rule application

2.1 Ship parts

2.1.1 General

For the purpose of application of the Rules, the ship is con-sidered as divided into the following three parts:

• fore part

• central part

• aft part.

2.1.2 Fore part

The fore part includes the structures located forward of the collision bulkhead, i.e.:

• the fore peak structures

• the stems.

In addition, it includes:

• the reinforcements of the flat bottom forward area

• the reinforcements of the bow flare area.

2.1.3 Central part

The central part includes the structures located between the collision bulkhead and the after peak bulkhead.

Where the flat bottom forward area or the bow flare area extend aft of the collision bulkhead, they are considered as belonging to the fore part.

2.1.4 Aft part

The aft part includes the structures located aft of the after peak bulkhead.

2.2 Rules applicable to various ship parts

2.2.1 The various Chapters and Sections of Part B are to be applied for the scantling and arrangement of ship parts according to Tab 1.

2.3 Rules applicable to other ship items

2.3.1 The various Chapters and Sections of Part B are to be applied for the scantling and arrangement of other ship items according to Tab 2.

Pt B, Ch 1, Sec 1


Table 1 : Part B Chapters and Sections applicable for the scantling of ship parts

Table 2 : Part B Chapters and Sections applicablefor the scantling of other items

3 Rounding off of scantlings

3.1

3.1.1 Plate thicknessesThe rounding off of plate thicknesses is to be obtained from the following procedure:

a) the net thickness (see Ch 4, Sec 2) is calculated in accordance with the rule requirements.

b) corrosion addition tC (see Ch 4, Sec 2) is added to the calculated net thickness, and this gross thickness is rounded off to the nearest half-millimetre.

c) the rounded net thickness is taken equal to the rounded gross thickness, obtained in b), minus the corrosion addition tC.

3.1.2 Stiffener section moduliStiffener section moduli as calculated in accordance with the rule requirements are to be rounded off to the nearest standard value; however, no reduction may exceed 3%.

PartApplicable Chapters and Sections

General Specific

Fore part Part B, Chapter 1 Part B, Chapter 2 Part B, Chapter 3 Part B, Chapter 4 Part B, Chapter 9 (2), excluding:• Ch 9, Sec 1 • Ch 9, Sec 2 Part B, Chapter 11 Part B, Chapter 12

Ch 9, Sec 1

Central partL 65 m (1)

Part B, Chapter 5 Part B, Chapter 6 Part B, Chapter 7

Central partL < 65 m (1)

Part B, Chapter 8

Aft part Ch 9, Sec 2

(1) The requirements applicable to ships less than 65 m in length apply also to category II ships less than 90 m in length.(2) See also [2.3].

ItemApplicable Chapter

and Section

Machinery space Ch 9, Sec 3

Superstructures and deckhouses Ch 9, Sec 4

Bow doors and inner doors Ch 9, Sec 5

Side shell doors and stern doors Ch 9, Sec 6

Hatch covers Ch 9, Sec 7

Movable decks and inner ramp External ramps

Ch 9, Sec 8

Helicopter decks Ch 9, Sec 10

Rudders Ch 10, Sec 1

Other hull outfitting Ch 10, Sec 2 Ch 10, Sec 3 Ch 10, Sec 4

Pt B, Ch 1, Sec 2


SECTION 2 SYMBOLS AND DEFINITIONS

1 Units

1.1

1.1.1 Unless otherwise specified, the units used in theRules are those defined in Tab 1.

2 Symbols

2.1

2.1.1 L : Rule length, in m, defined in [3.1]L1 : L, but to be taken not greater than 200 mL2 : L, but to be taken not greater than 120 mLLL : Load line length, in m, defined in [3.2]LS : Subdivision length, in m, defined inB : Moulded breadth, in m, defined in [3.4]D : Depth, in m, defined in [3.5]T : Moulded draught, in m, defined in [3.7] : Moulded displacement, in tonnes, at draught T,

in sea water (density = 1,025 t/m3)CB : Total block coefficient:

3 Definitions

3.1 Rule length

3.1.1 The rule length L is the distance, in m, measured onthe summer load waterline, from the forward side of thestem to the after side of the rudder post, or to the centre ofthe rudder stock where there is no rudder post. L is to be notless than 96% and need not exceed 97% of the extremelength on the summer load waterline.

3.1.2 In ships without rudder stock (e.g. ships fitted withazimuth thrusters), the rule length L is to be taken equal to97% of the extreme length on the summer load waterline.

3.1.3 In ships with unusual stem or stern arrangements, therule length L is considered on a case by case basis.

3.1.4 Where the stem contour is concave above the water-line at 85% of the least moulded depth, both the forwardterminal of the total length and the fore-side of the stemrespectively is taken at the vertical projection to that water-line of the aftermost point of the stem contour (see Fig 1).

Table 1 : Units

Figure 1 : Concave stem contourForward terminal of length

3.1.5 Ends of rule length

The fore end (FE) of the rule length L, see Fig 2, is the per-pendicular to the summer load waterline at the forward sideof the stem.

The aft end (AE) of the rule length L, see Fig 2, is the perpen-dicular to the waterline at a distance L aft of the fore end.

CB

1 025, LBT--------------------------=

DesignationUsual

symbolUnits

Ship’s dimensions See [2] m

Hull girder section modulus Z m3

Density t/m3

Concentrated loads P kN

Linearly distributed loads q kN/m

Surface distributed loads (pressures) p kN/m2

Thicknesses t mm

Span of ordinary stiffeners and pri-mary supporting members

m

Spacing of ordinary stiffeners and primary supporting members

s m

Bending moment M kN.m

Shear force Q kN

Stresses , N/mm2

Section modulus of ordinary stiffen-ers and primary supporting members

w cm3

Sectional area of ordinary stiffeners and primary supporting members

A cm2

��

��

��

Pt B, Ch 1, Sec 2


Figure 2 : Ends and midship

3.1.6 MidshipThe midship is the perpendicular to the waterline at a dis-tance 0,5L aft of the fore end.

3.2 Load line length

3.2.1 The load line length LLL is the distance, in m, on thewaterline at 85% of the least moulded depth from the topof the keel, measured from the forward side of the stem tothe centre of the rudder stock. LLL is to be not less than 96%of the total length on the same waterline.

3.2.2 In ship design with a rake of keel, the waterline onwhich this length is measured is parallel to the designedwaterline at 85% of the least moulded depth Dmin found bydrawing a line parallel to the keel line of the ship (includingskeg) tangent to the moulded sheer line of the freeboarddeck.The least moulded depth is the vertical distance meas-ured from the top of the keel to the top of the freeboarddeck beam at side at the point of tangency (see Fig 3).

Figure 3 : Length of ships with a rake of keel

3.3 Subdivision length

3.3.1 The subdivision LS of the ship is the greatest pro-jected moulded length of that part of the ship at or belowdeck or decks limiting the vertical extent of flooding withthe ship at the deepest subdivision draught.

3.4 Moulded breadth

3.4.1 The moulded breadth B is the greatest mouldedbreadth, in m, measured amidships below the weatherdeck.

3.5 Depth

3.5.1 The depth D is the distance, in m, measured verti-cally on the midship transverse section, from the mouldedbase line to the top of the deck beam at side on the upper-most continuous deck.In the case of a ship with a solid bar keel, the moulded baseline is to be taken at the intersection between the upper

face of the bottom plating with the solid bar keel at the mid-dle of length L.

3.6 Moulded depth

3.6.1 The moulded depth D1 is the vertical distance meas-ured from the top of the keel to the top of the freeboarddeck beam at side. Where the form at the lower part of themidship section is of a hollow character or where thick gar-boards are fitted, the distance is measured from the pointwhere the line of the flat of the bottom continued inwardscuts the side of the keel.

In ships having rounded gunwales, the moulded depth is tobe measured to the point of intersection of the mouldedlines of deck and sides, the lines extending as though thegunwales were of angular design.

Where the freeboard deck is stepped and the raised part ofthe deck extends over the point at which the mouldeddepth is to be determined, the moulded depth is to bemeasured to a line of reference extending from the lowerpart of the deck along a line parallel with the raised part.

3.7 Moulded draught

3.7.1 The moulded draught T is the distance, in m, meas-ured vertically on the midship transverse section, from themoulded base line to the summer load line.

In the case of ships with a solid bar keel, the moulded baseline is to be taken as defined in [3.5.1].

3.8 Lightweight

3.8.1 The lightweight is the displacement, in t, withoutcargo, fuel, lubricating oil, ballast water, fresh water andfeed water, consumable stores and passengers and crewand their effects, but including liquids in piping.

3.9 Deadweight

3.9.1 The deadweight is the difference, in t, between thedisplacement, at the summer draught in sea water of density = 1,025 t/m3, and the lightweight.

3.10 Freeboard deck

3.10.1 The freeboard deck is defined in Regulation 3 of the1966 International Convention on Load Lines, as amended.

3.11 Bulkhead deck

3.11.1 The bulkhead deck in a passenger ship means theuppermost deck at any point in the subdivision length LS towhich the main bulkheads and the ship’s shell are carriedwatertight. In a cargo ship the freeboard deck may be takenas the bulkhead deck.

3.12 Inner side

3.12.1 The inner side is the longitudinal bulkhead whichlimits the inner hull for ships fitted with double hull.

��

��

�

��

� ��

��

� ��

��

Pt B, Ch 1, Sec 2


3.13 Superstructure

3.13.1 General

A superstructure is a decked structure connected to thefreeboard deck, extending from side to side of the ship orwith the side plating not being inboard of the shell platingmore than 0,04 B.

3.13.2 Enclosed and open superstructure

A superstructure may be:

• enclosed, where:

- it is enclosed by front, side and aft bulkheads com-plying with the requirements of Ch 9, Sec 4

- all front, side and aft openings are fitted with effi-cient weathertight means of closing

• open, where it is not enclosed.

3.13.3 Bridge

A bridge is a superstructure which does not extend to eitherthe forward or after perpendicular.

3.13.4 Poop

A poop is a superstructure which extends from the after per-pendicular forward to a point which is aft of the forwardperpendicular. The poop may originate from a point aft ofthe aft perpendicular.

3.13.5 Forecastle

A forecastle is a superstructure which extends from the for-ward perpendicular aft to a point which is forward of theafter perpendicular. The forecastle may originate from apoint forward of the forward perpendicular.

3.13.6 Full superstructure

A full superstructure is a superstructure which, as a mini-mum, extends from the forward to the after perpendicular.

3.14 Raised quarterdeck

3.14.1 A raised quarterdeck is a partial superstructure ofreduced height as defined in [3.19].

It extends forward from the after perpendicular and has anintact front bulkhead (sidescuttles of the non-opening typefitted with efficient deadlights and bolted man hole covers).

Where the forward bulkhead is not intact due to doors andaccess openings, the superstructure is then to be consideredas a poop.

3.15 Superstructure deck

3.15.1 A superstructure deck is a deck forming the upperboundary of a superstructure.

3.16 Deckhouse

3.16.1 A deckhouse is a decked structure other than asuperstructure, located on the freeboard deck or above.

3.17 Trunk

3.17.1 A trunk is a decked structure similar to a deckhouse,but not provided with a lower deck.

3.18 Well

3.18.1 A well is any area on the deck exposed to theweather, where water may be entrapped. Wells are consid-ered to be deck areas bounded on two or more sides bydeck structures.

3.19 Standard height of superstructure

3.19.1 The standard height of superstructure is defined inTab 2.

Table 2 : Standard height of superstructure

3.20 Type A and Type B ships

3.20.1 Type A ship

A Type A ship is one which:

• is designed to carry only liquid cargoes in bulk;

• has a high integrity of the exposed deck with only smallaccess openings to cargo compartments, closed bywatertight gasketed covers of steel or equivalent mate-rial; and

• has low permeability of loaded cargo compartments.

A Type A ship is to be assigned a freeboard following therequirements reported in the International Load Line Con-vention 1966, as amended.

3.20.2 Type B ship

All ships which do not come within the provisions regardingType A ships stated in [3.20.1] are to be considered as TypeB ships.

A Type B ship is to be assigned a freeboard following therequirements reported in the International Load Line Con-vention 1966, as amended.

3.20.3 Type B-60 ship

A Type B-60 ship is any Type B ship of over 100 metres inlength which, fulfilling the requirements reported in Ch 3,App 4, [4.4], is assigned with a value of tabular freeboardwhich can be reduced up to 60 per cent of the differencebetween the “B” and “A” tabular values for the appropriateship lengths.

Load line length LLL ,

in m

Standard height hS, in m

Raised quarter deckAll other

superstructures

LLL 30 0,90 1,80

30 < LLL < 75 0,9 + 0,00667 (LLL 30) 1,80

75 LLL < 125 1,2 + 0,012 (LLL 75) 1,8 + 0,01 (LLL 75)

LLL 125 1,80 2,30

Pt B, Ch 1, Sec 2


3.20.4 Type B-100 shipsA Type B-100 ship is any Type B ship of over 100 metres inlength which, fulfilling the requirements reported in Ch 3,App 4, [4.4], is assigned with a value of tabular freeboardwhich can be reduced up to 100 per cent of the differencebetween the “B” and “A” tabular values for the appropriateship lengths.

3.21 Positions 1 and 2

3.21.1 Position 1Position 1 includes:

• exposed freeboard and raised quarter decks,

• exposed superstructure decks situated forward of0,25 LLL from the perpendicular, at the forward side ofthe stem, to the waterline at 85% of the least mouldeddepth measured from the top of the keel.

3.21.2 Position 2Position 2 includes:

• exposed superstructure decks situated aft of 0,25 L fromthe perpendicular, at the forward side of the stem, to thewaterline at 85% of the least moulded depth measuredfrom the top of the keel and located at least one stand-ard height of superstructure above the freeboard deck,

• exposed superstructure decks situated forward of0,25 LLL from the perpendicular, at the forward side ofthe stem, to the waterline at 85% of the least mouldeddepth measured from the top of the keel and located atleast two standard heights of superstructure above thefreeboard deck.

4 Reference co-ordinate system

4.1

4.1.1 The ship’s geometry, motions, accelerations and loadsare defined with respect to the following right-hand co-ordi-nate system (see Fig 4):• Origin: at the intersection among the longitudinal plane

of symmetry of ship, the aft end of L and the baseline• X axis: longitudinal axis, positive forwards• Y axis: transverse axis, positive towards portside• Z axis: vertical axis, positive upwards.

4.1.2 Positive rotations are oriented in anti-clockwisedirection about the X, Y and Z axes.

Figure 4 : Reference co-ordinate system

�

�

��

�

Pt B, Ch 1, Sec 3


SECTION 3 DOCUMENTATION TO BE SUBMITTED

1 Documentation to be submitted for all ships

1.1 Ships surveyed by the Society during the construction

1.1.1 Plans and documents to be submitted for approval

The plans and documents to be submitted to the Society for approval are listed in Tab 1.

The above plans and documents are to be supplemented by further documentation which depends on the service nota-tion and, possibly, the additional class notation (see Pt A, Ch 1, Sec 2) assigned to the ship, as specified in [2].

Structural plans are to show details of connections of the various parts and, in general, are to specify the materials used, including their manufacturing processes, welded pro-cedures and heat treatments. See also Ch 12, Sec 1, [1.6].

1.1.2 Plans and documents to be submitted for information

In addition to those in [1.1.1], the following plans and doc-uments are to be submitted to the Society for information:• general arrangement• capacity plan, indicating the volume and position of the

centre of gravity of all compartments and tanks• lines plan• hydrostatic curves• lightweight distribution.

In addition, when direct calculation analyses are carried out by the Designer according to the rule requirements, they are to be submitted to the Society.

1.2 Ships for which the Society acts on behalf of the relevant Administration

1.2.1 Plans and documents to be submitted for approval

The plans required by the National Regulations concerned are to be submitted to the Society for approval, in addition to those in [1.1]. Such plans may include:

• arrangement of lifesaving appliances and relevant embarking and launching devices (davits and winches)

• arrangement of compasses

• arrangement of navigation lights

• order transmission

• loading and unloading arrangement to be included in the ILO Register

• forced ventilation in cargo spaces intended for the car-riage of vehicles, dangerous goods in bulk or packaged form, etc.

• lashing of tank vehicles intended for the carriage of dan-gerous liquids

• cargo securing manual, where required.

2 Further documentation to be submitted for ships with certain service notations or additional class notations

2.1 General

2.1.1 Depending on the service notation and, possibly, the additional class notation (see Pt A, Ch 1, Sec 2) assigned to the ship, other plans or documents may be required to be submitted to the Society, in addition to those in [1.1]. They are listed in [2.2] and [2.3] for the service notations and additional class notations which require this additional doc-umentation.

2.2 Service notations

2.2.1 The plans or documents to be submitted to the Soci-ety for approval or for information are listed in Tab 2.

2.3 Additional class notations

2.3.1 The plans or documents to be submitted to the Soci-ety for approval or for information are listed in Tab 3.

Pt B, Ch 1, Sec 3


Table 1 : Plans and documents to be submitted for approval for all ships

Plan or document Containing also information on

Midship sectionTransverse sectionsShell expansionDecks and profilesDouble bottomPillar arrangementsFraming planDeep tank and ballast tank bulkheads, washbulkheads

Class characteristicsMain dimensionsMinimum ballast draughtFrame spacingContractual service speedDensity of cargoesDesign loads on decks and double bottomSteel gradesLocation and height of air vent outlets of various compartmentsCorrosion protectionOpenings in decks and shell and relevant compensationsBoundaries of flat areas in bottom and sidesDetails of structural reinforcements and/or discontinuitiesBilge keel with details of connections to hull structures

Loading manual and loading instruments See Ch 11, Sec 2, [3]

Watertight subdivision bulkheadsWatertight tunnels

Openings and their closing appliances, if any

Fore part structure Location and height of air vent outlets of various compartments

Transverse thruster, if any, general arrangement, tunnel structure, connections of thruster withtunnel and hull structures

Aft part structure Location and height of air vent outlets of various compartments

Machinery space structuresFoundations of propulsion machinery and boilers

Type, power and r.p.m. of propulsion machineryMass and centre of gravity of machinery and boilers

Superstructures and deckhousesMachinery space casing

Extension and mechanical properties of the aluminium alloy used(where applicable)

Bow doors, stern doors and inner doors, if any, side doors and other openings in the side shell

Closing appliancesElectrical diagrams of power control and position indication circuits for bow doors, stern doors, side doors, inner doors, television system and alarm systems for ingress of water

Hatch covers, if any Design loads on hatch coversSealing and securing arrangements, type and position of locking boltsDistance of hatch covers from the summer load waterline and from the fore end

Movable decks and ramps, if any

Windows and side scuttles, arrangements and details

Scuppers and sanitary discharges

Bulwarks and freeing ports Arrangement and dimensions of bulwarks and freeing ports on the freeboard deck and superstructure deck

Helicopter decks, if any General arrangementMain structureCharacteristics of helicopters: maximum mass, distance between axles or skids, print area of wheels or skids, rotor diameter

Rudder and rudder horn (1) Maximum ahead service speed

Sternframe or sternpost, sterntubePropeller shaft boss and brackets (1)

Derricks and cargo gearCargo lift structures

Design loads (forces and moments)Connections to the hull structures

Sea chests, stabiliser recesses, etc.

Hawse pipes

(1) Where other steering or propulsion systems are adopted (e.g. steering nozzles or azimuth propulsion systems), the plans show-ing the relevant arrangement and structural scantlings are to be submitted. For azimuth propulsion systems, see Ch 10, Sec 1, [11].

Pt B, Ch 1, Sec 3


Table 2 : Plans and documents to be submitted depending on service notations

Plan of outer doors and hatchways

Plan of manholes

Plan of access to and escape from spaces

Plan of ventilation Use of spaces

Plan of tank testing Testing procedures for the various compartmentsHeight of pipes for testing

Plan of watertight doors and scheme of relevant manoeuvring devices

Manoeuvring devicesElectrical diagrams of power control and position indication circuits

Freeboard calculations

Stability documentation See Ch 3, Sec 1, [2.1]

Calculations relevant to intact stability and,where required, damage stability

Equipment number calculation Geometrical elements for calculationList of equipmentConstruction and breaking load of steel wiresMaterial, construction, breaking load and relevant elongation of synthetic ropes

Emergency towing arrangement See Ch 10, Sec 4, [4.3]

Service notations Plans or documents

Ro-ro passenger shipRo-ro cargo ship

Plans of the bow or stern ramps, elevators for cargo handling and movable decks, if any, including:• structural arrangements of ramps, elevators and movable decks with their masses• arrangements of securing and locking devices• connection of ramps, lifting and/or hoisting appliances to the hull structures, with indication of

design loads (amplitude and direction)• wire ropes and hoisting devices in working and stowed position• hydraulic jacks• loose gear (blocks, shackles, etc.) indicating the safe working loads and the testing loads• test conditionsOperating and maintenance manual (see Ch 9, Sec 5 and Ch 9, Sec 6) of bow and stern doors and rampsPlan of arrangement of motor vehicles, railway cars and/or other types of vehicles which are intended to be carried and indicating securing and load bearing arrangementsCharacteristics of motor vehicles, railways cars and/or other types of vehicles which are intended to be carried: (as applicable) axle load, axle spacing, number of wheels per axle, wheel spacing, size of tyre printPlan of dangerous areas, in the case of ships intended for the carriage of motor vehicles with petrol in their tanks

Container ship Container arrangement in holds, on decks and on hatch covers, indicating size and gross mass ofcontainersContainer lashing arrangement indicating securing and load bearings arrangementsDrawings of load bearing structures and cell guides, indicating the design loads and including the connections to the hull structures and the associated structural reinforcements

Livestock carrier Livestock arrangementDistribution of fodder and consumable liquid on the various decks and platforms

Oil tanker ESPFLS tanker

Arrangement of pressure/vacuum valves in cargo tanksCargo temperatures

Tanker Cargo temperatures

Plan or document Containing also information on

(1) Where other steering or propulsion systems are adopted (e.g. steering nozzles or azimuth propulsion systems), the plans show-ing the relevant arrangement and structural scantlings are to be submitted. For azimuth propulsion systems, see Ch 10, Sec 1, [11].

Pt B, Ch 1, Sec 3


Chemical tanker ESP List of cargoes intended to be carried, with their densityTypes of cargo to be carried in each tankCargo temperatures Arrangement of pressure/vacuum valves in cargo tanksFor ships with independent tanks, connection of the cargo tanks to the hull structure

Liquefied gas carrier Arrangement of pressure/vacuum valves in cargo tanksHeat transfer analysisDistribution of steel qualitiesFor ships with independent tanks:• cargo tank structure• connection of the cargo tanks to the hull structure• anti-floating and anti-collision arrangements

Dredger Transverse sections through hoppers, wells, pump rooms and dredging machinery spacesStructural arrangement of hoppers and supporting structuresClosing arrangements, if anyConnection of dredging machinery with the hull structure

Hopper dredgerHopper unit

Transverse sections through hoppers, wells, pump rooms and dredging machinery spacesStructural arrangement of hoppers and supporting structures including:• location, mass, fore and aft extent of the movable dredging equipment, for each loading condition• calculations of the horizontal forces acting on the suction pipe and on the gallowsClosing arrangements, if anyConnection of dredging machinery with the hull structure

Split hopper dredgerSplit hopper unit

Transverse sections through hoppers, wells, pump rooms and dredging machinery spacesStructural arrangement of hoppers and supporting structures, including:• location, mass, fore and aft extent of the movable dredging equipment, for each loading condition• calculations of the horizontal forces acting on the suction pipe and on the gallowsClosing arrangements, if anyConnection of dredging machinery with the hull structureSuperstructure hinges and connections to the ship’s structure, including mass and location of the superstructure centre of gravityStructure of hydraulic jack spacesDeck hinges, including location of centre of buoyancy and of centre of gravity of each half-hull, mass of equipped half-hull, half mass of spoil or water, supplies for each half-hull and mass of superstruc-tures supported by each half-hullHydraulic jacks and connections to ship’s structure including operating pressure and maximumpressure of the hydraulic jacks (cylinder and rod sides) and corresponding forcesLongitudinal chocks of bottom and deckTransverse chocksHydraulic installation of jacks, with explanatory note

TugSalvage tugTug escort

Connection of the towing system (winch and hook) with the hull structures with indication of design loads

Tug, salvage tug, tug escort with additional servicefeature barge combined,Barge with additional serv-ice feature tug combined

Structural arrangement of the fore part of the tug, showing details of reinforcements in way of theconnecting point Structural arrangement of the aft part of the barge, showing details of reinforcements in way of the connecting point Details of the connection system

Supply vessel General plan showing the location of storage and cargo tanks with adjacent cofferdams andindicating the nature and density of cargoes intended to be carriedPlan of gas-dangerous spacesConnection of the cargo tanks with the hull structureStowage of deck cargoes and lashing arrangement with location of lashing points and indication of design loadsStructural reinforcements in way of load transmitting elements, such as winches, rollers, liftingappliances


Pt B, Ch 1, Sec 3


Table 3 : Plans and documents to be submitted depending on additional class notations

Oil recovery ship General plan showing the location of tanks intended for the retention of oily residues and systems for their treatmentPlan of the system for treatment of oily residues and specification of all relevant apparatusesSupporting structures of the system for treatment of oily residuesOperating manual

Cable laying ship Structural reinforcements in way of load transmitting elements, such as foundations and fastenings of the equipment to the ship structures

Fishing vessel Minimum design temperature of refrigerated spacesStructural reinforcements in way of load transmitting elements, such as masts, gantries, trawl gallows and winches, including the maximum brake load of the winches

Additional class notation Plans or documents

ICE CLASS IA SUPERICE CLASS IAICE CLASS IBICE CLASS ICICE CLASS ID

The plans relevant to shell expansion and fore and aft part structures are to defin(see Pt E, Ch 8, Sec 1, [2.2]) the maximum draught LWL, the minimum draught BWL (both draughts at midship, fore and aft ends), and the borderlines of fore, midship and aft regions defined in Pt E, Ch 8, Sec 2, [1.2]

LASHING Lashing arrangement plans, indicating:• container arrangement in holds, on decks and on hatch covers, with specification of the gross

mass of each container and of each container stack• arrangement of mobile lashing equipment with the specific location of the various pieces of

equipmentComplete list of the mobile lashing equipment, with detailed drawing and indication of materials, safety working loads, breaking loads or test toadsRemovable load-bearing structures for containers, such as guides, cells, buttresses, etc., connected to the hull structure or to hatch covers

MON-HULL See Pt E, Ch 5, Sec 1, [1.2]

SPM See Pt E, Ch 10, Sec 4, [2]


Pt B, Ch 1, Sec 4


SECTION 4 CALCULATION PROGRAMMES

1 Programme for the Rule based scantling

1.1 General

1.1.1 Computer programmes, dealing with rule checking, are available to the clients of the Society. They run on per-sonal computers under the WINDOWS operating system.

The Head Office of the Society or a local office should be contacted in order to have information on how to obtain one of these programmes.

1.2 MARS

1.2.1 The MARS programme performs the rule scantling check of plating and ordinary stiffeners at any transverse section along the ship hull.

1.2.2 In particular, MARS allows to:

• calculate the transverse section geometric properties

• carry out the hull girder strength checks, including ulti-mate strength

• carry out all the rule strength checks of:

- strakes

- longitudinal and transverse ordinary stiffeners

- strakes and ordinary stiffeners of transverse bulk-heads.

1.3 VERISTAR

1.3.1 Within VERISTAR system, the Society provides an integrated chain of computer programmes to perform rational design analysis of ship hulls.Transverse section scantlings verification and finite element analysis of hull structure, including automatic generation of part of the finite element model, are integrated in an unique software. Additionally there is automatic load calculation, model load cases generation, and scantling criteria verifica-tion, in accordance with the Rules.

1.4 BULK

1.4.1 The BULK programme is designed to assess, accord-ing to the IACS Unified Requirements adopted in the rules,the hold mass curves and the structural strength of transverse corrugated bulkheads and double bottoms of new and existing bulk carriers to which these requirements apply.

1.5 RUDDER

1.5.1 The RUDDER programme performs the rule checks of rudders. In particular, it allows to calculate and verify the compliance with the rules of: • the geometric characteristics of the rudder blade• the scantlings of rudder stock, rudder blade, pintles and

bearings• the geometric characteristics and the scantlings of rud-

der horns and sole piece cross sections.

Chapter 2 General Arrangement Design

Symbols

FPLL :

"forward freeboard perpendicular". The forward freeboard perpendicular is to be taken at the

forward end the length LLL and is to coincide with the foreside of the stem on the waterline

on which the length LLL is measured.

APLL :

"after freeboard perpendicular". The after freeboard perpendicular is to be taken at the after

end the length LLL.

Pt B, Ch 2, Sec 1


SECTION 1 SUBDIVISION ARRANGEMENT

1 Number and arrangement of transverse watertight bulkheads

1.1 Number of watertight bulkheads

1.1.1 GeneralAll ships, in addition to complying with the requirements of[1.1.2], are to have at least the following transverse water-tight bulkheads: • one collision bulkhead• one after peak bulkhead for passenger ships and ro-ro

passenger ships• two bulkheads forming the boundaries of the machinery

space in ships with machinery amidships, and a bulk-head forward of the machinery space in ships withmachinery aft. In the case of ships with an electrical pro-pulsion plant, both the generator room and the engineroom are to be enclosed by watertight bulkheads.

1.1.2 Additional bulkheadsFor ships not required to comply with subdivision regula-tions, transverse bulkheads adequately spaced and in gen-eral not less in number than indicated in Tab 1 are to befitted.

Additional bulkheads may be required for ships having tocomply with subdivision or damage stability criteria (seePart D for the different types of ships).

1.2 Water ingress detection

1.2.1 GeneralWhen a ship with a length less than 80 m and of 500 GTand over is fitted, below the freeboard deck, with singlecargo hold or cargo holds which are not separated by atleast one bulkhead made watertight up to the freeboarddeck, water ingress detection system is to be fitted accord-ing to Pt C, Ch 1, Sec 10, [6.12.2].

1.2.2 Bulk carriersFor ships granted with the service notation bulk carrier, bulkcarrier ESP, ore carrier ESP, combination carrier/OBO ESP orcombination carrier/OOC ESP, water ingress detection sys-tem is to be fitted according to Pt C, Ch 1, Sec 10, [6.12.1].

2 Collision bulkhead

2.1

2.1.1 A collision bulkhead is to be fitted which is to bewatertight up to the bulkhead deck. This bulkhead is to belocated at a distance from the forward perpendicular FPLL ofnot less than 5 per cent of the length LLL of the ship or 10 m,whichever is the less, and, except as may be permitted by

the Society, not more than 8 per cent of LLL or 5 per cent ofthe LLL + 3 m, whichever is the greater.

For ships not covered by the SOLAS Convention, the lengthLLL need not be taken less than 50 m, unless required by theNational Authorities.

2.1.2 Where any part of the ship below the waterlineextends forward of the forward perpendicular, e.g. a bul-bous bow, the distances, in metres, stipulated in [2.1.1] areto be measured from a point either:• at the midlength of such extension, or• at a distance 1,5 per cent of the length LLL of the ship

forward of the forward perpendicular, or• at a distance 3 metres forward of the forward perpen-

dicular; whichever gives the smallest measurement.

2.1.3 The bulkhead may have steps or recesses providedthey are within the limits prescribed in [2.1.1] or [2.1.2].No door, manhole, ventilation duct or any other opening isto be fitted in the collision bulkhead below the bulkheaddeck.

Table 1 : Number of bulkheads

2.1.4 At Owner request and subject to the agreement of theflag Administration, the Society may, on a case by casebasis, accept a distance from the collision bulkhead to theforward perpendicular FPLL greater than the maximum spec-ified in [2.1.1] and [2.1.2], provided that subdivision andstability calculations show that, when the ship is in uprightcondition on full load summer waterline, flooding of thespace forward of the collision bulkhead will not result inany part of the freeboard deck becoming submerged, or inany unacceptable loss of stability.In such a case, the attention of the Owner and the Shipyardis drawn to the fact that the flag Administration may imposeadditional requirements and that such an arrangement is, in

Length (m)Number of bulkheads

for ships with aft machinery (1)

Number ofbulkheads for

other ships

L < 65 3 4

65 L < 85 4 5

85 L < 105 4 5

105 L < 120 5 6

120 L < 145 6 7

145 L < 165 7 8

165 L < 190 8 9

L 190 to be defined on a case by case basis

(1) After peak bulkhead and aft machinery bulkhead are the same.

Pt B, Ch 2, Sec 1


principle, officialized by the issuance of a certificate ofexemption under the SOLAS Convention provisions. More-over, in case of change of flag, the taking Administrationmay not accept the exemption.

2.1.5 Where a long forward superstructure is fitted, the col-lision bulkhead is to be extended weathertight to the nextdeck above the bulkhead deck. The extension need not befitted directly above the bulkhead below provided it islocated within the limits prescribed in [2.1.1] or [2.1.2] withthe exemption permitted by [2.1.6] and the part of the deckwhich forms the step is made effectively weathertight.

2.1.6 Where bow doors are fitted and a sloping loadingramp forms part of the extension of the collision bulkheadabove the freeboard deck, the part of the ramp which ismore than 2,3 m above the freeboard deck may extend for-ward of the limit specified in [2.1.1] or [2.1.2] The ramp is tobe weathertight over its complete length.

2.1.7 The number of openings in the extension of the colli-sion bulkhead above the freeboard deck is to be restrictedto the minimum compatible with the design and normaloperation of the ship. All such openings are to be capable ofbeing closed weathertight.

3 After peak, machinery space bulkheads and stern tubes

3.1

3.1.1 General

Bulkheads are to be fitted separating the machinery spacefrom the cargo and accomodation spaces forward and aftand made watertight up to the bulkhead deck. In passengerships, an after peak bulkhead is also to be fitted and madewatertight up to the bulkhead deck. The after peak bulk-head may, however, be stepped below the bulkhead deck,provided the degree of safety of the ship as regards subdivi-sion is not thereby diminished.

3.1.2 Sterntubes

In all cases, sterntubes are to be enclosed in watertightspaces of moderate volume. In passenger ships, the sterngland is to be situated in a watertight shaft tunnel or otherwatertight space separate from the sterntube compartmentand of such volume that, if flooded by leakage through thestern gland, the bulkhead deck will not be immersed. Incargo ships, other measures to minimise the danger of waterpenetrating into the ship in case of damage to sterntubearrangements may be taken at the discretion of the Society.

For ships less than 65 m, where the after peak bulkhead inway of the sterntube stuffing box is not provided, sterntubesare to be enclosed in watertight spaces of moderate volume.

4 Height of transverse watertight bulkheads other than collision bulkhead and after peak bulkhead

4.1

4.1.1 Transverse watertight bulkheads are to extend water-tight up to the bulkhead deck. In exceptional cases at therequest of the Owner, the Society may allow transversewatertight bulkheads to terminate at a deck below that fromwhich freeboard is measured, provided that this deck is atan adequate distance above the full load waterline.

4.1.2 Where it is not practicable to arrange a watertightbulkhead in one plane, a stepped bulkhead may be fitted. Inthis case, the part of the deck which forms the step is to bewatertight and equivalent in strength to the bulkhead.

5 Openings in watertight bulkheads and decks for ships with service notation other than passenger ship or ro-ro passenger ship

5.1 Application

5.1.1 The requirements in [5.2] and [5.3] apply to shipswith service notation other than passenger ship or ro-ropassenger ship.

The requirements for openings in watertight bulkheadsbelow the bulkhead deck in ships with service notation pas-senger ship and ro-ro passenger ship are to comply withPart D, Chapter 11 and Part D, Chapter 12 respectively.

5.2 General

5.2.1 The number of openings in watertight subdivisions isto be kept to a minimum compatible with the design andproper working of the ship. Where penetrations of water-tight bulkheads and internal decks are necessary for access,piping, ventilation, electrical cables, etc., arrangements areto be made to maintain the watertight integrity. The Societymay permit relaxation in the watertightness of openingsabove the freeboard deck, provided that it is demonstratedthat any progressive flooding can be easily controlled andthat the safety of the ship is not impaired.

5.2.2 No door, manhole ventilation duct or any otheropening is permitted in the collision bulkhead below thesubdivision deck.

5.2.3 Lead or other heat sensitive materials may not beused in systems which penetrate watertight subdivisionbulkheads, where deterioration of such systems in the eventof fire would impair the watertight integrity of the bulk-heads.

5.2.4 Valves not forming part of a piping system are notpermitted in watertight subdivision bulkheads.

Pt B, Ch 2, Sec 1


5.2.5 The requirements relevant to the degree of tightness,as well as the operating systems, for doors or other closingappliances complying with the provisions in [5.3] are spec-ified in Tab 2.

5.3 Openings in the watertight bulkheads and internal decks

5.3.1 Openings used while at sea

Doors provided to ensure the watertight integrity of internalopenings which are used while at sea are to be slidingwatertight doors capable of being remotely closed from thebridge and are also to be operable locally from each side ofthe bulkhead. Indicators are to be provided at the controlposition showing whether the doors are open or closed, andan audible alarm is to be provided at the door closure. Thepower, control and indicators are to be operable in theevent of main power failure. Particular attention is to bepaid to minimise the effect of control system failure. Eachpower-operated sliding watertight door is to be providedwith an individual hand-operated mechanism. The possibil-ity of opening and closing the door by hand at the dooritself from both sides is to be assured.

5.3.2 Openings normally closed at sea

Access doors and access hatch covers normally closed atsea, intended to ensure the watertight integrity of internalopenings, are to be provided with means of indication

locally and on the bridge showing whether these doors orhatch covers are open or closed. A notice is to be affixed toeach such door or hatch cover to the effect that it is not tobe left open.

5.3.3 Doors or ramps in large cargo spaces

Watertight doors or ramps of satisfactory construction maybe fitted to internally subdivide large cargo spaces, pro-vided that the Society is satisfied that such doors or rampsare essential. These doors or ramps may be hinged, rollingor sliding doors or ramps, but are not to be remotely con-trolled. Such doors are to be closed before the voyage com-mences and are to be kept closed during navigation. Shouldany of the doors or ramps be accessible during the voyage,they are to be fitted with a device which prevents unauthor-ised opening.

The word “satisfactory” means that scantlings and sealingrequirements for such doors or ramps are to be sufficient towithstand the maximum head of the water at the floodedwaterline.

5.3.4 Openings permanently kept closed at sea

Other closing appliances which are kept permanentlyclosed at sea to ensure the watertight integrity of internalopenings are to be provided with a notice which is to beaffixed to each such closing appliance to the effect that it isto be kept closed. Manholes fitted with closely bolted cov-ers need not be so marked.

Table 2 : Doors

Sliding type Hinged type Rolling type

(cargo between

deck spaces)

Remote operation indication

on the bridge

Indicator on the bridge

Localoperation

only

Remote operation indication

on the bridge

Indicator on the bridge

Localoperation

only

Watertight Below the freeboard deck

Open at sea X

Normally closed (2)

X X (3)

Remain closed (2)

X (4) (5)

X (4) (5)

X (4) (5)

Weathertight / watertight (1)

Above the freeboard deck

Open at sea X

Normally closed (2)

X X

Remain closed (2)

X (4) (5)

(1) Watertight doors are required when they are located below the waterline at the equilibrium of the final stage of flooding;otherwise a weathertight door is accepted.

(2) Notice to be affixed on both sides of the door: “to be kept closed at sea”.(3) Type A ships of 150 m and upwards, and Type B ships with a reduced freeboard may have a hinged watertight door between

the engine room and the steering gear space, provided that the sill of this door is above the summer load waterline.(4) The door is to be closed before the voyage commences.(5) If the door is accessible during the voyage, a device which prevents unauthorised opening is to be fitted.

Pt B, Ch 2, Sec 2


SECTION 2 COMPARTMENT ARRANGEMENT

1 Definitions

1.1 Cofferdam

1.1.1 A cofferdam means an empty space arranged so thatcompartments on each side have no common boundary; acofferdam may be located vertically or horizontally. As arule, a cofferdam is to be properly ventilated and of suffi-cient size to allow for inspection.

1.2 Machinery spaces of category A

1.2.1 Machinery spaces of category A are those spaces ortrunks to such spaces which contain:

• internal combustion machinery used for main propul-sion; or

• internal combustion machinery used for purposes otherthan propulsion where such machinery has in the aggre-gate a total power output of not less than 375 kW; or

• any oil fired boiler or fuel oil unit.

2 Cofferdams

2.1 Cofferdam arrangement

2.1.1 Cofferdams are to be provided between:

• fuel oil tanks and lubricating oil tanks

• compartments intended for liquid hydrocarbons (fueloil, lubricating oil) and compartments intended for freshwater (drinking water, water for propelling machineryand boilers)

• compartments intended for liquid hydrocarbons (fueloil, lubricating oil) and tanks intended for the carriage ofliquid foam for fire extinguishing.

2.1.2 Cofferdams separating:

• fuel oil tanks from lubricating oil tanks

• lubricating oil tanks from compartments intended forfresh water or boiler feed water

• lubricating oil tanks from those intended for the carriageof liquid foam for fire extinguishing,

may not be required when deemed impracticable or unrea-sonable by the Society in relation to the characteristics anddimensions of the spaces containing such tanks, providedthat:

• the thickness of common boundary plates of adjacenttanks is increased, with respect to the thicknessobtained according to Ch 7, Sec 1, by 2 mm in the case

of tanks carrying fresh water or boiler feed water, and by1 mm in all other cases

• the sum of the throats of the weld fillets at the edges ofthese plates is not less than the thickness of the platesthemselves

• the structural test is carried out with a head increased by1 m with respect to Ch 12, Sec 3, [2].

2.1.3 Spaces intended for the carriage of flammable liquidsare to be separated from accommodation and servicespaces by means of a cofferdam. Where accommodationand service spaces are arranged immediately above suchspaces, the cofferdam may be omitted only where the deckis not provided with access openings and is coated with alayer of material recognized as suitable by the Society.

The cofferdam may also be omitted where such spaces areadjacent to a passageway, subject to the conditions stated in[2.1.2] for fuel oil or lubricating oil tanks.

3 Double bottoms

3.1 Double bottoms for ships other than tankers

3.1.1 A double bottom is to be fitted extending from thecollision bulkhead to the after peak bulkhead, as far as thisis practicable and compatible with the design and properworking of the ship.

3.1.2 Where a double bottom is required to be fitted, theinner bottom is to be continued out to the ship’s sides insuch a manner as to protect the bottom to the turn of thebilge. Such protection is to be deemed satisfactory if theinner bottom is not lower at any part than a plane parallelwith the keel line and which is located not less than a verti-cal distance h measured from the keel line, as calculated bythe formula:

h = B/20

However, in no case is the value of h to be less than760 mm, and need not to be taken as more than 2 m.

3.1.3 Small wells constructed in the double bottom, in con-nection with the drainage arrangements of holds, are not toextend downward more than necessary. A well extending tothe outer bottom, is, however, permitted at the after end ofthe shaft tunnel of the ship. Other wells may be permittedby the Society if it is satisfied that the arrangements giveprotection equivalent to that afforded by a double bottomcomplying with [3.1]. In no case, the vertical distance fromthe bottom of such a well to a plane coinciding with thekeel line is to be less than 500 mm.

Pt B, Ch 2, Sec 2


3.1.4 A double bottom need not be fitted in way of water-tight tanks, including dry tanks of moderate size, providedthe safety of the ship is not impaired in the event of bottomor side damage as defined in Ch 3, Sec 3, [3.4].

3.1.5 Any part of a ship that is not fitted with a double bot-tom in accordance with [3.1.1] or [3.1.4] is to be capable ofwithstanding bottom damages, as specified in Ch 3, Sec 3,[3.4], in that part of the ship.

3.1.6 In the case of unusual bottom arrangements, it is tobe demonstrated that the ship is capable of withstandingbottom damages as specified in Ch 3, Sec 3, [3.4].

3.1.7 Special requirements for passenger ships and tankersare specified in Part D.

4 Compartments forward of the collision bulkhead

4.1 General

4.1.1 The fore peak and other compartments located for-ward of the collision bulkhead cannot be used for the car-riage of fuel oil or other flammable products. This requirement does not apply to ships of less than 400tons gross tonnage, except for those where the fore peak isthe forward cofferdam of tanks arranged for the carriage offlammable liquid products having a flash point not exceed-ing 60°C.

5 Minimum bow height

5.1 General

5.1.1 The bow height Fb defined as the vertical distance atthe forward perpendicular between the waterline corre-sponding to the assigned summer freeboard and thedesigned trim and the top of the exposed deck at side, is tobe not less than:

Fb = (6075(LLL/100) 1875(LLL/100)2 + 200(LLL/100)3) x(2,08 + 0,609Cb 1,603Cwf 0,0129(L/T1))

where:Fb : Calculated minimum bow height, in mmT1 : Draught at 85% of the least moulded depth, in

m, as defined in Ch 1, Sec 2, [3.2.2] Cwf : Waterplane area coefficient forward of LLL/2:

Awf : Waterplane area forward of LLL/2 at draught T1,in m2.

For ships to which timber freeboards are assigned, the sum-mer freeboard (and not the timber summer freeboard) is tobe assumed when applying the formula above.

5.1.2 Where the bow height required in [5.1.1] is obtainedby sheer, the sheer is to extend for at least 15% of the lengthof the ship measured from the forward perpendicular.

Where it is obtained by fitting a superstructure, such super-structure is to extend from the stem to a point at least 0,07Labaft the forward perpendicular and is to be enclosed asdefined in Ch 9, Sec 4.

5.1.3 Ships which, to suit exceptional operational require-ments, cannot meet the requirements in [5.1.1] and [5.1.2]will be considered by the Society on a case by case basis.

5.1.4 The sheer of the forecastle deck may be taken intoaccount, even if the length of the forecastle is less than0,15L, but greater than 0,07L, provided that the forecastleheight is not less than one half of standard height of super-structure between 0,07L and the forward perpendicular.

5.1.5 Where the forecastle height is less than one half of thestandard height of superstructure, the credited bow heightmay be determined as follows:

a) Where the freeboard deck has sheer extending fromabaft 0,15L, by a parabolic curve having its origin at0,15L abaft the forward perpendicular at a height equalto the midship depth of the ship, extended through thepoint of intersection of forecastle bulkhead and deck,and up to a point at the forward perpendicular nothigher than the level of the forecastle deck (see Fig 1).However, if the value of the height denoted ht in Fig 1 issmaller than the value of the height denoted hb then ht

may be replaced by hb in the available bow height,where:

Zb , Zt : As defined in Fig 1

hf : Half standard height of superstructure.

b) Where the freeboard deck has sheer extending for lessthan 0,15L or has no sheer, by a line from the forecastledeck at side at 0,07L extended parallel to the base lineto the forward perpendicular (see Fig 2).

5.1.6 All ships assigned a type B freeboard, other than oiltankers, chemical tankers and gas carriers, are to have addi-tional reserve buoyancy in the fore end. Within the range of0,15LLL abaft of the forward perpendicular, the sum of theprojected area between the summer load waterline and thedeck at side (A1 and A2 in Fig 3) and the projected area ofan enclosed superstructure, if fitted, is, in m2, to be not lessthan:

A3 = (0,15 Fmin + 4 (LLL/3 + 10)) LLL/1000

where:

Fmin : Fmin = (F0 f1) + f2F0 : Tabular freeboard, in mm, taken from the Inter-

national Convention on Load Lines, asamended, Table 28.2, corrected for regulation27(9) or 27(10), as applicable

f1 : Correction for block coefficient given in theInternational Convention on Load Lines, asamended, regulation 30

f2 : Correction for depth, in mm, given in the Inter-national Convention on Load Lines, asamended, regulation 31.

CwfAwf

LLL

2-------B-----------=

ht Zb0 15L

xb

----------------

2

Zt–=

Pt B, Ch 2, Sec 2


Figure 1 : Credited bow height where the freeboard deck has sheer extending from abaft 0,15 L

Figure 2 : Credited bow height where the freeboard deck has sheer extending for less than 0,15 L

Figure 3 : Areas A1, A2 and A3

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��

��

��

�

��

��

��

��

��

��

��

��

�

�

��

��

FP

Freeboard deck

0.15L

Summer W.L.

Actual sheer curve

A3

A2

A1

Enclosed superstructure, if fitted

Pt B, Ch 2, Sec 2


6 Shaft tunnels

6.1 General

6.1.1 Shaft tunnels are to be watertight.See also Ch 9, Sec 2.

7 Watertight ventilators and trunks

7.1 General

7.1.1 Watertight ventilators and trunks are to be carried atleast up to the bulkhead deck in passenger ships and up tothe freeboard deck in ships other than passenger ships.

8 Fuel oil tanks

8.1 General

8.1.1 The arrangements for the storage, distribution andutilisation of the fuel oil are to be such as to ensure thesafety of the ship and persons on board.

8.1.2 As far as practicable, fuel oil tanks are to be part ofthe ship’s structure and are to be located outside machineryspaces of category A.Where fuel oil tanks, other than double bottom tanks, arenecessarily located adjacent to or within machinery spacesof category A, at least one of their vertical sides is to be con-

tiguous to the machinery space boundaries, they are prefer-ably to have a common boundary with the double bottomtanks and the area of the tank boundary common with themachinery spaces is to be kept to a minimum.

Where such tanks are situated within the boundaries ofmachinery spaces of category A, they may not contain fueloil having a flashpoint of less than 60°C.

8.1.3 Fuel oil tanks may not be located where spillage orleakage therefrom can constitute a hazard by falling onheated surfaces.

Precautions are to be taken to prevent any oil that mayescape under pressure from any pump, filter or heater fromcoming into contact with heated surfaces.

Fuel oil tanks in boiler spaces may not be located immedi-ately above the boilers or in areas subjected to high temper-atures, unless special arrangements are provided inagreement with the Society.

8.1.4 Where a compartment intended for goods or coal issituated in proximity of a heated liquid container, suitablethermal insulation is to be provided.

8.2 Fuel oil tank protection

8.2.1 All ships with an aggregate oil fuel capacity of600 m3 are to comply with the requirements of the Regula-tion 12 A of Annex I to Marpol Convention, as amended.

Pt B, Ch 2, Sec 3


SECTION 3 ACCESS ARRANGEMENT

1 General

1.1

1.1.1 The number and size of small hatchways for trimming and access openings to tanks or other enclosed spaces, are to be kept to the minimum consistent with access and main-tenance of the space.

2 Double bottom

2.1 Inner bottom manholes

2.1.1 Inner bottom manholes are to be not less than 400 mm x 400 mm. Their number and location are to be so arranged as to provide convenient access to any part of the double bottom.

2.1.2 Inner bottom manholes are to be closed by watertight plate covers.

Doubling plates are to be fitted on the covers, where secured by bolts.

Where no ceiling is fitted, covers are to be adequately pro-tected from damage by the cargo.

2.2 Floor and girder manholes

2.2.1 Manholes are to be provided in floors and girders so as to provide convenient access to all parts of the double bottom.

2.2.2 The size of manholes and lightening holes in floors and girders is, in general, to be less than 50 per cent of the local height of the double bottom.

Where manholes of greater sizes are needed, edge rein-forcement by means of flat bar rings or other suitable stiffen-ers may be required.

2.2.3 Manholes may not be cut into the continuous cen-treline girder or floors and girders below pillars, except where allowed by the Society on a case by case basis.

3 Access arrangement to and within spaces in, and forward of, the cargo area

3.1 General

3.1.1 The requirements in [3.2]to [3.4] are not applicable to ships with service notations bulk carrier ESP , ore carrier ESP , combination carrier ESP, of 20,000 gross tonnage and over, and to ships with service notation oil tanker ESP of

500 gross tonnage and over. For such ships, refer to the applicable requirements of Part D.

3.2 Access to tanks

3.2.1 Tanks with a length equal to or greater than 35 m

Tanks and subdivisions of tanks having lengths of 35 m and above are to be fitted with at least two access hatchways and ladders, as far apart as practicable longitudinally.

3.2.2 Tanks with a length less than 35 mTanks less than 35 m in length are to be served by at least one access hatchway and ladder.

3.2.3 Dimensions of access hatchwaysThe dimensions of any access hatchway are to be sufficient to allow a person wearing a self-contained breathing appa-ratus to ascend or descend the ladder without obstruction and also to provide a clear opening to facilitate the hoisting of an injured person from the bottom of the tank. In no case is the clear opening to be less than 600 mm x 600 mm.

3.2.4 Tanks subdivided by wash bulkheadsWhen a tank is subdivided by one or more wash bulkheads, at least two hatchways are to be fitted, and these hatchways are to be so located that the associated ladders effectively serve all subdivisions of the tank.

3.3 Access within tanks

3.3.1 Wash bulkheads in tanksWhere one or more wash bulkheads are fitted in a tank, they are to be provided with openings not less than 600 x 800 mm and so arranged as to facilitate the access of per-sons wearing breathing apparatus or carrying a stretcher with a patient.

3.3.2 Passage on the tank bottom To provide ease of movement on the tank bottom through-out the length and breadth of the tank, a passageway is to be fitted on the upper part of the bottom structure of each tank, or alternatively, manholes having at least the dimen-sions of 600 mm x 800 mm are to be arranged in the floors at a height of not more than 600 mm from the bottom shell plating.

3.3.3 Passageways in the tanksa) Passageways in the tanks are to have a minimum width

of 600 mm considering the requirement for the possibil-ity of carrying an unconscious person. Elevated passage-ways are to be provided with guard rails over their entire length. Where guard rails are provided on one side only, foot rails are to be fitted on the opposite side. Shelves and platforms forming a part of the access to the tanks are to be of non-skid construction where practicable

Pt B, Ch 2, Sec 3


and be fitted with guard rails. Guard rails are to be fitted to bulkhead and side stringers when such structures are being used for recognised access.

b) Access to elevated passageways from the ship's bottom is to be provided by means of easily accessible passage-ways, ladders or treads. Treads are to provide lateral support for the foot. Where rungs of ladders are fitted against a vertical surface, the distance from the centre of the rungs to that surface is to be at least 150 mm.

c) When the height of the bottom structure does not exceed 1,50 m, the passageways required in a) may be replaced by alternative arrangements having regard to the bottom structure and requirement for ease of access of a person wearing a self-contained breathing appara-tus or carrying a stretcher with a patient.

3.3.4 ManholesWhere manholes are fitted, as indicated in [2.2.2], access is to be facilitated by means of steps and hand grips with plat-form landings on each side.

3.3.5 Guard railsGuard rails are to be 900 mm in height and consist of a rail and intermediate bar. These guard rails are to be of substan-tial construction.

3.4 Construction of ladders

3.4.1 GeneralIn general, the ladders are not to be inclined at an angle exceeding 70°. The flights of ladders are not to be more than 9 m in actual length. Resting platforms of adequate dimensions are to be provided.

3.4.2 ConstructionLadders and handrails are to be constructed of steel of ade-quate strength and stiffness and securely attached to the tank structure by stays. The method of support and length of stay are to be such that vibration is reduced to a practical minimum.

3.4.3 Corrosive effect of the cargoProvision is to be made for maintaining the structural strength of the ladders and railings taking into account the corrosive effect of the cargo.

3.4.4 Width of laddersThe width of ladders between stringers is not to be less than 400 mm.

3.4.5 TreadsThe treads are to be equally spaced at a distance apart measured vertically not exceeding 300 mm. They are to be formed of two square steel bars of not less than 22 mm by 22 mm in section fitted to form a horizontal step with the edges pointing upward, or of equivalent construction. The treads are to be carried through the side stringers and attached thereto by double continuous welding.

3.4.6 Sloping laddersAll sloping ladders are to be provided with handrails of sub-stantial construction on both sides fitted at a convenient dis-tance above the treads.

4 Shaft tunnels

4.1 General

4.1.1 Tunnels are to be large enough to ensure easy access to shafting.

4.1.2 Access to the tunnel is to be provided by a watertight door fitted on the aft bulkhead of the engine room in com-pliance with Ch 2, Sec 1, [5], and an escape trunk which can also act as watertight ventilator is to be fitted up to the subdivision deck, for tunnels greater than 7 m in length.

5 Access to steering gear compartment

5.1

5.1.1 The steering gear compartment is to be readily acces-sible and, as far as practicable, separated from machinery spaces.

5.1.2 Suitable arrangements to ensure working access to steering gear machinery and controls are to be provided.These arrangements are to include handrails and gratings or other non-slip surfaces to ensure suitable working condi-tions in the event of hydraulic fluid leakage.

Pt B, Ch 2, Sec 3


Pt B, Ch 3, Sec 1


SECTION 1 GENERAL

1 General

1.1 Application

1.1.1 General

All ships equal to or greater than 24 m in length may be assigned class only after it has been demonstrated that their intact stability is adequate. Adequate intact stability means compliance with standards laid down by the relevant Administration or with the requirements specified in this Chapter taking into account the ship’s size and type. In any case, the level of intact stability is not to be less than that provided by the Rules.

1.1.2 Ships less than 24 m in length

The Rules also apply to ships less than 24 m in length. In this case, the requirements concerned may be partially omitted when deemed appropriate by the Society.

1.1.3 Approval of the Administration

Evidence of approval by the Administration concerned may be accepted for the purpose of classification.

2 Examination procedure

2.1 Documents to be submitted

2.1.1 List of documents

For the purpose of the examination of the stability, the doc-umentation listed in Ch 1, Sec 3, [1.1.2] is to be submitted for information.

The stability documentation to be submitted for approval, as indicated in Ch 1, Sec 3, [1.2.1], is as follows:

• Inclining test report for the ship, as required in [2.2] or:

- where the stability data is based on a sister ship, the inclining test report of that sister ship along with the lightship measurement report for the ship in ques-tion; or

- where lightship particulars are determined by meth-ods other than inclining of the ship or its sister, the lightship measurement report of the ship along with a summary of the method used to determine those particulars as indicated in [2.2.4].

• trim and stability booklet, as required in Ch 3, Sec 2, [1.1.1]

• and, as applicable:

- grain loading manual, as required in Pt D, Ch 4, Sec 3, [2.2.2]

- damage stability calculations, as required in Ch 3, Sec 3, [3.1]

- damage control documentation, as required in Ch 3, Sec 3, [4]

- loading computer documentation, as required in Ch 3, Sec 2, [1.1.2] and in Ch 3, Sec 3, [3.1.3].

A copy of the trim and stability booklet and, if applica-ble, the grain stability booklet, the damage control doc-umentation or the loading computer documentation is to be available on board for the attention of the Master.

2.1.2 Provisional documentation

The Society reserves the right to accept or demand the sub-mission of provisional stability documentation for examina-tion.

Provisional stability documentation includes loading condi-tions based on estimated lightship values.

2.1.3 Final documentation

Final stability documentation based on the results of the inclining test or the lightweight check is to be submitted for examination.

When provisional stability documentation has already been submitted and the difference between the estimated values of the lightship and those obtained after completion of the test is less than:

• 2% for the displacement, and,

• 1% of the length between perpendiculars for the longi-tudinal position of the centre of gravity,

and the determined vertical position of the centre of gravity is not greater than the estimated vertical position of the cen-tre of gravity, the provisional stability documentation may be accepted as the final stability documentation.

2.2 Inclining test/lightweight check

2.2.1 Definitions

a) Lightship

The lightship is a ship complete in all respects, but with-out consumables, stores, cargo, and crew and effects, and without any liquids on board except for machinery and piping fluids, such as lubricants and hydraulics, which are at operating levels.

Pt B, Ch 3, Sec 1


b) Inclining test

The inclining test is a procedure which involves moving a series of known weights, normally in the transverse direction, and then measuring the resulting change in the equilibrium heel angle of the ship. By using this information and applying basic naval architecture prin-ciples, the ship's vertical centre of gravity (VCG or KG) is determined.

c) Lightweight check

The lightweight check is a procedure which involves auditing all items which are to be added, deducted or relocated on the ship at the time of the inclining test so that the observed condition of the ship can be adjusted to the lightship condition. The weight and longitudinal, transverse and vertical location of each item are to be accurately determined and recorded. The lightship dis-placement and longitudinal centre of gravity (LCG) can be obtained using this information, as well as the static waterline of the ship at the time of the inclining test as determined by measuring the freeboard or verified draught marks of the ship, the ship's hydrostatic data and the sea water density.

2.2.2 General

Any ship for which a stability investigation is requested in order to comply with class requirements is to be initially subjected to an inclining test permitting the evaluation of the position of the lightship centre of gravity, or a light-weight check of the lightship displacement, so that the sta-bility data can be determined. Cases for which the inclining test is required and those for which the lightweight check is accepted in its place are listed in [2.2.4] and [2.2.5].

A detailed procedure of the test is to be submitted to the Society prior to the test. This procedure is to include:

a) identification of the ship by name and shipyard hull number, if applicable

b) date, time and location of the test

c) inclining weight data:

• type

• amount (number of units and weight of each)

• certification

• method of handling (i.e. sliding rail or crane)

• anticipated maximum angle of heel to each side

d) measuring devices:

• pendulums - approximate location and length

• U-tubes - approximate location and length

• inclinometers - Location and details of approvals and calibrations

e) approximate trim

f) condition of tanks

g) estimate weights to deduct, to complete, and to relocate in order to place the ship in its true lightship condition.

The inclining test or lightweight check is to be attended by a Surveyor of the Society. The Society may accept inclining tests or lightweight checks attended by a member of the flag Administration.

The inclining test is adaptable to ships less than 24 m in length, provided that precautions are taken, on a case by case basis, to ensure the accuracy of the test procedure.

2.2.3 Inclining test

The inclining test is required in the following cases:

• Any new ship, after its completion, except for the cases specified in [2.2.4]

• Any ship, if deemed necessary by the Society, where any alterations are made so as to materially affect the stability.

Note 1: Due attention is to be paid to SOLAS Ch.II.1 Reg.22 (if applicable) whereby it is stipulated that such allowance is subject to the Flag Authorities agreement (refer to Pt A, Ch 1, Sec 1, [3.1.1]).

2.2.4 Lightweight check

The Society may allow a lightweight check to be carried out in lieu of an inclining test in the case of:

• stability data are available from the inclining test of a sis-ter ship and it is shown to the satisfaction of the Society that reliable stability information for the exempted ship can be obtained from such basic data. A weight survey shall be carried out upon completion and the ship shall be inclined whenever in comparison with the data derived from the sister ship, a deviation from the light-ship displacement exceeding 1% for ships of 160 m or more in length and 2% for ships of 50 m or less in length and as determined by linear interpolation for intermediate lengths or a deviation from the lightship longitudinal centre of gravity exceeding 0.5% of LS is found.

• special types of ship, such as pontoons, provided that the vertical centre of gravity is considered at the level of the deck.

• special types of ship provided that:

- a detailed list of weights and the positions of their centres of gravity is submitted

- a lightweight check is carried out, showing accord-ance between the estimated values and those deter-mined

- adequate stability is demonstrated in all the loading conditions reported in the trim and stability booklet.

2.2.5 Detailed procedure

A detailed procedure for conducting an inclining test is included in Ch 3, App 1. For the lightweight check, the same procedure applies except as provided for in Ch 3, App 1, [1.1.9].

Pt B, Ch 3, Sec 2


SECTION 2 INTACT STABILITY

1 General

1.1 Information for the Master

1.1.1 Stability bookletEach ship is to be provided with a stability booklet,approved by the Society, which contains sufficient informa-tion to enable the Master to operate the ship in compliancewith the applicable requirements contained in this Section.

Where any alterations are made to a ship so as to materiallyaffect the stability information supplied to the Master,amended stability information is to be provided. If neces-sary the ship is to be re-inclined.

Stability data and associated plans are to be drawn up inthe working language of the ship and any other languagethe Society may require. reference is also made to the Inter-national Safety Management (ISM) Code, adopted by IMOby resolution A.741(18). All translations of the stabilitybooklet are to be approved.The format of the trim and stability booklet and the informa-tion included are specified in Ch 3, App 2.

1.1.2 Loading instrumentAs a supplement to the approved stability booklet, a loadinginstrument, approved by the Society, may be used to facili-tate the stability calculations mentioned in Ch 3, App 2.

A simple and straightforward instruction manual is to beprovided.

In order to validate the proper functioning of the computerhardware and software, pre-defined loading conditions areto be run in the loading instrument periodically, at least atevery periodical class survey, and the print-out is to bemaintained on board as check conditions for future refer-ence in addition to the approved test conditions booklet.

The procedure to be followed, as well as the list of technicaldetails to be sent in order to obtain loading instrumentapproval, are given in Ch 11, Sec 2, [4].

1.1.3 Operating booklets for certain shipsShips with innovative design are to be provided with addi-tional information in the stability booklet such as design lim-itations, maximum speed, worst intended weatherconditions or other information regarding the handling ofthe craft that the Master needs to operate the ship.

1.2 Permanent ballast

1.2.1 If used, permanent ballast is to be located in accord-ance with a plan approved by the Society and in a mannerthat prevents shifting of position. Permanent ballast is not tobe removed from the ship or relocated within the ship with-out the approval of the Society. Permanent ballast particu-lars are to be noted in the ship’s stability booklet.

1.2.2 Permanent solid ballast is to be installed under thesupervision of the Society.

2 Design criteria

2.1 General intact stability criteria

2.1.1 GeneralThe intact stability criteria specified in [2.1.2], [2.1.3],[2.1.4],and [2.1.5] are to be complied with for the loadingconditions mentioned in Ch 3, App 2, [1.2].

However, the lightship condition not being an operationalloading case, the Society may accept that part of the above-mentioned criteria are not fulfilled.

These criteria set minimum values, but no maximum valuesare recommended. It is advisable to avoid excessive valuesof metacentric height, since these might lead to accelerationforces which could be prejudicial to the ship, its equipmentand to safe carriage of the cargo.

2.1.2 GZ curve areaThe area under the righting lever curve (GZ curve) is to benot less than 0,055 m.rad up to = 30° angle of heel andnot less than 0,09 m.rad up to = 40° or the angle of downflooding f if this angle is less than 40°. Additionally, thearea under the righting lever curve (GZ curve) between theangles of heel of 30° and 40° or between 30° and f , if thisangle is less than 40°, is to be not less than 0,03 m.rad.Note 1: f is an angle of heel at which openings in the hull, super-structures or deckhouses which cannot be closed weathertight sub-merge. In applying this criterion, small openings through whichprogressive flooding cannot take place need not be considered asopen.This interpretation is not intended to be applied to existingships.

The means of closing air pipes are to be weathertight and of anautomatic type if the openings of the air pipes to which the devicesare fitted would be submerged at an angle of less than 40 degrees(or any lesser angle which may be needed to suit stability require-ments) when the ship is floating at its summer load line draught.Pressure/vacuum valves (P.V. valves) may be accepted on tankers.Wooden plugs and trailing canvas hoses may not be accepted inpositions 1 and 2 as defined in Ch 1, Sec 2, [3.21].

2.1.3 Minimum righting leverThe righting lever GZ is to be at least 0,20 m at an angle ofheel equal to or greater than 30°.

2.1.4 Angle of maximum righting leverThe maximum righting arm is to occur at an angle of heelpreferably exceeding 30° but not less than 25°.

When the righting lever curve has a shape with two maxi-mums, the first is to be located at a heel angle not less than25°.

Pt B, Ch 3, Sec 2


In cases of ships with a particular design and subject to theprior agreement of the flag Administration, the Society mayaccept an angle of heel max less than 25° but in no case lessthan 15°, provided that the area “A” below the righting levercurve is not less than the value obtained, in m.rad, from thefollowing formula:

A = 0,055 + 0,001 (30° max)

where max is the angle of heel in degrees at which the right-ing lever curve reaches its maximum.

2.1.5 Initial metacentric height

The initial metacentric height GM0 is not to be less than0,15 m.

2.1.6 Elements affecting stability

A number of influences such as beam wind on ships withlarge windage area, icing of topsides, water trapped ondeck, rolling characteristics, following seas, etc., whichadversely affect stability, are to be taken into account.

2.1.7 Elements reducing stability

Provisions are to be made for a safe margin of stability at allstages of the voyage, regard being given to additions ofweight, such as those due to absorption of water and icing(details regarding ice accretion are given in [6]) and tolosses of weight such as those due to consumption of fueland stores.

3 Severe wind and rolling criterion (weather criterion)

3.1 Scope

3.1.1 This criterion supplements the stability criteria givenin [2.1] for ships of 24 m in length and over. The more strin-gent criteria of [2.1] and the weather criterion are to governthe minimum requirements.

3.2 Weather criterion

3.2.1 Assumptions

The ability of a ship to withstand the combined effects ofbeam wind and rolling is to be demonstrated for eachstandard condition of loading, with reference to Fig 1 as fol-lows:

• the ship is subjected to a steady wind pressure actingperpendicular to the ship's centreline which results in asteady wind heeling lever (w1)

• from the resultant angle of equilibrium (), the ship isassumed to roll owing to wave action to an angle of roll() to windward

• the ship is then subjected to a gust wind pressure whichresults in a gust wind heeling lever (w2)

• free surface effects, as described in [4], are to beaccounted for in the standard conditions of loading asset out in Ch 3, App 2, [1.2].

Figure 1 : Severe wind and rolling

3.2.2 Criteria

Under the assumptions of [3.2.1], the following criteria areto be complied with:

• the area "b" is to be equal to or greater than area "a",where:

a : Area above the GZ curve and below w2,betweenR and the intersection of w2 withthe GZ curve

b : Area above the heeling lever w2 and belowthe GZ curve, between the intersection ofw2 with the GZ curve and 2

• the angle of heel under action of steady wind 0) is tobe limited to 16° or 80% of the angle of deck edgeimmersion, whichever is less.

3.2.3 Heeling levers

The wind heeling levers w1 and w2, in m, referred to in[3.2.2], are constant values at all angles of inclination andare to be calculated as follows:

and

where:

P : 504 N/m2 for unrestricted navigation notation.The value of P used for ships with restricted nav-igation notation may be reduced subject to theapproval of the Society

A : Projected lateral area in m2, of the portion of theship and deck cargo above the waterline

Z : Vertical distance in m, from the centre of A tothe centre of the underwater lateral area orapproximately to a point at one half the draught

: Displacement in t

g = 9,81 m/s2.

��

��

�

θ

θ�

θ� θ��

�

��

W1PAZ

1000g--------------------=

W2 1 5, W1=

Pt B, Ch 3, Sec 2


3.2.4 Angles of heelFor the purpose of calculating the criteria of [3.2.2], theangles in Fig 1 are defined as follows:

0 : Angle of heel, in degrees, under action of steadywind

1 : Angle of roll, in degress, to windward due towave action, calculated as follows:

2 : Angle of downflooding (f) in degrees, or 50° orc , whichever is less

f : Angle of heel in degrees, at which openings inthe hull, superstructures or deckhouses whichcannot be closed weathertight immerse. Inapplying this criterion, small openings throughwhich progressive flooding cannot take placeneed not be considered as open

c : Angle in degrees, of second intercept betweenwind heeling lever w2 and GZ curves

R = 0 1

X1 : Coefficient defined in Tab 1

X2 : Coefficient defined in Tab 2

k : Coefficient equal to:k = 1,0 for a round-bilged ship having no bilgeor bar keelsk = 0,7 for a ship having sharp bilge

For a ship having bilge keels, a bar keel or both,k is defined in Tab 3.

r = 0,73 0,6 (OG)/T1

OG : Distance in m, between the centre of gravityand the waterline (positive if centre of gravity isabove the waterline, negative if it is below)

T1 : Mean moulded draught in m, of the ship

s : Factor defined in Tab 4.Note 1: The angle of roll 1 for ships with anti-rolling devices is tobe determined without taking into account the operations of thesedevices.

Note 2: The angle of roll 1 may be obtained, in lieu of the aboveformula, from model tests or full scale measurements.

The rolling period TR, in s, is calculated as follows:

where:

The symbols in the tables and formula for the rolling periodare defined as follows:LW : Length in m, of the ship at the waterline

T1 : Mean moulded draught in m, of the ship

AK : Total overall area in m2 of bilge keels, or area ofthe lateral projection of the bar keel, or sum ofthese areas, or area of the lateral projection ofany hull appendages generating added massduring ship roll

GM : Metacentric height in m, corrected for free sur-face effect.

Table 1 : Values of coefficient X1

Table 2 : Values of coefficient X2

Table 3 : Values of coefficient k

Table 4 : Values of factor s

(Intermediate values in these tables are to be obtained bylinear interpolation)

1 109kX1X2 rs=

TR2CBGM

--------------=

C 0 373, 0 023, BT1

----- 0 043, LW

100----------–+=

B/T1 X1

2,4 1,00

2,5 0,98

2,6 0,96

2,7 0,95

2,8 0,93

2,9 0,91

3,0 0,90

3,1 0,88

3,2 0,86

3,4 0,82

3,5 0,80

CB X2

0,45 0,75

0,50 0,82

0,55 0,89

0,60 0,95

0,65 0,97

0,70 1,00

k

0,0 1,00

1,0 0,98

1,5 0,95

2,0 0,88

2,5 0,79

3,0 0,74

3,5 0,72

4,0 0,70

TR s

6 0,100

7 0,098

8 0,093

12 0,065

14 0,053

16 0,044

18 0,038

20 0,035

AK 100L B

----------------------

Pt B, Ch 3, Sec 2


3.2.5 Tab 1 toTab 4 and formulae described in [3.2.4]arebased on data from ships having:

• B/T1 smaller than 3,5

• (KG/T11) between 0,3 and 0,5

• TR smaller than 20 s.

For ships with parameters outside of the above limits theangle of roll (1) may be determined with model experi-ments of a subject ship with the procedure described inIMO MSC.1/Circ. 1200 as the alternative. In addition, theSociety may accept such alternative determinations for anyship, if deemed appropriate.

3.2.6 Alternative means for determining the wind heelinglever (W1) may be accepted, to the satisfaction of the Soci-ety as an equivalent to the calculation in [3.2.3]. When suchalternative tests are carried out, reference sahll be madebased on the Interim Guidelines for alternative assessmentof the weather criterion (IMO MSC.1/Circ.1200). the windvelocity used in the tests shall be 26 m/s in full scale withuniform velocity profile. the value of wind velocity used forships in restricted services may be reduced to the satisfac-tion of the Society.

4 Effects of free surfaces of liquids in tanks

4.1 General

4.1.1 For all loading conditions, the initial metacentricheight and the righting lever curve are to be corrected forthe effect of free surfaces of liquids in tanks.

4.2 Consideration of free surface effects

4.2.1 Free surface effects are to be considered wheneverthe filling level in a tank is less than 98% of full condition.Free surface effects need not be considered where a tank isnominally full, i.e. filling level is 98% or above. Free surfaceeffects for small tanks may be ignored under the conditionin [4.8.1].

4.2.2 Nominally full cargo tanks should be corrected forfree surface effects at 98% filling level. In doing so, the cor-rection to initial metacentric height should be based on theinertia moment of liquid surface at 5 of the heeling angledivided by displacement, and the correction to rightinglever is suggested to be on the basis of real shifting momentof cargo liquids.

4.3 Categories of tanks

4.3.1 Tanks which are taken into consideration when deter-mining the free surface correction may be one of two cate-gories:

• tanks with fixed filling level (e.g. liquid cargo, water bal-last). The free surface correction is to be defined for theactual filling level to be used in each tank.

• tanks with variable filling level (e.g. consumable liquidssuch as fuel oil, diesel oil, and fresh water, and also liq-uid cargo and water ballast during liquid transfer opera-tions). Except as permitted in [4.5.1] and [4.6.1], the freesurface correction is to be the maximum value attaina-ble among the filling limits envisaged for each tank, con-sistent with any operating instructions.

4.4 Consumable liquids

4.4.1 In calculating the free surfaces effect in tanks contain-ing consumable liquids, it is to be assumed that for eachtype of liquid at least one transverse pair or a single cen-treline tank has a free surface and the tank or combinationof tanks taken into account are to be those where the effectof free surface is the greatest.

4.5 Water ballast tanks

4.5.1 Where water ballast tanks, including anti-rolling tanksand anti-heeling tanks, are to be filled or discharged duringthe course of a voyage, the free surfaces effect is to be cal-culated to take account of the most onerous transitory stagerelating to such operations.

4.6 Liquid transfer operations

4.6.1 For ships engaged in liquid transfer operations, thefree surface corrections at any stage of the liquid transferoperations may be determined in accordance with the fillinglevel in each tank at the stage of the transfer operation.

4.7 GM0 and GZ curve corrections

4.7.1 The corrections to the initial metacentric height andto the righting lever curve are to be addressed separately asindicated in [4.7.2] and [4.7.3].

4.7.2 In determining the correction to the initial metacen-tric height, the transverse moments of inertia of the tanksare to be calculated at 0 degrees angle of heel according tothe categories indicated in [4.3.1].

4.7.3 The righting lever curve may be corrected by any ofthe following methods:

• correction based on the actual moment of fluid transferfor each angle of heel calculated; corrections may becalculated according to the categories indicated in[4.3.1]

• correction based on the moment of inertia, calculated at0 degrees angle of heel, modified at each angle of heelcalculated; corrections may be calculated according tothe categories indicated in [4.3.1].

4.7.4 Whichever method is selected for correcting the right-ing lever curve, only that method is to be presented in theship’s trim and stability booklet. However, where an alterna-tive method is described for use in manually calculatedloading conditions, an explanation of the differences whichmay be found in the results, as well as an example correc-tion for each alternative, are to be included.

Pt B, Ch 3, Sec 2


4.8 Small tanks

4.8.1 Small tanks which satisfy the following conditionusing the values of k corresponding to an angle of inclina-tion of 30° need not be included in the correction:

where:

min : Minimum ship displacement, in t, calculated atdmin

dmin : Minimum mean service draught, in m, of shipwithout cargo, with 10% stores and minimumwater ballast, if required.

4.9 Remainder of liquid

4.9.1 The usual remainder of liquids in the empty tanksneed not be taken into account in calculating the correc-tions, providing the total of such residual liquids does notconstitute a significant free surface effect.

5 Cargo ships carrying timber deck cargoes

5.1 Application

5.1.1 The provisions given hereunder apply to shipsengaged in the carriage of timber deck cargoes. Ships thatare provided with and make use of their timber load line arealso to comply with the requirements of regulations 41 to45 of the International Load Line Convention 1966, asamended.

5.2 Definitions

5.2.1 Timber

Timber means sawn wood or lumber, cants, logs, poles,pulpwood and all other types of timber in loose or pack-aged forms. The term does not include wood pulp or similarcargo.

5.2.2 Timber deck cargo

Timber deck cargo means a cargo of timber carried on anuncovered part of a freeboard or superstructure deck. Theterm does not include wood pulp or similar cargo.

5.2.3 Timber load line

Timber load line means a special load line assigned to shipscomplying with certain conditions related to their construc-tion set out in the International Convention on Load Lines1966, as amended, and used when the cargo complies withthe stowage and securing conditions of the Code of SafePractice for Ships Carrying Timber Deck Cargoes, 1991(Resolution A.715(17)).

5.3 Stability criteria

5.3.1 For ships loaded with timber deck cargoes and pro-vided that the cargo extends longitudinally between super-structures (where there is no limiting superstructure at theafter end, the timber deck cargo is to extend at least to theafter end of the aftermost hatchway) and transversely forthe full beam of ship after due allowance for a rounded gun-wale not exceeding 4% of the breadth of the ship and/orsecuring the supporting uprights and which remainssecurely fixed at large angles of heel, the Society may applythe criteria given in [5.3.2] to [5.3.5], which substitutethose given in [2.1.2], [2.1.3], [2.1.4] and [2.1.5] and in[3.2].

5.3.2 The area under the righting lever curve (GZ curve) isto be not less than 0,08 m.rad up to = 40° or the angle offlooding if this angle is less than 40°.

5.3.3 The maximum value of the righting lever (GZ) is to beat least 0,25 m.

5.3.4 At all times during a voyage, the metacentric heightGM0 is to be not less than 0,10 m after correction for thefree surface effects of liquid in tanks and, where appropri-ate, the absorption of water by the deck cargo and/or iceaccretion on the exposed surfaces. (Details regarding iceaccretion are given in [6]). Additionally, in the departurecondition the metacentric height is to be not less than0,10 m.

5.3.5 When determining the ability of the ship to withstandthe combined effect of beam wind and rolling according to[3.2], the 16° limiting angle of heel under action of steadywind is to be complied with, but the additional criterion of80% of the angle of deck edge immersion may be ignored.

5.4 Stability booklet

5.4.1 The ship is to be supplied with comprehensive stabil-ity information which takes into account timber deck cargo.Such information is to enable the Master, rapidly and sim-ply, to obtain accurate guidance as to the stability of theship under varying conditions of service. Comprehensiverolling period tables or diagrams have proved to be veryuseful aids in verifying the actual stability conditions.

5.4.2 For ships carrying timber deck cargoes, the Societymay deem it necessary that the Master be given informationsetting out the changes in deck cargo from that shown inthe loading conditions, when the permeability of the deckcargo is significantly different from 25% (see [5.5.1]).

5.4.3 For ships carrying timber deck cargoes, conditionsare to be shown indicating the maximum permissibleamount of deck cargo having regard to the lightest stowagerate likely to be met in service.

Mfs min 0 01 m,

Pt B, Ch 3, Sec 2


5.5 Calculation of the stability curve

5.5.1 In addition to the provisions given in Ch 3, App 2,[1.3], the Society may allow account to be taken of thebuoyancy of the deck cargo assuming that such cargo has apermeability of 25% of the volume occupied by the cargo.Additional curves of stability may be required if the Societyconsiders it necessary to investigate the influence of differ-ent permeabilities and/or assumed effective height of thedeck cargo.

5.6 Loading conditions to be considered

5.6.1 The loading conditions which are to be consideredfor ships carrying timber deck cargoes are specified in Ch 3,App 2, [1.2.2]. For the purpose of these loading conditions,the ship is assumed to be loaded to the summer timber loadline with water ballast tanks empty.

5.7 Assumptions for calculating loading conditions

5.7.1 The following assumptions are to be made for calcu-lating the loading conditions referred to in Ch 3, App 2,[1.2.2]:

• the amount of cargo and ballast is to correspond to theworst service condition in which all the relevant stabilitycriteria reported in [2.1.2], [2.1.3], [2.1.4] and [2.1.5], orthe optional criteria given in [5.3], are met

• in the arrival condition, it is to be assumed that theweight of the deck cargo has increased by 10% due towater absorption.

5.7.2 The stability of the ship at all times, including duringthe process of loading and unloading timber deck cargo, isto be positive and in compliance with the stability criteria of[5.3]. It is to be calculated having regard to:

• the increased weight of the timber deck cargo due to:

- absorption of water in dried or seasoned timber, and

- ice accretion, if applicable (as reported in [6])

• variations in consumable

• the free surface effect of liquid in tanks, and

• the weight of water trapped in broken spaces within thetimber deck cargo and especially logs.

5.7.3 Excessive initial stability is to be avoided as it willresult in rapid and violent motion in heavy seas which willimpose large sliding and racking forces on the cargo causinghigh stresses on the lashings. Unless otherwise stated in thestability booklet, the metacentric height is generally not toexceed 3% of the breadth in order to prevent excessiveacceleration in rolling provided that the relevant stability cri-teria given in [5.3] are satisfied.

5.8 Stowage of timber deck cargoes

5.8.1 The stowage of timber deck cargoes is to comply withthe provisions of chapter 3 of the Code of Safe Practice forShips Carrying Timber Deck Cargoes, 1991 (resolutionA.715(17)).

6 Icing

6.1 Application

6.1.1 For any ship having an ice class notation or operatingin areas where ice accretion is likely to occur, adverselyaffecting a ship's stability, icing allowances are to beincluded in the analysis of conditions of loading.

6.2 Ships carrying timber deck cargoes

6.2.1 The Master is to establish or verify the stability of hisship for the worst service condition, having regard to theincreased weight of deck cargo due to water absorptionand/or ice accretion and to variations in consumable.

6.2.2 When timber deck cargoes are carried and it is antici-pated that some formation of ice will take place, an allow-ance is to be made in the arrival condition for the additionalweight.

6.3 Calculation assumptions

6.3.1 For ships operating in areas where ice accretion islikely to occur, the following icing allowance is to be madein the stability calculations:• 30 kg per square metre on exposed weather decks and

gangways• 7,5 kg per square metre for the projected lateral area of

each side of the ship above the water plane• the projected lateral area of discontinuous surfaces of

rail, sundry booms, spars (except masts) and rigging ofships having no sails and the projected lateral area ofother small objects are to be computed by increasingthe total projected area of continuous surfaces by 5%and the static moments of this area by 10%.

6.3.2 Ships intended for operation in areas where ice isknown to occur are to be:• designed to minimise the accretion of ice, and• equipped with such means for removing ice as, for

example, electrical and pneumatic devices, and/or spe-cial tools such as axes or wooden clubs for removing icefrom bulwarks, rails and erections.

6.4 Guidance relating to ice accretion

6.4.1 The following icing areas are to be considered:

a) the area north of latitude 65°30'N, between longitude28°W and the west coast of Iceland; north of the northcoast of Iceland; north of the rhumb line running fromlatitude 66°N, longitude 15°W to latitude 73°30'N, lon-gitude 15°E, north of latitude 73°30'N between longi-tude 15°E and 35°E, and east of longitude 35°E, as wellas north of latitude 56°N in the Baltic Sea

b) the area north of latitude 43°N bounded in the west bythe North American coast and the east by the rhumbline running from latitude 43°N, longitude 48°W to lati-tude 63°N, longitude 28°W and thence along longitude28°W

Pt B, Ch 3, Sec 2


c) all sea areas north of the North American Continent,west of the areas defined in a) and b)

d) the Bering and Okhotsk Seas and the Tartary Strait dur-ing the icing season, and

e) south of latitude 60°S.

6.4.2 For ships operating where ice accretion may beexpected:

• within the areas defined in a), c), d) and e) of [6.4.1]known to having icing conditions significantly differentfrom those described in [6.3], ice accretion require-ments of one half to twice the required allowance maybe applied

• within the area defined in b), where ice accretion inexcess of twice the allowance required by [6.3] may beexpected, more severe requirements than those given in[6.3] may be applied.

Pt B, Ch 3, Sec 3


SECTION 3 DAMAGE STABILITY

1 Application

1.1 Ships for which damage stability is required

1.1.1 Damage stability calculation is required for ships which have been requested to receive SDS notation.

2 General

2.1 Approaches to be followed for damage stability investigation

2.1.1 GeneralDamage stability calculations are required in order to assess the attitude and stability of the ship after flooding.

In order to assess the behaviour of the ship after damage, two approaches have been developed: the deterministic and the probabilistic, which are to be applied depending on the ship type as specified in Part D.

The metacentric heights (GM), stability levers (GZ) and cen-tre of gravity positions for judging the final conditions are to be calculated by the constant displacement (lost buoyancy) method.

2.1.2 Deterministic approachThe deterministic approach is based on standard dimen-sions of damage extending anywhere along the ship’s length or between transverse bulkheads depending on the relevant requirements.

The consequence of such standard of damage is the crea-tion of a group of damage cases, the number of which, as well as the number of compartments involved in each case, depend on the ship’s dimensions and internal subdivision.

For each loading condition, each damage case is to be con-sidered, and the applicable criteria are to be complied with.

Different deterministic methods in damage stability have been developed depending on ship type, on freeboard reduction, and on the kind of cargo carried.

The deterministic methods to be applied for passenger ships, oil tankers, chemical tankers, gas carriers and special purpose ships are reported in the relevant chapters of Part D.

The deterministic methods to be applied in the case of free-board reduction are specified in Ch 3, App 4.

2.1.3 Probabilistic ApproachThe probabilistic concept takes the probability of survival after collision as a measure of ship safety in the damaged condition, referred to as the attained subdivision index A.

The damage stability calculations are performed for a lim-ited number of draughts and relevant GM values in order to

draw a minimum GM curve where the attained subdivision index A achieves the minimum required level of safety R. For cargo ships, each case of damage is not required to comply with the applicable criteria, but the attained index A, which is the sum of the contribution of all damage cases, is to be equal to or greater than R.

The probabilistic method developed on the basis of the above-mentioned concepts is detailed in Ch 3, App 3.

As a general rule, the probabilistic method applies to cargo ships of a length not less than 80 m, and for which no deter-ministic methods apply; the application of the probabilistic damage stability investigation is specified in the relevant chapters of Part D.

3 Documents to be submitted

3.1 Damage stability calculations

3.1.1 Damage stability documentationFor all ships to which damage stability requirements apply, documents including damage stability calculations are to be submitted.

The damage stability calculations are to include:

• list of the characteristics (volume, centre of gravity, per-meability) of each compartment which can be damaged

• a table of openings in bulkheads, decks and side shell reporting all the information about:

- identification of the opening

- vertical, transverse and horizontal location

- type of closure: sliding, hinged or rolling for doors

- type of tightness: watertight, weathertight, semi-watertight or unprotected

- operating system: remote control, local operation, indicators on the bridge, television surveillance, water leakage detection, audible alarm, as applica-ble

- foreseen utilization: open at sea, normally closed at sea, kept closed at sea

• list of all damage cases corresponding to the applicable requirements

• detailed results of damage stability calculations for all the loading conditions foreseen in the applicable requirements

• the limiting GM/KG curve, if foreseen in the applicable requirements

• capacity plan

• cross and down flooding devices and the calculations thereof according to Pt D, Ch 11, App 1 with informa-tions about diameter, valves, pipe lengths and coordi-nates of inlet/outlet

Pt B, Ch 3, Sec 3


• watertight and weathertight door plan with pressure cal-culation

• side contour and wind profile

• pipes and damaged area when the destruction of these pipes results in progressive flooding.

3.1.2 Additional information for the probabilistic approach

In addition to the information listed in [3.1.1], the following is to be provided:

• subdivision length LS

• initial draughts and the corresponding GM-values

• required subdivision index R

• attained subdivision index A with a summary table for all contributions for all damaged zones.

• draught, trim, GM in damaged condition

• damage extension and definition of damage cases with probabilistic values p, v and r

• righting lever curve (including GZmax and range) with factor of survivability s

• critical weathertight and unprotected openings with their angle of immersion

• details of sub-compartments with amount of in-flooded water/lost buoyancy with their centres of gravity.

3.1.3 Loading instrument

As a supplement to the approved damage stability docu-mentation, a loading instrument, approved by the Society, may be used to facilitate the damage stability calculations mentioned in [3.1.1].

The procedure to be followed, as well as the list of technical details to be sent in order to obtain loading instrument approval, are given in Ch 11, Sec 2, [4.6].

3.2 Permeabilities

3.2.1 Definition

The permeability of a space means the ratio of the volume within that space which is assumed to be occupied by water to the total volume of that space.

3.2.2 General

The permeabilities relevant to the type of spaces which can be flooded depend on the applicable requirements. Such permeabilities are indicated in Part D for each type of ship.

3.3 Progressive flooding

3.3.1 Definition

Progressive flooding is the additional flooding of spaces which were not previously assumed to be damaged. Such additional flooding may occur through openings or pipes as indicated in [3.3.2] and [3.3.3].

3.3.2 Openings

The openings may be listed in the following categories, depending on their means of closure:

• Unprotected

Unprotected openings may lead to progressive flooding if they are situated within the range of the positive right-ing lever curve or if they are located below the water-line after damage (at any stage of flooding). Unprotected openings are openings which are not fitted with at least weathertight means of closure.

• Weathertight

Openings fitted with weathertight means of closure are not able to sustain a constant head of water, but they can be intermittently immersed within the positive range of stability.

Weathertight openings may lead to progressive flooding if they are located below the waterline after damage (at any stage of flooding).

• Semi-watertight

Internal openings fitted with semi-watertight means of closure are able to sustain a constant head of water cor-responding to the immersion relevant to the highest waterline after damage at the equilibrium of the inter-mediate stages of flooding.

Semi-watertight openings may lead to progressive flood-ing if they are located below the final equilibrium waterline after damage.

• Watertight

Internal openings fitted with watertight means of closure are able to sustain a constant head of water correspond-ing to the distance between the lowest edge of this opening and the bulkhead/freeboard deck.

Air pipe closing devices complying with Pt C, Ch 1, Sec 10, [9.1.6] may not be considered watertight, unless additional arrangements are fitted in order to demon-strate that such closing devices are effectively water-tight.

The pressure/vacuum valves (PV valves) currently installed on tankers do not theoretically provide com-plete watertightness.

Manhole covers may be considered watertight provided the cover is fitted with bolts located such that the dis-tance between their axes is less than five times the bolt’s diameter.

Access hatch covers leading to tanks may be considered watertight.

Watertight openings do not lead to progressive flooding.

3.3.3 Pipes

Progressive flooding through pipes may occur when:

• the pipes and connected valves are located within the assumed damage, and no valves are fitted outside the damage

Pt B, Ch 3, Sec 3


• the pipes, even if located outside the damage, satisfy all of the following conditions:

- the pipe connects a damaged space to one or more spaces located outside the damage

- the highest vertical position of the pipe is below the waterline, and

- no valves are fitted.

The possibility of progressive flooding through ballast piping passing through the assumed extent of damage, where posi-tive action valves are not fitted to the ballast system at the open ends of the pipes in the tanks served, is to be consid-ered. Where remote control systems are fitted to ballast valves and these controls pass through the assumed extent of damage, then the effect of damage to the system is to be considered to ensure that the valves would remain closed in that event.

If pipes, ducts or tunnels are situated within assumed flooded compartments, arrangements are to be made to ensure that progressive flooding cannot thereby extend to compartments other than those assumed flooded. However, the Society may permit minor progressive flooding if it is demonstrated that the additional flooding of those compart-ments cannot lead to the capsizing or the sinking of the ship.

Requirements relative to the prevention of progressive flooding are specified in Pt C, Ch 1, Sec 10, [5.5].

3.4 Bottom damages

3.4.1 GeneralShips wich are not fitted with a double bottom as required by Ch 2, Sec 2, [3.1.2] or which are fitted with unusual bot-tom arrangments as defined in Ch 2, Sec 2, [3.1.6], are to comply with [3.4.2] and [3.4.3].

3.4.2 Bottom damage descriptionThe assumed extent of damage is described inTab 1.

If any damage of a lesser extent than the maximum damage specified inTab 1 would result in a more severe condition, such damage should be considered.

3.4.3 Stability criteriaCompliance with the requirements of Ch 2, Sec 2, [3.1.5] orCh 2, Sec 2, [3.1.6] is to be achieved by demonstrating that si when calculated in accordance with Ch 3, App 3, [1.6] is not less than 1 for all service conditions when subject to a bottom damage assumed at any position along the ship’s bottom and with an extent specified in [3.4.2] for the affected part of the ship.

Flooding of such spaces shall not render emergency power and lighting, internal communication, signals or other emer-gency devices inoperable in other parts of the ship

4 Damage control documentation

4.1 General

4.1.1 Application

The damage control documentation is to include a damage control plan which is intended to provide ship’s officers with clear information on the ship’s watertight compartmen-tation and equipment related to maintaining the boundaries and effectiveness of the compartmentation so that, in the event of damage causing flooding, proper precautions can be taken to prevent progressive flooding through openings therein and effective action can be taken quickly to mitigate and, where possible, recover the ship’s loss of stability.

The damage control documentation is to be clear and easy to understand. It is not to include information which is not directly relevant to damage control, and is to be provided in the language or languages of the ship’s officers. If the lan-guages used in the preparation of the documentation are not English or French, a translation into one of these lan-guages is to be included.

The use of a loading instrument performing damage stability calculations may be accepted as a supplement to the dam-age control documentation. This instrument is to be approved by the Society according to the requirements ofCh 11, Sec 2, [4.7].

The damage control plan is required for the following ships:

• Ships carrying passengers

• Dry cargo ships corresponding to:

- Part D, Chapter 1

- Part D, Chapter 2

- Part D, Chapter 3

- Part D, Chapter 4

- Part D, Chapter 5

- Part D, Chapter 6

- Part D, Chapter 18

Note 1: Dry cargo ship is intended to mean a cargo ship which has not been designed to carry liquid cargo in bulk; furthermore, the following ship types are not to be considered as dry cargo ships:

• tugs, as defined in Part D, Chapter 14

• supply vessels, as defined in Part D, Chapter 15

• fire-fighting ships, as defined in Part D, Chapter 16

• oil recovery ships, as defined in Part D, Chapter 17.

Table 1 : Assumed extent of damage

For 0.3 L from the forward perpendicular of the ship

Any other part of the ship

Longitudinal extent 1/3 L2/3 or 14.5 m, whichever is less 1/3 L2/3 or 14.5 m, whichever is less

Transverse extent B/6 or 10 m, whichever is less B/6 or 5 m, whichever is less

Vertical extent, measured from the keel line B/20 or 2 m, whichever is less B/20 or 2 m, whichever is less

Pt B, Ch 3, Sec 3


5 Specific interpretations

5.1 Assumed damage penetration in way of sponsons

5.1.1 If sponsons are fitted, it is necessary to establish the maximum assumed damage penetration (B/5) to be used when deciding on the various damage cases. For this pur-pose, the breadth B in the way of such sponsons is to be measured to the outside of the sponsons.

Clear of any suck sponsons, the breadth B is to be the mid-ship breadth measured to the outside of the original shell. In other words, the assumed penetration of B/5 is the same as that which applied before the fitting of sponsons.

5.2 Effect of progressive flooding on the GZ curve

5.2.1 When major progressive flooding occurs, that is when it causes a rapid reduction in the righting lever of 0,04 m or more, the righting lever curve is to be considered as termi-nated at the angle the progressive flooding occurs and the range and the area are to be measured to that angle, as shown in Fig 1.

5.2.2 In the case where the progressive flooding is of lim-ited nature that does not continue unabated and causes an acceptably slow reduction in righting lever of less than 0,04 m, the remainder of the curve is to be partially truncated by assuming that the progressively flooded space is so flooded from the beginning, as shown in Fig 2.

Figure 1 : Major progressive flooding

Figure 2 : Progressive flooding of limited nature

righting arms

�0.

04m

heeling angles��

heeling angles

righting arms

< 0

.04

m

Pt B, Ch 3, App 1


APPENDIX 1 INCLINING TEST AND LIGHTWEIGHT CHECK

1 Inclining test and lightweight check

1.1 General

1.1.1 General conditions of the ship

The following conditions are to be met, as far as praticable :

• the weather conditions are to be favourable

• the ship should be moored in a quiet, sheltered area freefrom extraneous forces such as propeller wash frompassing vessels, or sudden discharges from shore sidepumps. The tide conditions and the trim of the ship dur-ing the test should be considered. Prior to the test, thedepth of water should be measured and recorded in asmany locations as are necessary to ensure that the shipwill not contact the bottom. The specific gravity of watershould be accurately recorded. The ship should bemoored in a manner to allow unrestricted heeling. Theaccess ramps should be removed. Power lines, hoses,etc., connected to shore should be at a minimum,andkept slack at all times

• the ship should be as upright as possible; with incliningweights in the initial position, up to one-half degree oflist is acceptable. The actual trim and deflection of keel,if practical, should be considered in the hydrostaticdata. In order to avoid excessive errors caused by signif-icant changes in the water plane area during heeling,hydrostatic data for the actual trim and the maximumanticipated heeling angles should be checked before-hand

• cranes, derrick, lifeboats and liferafts capable of induc-ing oscillations are to be secured

• main and auxiliary boilers, pipes and any other systemcontaining liquids are to be filled

• the bilge and the decks are to be thoroughly dried

• the anticipated liquid loading for the test should beincluded in the planning for the test. Preferably, all tanksshould be empty and clean, or completely full. Thenumber of slack tanks should be kept to an absoluteminimum. The viscosity of the fluid, the depth of thefluid and the shape of the tank should be such that thefree surface effect can be accurately determined

• the weights necessary for the inclination are to bealready on board, located in the correct place

• all work on board is to be suspended and crew or per-sonnel not directly involved in the incline test are toleave the ship

• the ship is to be as complete as possible at the time ofthe test. The number of weights to be removed, addedor shifted is to be limited to a minimum. Temporarymaterial, tool boxes, staging, sand, debris, etc., onboard is to be reduced to an absolute minimum.

• Decks should be free of water. Water trapped on deckmay shift and pocket in a fashion similar to liquids in atank. Any rain, snow or ice accumulated on the shipshould be removed prior to the test.

1.1.2 Inclining weightsThe total weight used is preferably to be sufficient to pro-vide a minimum inclination of one degree and a maximumof four degrees of heel to each side. The Society may, how-ever, accept a smaller inclination angle for large ships pro-vided that the requirement on pendulum deflection or U-tube difference in height specified in [1.1.4] is compliedwith. Test weights are to be compact and of such a configu-ration that the VCG (vertical centre of gravity) of theweights can be accurately determined. Each weight is to bemarked with an identification number and its weight. Re-certification of the test weights is to be carried out prior tothe incline. A crane of sufficient capacity and reach, orsome other means, is to be available during the inclining testto shift weights on the deck in an expeditious and safe man-ner. Water ballast transfer may be carried out, when it isimpractical to incline using solid weights and subject torequirement of [1.1.3].Weights, such as porous concrete, that can absorb signifi-cant amounts of moisture should only be used if they areweighed just prior to the inclining test or if recent weightcertificates are presented. Each weight should be markedwith an identification number and its weight. For smallships, drums completely filled with water may be used.Drums should normally be full and capped to allow accu-rate weight control. In such cases, the weight of the drumsshould be verified in the presence of a surveyor of the Soci-ety using a recently calibrated scale.Precautions should be taken to ensure that the decks arenot overloaded during weight movements. If deck strengthis questionable then a structural analysis should be per-formed to determine if existing framing can support theweight.Generally, the test weights should be positioned as far out-board as possible on the upper deck. The test weightsshould be on board and in place prior to the scheduled timeof the inclining test.

1.1.3 Water ballast as inclining weightWhere the use of solid weights to produce the incliningmoment is deemed to be impracticable, the movement ofballast water may be permitted as an alternative method.This acceptance would be granted for a specific test only,and approval of the test procedure by the Society isrequired. As a minimal prerequisite for acceptability, thefollowing conditions are to be required:• inclining tanks are to be wall-sided and free of large

stringers or other internal members that create air pockets

Pt B, Ch 3, App 1


• tanks are to be directly opposite to maintain ship’s trim• specific gravity of ballast water is to be measured and

recorded• pipelines to inclining tanks are to be full. If the ship’s

piping layout is unsuitable for internal transfer, portablepumps and pipes/hoses may be used

• blanks must be inserted in transverse manifolds to pre-vent the possibility of liquids being “leaked” duringtransfer. Continuous valve control must be maintainedduring the test

• all inclining tanks must be manually sounded beforeand after each shift

• vertical, longitudinal and transverse centres are to becalculated for each movement

• accurate sounding/ullage tables are to be provided. Theship’s initial heel angle is to be established prior to theincline in order to produce accurate values for volumesand transverse and vertical centres of gravity for theinclining tanks at every angle of heel. The draught marksamidships (port and starboard) are to be used whenestablishing the initial heel angle

• verification of the quantity shifted may be achieved by aflowmeter or similar device

• the time to conduct the inclining is to be evaluated. Iftime requirements for transfer of liquids are consideredtoo long, water may be unacceptable because of thepossibility of wind shifts over long periods of time.

1.1.4 PendulumsThe use of three pendulums is recommended but a mini-mum of two are to be used to allow identification of badreadings at any one pendulum station. However, for ships ofa length equal to or less than 30 m, only one pendulum canbe accepted. They are each to be located in an area pro-tected from the wind. The pendulums are to be longenough to give a measured deflection, to each side ofupright, of at least 15 cm. To ensure recordings from indi-vidual instruments are kept separate, it is suggested that thependulums be physically located as far apart as practical.The use of an inclinometer or U-tube is to be considered ineach separate case. It is recommended that inclinometers orother measuring devices only be used in conjunction with atleast one pendulum.

1.1.5 Free surface and slack tanksThe number of slack tanks should normally be limited toone port/starboard pair or one centreline tank of the follow-ing:• fresh water reserve feed tanks• fuel/diesel oil storage tanks• fuel/diesel oil day tanks• lube oil tanks• sanitary tanks• potable water tanks.

To avoid pocketing, slack tanks are normally to be of regular(i.e. rectangular, trapezoidal, etc.) cross section and be20% to 80% full if they are deep tanks and 40% to 60%full if they are double-bottom tanks. These levels ensure thatthe rate of shifting of liquid remains constant throughout the

heel angles of the inclining test. If the trim changes as theship is inclined, then consideration are also to be given tolongitudinal pocketing. Slack tanks containing liquids of suf-ficient viscosity to prevent free movement of the liquids, asthe ship is inclined (such as bunker at low temperature), areto be avoided since the free surface cannot be calculatedaccurately. A free surface correction for such tanks is not tobe used unless the tanks are heated to reduce viscosity.Communication between tanks are never to be allowed.Cross-connections, including those via manifolds, are to beclosed. Equal liquid levels in slack tank pairs can be a warn-ing sign of open cross connections. A bilge, ballast, and fueloil piping plan can be referred to, when checking for crossconnection closures.

1.1.6 Means of communicationsEfficient two-way communications are to be providedbetween central control and the weight handlers andbetween central control and each pendulum station. Oneperson at a central control station is to have complete con-trol over all personnel involved in the test.

1.1.7 DocumentationThe person in charge of the inclining test is to have availablea copy of the following plans at the time of the test:• lines plan• hydrostatic curves or hydrostatic data• general arrangement plan of decks, holds, inner bot-

toms, etc...• capacity plan showing capacities and vertical and longi-

tudinal centres of gravity of cargo spaces, tanks, etc.When water ballast is used as inclining weights, thetransverse and vertical centres of gravity for the applica-ble tanks, for each angle of inclination, must be available

• tank sounding tables• draught mark locations, and• docking drawing with keel profile and draught mark cor-

rections (if available).

1.1.8 Determination of the displacement The operations necessary for the accurate evaluation of thedisplacement of the ship at the time of the inclining test, aslisted below, are to be carried out:• draught mark readings are to be taken at aft, midship

and forward, at starboard and port sides• the mean draught (average of port and starboard read-

ing) is to be calculated for each of the locations wheredraught readings are taken and plotted on the ship'slines drawing or outboard profile to ensure that all read-ings are consistent and together define the correctwaterline. The resulting plot is to yield either a straightline or a waterline which is either hogged or sagged. Ifinconsistent readings are obtained, the freeboards/draughts are to be retaken

• the specific gravity of the sea water is to be determined.Samples are to be taken from a sufficient depth of thewater to ensure a true representation of the sea waterand not merely surface water, which could contain freshwater from run off of rain. A hydrometer is to be placedin a water sample and the specific gravity read andrecorded. For large ships, it is recommended that sam-

Pt B, Ch 3, App 1


ples of the sea water be taken forward, midship and aft,and the readings averaged. For small ships, one sampletaken from midship is sufficient. The temperature of thewater is to be taken and the measured specific gravitycorrected for deviation from the standard, if necessary.A correction to water specific gravity is not necessary ifthe specific gravity is determined at the inclining experi-ment site. Correction is necessary if specific gravity ismeasured when the sample temperature differs from thetemperature at the time of the inclining (e.g., if thecheck of specific gravity is performed at the office).Where the value of the average calculated specific grav-ity is different from that reported in the hydrostaticcurves, adequate corrections are to be made to the dis-placement curve

• all double bottoms, as well as all tanks and compart-ments which can contain liquids, are to be checked,paying particular attention to air pockets which mayaccumulate due to the ship’s trim and the position of airpipes, and also taking into account the provisions of[1.1.1]

• it is to be checked that the bilge is dry, and an evalua-tion of the liquids which cannot be pumped, remainingin the pipes, boilers, condenser, etc., is to be carried out

• the entire ship is to be surveyed in order to identify allitems which need to be added, removed or relocated tobring the ship to the lightship condition. Each item is tobe clearly identified by weight and location of the cen-tre of gravity

• the possible solid permanent ballast is to be clearlyidentified and listed in the report.

• normally , the total value of missing weights is not toexceed 2% and surplus weights, excluding liquid bal-last, not exceed 4% of the lightship displacement. Forsmaller vessels, higher percentages may be allowed.

1.1.9 The inclineThe standard test generally employs eight distinct weightmovements as shown in Fig 1.

Movement No.8, a recheck of the zero point, may be omit-ted if a straight line plot is achieved after movement No.7. Ifa straight line plot is achieved after the initial zero and sixweight movements, the inclining test is complete and thesecond check at zero may be omitted. If a straight line plotis not achieved, those weight movements that did not yieldacceptable plotted points should be repeated or explained.

The weights are to be transversally shifted, so as not to mod-ify the ship’s trim and vertical position of the centre of grav-ity.

After each weight shifting, the new position of the trans-verse centre of gravity of the weights is to be accuratelydetermined.

After each weight movement, the distance the weight wasmoved (centre to centre) is to be measured and the heelingmoment calculated by multiplying the distance by theamount of weight moved. The tangent is calculated for each

pendulum by dividing the deflection by the length of thependulum. The resultant tangents are plotted on the graphas shown in Fig 2.

The plot is to be run during the test to ensure that accept-able data are being obtained.

The pendulum deflection is to be read when the ship hasreached a final position after each weight shifting.

During the reading, no movements of personnel areallowed.

For ships with a length equal to or less than 30 m, six dis-tinct weight movements may be accepted.

Figure 1 : Weight shift procedure

Figure 2 : Graph of resultant tangents

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APPENDIX 2 TRIM AND STABILITY BOOKLET

1 Trim and stability booklet

1.1 Information to be included in the trim and stability booklet

1.1.1 GeneralA trim and stability booklet is a stability manual, to be approved by the Society, which is to contain information to enable the Master to operate the ship in compliance with the applicable requirements contained in the Rules.

The format of the stability booklet and the information included vary depending on the ship type and operation.

1.1.2 List of informationThe following information is to be included in the trim and stability booklet:• a general description of the ship, including:

- the ship’s name and the Society classification number

- the ship type and service notation - the class notations - the yard, the hull number and the year of delivery - the Flag, the port of registry, the international call

sign and the IMO number- the moulded dimensions- the draught corresponding to the assigned summer

load line, the draught corresponding to the assigned summer timber load line and the draught corre-sponding to the tropical load line, if applicable

- the displacement corresponding to the above- men-tioned draughts

• instructions on the use of the booklet• general arrangement and capacity plans indicating the

assigned use of compartments and spaces (cargo, pas-senger, stores, accommodation, etc.)

• a sketch indicating the position of the draught marks referred to the ship’s perpendiculars

• hydrostatic curves or tables corresponding to the design trim, and, if significant trim angles are foreseen during the normal operation of the ship, curves or tables corre-sponding to such range of trim are to be introduced. A reference relevant to the sea density, in t/m3, is to be included as well as the draught measure (from keel or underkeel)

• cross curves (or tables) of stability calculated on a free trimming basis, for the ranges of displacement and trim anticipated in normal operating conditions, with indica-tion of the volumes which have been considered in the computation of these curves

• tank sounding tables or curves showing capacities, cen-tres of gravity, and free surface data for each tank

• lightship data from the inclining test, as indicated in Ch 3, Sec 1, [2.2], including lightship displacement, centre of gravity co-ordinates, place and date of the inclining test, as well as the Society approval details specified in the inclining test report. It is suggested that a copy of the approved test report be included

Where the above-mentioned information is derived from a sister ship, the reference to this sister ship is to be indicated, and a copy of the approved inclining test report relevant to this sister ship is to be included

• standard loading conditions as indicated in [1.2] and examples for developing other acceptable loading con-ditions using the information contained in the booklet

• intact stability results (total displacement and its centre of gravity co-ordinates, draughts at perpendiculars, GM, GM corrected for free surfaces effect, GZ values and curve, criteria as indicated in Ch 3, Sec 2, [2] and Ch 3, Sec 2, [3] as well as possible additional criteria speci-fied in Part D when applicable, reporting a comparison between the actual and the required values) are to be available for each of the above-mentioned operating conditions. The method and assumptions to be followed in the stability curve calculation are specified in [1.3]

• information on loading restrictions (maximum allowa-ble load on double bottom, maximum specific gravity allowed in liquid cargo tanks, maximum filling level or percentage in liquid cargo tanks, maximum KG or mini-mum GM curve or table which can be used to deter-mine compliance with the applicable intact and damage stability criteria) when applicable

• information about openings (location, tightness, means of closure), pipes or other progressive flooding sources

• information concerning the use of any special cross-flooding fittings with descriptions of damage conditions which may require cross-flooding, when applicable

• any other guidance deemed appropriate for the opera-tion of the ship

• a table of contents and index for each booklet.

1.2 Loading conditions

1.2.1 General

The standard loading conditions to be included in the trim and stability booklet are:

• lightship condition

• ship in ballast in the departure condition, without cargo but with full stores and fuel

• ship in ballast in the arrival condition, without cargo and with 10% stores and fuel remaining.

Pt B, Ch 3, App 2


Further loading cases may be included when deemed nec-essary or useful.

When a tropical freeboard is to be assigned to the ship, the corresponding loading conditions are also to be included.

1.2.2 Ships carrying cargo on deck

In addition to the loading conditions indicated in [1.2.1] to[1.2.13], in the case of cargo carried on deck the following cases are to be considered:

• ship in the fully loaded departure condition having cargo homogeneously distributed in the holds and a cargo specified in extension and weight on deck, with full stores and fuel

• ship in the fully loaded arrival condition having cargo homogeneously distributed in holds and a cargo speci-fied in extension and weight on deck, with 10% stores and fuel.

1.2.3 General cargo ships

In addition to the standard loading conditions reported in[1.2.1], the following loading cases are to be included in the trim and stability booklet:

• ship in the fully loaded departure condition, with cargo homogeneously distributed throughout all cargo spaces and with full stores and fuel

• ship in the fully loaded arrival condition with cargo homogeneously distributed throughout all cargo spaces and with 10% stores and fuel remaining.

For ships with service notation general cargo ship com-pleted by the additional feature nonhomload, the following loading cases are also to be included in the trim and stabil-ity booklet:

• ship in the departure condition, with cargo in alternate holds, for at least three stowage factors, one of which is relevant to the summer load waterline and with full stores and consumables

Where the condition with cargo in alternate holds rele-vant to the summer load waterline leads to local loads on the double bottom greater than those allowed by the Society, it is to be replaced by the one in which each hold is filled in order to reach the maximum load allowed on the double bottom; in no loading case is such value to be exceeded

• same conditions as above, but with 10% stores and con-sumables.

1.2.4 Container ships

In addition to the standard loading conditions specified in[1.2.1], for ships with the service notation container shipthe following loading cases are to be included in the trim and stability booklet:

• ship with a number of containers having a weight corre-sponding to the maximum permissible weight for each

container at the summer load waterline when loaded with full stores and consumables

• same loading condition as above, but with 10% stores and consumables

• lightship condition with full stores and consumables

• lightship condition with 10% stores and consumables.

The vertical location of the centre of gravity for each con-tainer is generally to be taken at one half of the container height. Different locations of the vertical centre of gravity may be accepted in specific cases, if documented.

1.2.5 Bulk carriers, ore carriers and combination carriers

Dry cargo is intended to mean grain, as well as any other type of solid bulk cargo.

The term grain covers wheat, maize (corn), oats, rye, barley, rice, pulses, seeds and processed forms thereof, whose behaviour is similar to that of grain in its natural state.

The term solid bulk cargo covers any material, other than liquid or gas, consisting of a combination of particles, gran-ules or any larger pieces of material, generally uniform in composition, which is loaded directly into the cargo spaces of a ship without any intermediate form of containment.

In addition to the standard loading conditions defined in[1.2.1], for ships with the service notation bulk carrier ESP, ore carrier ESP and combination carrier ESP the following loading cases are to be included in the trim and stability booklet:

• ship in the fully loaded departure conditions at the sum-mer load waterline, with cargo homogeneously distrib-uted throughout all cargo holds and with full stores and consumables, for at least three specific gravities, one of which is relevant to the complete filling of all cargo holds

• same conditions as above, but with 10% stores and con-sumables

• ship in the departure condition, with cargo holds not entirely filled, for at least three stowage factors, one of which is relevant to the summer load waterline and with full stores and consumables


For ships with one of the service notations ore carrier ESPand combination carrier ESP and for ships with the service notation bulk carrier ESP completed by the additional fea-tures BC-A or nonhomload, the following loading cases are also to be included in the trim and stability booklet:

• ship in the departure conditions, with cargo in alternate holds, for at least three stowage factors, one of which is relevant to the summer load waterline, and with full stores and consumables.

Where the condition with cargo in alternate holds rele-vant to the summer load waterline leads to local loads on the double bottom greater than those allowed by the Society, it is to be replaced by the one in which each

Pt B, Ch 3, App 2


hold is filled in order to reach the maximum load allowed on the double bottom; in no loading case is such value to be exceeded.


1.2.6 Oil tankers and FLS tankers

All the intended cargo loading conditions are to be included in the trim and stability booklet for examination within the scope of Pt D, Ch 7, Sec 3, [1].

Further cases are subject to prior examination by the Soci-ety before the loading; alternatively, an approved loading instrument capable of performing damage stability calcula-tions in accordance with the requirements in Pt D, Ch 7, Sec 3, [1] may be used.

In addition to the standard loading conditions specified in[1.2.1], for ships with the service notation oil tanker ESP or FLS tanker the following loading cases are to be included in the trim and stability booklet:

• ship in the fully loaded departure condition at the sum-mer load waterline, with cargo homogeneously distrib-uted throughout all cargo tanks and with full stores and consumables

• same condition as above, but with 10% stores and con-sumables

• ship in the departure condition loaded with a cargo hav-ing a density in order to fill all cargo tanks, with full stores and consumables, but immersed at a draught less than the summer load waterline


• ship in the fully loaded departure condition at the sum-mer load waterline, with cargo tanks not entirely filled and with full stores and consumables


• two loading conditions corresponding to different cargo segregations in order to have slack tanks with full stores and consumables

When it is impossible to have segregations, these condi-tions are to be replaced by loading conditions with the same specific gravity and with slack cargo tanks


• For oil tankers having segregated ballast tanks as defined in Pt D, Ch 7, Sec 2, [2], the lightship condition with segregated ballast only is also to be included in the trim and stability booklet for examination.

1.2.7 Chemical tankers


Further cases are subject to prior examination by the Society before the loading; alternatively, an approved loading instru-ment capable of performing damage stability calculations in accordance with Pt D, Ch 8, Sec 2, [6] may be used.

In addition to the standard loading conditions defined in[1.2.1], for ships with the service notation chemical tanker ESP the following loading cases are to be included in the trim and stability booklet:

• ship in the fully loaded departure condition, with cargo homogeneously distributed throughout all cargo tanks and with full stores and consumables


• three loading conditions corresponding to different spe-cific gravities with cargo homogeneously distributed throughout all cargo tanks and with full stores and con-sumables

• same loading conditions as above, but with 10% stores and consumables

• four loading conditions corresponding to different cargo segregations in order to have slack tanks with full stores and consumables. Cargo segregation is intended to mean loading conditions with liquids of different spe-cific gravities

When it is impossible to have segregations, these condi-tions are to be replaced by loading conditions corre-sponding to different specific gravities with slack cargo tanks

• same loading conditions as above, but with 10% stores and consumables.

When it is impossible to have segregations, these condi-tions may be replaced by cases corresponding to differ-ent specific gravities with slack cargo tanks.

1.2.8 Liquefied gas carriers


Further cases are subject to prior examination by the Soci-ety before the loading; alternatively, an approved loading instrument capable of performing damage stability calcula-tions in accordance with Pt D, Ch 9, Sec 2, [6] may be used.

In addition to the standard loading conditions defined in[1.2.1], for ships with the service notation liquefied gas car-rier the following loading cases are to be included in the trim and stability booklet:

• ship in the fully loaded departure condition, with cargo homogeneously distributed throughout all cargo spaces and with full stores and fuel

• ship in the fully loaded arrival condition with cargo homogeneously distributed throughout all cargo spaces and with 10% stores and fuel remaining.

Pt B, Ch 3, App 2


1.2.9 Passenger ships

In addition to the standard loading conditions specified in[1.2.1], for ships with the service notation passenger shipthe following loading cases are to be included in the trim and stability booklet:

• ship in the fully loaded departure condition with full stores and fuel and with the full number of passengers with their luggage

• ship in the fully loaded arrival condition, with the full number of passengers and their luggage but with only 10% stores and fuel remaining

• ship without cargo, but with full stores and fuel and the full number of passengers and their luggage

• ship in the same condition as above, but with only 10% stores and fuel remaining.

1.2.10 Dredgers

For ships with one of the service notations dredger, hopper dredger, hopper unit, split hopper dredger and split hop-per unit, the loading conditions described in a) and b) are to replace the standard loading conditions defined in[1.2.1].

a) State of cargo : liquid

• ship loaded to the dredging draught with cargo con-sidered as a liquid

• hopper(s) fully loaded with a homogeneous cargo having density m, up to the spill out edge of the hopper coaming

m = M1 / V1

M1 : Mass of cargo, in t, in the hopper when loaded at the dredging draught

V1 : Volume, in m3, of the hopper at the spill out edge of the hopper coaming

The conditions of stores and fuel are to be equal to 100% and 10%, and an intermediate condition is to be considered if it is more critical than both 100% and 10%.

• hopper(s) filled or partly filled with a homogeneous cargo having densities equal to 1000, 1200, 1400, 1600, 1800 and 2000 kg/m3

When the dredging draught cannot be reached due to the density of the cargo, the hopper is to be con-sidered filled up to the spill out edge of the hopper coaming.

The conditions of stores and fuel are to be the most conservative obtained from the stability calculations with the density m .

b) State of the cargo : solid

• ship loaded to the dredging draught with cargo con-sidered as a solid

• hopper(s) fully loaded with a homogeneous cargo having density mup to the spill out edge of the hop-per coaming, as calculated in a)

The conditions of stores and fuel are to be equal to 100% and 10%, and an intermediate condition is to

be considered if it is more conservative than both 100% and 10%

• hopper(s) filled or partly filled with a homogeneous cargo having densities equal to 1400, 1600, 1800, 2000 and 2200 kg/m3 if greater than m.

1.2.11 Tugs and fire-fighting ships

In addition to the standard loading conditions defined in[1.2.1], for ships with one of the service notations tug and fire fighting ship the following loading cases are to be included in the trim and stability booklet:

• ship in the departure condition at the waterline corre-sponding to the maximum assigned immersion, with full stores, provisions and consumables


1.2.12 Supply vessels

In addition to the standard loading conditions specified in[1.2.1], for ships with the service notation supply vessel the following loading cases are to be included in the trim and stability booklet:

• ship in the fully loaded departure condition having under deck cargo, if any, and cargo specified by posi-tion and weight on deck, with full stores and fuel, corre-sponding to the worst service condition in which all the relevant stability criteria are met

• ship in the fully loaded arrival condition with cargo as specified above, but with 10 per cent stores and fuel

• vessel in the worst anticipated operating condition.

1.2.13 Fishing vessels

In addition to the standard loading conditions defined in[1.2.1], for ships with the service notation fishing vessel the following loading cases are to be included in the trim and stability booklet:

• departure conditions for the fishing grounds with full fuel stores, ice, fishing gear, etc.

• departure from the fishing grounds with full catch

• arrival at home port with 10% stores, fuel, etc. remain-ing and full catch

• arrival at home port with 10% stores, fuel, etc. and a minimum catch, which is normally to be 20% of the full catch but may be up to 40% if documented.

1.3 Stability curve calculation

1.3.1 General

Hydrostatic and stability curves are normally prepared on a designed trim basis. However, where the operating trim or the form and arrangement of the ship are such that change in trim has an appreciable effect on righting arms, such change in trim is to be taken into account.

The calculations are to take into account the volume to the upper surface of the deck sheathing.

Pt B, Ch 3, App 2


1.3.2 Superstructures, deckhouses, etc. which may be taken into account

Enclosed superstructures complying with Ch 1, Sec 2, [3.13]may be taken into account.The second tier of similarly enclosed superstructures may also be taken into account.Deckhouses on the freeboard deck may be taken into account, provided that they comply with the conditions for enclosed superstructures laid down in Ch 1, Sec 2, [3.16].Where deckhouses comply with the above conditions, except that no additional exit is provided to a deck above, such deckhouses are not to be taken into account; however, any deck openings inside such deckhouses are to be consid-ered as closed even where no means of closure are pro-vided.Deckhouses, the doors of which do not comply with the requirements of Ch 9, Sec 4, [1.5.4], are not to be taken into account; however, any deck openings inside the deckhouse are regarded as closed where their means of closure comply with the requirements of Ch 9, Sec 7, [7.3].Deckhouses on decks above the freeboard deck are not to be taken into account, but openings within them may be regarded as closed.

Superstructures and deckhouses not regarded as enclosed may, however, be taken into account in stability calculations up to the angle at which their openings are flooded (at this angle, the static stability curve is to show one or more steps, and in subsequent computations the flooded space are to be considered non-existent).

Trunks may be taken into account. Hatchways may also be taken into account having regard to the effectiveness of their closures.

1.3.3 Angle of flooding

In cases where the ship would sink due to flooding through any openings, the stability curve is to be cut short at the cor-responding angle of flooding and the ship is to be consid-ered to have entirely lost its stability.

Small openings such as those for passing wires or chains, tackle and anchors, and also holes of scuppers, discharge and sanitary pipes are not to be considered as open if they submerge at an angle of inclination more than 30°. If they submerge at an angle of 30° or less, these openings are to be assumed open if the Society considers this to be a source of significant progressive flooding; therefore such openings are to be considered on a case by case basis.

Pt B, Ch 3, App 3


APPENDIX 3 PROBABILISTIC DAMAGE STABILITY METHOD FOR CARGO SHIPS

1 Probabilistic damage stability method for cargo ships

1.1 Application

1.1.1 The requirements included in this Appendix are to beapplied to cargo ships over 80 m in length LS as defined in[1.2.4], but are not to be applied to those ships which areshown to comply with subdivision and damage stability reg-ulations already required in Part D.

Any reference hereinafter to regulations refers to the set ofregulations contained in this Appendix.

The Society may for a particular ship or group of shipsaccept alternative arrangements, if it is satisfied that at leastthe same degree of safety as represented by these regula-tions is achieved.

This includes, for example, the following:

• ships constructed in accordance with a standard ofdamage stability with a set of damage criteria agreed bythe Society

• ships of a multi-hull design, where the subdivisionarrangements need to be evaluated against the basicprinciples of the probabilistic method since the regula-tions have been written specifically for mono-hulls.

1.1.2 The requirements of this appendix are to be appliedin conjunction with the explanatory notes as set out by theIMO resolution MSC 281 (85).

1.2 Definitions

1.2.1 Deepest subdivision draughtThe deepest subdivision draught (dS) is the waterline whichcorresponds to the summer load line draught of the ship.

1.2.2 Light service draughtLight service draught (dL) is the service draught correspond-ing to the lightest anticipated loading and associated tank-age, including, however, such ballast as may be necessaryfor stability and/or immersion.

1.2.3 Partial subdivision draughtThe partial subdivision draught (dP) is the light servicedraught plus 60% of the difference between the light ser-vice draught and the deepest subdivision draught.

1.2.4 Subdivision length Ls

The subdivision length Ls is the greatest projected mouldedlength of that part of the ship at or below deck or decks lim-

iting the vertical extent of flooding with the ship at the deep-est subdivision draught.

1.2.5 Machinery spaceMachinery spaces are spaces between the watertightboundaries of a space containing the main and auxiliarypropulsion machinery, including boilers, generators andelectric motors primarily intended for propulsion. In thecase of unusual arrangements, the Society may define thelimits of the machinery spaces.

1.2.6 Other definitionsMid-length is the mid point of the subdivision length of theship.Aft terminal is the aft limit of the subdivision length.Forward terminal is the forward limit of the subdivisionlength.Breadth B is the greatest moulded breadth, in m, of the shipat or below the deepest subdivision draught.Draught d is the vertical distance, in m, from the mouldedbaseline at mid-length to the waterline in question.Permeability of a space is the proportion of the immersedvolume of that space which can be occupied by water.

1.3 Required subdivision index R

1.3.1 These regulations are intended to provide ships witha minimum standard of subdivision.The degree of subdivision to be provided is to be deter-mined by the required subdivision index R, as follows:• for ships over 100 m in LS:

where LS is in m; and

• for ships of 80 m in LS and upwards, but not exceeding100 m in length LS:

where R0 is the value R as calculated in accordance withthe formula relevant to ships over 100 m in LS.

1.4 Attained subdivision index A

1.4.1 The attained subdivision index A is obtained by thesummation of the partial indices As, Ap and AL, (weighted asshown) calculated for the draughts ds, dp and dL defined in[1.2.1] [1.2.2] and [1.2.3] in accordance with the followingformula:A = 0,4 AS + 0,4 AP + 0,2 AL

R 1 128LS 152+---------------------–=

R 1 1

1LS

100---------- R0

1 R0– --------------------+

----------------------------------------------–=

Pt B, Ch 3, App 3


The partial indices As, Ap and AL are not to be less than 0.9 R

for passenger ships and 0.5 R for cargo ships.

1.4.2 Each partial index is a summation of contributionsfrom all damage cases taken in consideration, using the fol-lowing formula:A = pi si

where:i : Represents each compartment or group of com-

partments under considerationpi : Accounts for the probability that only the com-

partment or group of compartments under con-sideration may be flooded, disregarding anyhorizontal subdivision

si : Accounts for the probability of survival afterflooding the compartment or group of compart-ments under consideration, including the effectsof any horizontal subdivision.

1.4.3 In the calculation of A, the level trim is to be used forthe deepest subdivision draught and the partial subdivisiondraught. The actual service trim is to be used for the lightservice draught. If in any service condition, the trim varia-tion in comparison with the calculated trim is greater than0.5% of LS, one or more additional calculations of A are tobe submitted for the same draughts but different trims sothat, for all service conditions, the difference in trim in com-parison with the reference trim used for one calculation willbe less than 0.5% of LS.

When determining the positive righting lever (GZ) of theresidual stability curve, the displacement used is to be thatof the intact condition. That is, the constant displacementmethod of calculation is to be used.

The summation indicated by the above formula is to betaken over the ship’s subdivision length (LS) for all cases offlooding in which a single compartment or two or moreadjacent compartments are involved. In the case of unsym-metrical arrangements, the calculated A value is to be themean value obtained from calculations involving both sides.Alternatively, it is to be taken as that corresponding to theside which evidently gives the least favourable result.

1.4.4 Wherever wing compartments are fitted, contributionto the summation indicated by the formula is to be taken forall cases of flooding in which wing compartments areinvolved. Additionally, cases of simultaneous flooding of awing compartment or group of compartments and the adja-cent inboard compartment or group of compartments, butexcluding damage of transverse extent greater than one halfof the ship breadth B, may be added. For the purpose of thisregulation, transverse extent is measured inboard fromship’s side, at right angle to the centreline at the level of thedeepest subdivision draught.

1.4.5 In the flooding calculations carried out according tothe regulations, only one breach of the hull and only onefree surface need to be assumed. The assumed verticalextent of damage is to extend from the baseline upwards toany watertight horizontal subdivision above the waterline or

higher. However, if a lesser extent of damage will give amore severe result, such extent is to be assumed.

1.4.6 If pipes, ducts or tunnels are situated within theassumed extent of damage, arrangements are to be made toensure that progressive flooding cannot thereby extend tocompartments other than those assumed flooded. However,the Society may permit minor progressive flooding if it isdemonstrated that its effects can be easily controlled andthe safety of the ship is not impaired.

1.5 Calculation of factor pi

1.5.1 The factor pi for a compartment or group of compart-ments is to be calculated in accordance with [1.5.2] to[1.5.6] using the following notations:j : The aftmost damage zone number involved in

the damage starting with no.1 at the sternn : The number of adjacent damage zones involved

in the damagek : The number of a particular longitudinal bulk-

head as barrier for transverse penetration in adamage zone counted from shell towards thecentre line. The shell has k = 0

x1 : The distance from the aft terminal of LS to the aftend of the zone in question

x2 : The distance from the aft terminal of LS to theforward end of the zone in question

b : The mean transverse distance in metres mea-sured at right angles to the centreline at thedeepest subdivision draught between the shelland an assumed vertical plane extendedbetween the longitudinal limits used in calculat-ing the factor pi and which is a tangent to, orcommon with, all or part of the outermost por-tion of the longitudinal bulkhead under consid-eration. This vertical plane is to be so orientatedthat the mean transverse distance to the shell isa maximum, but not more than twice the leastdistance between the plane and the shell. If theupper part of a longitudinal bulkhead is belowthe deepest subdivision draught the verticalplane used for determination of b is assumed toextend upwards to the deepest subdivisionwaterline. In any case, b is not to be takengreater than B/2.

If the damage involves a single zone only:pi = p(x1(j) ,x2(j)) · [r(x1(j) ,x2(j) ,bk) r(x1(j) ,x2(j) ,b(k-1))]

If the damage involves two adjacent zones:pi = p(x1(j) ,x2(j+1)) · [r(x1(j) ,x2(j+1) ,bk) r(x1(j) ,x2(j+1) ,b(k-1))] p(x1(j) ,x2(j)) · [r(x1(j) ,x2(j) ,bk) r(x1(j) ,x2(j) ,b(k-1))] p(x1(j+1) ,x2(j+1)) · [r(x1(j+1) ,x2(j+1) ,bk) r(x1(j+1) ,x2(j+1) ,b(k-1))]

If the damage involves three or more adjacent zones:pi = p(x1(j) ,x2(j+n-1))·[r(x1(j) ,x2(j+n-1) ,bk) r(x1(j) ,x2(j+n-1) ,b(k-1))] p(x1(j) ,x2(j+n-2))·[r(x1(j) ,x2(j+n-2) ,bk) r(x1(j) ,x2(j+n-2) ,b(k-1))] p(x1(j+1) ,x2(j+n-1))·[r(x1(j) ,x2(j+n-1) ,bk) r(x1(j+1) ,x2(j+n-1) ,b(k-1))]p(x1(j+1) ,x2(j+n-2))·[r(x1(j+1) ,x2(j+n-2) ,bk) r(x1(j+1) ,x2(j+n-2) ,b(k-1))]

and where r(x1, x2, b0) = 0

Pt B, Ch 3, App 3


1.5.2 The factor p(x1, x2) is to be calculated according tothe following formulae with:

Jmax : Overall normalized max damage length

Jmax = 10 /33

Jkn : Knuckle point in the distribution

Jkn = 5 /33

pk : Cumulative probability at Jkn

pk = 11 /12

max : Maximum absolute damage length

max = 60 m

L* : Length where normalized distribution ends

L* = 260 m

b0 : Probability density at J = 0

• When LS L*:

• When LS > L*:

The non-dimensional damage length:

The normalized length of a compartment or group of com-partments:

Jn is to be taken as lesser as J and Jm

1.5.3 Where neither limits of the compartment or group ofcompartments under consideration coincides with the aft orforward terminals:

• J Jk:

• J > Jk:

1.5.4 Where the aft limit of the compartment or group ofcompartments under consideration coincides with the aftterminal or the forward limit of the compartment or groupof compartments under consideration coincides with theforward terminal:

• J Jk:

• J > Jk:

1.5.5 Where the compartment or groups of compartmentsconsidered extends over the entire subdivision length (LS):

1.5.6 The factor r(x1, x2, b) is to be determined by the fol-lowing formulae:

where:

Where the compartment or groups of compartments con-sidered extends over the entire subdivision length (LS):

Where neither limits of the compartment or group of com-partments under consideration coincides with the aft or for-ward terminals:

where:

Where the aft limit of the compartment or group of com-partments under consideration coincides with the aft termi-nal or the forward limit of the compartment or group ofcompartments under consideration coincides with the for-ward terminal:

b0 2pk

Jkn

----- 1 pk–Jmax Jkn–--------------------–

=

Jm min Jmaxlmax

LS

--------

=

JkJm

2----

1 1 1 2pk– b0Jm14---b0

2Jm2+ +–

b0

-----------------------------------------------------------------------------------+=

b12 b0=

Jm min Jmaxlmax

L--------

=

JkJm2

-------1 1 1 2pk– b0Jm

14---b0

2Jm2+ +–

b0

-----------------------------------------------------------------------------------------+=

JmJm L

LS

------------------=

JkJk L

LS

-----------------=

b12 2pk

Jk

----- 1 pk–Jm Jk–--------------–

=

b11 41 pk–

Jm Jk– Jk

----------------------- 2pk

Jk2

-----–=

b21 2– 1 pk–Jm Jk– 2

---------------------=

b22 b21– Jm=

Jx2 x1–

LS

----------------=

p x1 x2 p116--- J2 b11J 3b12+ = =

p x1 x2 p2b11Jk

3

3-------------– b11J b12– Jk

2

2---------------------------------- b12JJk

b21 Jn3 Jk

3– 3

------------------------------ b21J b22– Jn2 Jk

2– 2

------------------------------------------------- b22J Jn Jk– + +–

+ += =

p x1 x2 12--- p1 J+ =

p x1 x2 12--- p2 J+ =

p x1 x2 1=

r x1 x2 b 1 1 C– 1 Gp x1 x2 ----------------------––=

C 12Jb 45Jb– 4+ =

Jbb

15B----------=

G G112---b11Jb

2 b12Jb+= =

G G213---b11J0

3– 12--- b11J b12– J0

2 b12JJ0+ += =

J0 min J Jb =

G 12--- G2 G1J+ =

Pt B, Ch 3, App 3


1.6 Calculation of factor si

1.6.1 The factor si is to be determined for each case ofassumed flooding involving a compartment or group ofcompartments according to the requirement indicated in[1.6.2] to [1.6.9].

1.6.2 The factor si is to be obtained from the formula:

where:

GZmax : Maximum positive righting lever, in metres, upto the angle v, GZmax is not to be taken as morethan 0,12 m

Range : Range of positive righting levers, in degrees,measured from the angle e. The positive rangeis to be taken up to the angle v. The range isnot to be taken as more than 16°

v : v is the angle, where the righting lever becomesnegative, or the angle at which an opening inca-pable of being closed weather tight becomessubmerged

e : Final equilibrium angle of heel (in degrees)

K = 1 if e min

K = 0 if e max

otherwise:

where:

min is equal to 25

max is equal to 30

1.6.3 In all cases, si is to be taken as zero in those caseswhere the final waterline, taking into account sinkage, heeland trim, immerses:

• the lower edge of openings through which progressiveflooding may take place and such flooding is notaccounted for in the calculation of factor si. Such open-ings shall include air-pipes, ventilators and openingswhich are closed by means of weathertight doors orhatch covers; but openings closed by means of water-tight manhole covers and flush scuttles, small watertighthatch covers, remotely operated sliding watertightdoors, side scuttles of the non-opening type as well aswatertight access doors and hatch covers required to bekept closed at sea need not be considered.

• immersion of any vertical escape hatch in the freeboarddeck intended for compliance with the applicablerequirements of Pt C, Ch 4, Sec 8

• any controls intended for the operation of watertightdoors, equalization devices, valves on piping or on ven-tilation ducts intended to maintain the integrity of water-tight bulkheads from above the bulkhead deck becomeinaccessible or inoperable

• immersion of any part of piping or ventilation ducts car-ried through a watertight boundary that is locatedwithin any compartment included in damage cases con-tributing to the attained index A, if not fitted with water-tight means of closure at each boundary.

1.6.4 Unsymmetrical flooding is to be kept to a minimumconsistent with the efficient arrangements. Where it is nec-essary to correct large angles of heel, the means adoptedare, where practicable, to be self-acting, but in any casewhere controls to equalization devices are provided theyare to be operable from above the bulkhead deck. These fit-tings together with their controls shall be acceptable to theSociety. Suitable information concerning the use of equal-ization devices shall be supplied to the master of the ship

1.6.5 Tanks and compartments taking part in such equal-ization is to be fitted with air pipes or equivalent means ofsufficient cross-section to ensure that the flow of water intothe equalization compartments is not delayed.

1.6.6 Where horizontal watertight boundaries are fittedabove the waterline under consideration the s-value calcu-lated for the lower compartment or group of compartmentsis to be obtained by multiplying the value as determined in[1.6.2] by the reduction factor m according to [1.6.7],which represents the probability that the spaces above thehorizontal subdivision will not be flooded.

1.6.7 The factor m is to be obtained from the formula:

where:

Hj, n, m : Least height above the baseline, in metres, withinthe longitudinal range of x1(j)...x2(j+n-1) of themth horizontal boundary which is assumed tolimit the vertical extent of flooding for the dam-aged compartments under consideration

Hj, n, m-1 : Least height above the baseline, in metres, withinthe longitudinal range of x1(j)...x2(j+n-1) of the(m-1)th horizontal boundary which is assumed tolimit the vertical extent of flooding for the dam-aged compartments under consideration

j : The aft terminal of the damaged compartmentsunder consideration

m : Each horizontal boundary counted upwardsfrom the waterline under consideration

d : Draught in question as defined in [1.2]

x1 and x2: Terminals of the compartment or group of com-partments considered in [1.5.1].

si KGZmax

0 12---------------- Range

16-----------------

14---

=

K max e–max min–--------------------------=

m Hj n m d Hj n m 1– d –=

Pt B, Ch 3, App 3


1.6.8 The factors (Hj, n, m, d) and (Hj, n, m-1, d) are to beobtained from the formulas:

if (Hm-d) is less than, or equal to 7,8 m,

in all other cases,

where:

• (Hj, n, m,,d) is to be taken as 1, if Hm coincides with theuppermost watertight boundary of the ship within therange (x1(j)...x2(j+n-1))

• (Hj, n, 0, d) is to be taken as 0.

In no case is m to be taken as less than zero or more than 1.

1.6.9 In general, each contribution dA to the index A in thecase of horizontal subdivisions is obtained from the for-mula:

where:

m : The -value calculated in accordance with[1.6.7] and [1.6.8]

smin : The least s-factor for all combinations of dam-ages obtained when the assumed damageextends from the assumed damage height Hm

downwards.

1.7 Permeability

1.7.1 For the purpose of the subdivision and damage stabil-ity calculations reported in this appendix, the permeabilityof each space or part of a space is to be as per Tab 1.

Table 1 : Permeabilities

1.7.2 For the purpose of the subdivision and damage stabil-ity calculations of the regulations, the permeability of eachcargo compartment is to be as per Tab 2.Other figures for permeability may be used if substantiatedby calculations.

1.8 Stability information

1.8.1 The master is to be supplied with such informationsatisfactory to the Society as is necessary to enable him byrapid and simple processes to obtain accurate guidance as

to the stability of the ship under varying conditions of ser-vice. A copy of the stability information shall be furnished tothe Society.

1.8.2 Information to be submitted:

• curves or tables of minimum operational metacentricheight (GM) versus draught which assures compliancewith the relevant intact and damage stability require-ments, alternatively corresponding curves or tables ofthe maximum allowable vertical centre of gravity (KG)versus draught, or with the equivalents of either of thesecurves

• instructions concerning the operation of cross-floodingarrangements

• all other data and aids which might be necessary tomaintain the required intact stability and stability afterdamage.

1.8.3 The stability information is to show the influence ofvarious trims in cases where the operational trim rangeexceeds 0.5% of LS.

1.8.4 For ships which have to fulfil these stability require-ments, information referred to above are determined fromconsiderations related to the subdivision index, in the follow-ing manner: Minimum required GM (or maximum permissiblevertical position of centre of gravity KG) for the three draughtsds, dp and dl are equal to the GM (or KG values) of corre-sponding loading cases used for the calculation of survivalfactor si. For intermediate draughts, values to be used are tobe obtained by linear interpolation applied to the GM valueonly between the deepest subdivision draught and the partialsubdivision draught and between the partial load line and thelight service draught respectively. Intact stability criteria willalso be taken into account by retaining for each draft the max-imum among minimum required GM values or the minimumof maximum permissible KG values for both criteria. If thesubdivision index is calculated for different trims, severalrequired GM curves will be established in the same way

1.8.5 When curves or tables of minimum operational meta-centric height (GM) versus draught are not appropriate, themaster is to ensure that the operating condition does notdeviate from a studied loading condition, or verify by calcu-lation that the stability criteria are satisfied for this loadingcondition.

Table 2 : Permeabilities of cargo compartments

Spaces Permeabilities

Appropriated to stores 0,60

Occupied by accommodations 0,95

Occupied by machinery 0,85

Void spaces 0,95

Intended for liquids 0 or 0,95 (1)

(1) whichever results in the more severe requirements

H d 0 8 H d– 7 8

------------------=

H d 0 8 0 2 H d– 7 8–4 7

----------------------------------+=

dA pi 1smin1 2 1– smin2 1 m 1–– smin m+ + + =

SpacesPermeability at draught ds

Permeability at draught dp

Permeability at draught dl

Dry cargo spaces

0,70 0,80 0,95

Container spaces

0,70 0,80 0,95

Ro-ro spaces 0,90 0,90 0,95Cargo liquids 0,70 0,80 0,95

Pt B, Ch 3, App 4


APPENDIX 4 DAMAGE STABILITY CALCULATION FOR SHIPS ASSIGNED WITH A REDUCED FREEBOARD

1 Application

1.1 General

1.1.1 The requirements of this Appendix apply to Type A ships having length greater than 150 m, Type B-60 ships and Type B-100 ships having a lenght greater than 100 m.

Any reference hereafter to regulations refers to the set of regulations contained in this Appendix.

2 Initial loading condition

2.1 Initial condition of loading

2.1.1 The initial condition of loading before flooding is to be determined according to [2.1.2] and [2.1.3].

2.1.2 The ship is loaded to its summer load waterline on an imaginary even keel.

2.1.3 When calculating the vertical centre of gravity, the following principles apply:

a) Homogeneous cargo is carried.

b) All cargo compartments, except those referred to under c), but including compartments intended to be partially filled, are to be considered fully loaded except that in the case of fluid cargoes each compartment is to be treated as 98 per cent full.

c) If the ship is intended to operate at its summer load waterline with empty compartments, such compart-ments are to be considered empty provided the height of the centre of gravity so calculated is not less than as calculated under b).

d) Fifty per cent of the individual total capacity of all tanks and spaces fitted to contain consumable liquids and stores is allowed for. It is to be assumed that for each type of liquid, at least one transverse pair or a single centre line tank has maximum free surface, and the tank or combination of tanks to be taken into account are to be those where the effect of free surfaces is the greatest; in each tank the centre of gravity of the contents is to be taken at the centre of volume of the tank. The remaining tanks are to be assumed either completely empty or completely filled, and the distribution of consumable liquids between these tanks is to be effected so as to obtain the greatest possible height above the keel for the centre of gravity.

e) At an angle of heel of not more than 5 degrees in each compartment containing liquids, as prescribed in b) except that in the case of compartments containing con-

sumable fluids, as prescribed in d), the maximum free surface effect is to be taken into account.Alternatively, the actual free surface effects may be used, provided the methods of calculation are accept-able to the Society.

f) Weights are to be calculated on the basis of Tab 1.

Table 1 : Specific gravities

3 Damage assumptions

3.1 Damage dimension

3.1.1 The principles indicated in [3.1.2] to [3.1.5] regard-ing the character of the assumed damage apply.

3.1.2 The vertical extent of damage in all cases is assumed to be from the base line upwards without limit.

3.1.3 The transverse extent of damage is equal to B/5 or 11,5 metres, whichever is the lesser, measured inboard from the side of the ship perpendicularly to the centre line at the level of the summer load waterline.

3.1.4 If damage of a lesser extent than specified in [3.1.2]and [3.1.3] results in a more severe condition, such lesser extent is to be assumed.

3.1.5 Except where otherwise required in [3.4.3], the flood-ing is to be confined to a single compartment between adja-cent transverse bulkheads provided the inner longitudinal boundary of the compartment is not in a position within the transverse extent of assumed damage. Transverse boundary bulkheads of wing tanks, which do not extend over the full breadth of the ship are to be assumed not to be damaged, provided they extend beyond the transverse extent of assumed damage prescribed in [3.1.3].

3.2 Steps and recesses

3.2.1 If in a transverse bulkhead there are steps or recesses of not more than 3,05 metres in length located within the transverse extent of assumed damage as defined in [3.1.3], such transverse bulkhead may be considered intact and the

Weight item Specific gravity, in t/m3

Salt water 1,025

Fresh water 1,000

Fuel oil 0,950

Diesel oil 0,900

Lubricating oil 0,900

Pt B, Ch 3, App 4


adjacent compartment may be floodable singly. If, however, within the transverse extent of assumed damage there is a step or recess of more than 3,05 metres in length in a trans-verse bulkhead, the two compartments adjacent to this bulk-head are to be considered as flooded. The step formed by the after peak bulkhead and the after peak tank top is not to be regarded as a step for the purpose of this regulation.

3.2.2 Where a main transverse bulkhead is located within the transverse extent of assumed damage and is stepped in way of a double bottom or side tank by more than 3,05 metres, the double bottom or side tanks adjacent to the stepped portion of the main transverse bulkhead are to be considered as flooded simultaneously. If this side tank has openings into one or several holds, such as grain feeding holes, such hold or holds are to be considered as flooded simultaneously. Similarly, in a ship designed for the carriage of fluid cargoes, if a side tank has openings into adjacent compartments, such adjacent compartments are to be con-sidered as empty and flooded simultaneously. This provision is applicable even where such openings are fitted with clos-ing appliances, except in the case of sluice valves fitted in bulkheads between tanks and where the valves are con-trolled from the deck. Manhole covers with closely spaced bolts are considered equivalent to the unpierced bulkhead except in the case of openings in topside tanks making the topside tanks common to the holds.

3.2.3 Where a transverse bulkhead forming the forward or aft limit of a wing tank or double bottom tank is not in line with the main transverse bulkhead of the adjacent inboard compartment, it is considered to form a step or recess in the main transverse bulkhead.

Such a step or recess may be assumed not to be damaged provided that, either:

• the longitudinal extent of the step or recess, measured from the plan of the main transverse bulkhead, is not more than 3,05 metres, or

• any longitudinal surface forming the step or recess is located inboard of the assumed damage.

Figure 1 : Step and recesses - Example 1

3.2.4 Where, otherwise, the transverse and longitudinal bulkheads bounding a main inboard compartment are entirely inboard of the assumed damage position, damage is assumed to occur between the transverse bulkheads and the adjacent wing compartment. Any step or recess in such wing tank is to be treated as indicated above.

Examples are shown in Fig 1 to Fig 4:

• Fig 1and Fig 2 refer to [3.2.2]

• Fig 3 and Fig 4 refer to [3.2.1] and [3.2.2].

3.3 Transverse bulkhead spacing

3.3.1 Where the flooding of any two adjacent fore and aft compartments is envisaged, main transverse watertight bulkheads are to be spaced at least 1/3(L)2/3 or 14,5 metres, whichever is the lesser, in order to be considered effective. Where transverse bulkheads are spaced at a lesser distance, one or more of these bulkheads are to be assumed as non-existent in order to achieve the minimum spacing between bulkheads.

3.4 Damage assumption

3.4.1 A Type A ship, if over 150 metres in length to which a freeboard less than Type B has been assigned, when loaded as considered in [2.1], is to be able to withstand the flood-ing of any compartment or compartments, with an assumed permeability of 0,95, consequent upon the damage assumptions specified in [3.1], and is to remain afloat in a satisfactory condition of equilibrium as specified in [3.5]and [3.6]. In such a ship, the machinery space is to be treated as a floodable compartment, but with a permeability of 0,85. See Tab 2.


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Pt B, Ch 3, App 4



Table 2 : Damage assumption

3.4.2 A Type B-60 ship, when loaded as considered in[2.1], is to be able to withstand the flooding of any compart-ment or compartments, with an assumed permeability of 0,95, consequent upon the damage assumptions specified in [3.1], and is to remain afloat in a satisfactory condition of equilibrium as specified in [3.5] and [3.6]. In such a ship, if over 150 metres in length, the machinery space is to be treated as a floodable compartment, but with a permeability of 0,85. See Tab 2.

3.4.3 A Type B-100 ship, when loaded as considered in[2.1], is to be able to withstand the flooding of any compart-ment or compartments, with an assumed permeability of 0,95, consequent upon the damage assumptions specified in [3.1], and is to remain afloat in a satisfactory condition of equilibrium as specified in [3.5] and [3.6]. Furthermore all the requirements stated in [4.1] are to be complied with, provided that throughout the length of the ship any one transverse bulkhead will be assumed to be damaged, such that two adjacent fore and aft compartments are to be flooded simultaneously, except that such damage will not apply to the boundary bulkheads of a machinery space. In such a ship, if over 150 metres in length, the machinery space is to be treated as a floodable compartment, but with a permeability of 0,85. See Tab 2.


3.5 Condition of equilibrium

3.5.1 The condition of equilibrium after flooding is to be regarded as satisfactory according to [3.5.2] and [3.5.3].

3.5.2 The final waterline after flooding, taking into account sinkage, heel and trim, is below the lower edge of any open-ing through which progressive downflooding may take place. Such openings are to include air pipes, ventilators and openings which are closed by means of weathertight doors or hatch covers, unless closed by watertight gasketed covers of steel or equivalent material, and may exclude those openings closed by means of manhole covers and flush scuttles, cargo hatch covers, remotely operated sliding watertight doors, and side scuttles of the non-opening type. However, in the case of doors separating a main machinery space from a steering gear compartment, watertight doors may be of a hinged, quick acting type kept closed at sea, whilst not in use, provided also that the lower sill of such doors is above the summer load waterline.

3.5.3 If pipes, ducts or tunnels are situated within the assumed extent of damage penetration as defined in [3.1.3], arrangements are to be made so that progressive flooding cannot thereby extend to compartments other than those assumed to be floodable in the calculation for each case of damage.

3.6 Damage stability criteria

3.6.1 The angle of heel due to unsymmetrical flooding does not exceed 15 degrees. If no part of the deck is immersed, an angle of heel of up to 17 degrees may be accepted.

3.6.2 The metacentric height in the flooded condition is positive.

Type L, in m Standard of flooding (1)

A 150 one compartment

B - 60 100 one compartment

B -100 100 two adjacent compartments (exemp-tion for machinery space which is to be flooded alone)

(1) except where otherwise required by [4.2].

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Pt B, Ch 3, App 4


3.6.3 When any part of the deck outside the compartment assumed flooded in a particular case of damage is immersed, or in any case where the margin of stability in the flooded condition may be considered doubtful, the residual stability is to be investigated. It may be regarded as suffi-cient if the righting lever curve has a minimum range of 20 degrees beyond the position of equilibrium with a maxi-mum righting lever of at least 0,1 metre within this range. The area under the righting lever curve within this range is to be not less than 0,0175 metre-radians. The Society is to give consideration to the potential hazard presented by pro-tected or unprotected openings which may become tempo-rarily immersed within the range of residual stability.

3.6.4 The Society is satisfied that the stability is sufficient during intermediate stages of flooding. In this regard, the Society will apply the same criteria relevant to the final stage, also during the intermediate stages of flooding.

4 Requirements for Type B-60 and B-100 ships

4.1 Requirements for Type B-60 ships

4.1.1 Any Type B ships of over 100 metres, having hatch-ways closed by weathertight covers as specified in [4.3], may be assigned freeboards less than those required for Type B, provided that, in relation to the amount of reduc-tion granted, the requirements in [4.1.2] to [4.1.4] are con-sidered satisfactory by the Society.In addition, the requirements stated in [3.4.2] are to be complied with.

4.1.2 The measures provided for the protection of the crew are to be adequate.

4.1.3 The freeing arrangements are to comply with the pro-visions of Ch 9, Sec 9.

4.1.4 The covers in positions 1 and 2 comply with the pro-visions of [4.3] and have strength complying with Ch 9, Sec 7, special care being given to their sealing and securing arrangements.

4.2 Requirements for Type B-100 ships

4.2.1 In addition to the requirements specified in [4.1], not taking into account the prescription stated in [3.4.2], the requirements in [4.2.2] to [4.2.4] are to be complied with.In addition, the provisions of [3.4.3] are to be complied with.

4.2.2 Machinery casingsMachinery casings on Type A ships are to be protected by an enclosed poop or bridge of at least standard height, or by a deckhouse of equal height and equivalent strength, provided that machinery casings may be exposed if there are no openings giving direct access from the freeboard deck to the machinery space. A door complying with the requirements of [4.4] may, however, be permitted in the machinery casing, provided that it leads to a space or pas-

sageway which is as strongly constructed as the casing and is separated from the stairway to the engine room by a sec-ond weathertight door of steel or other equivalent material.

4.2.3 Gangway and accessAn efficiently constructed fore and aft permanent gangway of sufficient strength is to be fitted on Type A ships at the level of the superstructure deck between the poop and the midship bridge or deckhouse where fitted, or equivalent means of access is to be provided to carry out the purpose of the gangway, such as passages below deck. Elsewhere, and on Type A ships without a midship bridge, arrange-ments to the satisfaction of the Society are to be provided to safeguard the crew in reaching all parts used in the neces-sary work of the ship.Safe and satisfactory access from the gangway level is to be available between separate crew accommodation spaces and also between crew accommodation spaces and the machinery space.

4.2.4 Freeing arrangementsType A ships with bulwarks are to be provided with open rails fitted for at least half the length of the exposed parts of the weather deck or other effective freeing arrangements. The upper edge of the sheer strake is to be kept as low as practicable.Where superstructures are connected by trunks, open rails are to be fitted for the whole length of the exposed parts of the freeboard deck.

4.3 Hatchways closed by weathertight cov-ers of steel or other equivalent material fitted with gaskets and clamping devices

4.3.1 At positions 1 and 2 the height above the deck of hatchway coamings fitted with weathertight hatch covers of steel or other equivalent material fitted with gaskets and clamping devices is to be:• 600 millimetres if in position 1• 450 millimetres if in position 2.

The height of these coamings may be reduced, or the coam-ings omitted entirely, upon proper justification. Where coamings are provided they are to be of substantial con-struction.

4.3.2 Where weathertight covers are of mild steel the strength is to be calculated with assumed loads not less than those specified in Ch 9, Sec 7.

4.3.3 The strength and stiffness of covers made of materials other than mild steel are to be equivalent to those of mild steel to the satisfaction of the Society.

4.3.4 The means for securing and maintaining weather-tightness are to be to the satisfaction of the Society. The arrangements are to ensure that the tightness can be main-tained in any sea conditions, and for this purpose tests for tightness are required at the initial survey, and may be required at periodical surveys and at annual inspections or at more frequent intervals.

Pt B, Ch 3, App 4


4.4 Doors

4.4.1 All access openings in bulkheads at ends of enclosed superstructures are to be fitted with doors of steel or other equivalent material, permanently and strongly attached to the bulkhead, and framed, stiffened and fitted so that the whole structure is of equivalent strength to the unpierced bulkhead and weathertight when closed. The means for securing these doors weathertight are to consist of gaskets

and clamping devices or other equivalent means and are to be permanently attached to the bulkhead or to the doors themselves, and the doors are to be so arranged that they can be operated from both sides of the bulkhead.

4.4.2 Except as otherwise provided, the height of the sills of access openings in bulkheads at ends of enclosed super-structures is to be at least 380 millimetres above the deck.

Pt B, Ch 3, App 4


Pt B, Ch 4, Sec 1


SECTION 1 MATERIALS

1 General

1.1 Characteristics of materials

1.1.1 The characteristics of the materials to be used in theconstruction of ships are to comply with the applicablerequirements of NR216 Materials and Welding.

1.1.2 Materials with different characteristics may beaccepted, provided their specification (manufacture, chemi-cal composition, mechanical properties, welding, etc.) issubmitted to the Society for approval.

1.2 Testing of materials

1.2.1 Materials are to be tested in compliance with theapplicable requirements of NR216 Materials and Welding.

1.3 Manufacturing processes

1.3.1 The requirements of this Section presume that weld-ing and other cold or hot manufacturing processes are car-ried out in compliance with current sound working practiceand the applicable requirements of NR216 Materials andWelding. In particular:

• parent material and welding processes are to be withinthe limits stated for the specified type of material forwhich they are intended

• specific preheating may be required before welding

• welding or other cold or hot manufacturing processesmay need to be followed by an adequate heat treatment.

2 Steels for hull structure

2.1 Application

2.1.1 Tab 1 gives the mechanical characteristics of steelscurrently used in the construction of ships.

Table 1 : Mechanical properties of hull steels

2.1.2 Higher strength steels other than those indicated inTab 1 are considered by the Society on a case by case basis.

2.1.3 When steels with a minimum guaranteed yield stressReH other than 235 N/mm2 are used on a ship, hull scant-lings are to be determined by taking into account the mate-rial factor k defined in [2.3].

2.1.4 When no other information is available, the mini-mum guaranteed yield stress ReH and the Young’s modulus Eof steels used at temperatures between 90°C and 300°Cmay be taken respectively equal to:

where:

ReH0 : Value of the minimum guaranteed yield stress atambient temperature

E0 : Value of the Young’s modulus at ambient tem-perature.

2.1.5 Characteristics of steels with specified through thick-ness properties are given in NR216 Materials and Welding,Ch 2, Sec 1, [9].

2.2 Information to be kept on board

2.2.1 It is advised to keep on board a plan indicating thesteel types and grades adopted for the hull structures.Where steels other than those indicated in Tab 1 are used,their mechanical and chemical properties, as well as anyworkmanship requirements or recommendations, are to beavailable on board together with the above plan.

2.3 Material factor k

2.3.1 General

Unless otherwise specified, the material factor k has the val-ues defined in Tab 2, as a function of the minimum guaran-teed yield stress ReH.

Table 2 : Material factor k

Steel gradest 100 mm

Minimum yield stress ReH ,in N/mm2

Ultimate minimum tensile strength Rm ,

in N/mm2

A-B-D-E 235 400 - 520

AH32-DH32-EH32FH32

315 440 - 590

AH36-DH36-EH36FH36

355 490 - 620

AH40-DH40-EH40 FH40

390 510 - 650

Note 1: Ref.: NR216 Materials and Welding, Ch 2, Sec 1, [2]

ReH , in N/mm2 k

235 1

315 0,78

355 0,72

390 0,68

ReH ReH0 1 04 0 751000-------------–

=

E E0 1 03 0 51000-------------–

=

Pt B, Ch 4, Sec 1


For intermediate values of ReH , k may be obtained by linearinterpolation.

Steels with a yield stress lower than 235 N/mm2 or greaterthan 390 N/mm2 are considered by the Society on a case bycase basis.

2.4 Grades of steel

2.4.1 Materials in the various strength members are not tobe of lower grade than those corresponding to the material

classes and grades specified in Tab 3, Tab 4, Tab 5, Tab 6and Tab 7, and Tab 8.

General requirements are given in Tab 3. Additional mini-mum requirements are given in:

• Tab 4 for ships greater than 150 m in length and havinga single strength deck

• Tab 5 for ships greater than 250 m in length

• Tab 6 for single-side bulk carrier ESP and combinationcarrier / OBO ESP

• Tab 7 for ships with ice strengthening.

Table 3 : Application of material classes and grades for ships in general

Table 4 : Application of material classes and gradesfor ships greater than 150 m in length and having a single strength deck

Structural member categoryMaterial class or grade

Within 0,4L amidships Outside 0,4L amidships

SEC

ON

DA

RY

• Longitudinal bulkhead strakes, other than that belonging to the primary category

• Deck plating exposed to weather, other than that belonging to the primary or special category

• Side plating

I A / AH

PRIM

ARY

• Bottom plating, including keel plate• Strength deck plating, excluding that belonging to the special

category• Continuous longitudinal members above strength deck, exclud-

ing hatch coamings, for ships equal to or greater than 90 m in length

• Uppermost strake in longitudinal bulkhead• Vertical strake (hatch side girder) and uppermost sloped strake

in top wing tank

II A / AH

SPEC

IAL

• Sheer strake at strength deck (1)• Stringer plate in strength deck (1)• Deck strake at longitudinal bulkhead excluding deck plating in

way of inner-skin bulkhead of double hull ships (1)

IIIII

I outside 0,6L amidships

• Strength deck plating at outboard corners of cargo hatch open-ings in container carriers and other ships with similar hatch openings configurations

IIIII

I outside 0,6L amidshipsMin. class III within cargo region

• Strength deck plating at corners of cargo hatch openings in bulk carriers, ore carriers, combination carriers and other ships with similar hatch openings configurations

IIIIII within 0,6L amidships

II within the rest of cargo region

• Bilge strake in ships with double bottom over the full breadth and length less than 150 m (1) II

II within 0,6L amidshipsI outside 0,6L amidships

• Bilge strake in other ships (1)III

III outside 0,6L amidships

• Longitudinal hatch coamings of length greater than 0,15 L for ships equal to or greater than 90 min length

• End brackets and deck house transition of longitudinal cargo hatch coamings

III Not to be less than

grade D/DH

III outside 0,6L amidships

Not to be less than grade D/DH

(1) Single strakes required to be of class III within 0.4L amidships are to have breadths not less than (800 + 5 L) mm, need not to be greater than 1800 mm, unless limited by the geometry of the ship’s design.

Structural member category Material gradeLongitudinal strength members of strength deck plating B/AH within 0,4 L amidshipsContinuous longitudinal strength members above strength deck B/AH within 0,4 L amidshipsSingle side strakes for ships without inner continuous longitudinal bulkhead(s) between the bottom and the strength deck

B/AH within cargo region

Pt B, Ch 4, Sec 1


Table 5 : Application of material classes and grades for ships greater than 250 m in length

2.4.2 Materials are to be of a grade not lower than thatindicated in Tab 8 depending on the material class andstructural member gross thickness (see [2.4.5]).

2.4.3 For strength members not mentioned in Tab 3, Tab 4,Tab 5, Tab 6 and Tab 7, grade A/AH may generally be used.

2.4.4 Plating materials for sternframes, rudders, rudderhorns and shaft brackets are generally to be of grades notlower than those corresponding to Class II.

For rudder and rudder body plates subjected to stress con-centrations (e.g. in way of lower support of semi-spade rud-ders or at upper part of spade rudders) Class III is to beapplied.

2.4.5 The steel grade is to correspond to the as fitted grossthickness when this is greater than the gross thicknessobtained from the net thickness required by the Rules,according to Ch 4, Sec 2, [1].

2.4.6 Steel grades of plates or sections of gross thicknessgreater than the limiting thicknesses in Tab 8 are consideredby the Society on a case by case basis.

2.4.7 In specific cases, such as [2.4.8], with regard to stressdistribution along the hull girder, the classes required within0,4L amidships may be extended beyond that zone, on acase by case basis.

2.4.8 The material classes required for the strength deckplating, the sheerstrake and the upper strake of longitudinalbulkheads within 0,4L amidships are to be maintained foran adequate length across the poop front and at the ends ofthe bridge, where fitted.

2.4.9 Rolled products used for welded attachments on hullplating, such as gutter bars and bilge keels, are to be of thesame grade as that used for the hull plating in way.Where it is necessary to weld attachments to the sheerstrakeor stringer plate, attention is to be given to the appropriatechoice of material and design, the workmanship and weld-ing and the absence of prejudicial undercuts and notches,with particular regard to any free edges of the material.

2.4.10 In the case of full penetration welded joints locatedin positions where high local stresses may occur perpendic-ular to the continuous plating, the Society may, on a case bycase basis, require the use of rolled products having ade-quate ductility properties in the through thickness direction,such as to minimize the risk of lamellar tearing (Z type steel,see NR216 Materials and Welding).

2.4.11 In highly stressed areas, the Society may require thatplates of gross thickness greater than 20 mm are of gradeD/DH or E/EH.

2.5 Grades of steel for structures exposed to low air temperatures

2.5.1 For ships intended to operate in areas with low airtemperatures (20°C or below), e.g. regular service duringwinter seasons to Arctic or Antarctic waters, the materials inexposed structures are to be selected based on the designtemperature tD, to be taken as defined in [2.5.2].

2.5.2 The design temperature tD is to be taken as the lowestmean daily average air temperature in the area of operation,where:Mean : Statistical mean over observation period (at least

20 years)Average : Average during one day and nightLowest : Lowest during one year Fig 1 illustrates the temperature definition for Arctic waters.

For seasonally restricted service, the lowest value within theperiod of operation applies.

2.5.3 For the purpose of the selection of steel grades to beused for the structural members above the lowest ballastwaterline and exposed to air, the latter are divided into cat-egories (SECONDARY, PRIMARY and SPECIAL), as indi-cated in Tab 9.Tab 9 also specifies the classes (I, II and III) of the materialsto be used for the various categories of structural members.

For non-exposed structures and structures below the lowestballast waterline, see [2.4].

Table 6 : Application of material classes and grades for single-side bulk carrier ESP and combination carrier / OBO ESP

Structural member categoryMaterial grade within

0,4 L amidships

Shear strake at strength deck (1) E/EH

Stringer plate in strength deck (1) E/EH

Bilge strake (1) D/EH

(1) Single strakes are required to be of grade E/EH and within 0,4 L amidships are to have breadths not less than (800 + 5 L) mm, but need not be greater than 1800 mm, unless limited by the geometry of the ship’s design.

Structural member category Material grade

Lower bracket of ordinary side frame (1) (2) D/DH

Side shell strakes included totally or partially between the two points located to 0,125 above and below the intersection of side shell and bilge hopper sloping plate or inner bottom plate (2)

D/DH

(1) the term “lower bracket” means web of lower bracket and web of the lower part of side frames up the point of 0,125 above the intersection of side shell and bilge hopper sloping plate or inner bottom plate.

(2) the span of the side frame, , is defined as the distance between the supporting structures.

Pt B, Ch 4, Sec 1


Figure 1 : Commonly used definitions of temperatures

Table 7 : Application of material classes and grades for ships with ice strengthening

Table 8 : Material grade requirementsfor classes I, II and III

Table 9 : Application of material classes and grades - Structures exposed to low air temperatures

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Structural member category Material grade

Shell strakes in way of ice strengthening area for plates

B/AH

Class I II III

Gross thickness,in mm

NSS HSS NSS HSS NSS HSS

t 15 A AH A AH A AH

15 < t 20 A AH A AH B AH

20 < t 25 A AH B AH D DH

25 < t 30 A AH D DH D DH

30 < t 35 B AH D DH E EH

35 < t 40 B AH D DH E EH

40 < t 50 D DH E EH E EH

Note 1: “NSS” and “HSS” mean, respectively: “Normal Strength Steel” and “Higher Strength Steel”.

Structural member categoryMaterial class

Within 0,4L amidships Outside 0,4L amidshipsSECONDARY:Deck plating exposed to weather (in general)Side plating above TB (1)Transverse bulkheads above TB (1)

I I

PRIMARY:Strength deck plating (2)Continuous longitudinal members above strength deck (excluding longitudinal hatch coamings of ships equal to or greater than 90 m in length)Longitudinal bulkhead above TB (1)Topside tank bulkhead above TB (1)

II I

SPECIAL:Sheer strake at strength deck (3)Stringer plate in strength deck (3)Deck strake at longitudinal bulkhead (4)Continuous longitudinal hatch coamings of ships equal to or greater than 90 m in length (5)

III II

(1) TB is the draught in light ballast condition, defined in Ch 5, Sec 1, [2.4.3].(2) Plating at corners of large hatch openings to be considered on a case by case basis.

Class III or grade E/EH to be applied in positions where high local stresses may occur.(3) To be not less than grade E/EH within 0,4 L amidships in ships with length exceeding 250 m.(4) In ships with breadth exceeding 70 metres at least three deck strakes to be class III.(5) To be not less than grade D/DH.Note 1: Plating materials for sternframes, rudder horns, rudders and shaft brackets are to be of grades not lower than those corre-sponding to the material classes in [2.4].

Pt B, Ch 4, Sec 1


2.5.4 Materials may not be of a lower grade than that indi-cated in Tab 10 to Tab 12 depending on the material class,structural member gross thickness and design temperature tD.

For design temperatures tD < 55°C, materials will be spe-cially considered by the Society on a case by case basis.

2.5.5 Single strakes required to be of class III or of gradeE/EH of FH are to have breadths not less than (800+5L) mm,but not necessarily greater than 1800 mm.

2.6 Grades of steel within refrigerated spaces

2.6.1 For structural members within or adjacent to refriger-ated spaces, when the design temperatures is below 0°C,the materials are to be of grade not lower than those indi-cated in Tab 13, depending on the design temperature, thestructural member gross thickness and its category (asdefined in Tab 3).

Table 10 : Material grade requirements for class I at low temperatures

Table 11 : Material grade requirements for class II at low temperatures

Table 12 : Material grade requirements for class III at low temperatures


20°C / 25°C 26°C / 35°C 36°C / 45°C 46°C / 55°C

NSS HSS NSS HSS NSS HSS NSS HSS

t 10 A AH B AH D DH D DH

10 < t 15 B AH D DH D DH D DH

15 < t 20 B AH D DH D DH E EH

20 < t 25 D DH D DH D DH E EH

25 < t 30 D DH D DH E EH E EH


35 < t 45 D DH E EH E EH N.A. FH

45 < t 50 E EH E EH N.A. FH N.A. FH

Note 1: “NSS” and “HSS” mean, respectively, “Normal Strength Steel” and “Higher Strength Steel”.Note 2: N.A. = not applicable.


20°C / 25°C 26°C / 35°C 36°C / 45°C 46°C / 55°C


t 10 B AH D DH D DH E EH




40 < t 45 E EH N.A. FH N.A. FH N.A. N.A.




20°C / 25°C 26°C / 35°C 36°C / 45°C 46°C / 55°C


t 10 D DH D DH E EH E EH


20 < t 25 E EH E EH E FH N.A. FH




40 < t 50 N.A. FH N.A. FH N.A. N.A. N.A. N.A.


Pt B, Ch 4, Sec 1


Table 13 : Material grade requirements for members within or adjacent to refrigerated spaces

2.6.2 Unless a temperature gradient calculation is carriedout to assess the design temperature and the steel grade inthe structural members of the refrigerated spaces, the tem-peratures to be assumed are specified below:

• temperature of the space on the uninsulated side, forplating insulated on one side only, either with uninsu-lated stiffening members (i.e. fitted on the uninsulatedside of plating) or with insulated stiffening members (i.e.fitted on the insulated side of plating)

• mean value of temperatures in the adjacent spaces, forplating insulated on both sides, with insulated stiffeningmembers, when the temperature difference between theadjacent spaces is generally not greater than 10 °C(when the temperature difference between the adjacentspaces is greater than 10°C, the temperature value isestablished by the Society on a case by case basis)

• in the case of non-refrigerated spaces adjacent to refrig-erated spaces, the temperature in the non-refrigeratedspaces is to be conventionally taken equal to 0°C.

2.6.3 Situations other than those mentioned in [2.6.1] and[2.6.2] or special arrangements will be considered by theSociety on a case by case basis.

2.6.4 Irrespective of the provisions of [2.6.1], [2.6.2] andTab 13, steel having grades lower than those required in[2.4], Tab 3 and Tab 8, in relation to the class and grossthickness of the structural member considered, may not beused.

3 Steels for forging and casting

3.1 General

3.1.1 Mechanical and chemical properties of steels forforging and casting to be used for structural members are tocomply with the applicable requirements of NR216 Materi-als and Welding.

3.1.2 Steels of structural members intended to be weldedare to have mechanical and chemical properties deemedappropriate for this purpose by the Society on a case bycase basis.

3.1.3 The steels used are to be tested in accordance with theapplicable requirements of NR216 Materials and Welding.

3.2 Steels for forging

3.2.1 For the purpose of testing, which is to be carried outin accordance with the applicable requirements of NR216Materials and Welding, the above steels for forging areassigned to class 1 (see NR216 Materials and Welding, Ch2, Sec 3, [1.2]).

3.2.2 Rolled bars may be accepted in lieu of forged prod-ucts, after consideration by the Society on a case by casebasis.

In such case, compliance with the requirements of NR216Materials and Welding, Ch 2, Sec 1, relevant to the qualityand testing of rolled parts accepted in lieu of forged parts,may be required.

3.3 Steels for casting

3.3.1 Cast parts intended for stems, sternframes, rudders,parts of steering gear and deck machinery in general may bemade of C and C-Mn weldable steels of quality 1, havingspecified minimum tensile strength Rm = 400 N/mm2 or440 N/mm2, in accordance with the applicable require-ments of NR216 Materials and Welding, Ch 2, Sec 4.

Items which may be subjected to high stresses may berequired to be of quality 2 steels of the above types.

3.3.2 For the purpose of testing, which is to be carried outin accordance with NR216 Materials and Welding, Ch 2,Sec 4, the above steels for casting are assigned to class 1irrespective of their quality.

3.3.3 The welding of cast parts to main plating contributingto hull strength members is considered by the Society on acase by case basis.

The Society may require additional properties and tests forsuch casting, in particular impact properties which areappropriate to those of the steel plating on which the castparts are to be welded and non-destructive examinations.

3.3.4 Heavily stressed cast parts of steering gear, particu-larly those intended to form a welded assembly and tillersor rotors mounted without key, are to be subjected to sur-face and volumetric non-destructive examination to checktheir internal structure.

4 Aluminium alloy structures

4.1 General

4.1.1 The characteristics of aluminium alloys are to complywith the requirements of NR216 Materials and Welding, Ch3, Sec 2.

Series 5000 aluminium-magnesium alloys or series 6000aluminium-magnesium-silicon alloys are generally to beused (see NR216 Materials and Welding, Ch 3, Sec 2, [2]).

Designtemperature,

in °C

Gross thickness,

in mm

Structural member category

SecondaryPrimary or

Special

t 20 B / AH B / AH

10 tD < 0 20 < t 25 B / AH D / DH

t > 25 D / DH E / EH

t 15 B / AH D / DH

25 tD < 10 15 < t 25 D / DH E / EH

t > 25 E / EH E / EH

40 tD < 25 t 25 D / DH E / EH

t > 25 E / EH E / EH

Pt B, Ch 4, Sec 1


4.1.2 In the case of structures subjected to low service tem-peratures or intended for other specific applications, thealloys to be employed are to be agreed by the Society.

4.1.3 Unless otherwise agreed, the Young’s modulus foraluminium alloys is equal to 70000 N/mm2 and the Pois-son’s ratio equal to 0,33.

4.2 Extruded plating

4.2.1 Extrusions with built-in plating and stiffeners, referredto as extruded plating, may be used.

4.2.2 In general, the application is limited to decks, bulk-heads, superstructures and deckhouses. Other uses may bepermitted by the Society on a case by case basis.

4.2.3 Extruded plating is preferably to be oriented so thatthe stiffeners are parallel to the direction of main stresses.

4.2.4 Connections between extruded plating and primarymembers are to be given special attention.

4.3 Mechanical properties of weld joints

4.3.1 Welding heat input lowers locally the mechanicalstrength of aluminium alloys hardened by work hardening(series 5000 other than condition 0 or H111) or by heattreatment (series 6000).

4.3.2 The as welded properties of aluminium alloys ofseries 5000 are in general those of condition 0 or H111.

Higher mechanical characteristics may be taken intoaccount, provided they are duly justified.

4.3.3 The as welded properties of aluminium alloys ofseries 6000 are to be agreed by the Society.

4.4 Material factor k

4.4.1 The material factor k for aluminium alloys is to beobtained from the following formula:

where:

R’lim : Minimum guaranteed yield stress of the parentmetal in welded condition R’p0,2, in N/mm2, butnot to be taken greater than 70% of the mini-mum guaranteed tensile strength of the parentmetal in welded condition R’m, in N/mm2

R’p0,2 = 1 Rp0,2

R’m = 2 Rm

Rp0,2 : Minimum guaranteed yield stress, in N/mm2, ofthe parent metal in delivery condition

Rm : Minimum guaranteed tensile stress, in N/mm2,of the parent metal in delivery condition.

1 and 2 are given in Tab 14.

Table 14 : Aluminium alloys for welded construction

Table 15 : Aluminium alloysMetallurgical efficiency coefficient

4.4.2 In the case of welding of two different aluminiumalloys, the material factor k to be considered for the scant-lings is the greater material factor of the aluminium alloys ofthe assembly.

4.4.3 For welded constructions in hardened aluminiumalloys (series 5000 other than condition 0 or H111 andseries 6000), greater characteristics than those in weldedcondition may be considered, provided that welded con-nections are located in areas where stress levels are accept-able for the alloy considered in annealed or weldedcondition.

5 Other materials and products

5.1 General

5.1.1 Other materials and products such as parts made ofiron castings, where allowed, products made of copper andcopper alloys, rivets, anchors, chain cables, cranes, masts,derrick posts, derricks, accessories and wire ropes are tocomply with the applicable requirements of NR216 Materi-als and Welding.

k 235R l im-----------=

Aluminium alloy 1 2

Alloys without work-hardeningtreatment (series 5000 in annealed condition 0 or annealed flattened condition H111)

1 1

Alloys hardened by work hardening (series 5000 other than condition 0 or H111)

R’p0,2/Rp0,2 R’m / Rm

Alloys hardened by heat treatment (series 6000) (1)

R’p0,2/Rp0,2 0,6

(1) When no information is available, coefficient 1 is to be taken equal to the metallurgical efficiency coeffi-cient defined in Tab 15.

Note 1:R’p0,2 : Minimum guaranteed yield stress, in N/mm2,

of material in welded condition (see [4.3])R’m : Minimum guaranteed tensile stress, in

N/mm2, of material in welded condition (see [4.3]).

Aluminium alloyTemper

condition

Gross thickness,

in mm

6005 A(Open sections)

T5 or T6 t 6 0,45

t > 6 0,40

6005 A(Closed sections)

T5 or T6 All 0,50

6061 (Sections) T6 All 0,53

6082 (Sections) T6 All 0,45

Pt B, Ch 4, Sec 1


5.1.2 The use of plastics or other special materials not cov-ered by these Rules is to be considered by the Society on acase by case basis. In such cases, the requirements for theacceptance of the materials concerned are to be agreed bythe Society.

5.1.3 Materials used in welding processes are to complywith the applicable requirements of NR216 Materials andWelding.

5.2 Iron cast parts

5.2.1 As a rule, the use of grey iron, malleable iron or sphe-roidal graphite iron cast parts with combined ferritic/perliticstructure is allowed only to manufacture low stressed ele-ments of secondary importance.

5.2.2 Ordinary iron cast parts may not be used for windowsor sidescuttles; the use of high grade iron cast parts of a suit-able type will be considered by the Society on a case bycase basis.

Pt B, Ch 4, Sec 2


SECTION 2 NET SCANTLING APPROACH

Symbols

tC : Rule corrosion addition, in mm, see [3]wN : Net section modulus, in cm3, of ordinary stiffenerswG : Gross section modulus, in cm3, of ordinary stiff-

eners.

1 Application criteria

1.1 General

1.1.1 The scantlings obtained by applying the criteria spec-ified in Part B are net scantlings, i.e. those which provide the strength characteristics required to sustain the loads, excluding any addition for corrosion. Exceptions are the scantlings:• obtained from the yielding checks of the hull girder in

Ch 6, Sec 2• of bow doors and inner doors in Ch 9, Sec 5• of side doors and stern doors in Ch 9, Sec 6• of rudder structures and hull appendages in Part B,

Chapter 10 • of massive pieces made of steel forgings, steel castings

or iron castings,

which are gross scantlings, i.e. they include additions for corrosion.

1.1.2 The required strength characteristics are:• thickness, for plating including that which constitutes

primary supporting members • section modulus, shear area, moments of inertia and

local thickness, for ordinary stiffeners and, as the case may be, primary supporting members

• section modulus, moments of inertia and first moment for the hull girder.

1.1.3 The ship is to be built at least with the gross scant-lings obtained by adding the corrosion additions, specified in Tab 2, to the net scantlings.

2 Net strength characteristic calculation

2.1 Designer’s proposal based on gross scantlings

2.1.1 General criteriaIf the Designer provides the gross scantlings of each struc-tural element without providing their corrosion additions, the structural checks are to be carried out on the basis of the net strength characteristics derived as specified in [2.1.2] to[2.1.6].

2.1.2 Plating The net thickness is to be obtained by deducting tc from the gross thickness.

2.1.3 Ordinary stiffenersThe net transverse section is to be obtained by deducting tCfrom the gross thickness of the elements which constitute the stiffener profile. For bulb profiles, an equivalent angle profile, as specified in Ch 4, Sec 3, [3.1.2], may be consid-ered.

The net strength characteristics are to be calculated for the net transverse section. As an alternative, the net section modulus may be obtained from the following formula:

wN = wG (1 tC) tC

where and are the coefficients defined in Tab 1.

Table 1 : Coefficients and

2.1.4 Primary supporting members analysed through an isolated beam structural model

The net transverse section is to be obtained by deducting tCfrom the gross thickness of the elements which constitute the primary supporting members.

The net strength characteristics are to be calculated for the net transverse section.

2.1.5 Primary supporting members analysed through a three dimensional model or a complete ship model

The net thickness of plating which constitutes primary sup-porting members is to be obtained by deducting 0,5tc from the gross thickness.

2.1.6 Hull girder net strength characteristics to be used for the check of plating, ordinary stiffeners and primary supporting members

For the hull girder, the net hull transverse sections are to be considered as being constituted by plating and stiffeners having net scantlings calculated on the basis of the corro-sion additions tC , according to [2.1.2] to [2.1.4].

It is to be checked whether:

ZNA 0,9 ZGD

Type of ordinary stiffeners

Flat bars 0,035 2,8

Flanged profiles 0,060 14,0

Bulb profiles:wG 200 cm3

wG > 200 cm3

0,0700,035

0,4 7,4

Pt B, Ch 4, Sec 2


where:

ZNA : Net midship section modulus, in m3, calculated on the basis of the net scantlings obtained con-sidering the corrosion additions tC according to[2.1.2] to [2.1.4]

ZGD : Gross midship section modulus, in m3, calcu-lated on the basis of the gross scantlings pro-posed by the Designer.

Where the above condition is not satisfied, the hull girder normal and shear stresses, to be used for the checks of plat-ing, ordinary stiffeners and primary supporting members analysed through an isolated beam structural model, are to be obtained by dividing by 0,9 those obtained by consider-ing the hull girder transverse sections with their gross scant-lings.

2.1.7 Hull girder net strength characteristics to be used for the check of hull girder ultimate strength

For the hull girder, the net hull transverse sections are to be considered as being constituted by plating and stiffeners having net scantlings calculated on the basis of the corro-sion additions tC , according to [2.1.2] to [2.1.4].


ZNA 0,9 ZGD

where:

ZNA : Net midship section modulus, in m3, calculated on the basis of the net scantlings obtained con-sidering the corrosion additions tC according to[2.1.2] to [2.1.4]


Where the above condition is not satisfied, the net scantling of plating and ordinary stiffeners constituting the transverse section are to be calculated on the basis of the corrosion additions tc, where:

: Coefficient to be calculated so that:

ZNA 0,9 ZGD

2.2 Designer’s proposal based on net scant-lings

2.2.1 Net strength characteristics and corrosion additions

If the Designer provides the net scantlings of each structural element, the structural checks are to be carried out on the basis of the proposed net strength characteristics.

The Designer is also to provide the corrosion additions or the gross scantlings of each structural element. The pro-posed corrosion additions are to be not less than the values specified in [3].

2.2.2 Hull girder net strength characteristics to be used for the check of plating, ordinary stiffeners and primary supporting members

For the hull girder, the net hull transverse sections are to be considered as being constituted by plating and stiffeners having the net scantlings proposed by the Designer.


ZNAD 0,9 ZGD

where:

ZNAD : Net midship section modulus, in m3, calculated on the basis of the net scantlings proposed by the Designer


Where the above condition is not satisfied, the hull girder normal and shear stresses, to be used for the checks of plat-ing, ordinary stiffeners and primary supporting members analysed through an isolated beam structural model, are to be obtained by dividing by 0,9 those obtained by consider-ing the hull girder transverse sections with their gross scant-lings.

2.2.3 Hull girder net strength characteristics to be used for the check of hull girder ultimate strength

The hull girder strength characteristic calculation is to be carried out according to [2.1.7] by using the corrosion addi-tions proposed by the Designer in lieu of tc.

3 Corrosion additions

3.1 Values of corrosion additions

3.1.1 General

The values of the corrosion additions specified in this Arti-cle are to be applied in relation to the relevant protective coatings required by the Rules.

The Designer may define values of corrosion additions greater than those specified in [3.1.2].

3.1.2 Corrosion additions for steel other than stainless steel

In general, the corrosion addition to be considered for plat-ing forming the boundary between two compartments of different types is equal to:

• for plating with a gross thickness greater than 10 mm, the sum of the values specified in Tab 2 for one side exposure to each compartment

• for plating with a gross thickness less than or equal to 10 mm, the smallest of the following values:

- 20 % of the gross thickness of the plating

- sum of the values specified in Tab 2 for one side exposure to each compartment.

For an internal member within a given compartment, or for plating forming the boundary between two compartments of the same type, the corrosion addition to be considered is twice the value specified in Tab 2 for one side exposure to that compartment.

Pt B, Ch 4, Sec 2


Table 2 : Corrosion additions tc , in mm, for each exposed side

When, according to Tab 2, a structural element is affected by more than one value of corrosion additions (e.g. a side frame in a dry bulk cargo hold extending above the lower zone), the scantling criteria are generally to be applied con-sidering the value of corrosion addition applicable at the lowest point of the element.

3.1.3 Corrosion additions for stainless steelFor structural members made of stainless steel, the corro-sion addition tc is to be taken equal to 0.

3.1.4 Corrosion additions for non-alloyed steel clad with stainless steel

For plates made of non-alloyed steel clad with stainless steel, the corrosion addition tc is to be taken equal to 0 only for the plate side clad with stainless steel.

3.1.5 Corrosion additions for aluminium alloys

For structural members made of aluminium alloys, the cor-rosion addition tc is to be taken equal to 0.

Compartment type General (1) Special cases

Ballast tank (2) 1,00 1,25 in upper zone (6)

Cargo oil tank and fuel oil tank (3)

Plating of horizontal surfaces 0,75 1,00 in upper zone (6)

Plating of non-horizontal surfaces 0,50 1,00 in upper zone (6)

Ordinary stiffeners and primary supporting members 0,75 1,00 in upper zone (6)

Independant tank of ships with service notation liquefied gas carrier (4) 0,00

Cofferdam in cargo area of ships with the service notation liquefied gas carrier 1,00

Dry bulk cargo hold (5) General 1,00

Inner bottom platingSide plating for single hull shipInner side plating for double hull shipSloping stool plate of hopper tanks and lower stoolTransverse bulkhead plating

1,75

Frames, ordinary stiffeners and primary supporting members

1,00 1,50 in lower zone (7)

Compartment located between independant tank and inner side of ships with the additional service feature asphalt carrier

1,00

Hopper well of dredging ships 2,00

Accommodation space 0,00

Compartments other than those mentioned aboveOutside sea and air

0,50

(1) General: corrosion additions tc are applicable to all members of the considered item with possible exceptions given for upper and lower zones.

(2) Ballast tank: does not include cargo oil tanks which may carry ballast according to Regulation 13 of MARPOL 73/78.(3) For ships with the service notation chemical tanker ESP, the corrosion addition tC may be taken equal to 0 for cargo tanks cov-

ered with a protective lining or coating (see IBC, 6).(4) The corrosion addition tC specified for cargo tanks is to be applied when required in IGC, 4.5.2.(5) Dry bulk cargo hold: includes holds, intended for the carriage of dry bulk cargoes, which may carry oil or water ballast.(6) Upper zone: area within 1,5 m below the top of the tank or the hold. This is not to be applied to tanks in the double bottom.(7) Lower zone: area within 3 m above the bottom of the tank or the hold.

Pt B, Ch 4, Sec 3


SECTION 3 STRENGTH PRINCIPLES

Symbols

E : Young’s modulus, in N/mm2, to be taken equalto:

• for steels in general:

E = 2,06105 N/mm2

• for stainless steels:

E = 1,95105 N/mm2

• for aluminium alloys:

E = 7,0104 N/mm2

s : Spacing, in m, of ordinary stiffeners or primarysupporting members, as the case may be

: Span, in m, of an ordinary stiffener or a primarysupporting member, as the case may be, meas-ured between the supporting members (see Fig2 to Fig 5)

b : Length, in m, of brackets (see Fig 4 and Fig 5)

hw : Web height, in mm, of an ordinary stiffener or aprimary supporting member, as the case may be

tw : Net web thickness, in mm, of an ordinary stiff-ener or a primary supporting member, as thecase may be

bf : Face plate width, in mm, of an ordinary stiffeneror a primary supporting member, as the casemay be

tf : Net face plate thickness, in mm, of an ordinarystiffener or a primary supporting member, as thecase may be

tp : Net thickness, in mm, of the plating attached toan ordinary stiffener or a primary supportingmember, as the case may be

w : Net section modulus, in cm3, of an ordinarystiffener or a primary supporting member, as thecase may be, with attached plating of width bp

I : Net moment of inertia, in cm4, of an ordinarystiffener or a primary supporting member, as thecase may be, without attached plating, aroundits neutral axis parallel to the plating (see Fig 4and Fig 5)

IB : Net moment of inertia, in cm4, of an ordinarystiffener or a primary supporting member, as thecase may be, with bracket and without attachedplating, around its neutral axis parallel to theplating, calculated at mid-length of the bracket(see Fig 4 and Fig 5).

1 General principles

1.1 Structural continuity

1.1.1 The variation in scantlings between the midshipregion and the fore and aft parts is to be gradual.

1.1.2 Attention is to be paid to the structural continuity:

• in way of changes in the framing system

• at the connections of primary or ordinary stiffeners

• in way of the ends of the fore and aft parts (see Ch 9, Sec1 and Ch 9, Sec 2) and machinery space (see Ch 9, Sec3)

• in way of ends of superstructures (see Ch 9, Sec 4).

1.1.3 Longitudinal members contributing to the hull girderlongitudinal strength, according to Ch 6, Sec 1, [2], are toextend continuously for a sufficient distance towards theends of the ship.

Ordinary stiffeners contributing to the hull girder longitudinalstrength are generally to be continuous when crossing pri-mary supporting members. Otherwise, the detail of connec-tions is considered by the Society on a case by case basis.

Longitudinals of the bottom, bilge, sheerstrake, deck, upperand lower longitudinal bulkhead and inner side strakes, aswell as the latter strakes themselves, the lower strake of thecentreline bottom girder and the upper strake of the cen-treline deck girder, where fitted, are to be continuousthrough the transverse bulkheads of the cargo area and cof-ferdams. Alternative solutions may be examined by theSociety on a case by case basis, provided they are equallyeffective.

1.1.4 Where stress concentrations may occur in way ofstructural discontinuities, adequate compensation and rein-forcements are to be provided.

1.1.5 Openings are to be avoided, as far as practicable, inway of highly stressed areas.

Where necessary, the shape of openings is to be speciallydesigned to reduce the stress concentration factors.

Openings are to be generally well rounded with smoothedges.

1.1.6 Primary supporting members are to be arranged insuch a way that they ensure adequate continuity of strength.Abrupt changes in height or in cross-section are to beavoided.

Pt B, Ch 4, Sec 3


1.2 Connections with higher strength steel

1.2.1 The vertical extent of higher strength steel is to com-ply with the requirements of Ch 6, Sec 2, [4.5].

1.2.2 When a higher strength steel is adopted at deck,members not contributing to the longitudinal strength andwelded on the strength deck (e.g. hatch coamings, strength-ening of deck openings) are also generally to be made of thesame higher strength steel.

1.3 Connections between steel and alumin-ium

1.3.1 Any direct contact between steel and aluminiumalloy is to be avoided (e.g. by means of zinc or cadmiumplating of the steel parts and application of a suitable coat-ing on the corresponding light alloy parts).

1.3.2 Any heterogeneous jointing system is considered bythe Society on a case by case basis.

1.3.3 The use of transition joints made of aluminium/steel-clad plates or profiles is considered by the Society on a caseby case basis (see NR216 Materials, Ch 3, Sec 2, [4]).

2 Plating

2.1 Insert plates and doublers

2.1.1 A local increase in plating thickness is generally tobe achieved through insert plates. Local doublers, whichare normally only allowed for temporary repair, may how-ever be accepted by the Society on a case by case basis.

In any case, doublers and insert plates are to be made ofmaterials of a quality at least equal to that of the plates onwhich they are welded.

2.1.2 Doublers having width, in mm, greater than:

• 20 times their thickness, for thicknesses equal to or lessthan 15 mm

• 25 times their thickness, for thicknesses greater than 15mm

are to be fitted with slot welds, to be effected according toCh 12, Sec 1, [2.6].

2.1.3 When doublers fitted on the outer shell and strengthdeck within 0,6L amidships are accepted by the Society,their width and thickness are to be such that slot welds arenot necessary according to the requirements in [2.1.2]. Out-side this area, the possibility of fitting doublers requiringslot welds will be considered by the Society on a case bycase basis.

3 Ordinary stiffeners

3.1 General

3.1.1 Stiffener not perpendicular to the attached plating

Where the stiffener is not perpendicular to the attachedplating, the actual net section modulus may be obtained, incm3, from the following formula:

w = w0 sin

where:

w0 : Actual net section modulus, in cm3, of the stiff-ener assumed to be perpendicular to the plating

: Angle between the stiffener web and theattached plating.

3.1.2 Bulb section: equivalent angle profile

A bulb section may be taken as equivalent to an angle pro-file.

The dimensions of the equivalent angle profile are to beobtained, in mm, from the following formulae:

where:

h’w , t’w : Height and net thickness of the bulb section, in

mm, as shown in Fig 1

: Coefficient equal to:

Figure 1 : Dimensions of a bulb section

hw hw hw

9 2,-------- 2+–=

tw tw=

bf tw hw

6 7,-------- 2–+=

tfhw

9 2,-------- 2–=

1 1, 120 hw– 2

3000-----------------------------+ for hw

120

1 for hw 120

��

��

Pt B, Ch 4, Sec 3


3.2 Span of ordinary stiffeners

3.2.1 GeneralThe span of ordinary stiffeners is to be measured as shownin Fig 2 to Fig 5.

3.2.2 Ordinary stiffeners connected by strutsThe span of ordinary stiffeners connected by one or twostruts, dividing the span in equal lengths, may be takenequal to 0,7.

Figure 2 : Ordinary stiffener without brackets

Figure 3 : Ordinary stiffener with a stiffener at one end

Figure 4 : Ordinary stiffener with end bracket

Figure 5 : Ordinary stiffener with a bracketand a stiffener at one end

3.3 Width of attached plating

3.3.1 Yielding checkThe width of the attached plating to be considered for theyielding check of ordinary stiffeners is to be obtained, in m,from the following formulae:• where the plating extends on both sides of the ordinary

stiffener:bP = s

• where the plating extends on one side of the ordinarystiffener (i.e. ordinary stiffeners bounding openings):bP = 0,5s.

3.3.2 Buckling check and ultimate strength checkThe attached plating to be considered for the buckling andultimate strength check of ordinary stiffeners is defined inCh 7, Sec 2, [4.1] and Ch 7, Sec 2, [5.2], respectively.

3.4 Geometric properties

3.4.1 Built sectionThe geometric properties of built sections as shown in Fig 6may be calculated as indicated in the following formulae.

Figure 6 : Dimensions of a built section

These formulae are applicable provided that:

where:Aa : Net sectional area, in mm2, of the attached plat-

ing.The net section modulus of a built section with attachedplating is to be obtained, in cm3, from the following for-mula:

The distance from face plate to neutral axis is to beobtained, in cm, from the following formula:

�

�

�

�b

I

IB

�

�b

I

IB

tp

tf

tw

bf

h w

Aa tfbf

hw

tp

------ 10

hw

tf

------ 10

whwtfbf

1000-------------- tWhW

2

6000------------- 1

Aa tfbf–

AatWhW

2------------+

-------------------------+

+=

vhW Aa 0 5tWhW+

10 Aa tfbf tWhW+ + ---------------------------------------------------=

Pt B, Ch 4, Sec 3


The net moment of inertia of a built section with attachedplating is to be obtained, in cm4, from the following for-mula:

I = w v

The net shear sectional area of a built section with attachedplating is to be obtained, in cm2, from the following for-mula:

3.4.2 CorrugationsThe net section modulus of a corrugation is to be obtained,in cm3, from the following formula:

where:

t : Net thickness of the plating of the corrugation,in mm

d, b, c : Dimensions of the corrugation, in mm, shownin Fig 7.

Where the web continuity is not ensured at ends of thebulkhead, the net section modulus of a corrugation is to beobtained, in cm3, from the following formula:

w = 0,5 b t d 103

Figure 7 : Dimensions of a corrugation

3.5 End connections

3.5.1 Where ordinary stiffeners are continuous through pri-mary supporting members, they are to be connected to theweb plating so as to ensure proper transmission of loads,e.g. by means of one of the connection details shown in Fig8 to Fig 11.

Connection details other than those shown in Fig 8 to Fig 11may be considered by the Society on a case by case basis.In some cases, the Society may require the details to be sup-ported by direct calculations submitted for review.

Figure 8 : End connection of ordinary stiffenerWithout collar plate

Figure 9 : End connection of ordinary stiffenerCollar plate

Figure 10 : End connection of ordinary stiffenerOne large collar plate

Figure 11 : End connection of ordinary stiffenerTwo large collar plates

3.5.2 Where ordinary stiffeners are cut at primary support-ing members, brackets are to be fitted to ensure the struc-tural continuity. Their net section modulus and their netsectional area are to be not less than those of the ordinarystiffeners.

The net thickness of brackets is to be not less than that ofordinary stiffeners. Brackets with net thickness, in mm, lessthan 15Lb, where Lb is the length, in m, of the free edge ofthe end bracket, are to be flanged or stiffened by a weldedface plate. The net sectional area, in cm2, of the flangededge or face plate is to be at least equal to 10 Lb .

3.5.3 Where necessary, the Society may require backingbrackets to be fitted, as shown in Fig 12, in order to improvethe fatigue strength of the connection (see also [4.7.4]).

Figure 12 : End connection of ordinary stiffenerBacking bracket

AShhwtw

100-----------=

w td6----- 3b c+ 10 3–=

b

t

d

c

X X/2

Pt B, Ch 4, Sec 3


4 Primary supporting members

4.1 Span of primary supporting members

4.1.1 The span of primary supporting members is to bedetermined in accordance with [3.2].


4.2.1 General

The width of the attached plating to be considered for theyielding check of primary supporting members analysedthrough beam structural models is to be obtained, in m,from the following formulae:

• where the plating extends on both sides of the primarysupporting member:

bP = min (s; 0,2)

• where the plating extends on one side of the primarysupporting member (i.e. primary supporting membersbounding openings):

bP = 0,5 min (s; 0,2)

4.2.2 Corrugated bulkheads

The width of attached plating of corrugated bulkhead pri-mary supporting members is to be determined as follows:

• when primary supporting members are parallel to thecorrugations and are welded to the corrugation flanges,the width of the attached plating is to be calculated inaccordance with [4.2.1] and is to be taken not greaterthan the corrugation flange width

• when primary supporting members are perpendicular tothe corrugations, the width of the attached plating is tobe taken equal to the width of the primary supportingmember face plate.

4.3 Geometric properties

4.3.1 Standard roll sections

The geometric properties of primary supporting membersmade of standard roll sections may be determined inaccordance with [3.4.1], reducing the web height hw by thedepth of the cut-out for the passage of ordinary stiffeners, ifany (see [4.6.1]).

4.3.2 Built sections

The geometric properties of primary supporting membersmade of built sections (including primary supporting mem-bers of double skin structures, such as double bottom floorsand girders) are generally determined in accordance with[3.4.1], reducing the web height hw by the depth of the cut-out for the passage of ordinary stiffeners, if any (see [4.6.1]).

Additional requirements relevant to the net shear sectionalarea are provided in [4.3.3].

4.3.3 Net shear sectional area in the case of web large openings

Where large openings are fitted in the web of primary sup-porting members (e.g. where a pipe tunnel is fitted in the

double bottom, see Fig 13), their influence is to be takeninto account by assigning an equivalent net shear sectionalarea to the primary supporting member.

This equivalent net shear sectional area is to be obtained, incm2, from the following formula:

where (see Fig 13):

I1, I2 : Net moments of inertia, in cm4, of deep webs(1) and (2), respectively, with attached platingaround their neutral axes parallel to the plating

ASh1, ASh2 : Net shear sectional areas, in cm2, of deep webs(1) and (2), respectively, to be calculatedaccording to [4.3.2]

: Span, in cm, of deep webs (1) and (2).

Figure 13 : Large openings in the webof primary supporting members

4.4 Bracketed end connections

4.4.1 Arm lengths of end brackets are to be equal, as far aspracticable.

With the exception of primary supporting members of trans-versely framed single sides (see Ch 4, Sec 5, [3.2]), theheight of end brackets is to be not less than that of the pri-mary supporting member.

4.4.2 The net thickness of the end bracket web is generallyto be not less than that of the primary supporting memberweb.

4.4.3 The net scantlings of end brackets are generally to besuch that the net section modulus of the primary supportingmember with end brackets is not less than that of the pri-mary supporting member at mid-span.

4.4.4 The width, in mm, of the face plate of end brackets isto be not less than 50(Lb+1), where Lb is the length, in m, ofthe free edge of the end bracket.

Moreover, the net thickness of the face plate is to be not lessthan that of the bracket web.

AShASh1

10 00322, ASh1

I1

----------------------------------+-------------------------------------------- ASh2

10 00322, ASh2

I2

----------------------------------+--------------------------------------------+=

�

��

��

Pt B, Ch 4, Sec 3


4.4.5 Where deemed necessary, face plates of end con-necting brackets are to be symmetrical. In such a case, thefollowing requirements are in general to be complied with:

• face plates are to be tapered at ends with a total anglenot greater than 30°

• the breath of face plates at ends is not to be greater than25 mm

• face plates of 20 mm thick and above are to be taperedin thickness at their ends down to their mid-thickness

• bracket toes are to be of increased thickness

• an additional tripping bracket is to be fitted

• the radius R of the face plate is to be as large as possible

• collar plates welded to the plating are to be fitted in wayof the bracket toes

• throat thickness of fillet welds is not to be less than t/2,with t being the thickness of the bracket toe.

An example of bracket with symmetrical face plate is indi-cated in Fig 14.

4.4.6 Stiffening of end brackets is to be designed such thatit provides adequate buckling web stability.

Figure 14 : Bracket with symmetrical face plate

As guidance, the following prescriptions may be applied:

• where the length Lb is greater than 1,5 m, the web of thebracket is to be stiffened

• the net sectional area, in cm2, of web stiffeners is to benot less than 16,5, where is the span, in m, of thestiffener

• tripping flat bars are to be fitted to prevent lateral buck-ling of web stiffeners. Where the width of the symmetri-

cal face plate is greater than 400 mm, additionalbacking brackets are to be fitted.

4.4.7 In addition to the above requirements, the net scant-lings of end brackets are to comply with the applicablerequirements given in Ch 4, Sec 4 to Ch 4, Sec 7.

4.5 Bracketless end connections

4.5.1 In the case of bracketless crossing between two pri-mary supporting members (see Fig 15), the net thickness ofthe common part of the webs, in mm, is to be not less thanthe greatest value obtained from the following formula:

where:

R, m : Partial safety factors as defined in Ch 7, Sec 3,[1.4]

Sf1, Sf2 : Net flange section, in mm2,of member 1 andmember 2 respectively

1, 2 : Normal stresses, in N/mm2 , in member 1 andmember 2 respectively

t1, t2 : Net web thicknesses, in mm, of member 1 andmember 2 respectively

Figure 15 : Bracketless end connectionsbetween two primary supporting members

4.5.2 In the case of bracketless crossing between three pri-mary supporting members (see Fig 16), when the flange ofmember 2 and member 3 is continuous, the net thickness,in mm, of the common part of the webs is not to be lessthan the greater of:

≤ ��

��

tbRmSf11

0 5h2Ry-------------------------=

tbRmSf22

0 5h1Ry-------------------------=

tb max t1 t2( , )=

Member 2

Member 1

h1tb

h2

tbRmSf11

0 5h2Ry-------------------------=

tb max t1 t2( , )=

Pt B, Ch 4, Sec 3


Figure 16 : Bracketless end connectionsbetween three primary supporting members

When the flanges of member 2 and member 3 are not con-tinuous, the net thickness of the common part of the webs isto be defined as [4.5.1].

4.5.3 The common part of the webs is to be generally stiff-ened where the minimum height of the member 1 andmember 2 is greater than 100tb.

4.5.4 When lamellar tearing of flanges may occur, theflange in way of the connection may be requested to be of Zquality or a 100% ultrasonic testing of the flange in way ofthe weld may be required prior to and after welding.

4.6 Cut-outs and holes

4.6.1 Cut-outs for the passage of ordinary stiffeners are tobe as small as possible and well rounded with smoothedges.

In general, the depth of cut-outs is to be not greater than50% of the depth of the primary supporting member.

4.6.2 Where openings such as lightening holes are cut inprimary supporting members, they are to be equidistantfrom the face plate and corners of cut-outs and, in general,their height is to be not greater than 20% of the web height.

4.6.3 Openings may not be fitted in way of toes of endbrackets.

4.6.4 Over half of the span of primary supporting members,the length of openings is to be not greater than the distancebetween adjacent openings.

At the ends of the span, the length of openings is to be notgreater than 25% of the distance between adjacent open-ings.

4.6.5 In the case of large openings as shown in Fig 17, thesecondary stresses in primary supporting members are to beconsidered for the reinforcement of the openings.

The secondary stresses may be calculated in accordancewith the following procedure.

Figure 17 : Large openings in primary supporting members - Secondary stresses

Members (1) and (2) are subjected to the following forces,moments and stresses:

where:

MA, MB : Bending moments, in kN.m, in sections A and Bof the primary supporting member

m1, m2 : Bending moments, in kN.m, in (1) and (2)

d : Distance, in m, between the neutral axes of (1)and (2)

F1, F2 : Axial stresses, in N/mm2, in (1) and (2)

m1, m2 : Bending stresses, in N/mm2, in (1) and (2)

QT : Shear force, in kN, equal to QA or QB, which-ever is greater

1, 2 : Shear stresses, in N/mm2, in (1) and (2)

w1, w2 : Net section moduli, in cm3, of (1) and (2)

S1, S2 : Net sectional areas, in cm2, of (1) and (2)

Member 2

Member 1

Member 3

h1tb

h2

MA

MMBQA

Q QB

R/2

1

2 BA

R

2

1

d

FK2 QT

- F

K1 QT

m2

m1

FMA MB+

2d----------------------=

m1MA MB–

2--------------------- K1=

m2MA MB–

2--------------------- K2=

F1 10 FS1

-----=

F2 10 FS2

-----=

m1m1

w1

-------103=

m2m2

w2

-------103=

1 10K1QT

Sw1

-------------=

2 10K2QT

Sw2

-------------=

Pt B, Ch 4, Sec 3


Sw1, Sw2 : Net sectional areas, in cm2, of webs in (1) and(2)

I1, I2 : Net moments of inertia, in cm4, of (1) and (2)with attached plating

The combined stress C calculated at the ends of members(1) and (2) is to be obtained from the following formula:

The combined stress C is to comply with the checking cri-teria in Ch 7, Sec 3, [3.6] or Ch 7, Sec 3, [4.3], as applica-ble. Where these checking criteria are not complied with,the cut-out is to be reinforced according to one of the solu-tions shown in Fig 18 to Fig 20:

• continuous face plate (solution 1): see Fig 18

• straight face plate (solution 2): see Fig 19

• compensation of the opening (solution 3): see Fig 20

• combination of the above solutions.

Other arrangements may be accepted provided they aresupported by direct calculations submitted to the Society forreview.

Figure 18 : Stiffening of large openings in primary supporting members - Solution 1



Inserted plate

4.7 Stiffening arrangement

4.7.1 Webs of primary supporting members are generallyto be stiffened where the height, in mm, is greater than100t, where t is the web net thickness, in mm, of the pri-mary supporting member.In general, the web stiffeners of primary supporting mem-bers are to be spaced not more than 110t.

4.7.2 Where primary supporting member web stiffeners arewelded to ordinary stiffener face plates, their net sectionalarea at the web stiffener mid-height is to be not less than thevalue obtained, in cm2, from the following formula:

where:k1 : Coefficient depending on the web connection

with the ordinary stiffener, to be taken as:• k1 = 0,30 for connections without collar

plate (see Fig 8)• k1 = 0,225 for connections with a collar

plate (see Fig 9)• k1 = 0,20 for connections with one or two

large collar plates (see Fig 10 and Fig 11)pS, pW : Still water and wave pressure, respectively, in

kN/m2, acting on the ordinary stiffener, definedin Ch 7, Sec 2, [3.3.2] or Ch 8, Sec 4, [3.3.2]

S2, W2 : Partial safety factors, defined in Ch 7, Sec 2, Tab1 or Ch 8, Sec 4, Tab 1 for yielding check (gen-eral).

4.7.3 The net section modulus of web stiffeners of non-watertight primary supporting members is to be not lessthan the value obtained, in cm3, from the following formula:

w = 2,5 s2 t Ss2

where:s : Length, in m, of web stiffenerst : Web net thickness, in mm, of the primary sup-

porting memberSs : Spacing, in m, of web stiffeners.Moreover, web stiffeners located in areas subject to com-pression stresses are to be checked for buckling in accord-ance with Ch 7, Sec 2, [4].

K1I1

I1 I2+--------------=

K2I2

I1 I2+--------------=

c F m+ 2 32+=

0,5 H1,5 H

H

t1 t

H

H

A 0 1k, 1 S2pS W2pW+ s=

Pt B, Ch 4, Sec 3


4.7.4 Tripping brackets (see Fig 21) welded to the face plateare generally to be fitted: • every fourth spacing of ordinary stiffeners, without

exceeding 4 m• at the toe of end brackets• at rounded face plates• in way of cross ties• in way of concentrated loads.

Where the width of the symmetrical face plate is greaterthan 400 mm, backing brackets are to be fitted in way of thetripping brackets.

Figure 21 : Primary supporting member:web stiffener in way of ordinary stiffener

4.7.5 In general, the width of the primary supporting mem-ber face plate is to be not less than one tenth of the depth ofthe web, where tripping brackets are spaced as specified in[4.7.4].

4.7.6 The arm length of tripping brackets is to be not lessthan the greater of the following values, in m:

where:

b : Height, in m, of tripping brackets, shown in Fig21

st : Spacing, in m, of tripping brackets

t : Net thickness, in mm, of tripping brackets.

It is recommended that the bracket toe should be designedas shown in Fig 21.

4.7.7 Tripping brackets with a net thickness, in mm, lessthan 15Lb are to be flanged or stiffened by a welded faceplate.

The net sectional area, in cm2, of the flanged edge or theface plate is to be not less than 10Lb, where Lb is the length,in m, of the free edge of the bracket.

Where the depth of tripping brackets is greater than 3 m, anadditional stiffener is to be fitted parallel to the bracket freeedge.

b

dδ

d 0 38b,=

d 0 85b st

t---,=

Pt B, Ch 4, Sec 4


SECTION 4 BOTTOM STRUCTURE

1 General

1.1 Application

1.1.1 The requirements of this Section apply to longitudi-nally or transversely framed single and double bottom struc-tures.

1.2 General arrangement

1.2.1 In ships greater than 120 m in length, the bottom is,in general, to be longitudinally framed.

1.2.2 The bottom structure is to be checked by theDesigner to make sure that it withstands the loads resultingfrom the dry-docking of the ship.

1.2.3 The bottom is to be locally stiffened where concen-trated loads are envisaged.

1.2.4 Girders or floors are to be fitted under each line ofpillars, when deemed necessary by the Society on the basisof the loads carried by the pillars.

1.2.5 Adequate tapering is to be provided between doublebottom and adjacent single bottom structures. Similarly,adequate continuity is to be provided in the case of heightvariation in the double bottom. Where such a height varia-tion occurs within 0,6 L amidships, the inner bottom is gen-erally to be maintained continuous by means of inclinedplating.

1.2.6 Provision is to be made for the free passage of waterfrom all parts of the bottom to the suctions, taking intoaccount the pumping rate required.

1.2.7 When solid ballast is fitted, it is to be securely posi-tioned. If necessary, intermediate floors may be required forthis purpose.

1.3 Keel

1.3.1 The width of the keel is to be not less than the valueobtained, in m, from the following formula:

1.4 Drainage and openings for air passage

1.4.1 Holes are to be cut into floors and girders to ensurethe free passage of air and liquids from all parts of the dou-ble bottom.

1.4.2 Air holes are to be cut as near to the inner bottomand draining holes as near to the bottom shell as practica-ble.

2 Longitudinally framed single bottom

2.1 General

2.1.1 Single bottom ships are to be fitted with a centregirder formed by a vertical continuous or intercostal webplate and a horizontal face plate continuous over the floors.

Intercostal web plates are to be aligned and welded tofloors.

2.1.2 In general, girders are to be fitted spaced not morethan 2,5 m apart and formed by a vertical intercostal webplate and a horizontal face plate continuous over the floors.

Intercostal web plates are to be aligned and welded tofloors.

2.1.3 Centre and side girders are to be extended as far aftand forward as practicable.

2.1.4 Where side girders are fitted in lieu of the centregirder, the scarfing is to be adequately extended and addi-tional stiffening of the centre bottom may be required.

2.1.5 Longitudinal girders are to be fitted in way of eachline of pillars.

2.1.6 Floors are to be made with a welded face platebetween the collision bulkhead and 0,25L from the foreend.

2.2 Floors

2.2.1 In general, the floor spacing is to be not greater than5 frame spacings.

2.3 Longitudinal ordinary stiffeners

2.3.1 Longitudinal ordinary stiffeners are generally to becontinuous when crossing primary members.

3 Transversely framed single bottom

3.1 General

3.1.1 The requirements in [2.1] apply also to transverselyframed single bottoms.

3.2 Floors

3.2.1 Floors are to be fitted at every frame.

3.2.2 The height, in m, of floors at the centreline is to benot less than /16. In the case of ships with considerablerise of floor, this height may be required to be increased soas to assure a satisfactory connection to the frames.

b 0 8 0 5 L100----------,+,=

Pt B, Ch 4, Sec 4


4 Longitudinally framed double bottom

4.1 General

4.1.1 The centre girder is to be continuous and extendedover the full length of ship and the spacing of adjacent lon-gitudinal girders is generally to be not greater than 6,5 m.

4.2 Double bottom height

4.2.1 The double bottom height is given in Ch 2, Sec 2,[3].

4.3 Floors

4.3.1 The spacing of plate floors, in m, is generally to benot greater than 0,05L or 3,8 m, whichever is the lesser.

Additional plate floors are to be fitted in way of transversewatertight bulkheads.

4.3.2 Plate floors are generally to be provided with stiffen-ers in way of longitudinal ordinary stiffeners.

4.3.3 Where the double bottom height exceeds 0,9 m,watertight floors are to be fitted with stiffeners having a netsection modulus not less than that required for tank bulk-head vertical stiffeners.

4.4 Bottom and inner bottom longitudinal ordinary stiffeners

4.4.1 Bottom and inner bottom longitudinal ordinary stiff-eners are generally to be continuous through the floors.

4.5 Brackets to centreline girder and margin plate

4.5.1 In general, intermediate brackets are to be fitted con-necting either the margin plate or the centre girder to thenearest bottom and inner bottom ordinary stiffeners.

4.5.2 Such brackets are to be stiffened at the edge with aflange having a width not less than 1/10 of the local doublebottom height.

If necessary, the Society may require a welded flat bar to bearranged in lieu of the flange.

4.5.3 Where the side shell is transversely stiffened, marginplate brackets are to be fitted at every frame.

4.6 Duct keel

4.6.1 Where a duct keel is arranged, the centre girder maybe replaced by two girders conveniently spaced, generallyno more than 2 m apart.

4.6.2 The structures in way of the floors are to ensure suffi-cient continuity of the latter.

4.7 Bilge wells

4.7.1 Bilge wells arranged in the double bottom are to belimited in depth and formed by steel plates having a netthickness not less than the greater of that required for water-tight floors and that required for the inner bottom.

4.7.2 In ships for which damage stability requirements areto comply with, such bilge wells are to be fitted so that thedistance of their bottom from the shell plating is not lessthan 460 mm.

4.7.3 Where there is no margin plate, well arrangement isconsidered by the Society on a case by case basis.

5 Transversely framed double bottom

5.1 General

5.1.1 The requirements in [4.1], [4.2], [4.5], [4.6] and [4.7]apply also to transversely framed double bottoms.

5.2 Floors

5.2.1 Plate floors are to be fitted at every frame forward of0,75L from the aft end.

Plate floors are also to be fitted:

• in way of transverse watertight bulkheads

• in way of double bottom steps.

Elsewhere, plate floors may be arranged at a distance notexceeding 3 m.

5.2.2 In general, plate floors are to be continuous betweenthe centre girder and the margin plate.

5.2.3 Open floors are to be fitted in way of intermediateframes.

5.2.4 Where the double bottom height exceeds 0,9 m,plate floors are to be fitted with vertical stiffeners spaced notmore than 1,5 m apart.

These stiffeners may consist of flat bars with a width equalto one tenth of the floor depth and a net thickness, in mm,not less than 0,8 L0,5.

5.3 Girders

5.3.1 Side girders are to be arranged in such a way thattheir distance to adjacent girders or margin plate does notgenerally exceed 4,5 m.

5.3.2 Where the double bottom height exceeds 0,9 m, lon-gitudinal girders are to be fitted with vertical stiffenersspaced not more than 1,5 m apart.

These stiffeners may consist of flat bars with a width equalto one tenth of the girder height and a net thickness, in mm,not less than 0,8L0,5.

5.3.3 In way of open floors, side girders are to be providedwith stiffeners having a web height which is generally to benot less than 150 mm.

Pt B, Ch 4, Sec 4


5.4 Open floors

5.4.1 At each frame between plate floors, open floors are tobe arranged consisting of a frame connected to the bottomplating and a reverse frame connected to the inner bottomplating (See Fig 1).

5.4.2 Open floors are to be attached to the centrelinegirder and to the margin plate by means of flanged bracketshaving a width of flange not less than 1/10 of the local dou-ble bottom height.

5.4.3 Where frames and reverse frames are interrupted inway of girders, double brackets are to be fitted.

6 Bilge keel

6.1 Arrangement, scantlings and connec-tions

6.1.1 Arrangement

Bilge keels may not be welded directly on the shell plating.An intermediate flat, or doubler, is required on the shellplating.

The ends of the bilge keel are to be sniped at an angle of15° or rounded with large radius. They are to be located inway of a transverse bilge stiffener. The ends of the interme-diate flat are to be sniped at an angle of 15°.

The arrangement shown in Fig 2 is recommended.

The arrangement shown in Fig 3 may also be accepted.

6.1.2 Materials

The bilge keel and the intermediate flat are to be made ofsteel with the same yield stress and grade as that of the bilgestrake.

6.1.3 Scantlings

The net thickness of the intermediate flat is to be equal tothat of the bilge strake. However, this thickness may gener-ally not be greater than 15 mm.

6.1.4 Welding

Welding of bilge keel and intermediate plate connections isto be in accordance with Ch 12, Sec 1, [3.2].

Figure 1 : Open floor

Figure 2 : Bilge keel arrangement

Figure 3 : Bilge keel arrangement

shell plating

Pt B, Ch 4, Sec 5


SECTION 5 SIDE STRUCTURE

1 General

1.1 Application

1.1.1 The requirements of this Section apply to longitudi-nally or transversely framed single and double side struc-tures.

1.1.2 The transversely framed side structures are built with transverse frames possibly supported by side girders (see[5.3.1]).

1.1.3 The longitudinally framed side structures are built with longitudinal ordinary stiffeners supported by side verti-cal primary supporting members.


1.2.1 Unless otherwise specified, side girders are to be fit-ted aft of the collision bulkhead up to 0,2L aft of the fore end, in line with fore peak girders.

1.2.2 Side vertical primary supporting members are to be fitted in way of hatch end beams.

1.3 Sheerstrake

1.3.1 The width of the sheerstrake is to be not less than the value obtained, in m, from the following formula (see alsoCh 4, Sec 1, [2.4.5]):

1.3.2 The sheerstrake may be either welded to the stringer plate or rounded. If it is rounded, the radius, in mm, is to be not less than 17tS , where tS is the net thickness, in mm, of the sheerstrake.

1.3.3 The upper edge of the welded sheerstrake is to be rounded and free of notches.

1.3.4 The transition from a rounded sheerstrake to an angled sheerstrake associated with the arrangement of superstructures at the ends of the ship is to be carefully designed so as to avoid any discontinuities.

Plans showing details of this transition are to be submitted for approval to the Society.

2 Longitudinally framed single side


2.1.1 Longitudinal ordinary stiffeners are generally to be continuous when crossing primary members.

2.2 Primary supporting members

2.2.1 In general, the side vertical primary supporting mem-ber spacing may not exceed 5 frame spacings.

2.2.2 In general, the side vertical primary supporting mem-bers are to be bracketed to the double bottom transverse floors.

3 Transversely framed single side

3.1 Frames

3.1.1 Transverse frames are to be fitted at every frame.

3.1.2 Frames are generally to be continuous when crossing primary members.Otherwise, the detail of the connection is to be examined by the Society on a case by case basis.

3.1.3 In general, the net section modulus of ‘tween deck frames is to be not less than that required for frames located immediately above.


3.2.1 In 'tweendecks of more than 4 m in height, side gird-ers or side vertical primary supporting members or both may be required by the Society.

3.2.2 Side girders are to be flanged or stiffened by a welded face plate.The width of the flanged edge or face plate is to be not less than 22t, where t is the web net thickness, in mm, of the girder.

3.2.3 The height of end brackets is to be not less than half the height of the primary supporting member.

4 Longitudinally framed double side

4.1 General

4.1.1 Adequate continuity of strength is to be ensured in way of breaks or changes in width of the double side.In particular, scarfing of the inner side is to be ensured beyond the cargo hold region.

4.1.2 Knuckles of the inner side are to be adequately stiff-ened.


4.2.1 The height of side vertical primary supporting mem-bers may be gradually tapered from bottom to deck. The maximum acceptable taper, however, is 8 cm per metre.

b 0 715, 0 425 L100----------,+=

Pt B, Ch 4, Sec 5


4.2.2 Side vertical primary supporting members supported by a strut and two diagonals converging on the former are to be considered by the Society on a case by case basis.

5 Transversely framed double side

5.1 General

5.1.1 The requirements in [4.1] also apply to transversely framed double side.

5.1.2 Transverse frames may be connected to the vertical ordinary stiffeners of the inner side by means of struts.

Struts are generally to be connected to transverse frames and vertical ordinary stiffeners of the inner side by means of vertical brackets.

5.2 Frames

5.2.1 Transverse frames are to be fitted at every frame.


5.3.1 Unless otherwise specified, transverse frames are to be supported by side girders if D 6 m.These girders are to be supported by side vertical primary supporting members spaced no more than 3,8 m apart.

5.3.2 In the case of ships having 4,5 < D < 6 m, side verti-cal primary supporting members are to be fitted, in general not more than 5 frame spacings apart.

6 Frame connections

6.1 General

6.1.1 End connections of frames are to be bracketed.

6.1.2 'Tweendeck frames are to be bracketed at the top and welded or bracketed at the bottom to the deck.In the case of bulb profiles, a bracket may be required to be fitted at bottom.

6.1.3 Brackets are normally connected to frames by lap welds. The length of overlap is to be not less than the depth of frames.

6.2 Upper brackets of frames

6.2.1 The arm length of upper brackets connecting frames to deck beams is to be not less than the value obtained, in mm, from the following formula:

where: : Coefficient equal to:

• for unflanged brackets:

= 48• for flanged brackets:

= 43,5

w : Required net section modulus of the stiffener, in cm3, given in [6.2.2] and [6.2.3] and depending on the type of connection

t : Bracket net thickness, in mm.

6.2.2 For connections of perpendicular stiffeners located in the same plane (see Fig 1) or connections of stiffeners located in perpendicular planes (see Fig 2), the required net section modulus is to be taken equal to:

where w1 and w2 are the required net section moduli of stiffeners, as shown in Fig 1 and Fig 2.

Figure 1 : Connections of perpendicular stiffenersin the same plane

Figure 2 : Connections of stiffeners locatedin perpendicular planes

6.2.3 For connections of frames to deck beams (see Fig 3), the required net section modulus is to be taken equal to:

• for bracket “A”:

wA = w1 if w2 w1

wA = w2 if w2 > w1

• for bracket “B”:

wB = w’1 need not be greater than w1 ,

d w 30+t

-----------------=

w w2 if w2 w1=w w1 if w2 w1=

w2

w1

d

d

w2

w1

d

d

theoriticalbracket

actualbracket

Pt B, Ch 4, Sec 5


where w1 , w’1 and w2 are the required net section moduli of stiffeners, as shown in Fig 3.

Figure 3 : Connections of frames to deck beams

6.3 Lower brackets of frames

6.3.1 In general, frames are to be bracketed to the inner bottom or to the face plate of floors as shown in Fig 4.

6.3.2 The arm lengths d1 and d2 of lower brackets of frames are to be not less than the value obtained, in mm, from the following formula:

where:


• for unflanged brackets: = 50

• for flanged brackets: = 45

w : Required net section modulus of the frame, in cm3

t : Bracket net thickness, in mm.

6.3.3 Where the bracket net thickness, in mm, is less than 15 Lb , where Lb is the length, in m, of the bracket free edge, the free edge of the bracket is to be flanged or stiffened by a welded face plate.

The net sectional area, in cm2, of the flange or the face plate is to be not less than 10 Lb.

7 Openings in the shell plating

7.1 Position of openings

7.1.1 Openings in the shell plating are to be located at a vertical distance from the decks at side not less than:

• two times the opening diameter, in case of circular opening

• the opening minor axis, in case of elliptical openings.

See also Ch 4, Sec 6, Fig 1.

7.2 Local strengthening

7.2.1 Openings in the ship sides, e.g. for cargo ports, are to be well rounded at the corners and located well clear of superstructure ends or any openings in the deck areas at sides of hatchways.

7.2.2 Openings for sea intakes are to be well rounded at the corners and, within 0,6 L amidships, located outside the bilge strakes. Where arrangements are such that sea intakes are unavoidably located in the curved zone of the bilge strakes, such openings are to be elliptical with the major axis in the longitudinal direction. Openings for stabiliser fins are considered by the Society on a case by case basis. The thickness of sea chests is generally to be that of the local shell plating, but in no case less than 12 mm.

7.2.3 Openings in [7.2.1] and [7.2.2] and, when deemed necessary by the Society, other openings of considerable size are to be adequately compensated by means of insert plates of increased thickness or doublers sufficiently extended in length. Such compensation is to be partial or total depending on the stresses occurring in the area of the openings.

Circular openings on the sheerstrake need not be compen-sated where their diameter does not exceed 20% of the sheerstrake minimum width, defined in [1.3], or 380 mm, whichever is the lesser, and where they are located away from openings on deck at the side of hatchways or super-structure ends.

Figure 4 : Lower brackets of main frames

w2

w1

w'1

dA

dB

d B

h'1

A

B

h'1

dA

d w 30+t

-----------------=

d1

d2

h

2h

1,5

h

7575

Pt B, Ch 4, Sec 6


SECTION 6 DECK STRUCTURE

1 General

1.1 Application

1.1.1 The requirements of this Section apply to longitudi-nally or transversely framed deck structures.


1.2.1 The deck supporting structure consists of ordinary stiffeners (beams or longitudinals), longitudinally or trans-versely arranged, supported by primary supporting mem-bers which may be sustained by pillars.

1.2.2 Where beams are fitted in a hatched deck, these are to be effectively supported by at least two longitudinal gird-ers located in way of hatch side girders to which they are to be connected by brackets and/or clips.

1.2.3 In ships greater than 120 m in length, the zones out-side the line of openings of the strength deck and other decks contributing to longitudinal strength are, in general, to be longitudinally framed.

Where a transverse framing type is adopted for such ships, it is considered by the Society on a case by case basis.

1.2.4 Adequate continuity of strength is to be ensured in way of:

• stepped strength decks

• changes in the framing system.

Details of structural arrangements are to be submitted for review to the Society.

1.2.5 Where applicable, deck transverses of reinforced scantlings are to be aligned with floors.

1.2.6 Inside the line of openings, a transverse structure is generally to be adopted for cross-deck structures, beams are to be adequately supported by girders and, in ships greater than 120 m in length, extend up to the second longitudinal from the hatch side girders toward the bulwark.

Where this is impracticable, intercostal stiffeners are to be fitted between the hatch side girder and the second longitu-dinal.

Other structural arrangements may be accepted, subject to their strength verification. In particular, their buckling strength against the transverse compression loads is to be checked. Where needed, deck transverses may be required to be fitted.

1.2.7 Deck supporting structures under deck machinery, cranes and king posts are to be adequately stiffened.

1.2.8 Pillars or other supporting structures are generally to be fitted under heavy concentrated cargoes.

1.2.9 Special arrangements, such as girders supported by cantilevers, are considered by the Society on a case by case basis.

1.2.10 Where devices for vehicle lashing arrangements and/or corner fittings for containers are directly attached to deck plating, provision is to be made for the fitting of suita-ble additional reinforcements of the sizes required by the load carried.

1.2.11 Stiffeners are also to be fitted in way of the ends and corners of deck houses and partial superstructures.

1.3 Construction of watertight decks

1.3.1 Watertight decks are to be of the same strength as watertight bulkheads at corresponding levels. The means used for making them watertight, and the arrangements adopted for closing openings in them, are to be to the satis-faction of the Society.

1.4 Stringer plate

1.4.1 The width of the stringer plate is to be not less than the value obtained, in m, from the following formula (see also Ch 4, Sec 1, [2.4.5]):

However, the stringer plate is also to comply with the requirements in Ch 4, Sec 1, [2.4.5] and Ch 4, Sec 1, [2.5.5].

1.4.2 Stringer plates of lower decks not extending over the full ship's length are to be gradually tapered or overlapped by adequately sized brackets.

2 Longitudinally framed deck

2.1 General

2.1.1 Deck longitudinals are to be continuous, as far as practicable, in way of deck transverses and transverse bulk-heads.Other arrangements may be considered, provided adequate continuity of longitudinal strength is ensured.

2.1.2 In general, the spacing of deck transverses is not to exceed 5 frame spacings.

2.1.3 In case of deck transverses located above the deck, longitudinal girders are to be fitted above the deck, in addi-tion of tripping brackets.

b 0 35, 0 5 L100----------,+=

Pt B, Ch 4, Sec 6



2.2.1 In ships equal to or greater than 120 m in length, strength deck longitudinal ordinary stiffeners are to be con-tinuous through the watertight bulkheads and/or deck trans-verses.

2.2.2 Frame brackets, in ships with transversely framed sides, are generally to have their horizontal arm extended to the adjacent longitudinal ordinary stiffener.

3 Transversely framed deck

3.1 General

3.1.1 In general, deck beams are to be fitted at each frame.

4 Pillars

4.1 General

4.1.1 Pillars are to be fitted, as far as practicable, in the same vertical line.

4.1.2 In general, pillars are to be fitted below winches, cranes, windlasses and steering gear, in the engine room and at the corners of deckhouses.

4.1.3 In tanks, solid or open section pillars are generally to be fitted. Pillars located in spaces intended for products which may produce explosive gases are to be of open sec-tion type.

4.1.4 Tight or non-tight bulkheads may be considered as pillars, provided that their arrangement complies with Ch 4, Sec 7, [4].

4.2 Connections

4.2.1 Heads and heels of pillars are to be attached to the surrounding structure by means of brackets or insert plates so that the loads are well distributed.Insert plates may be replaced by doubling plates, except in the case of pillars which may also work under tension such as those in tanks.

In general, the net thickness of doubling plates is to be not less than 1,5 times the net thickness of the pillar.

4.2.2 Pillars are to be attached at their heads and heels by continuous welding.

4.2.3 Pillars are to be connected to the inner bottom at the intersection of girders and floors.

4.2.4 Where pillars connected to the inner bottom are not located in way of intersections of floors and girders, partial floors or girders or equivalent structures suitable to support the pillars are to be arranged.

4.2.5 Manholes may not be cut in the girders and floors below the heels of pillars.

4.2.6 Where pillars are fitted in tanks, head and heel brack-ets may be required if tensile stresses are expected.

4.2.7 Where side pillars are not fitted in way of hatch ends, vertical stiffeners of bulkheads supporting hatch side girders or hatch end beams are to be bracketed at their ends.

5 Hatch supporting structures

5.1 General

5.1.1 Hatch side girders and hatch end beams of reinforced scantlings are to be fitted in way of cargo hold openings.

In general, hatched end beams and deck transverses are to be in line with bottom and side transverse structures, so as to form a reinforced ring.

5.1.2 Clear of openings, adequate continuity of strength of longitudinal hatch coamings is to be ensured by underdeck girders.

5.1.3 The details of connection of deck transverses to longi-tudinal girders and web frames are to be submitted to the Society for approval.

6 Openings in the strength deck

6.1 Position of openings and local strength-ening

6.1.1 Openings in the strength deck are to be kept to a minimum and spaced as far apart from one another and from breaks of effective superstructures as practicable. Openings are generally to be cut outside the hatched areas; in particular, they are to be cut as far as practicable from hatchway corners.

The dashed areas in Fig 1 are those where openings are gen-erally to be avoided. The meaning of the symbols in Fig 1 is as follows:

c, e : Longitudinal and transverse dimensions of hatched area:

c = 0,07 + 0,10 b without being less than 0,25 b,

e = 0,25 (B b)

a : Transverse dimension of openings

g : Transverse dimension of the area where open-ings are generally to be avoided in way of the connection between deck and side (as shown inFig 1), deck and longitudinal bulkheads, deck and large deck girders:

• in the case of circular openings:

g = 2 a

• in the case of elliptical openings:

g = a

6.1.2 No compensation is required where the openings are:

• circular of less than 350 mm in diameter and at a dis-tance from any other opening in compliance with Fig 2

• elliptical with the major axis in the longitudinal direc-tion and the ratio of the major to minor axis not less than 2.

Pt B, Ch 4, Sec 6


Figure 1 : Position of openings in the strength deck

Figure 2 : Circular openings in the strength deck

6.2 Corners of hatchways

6.2.1 For hatchways located within the cargo area, insert plates, whose thickness is to be determined according to[6.2.3], are generally to be fitted in way of corners where the plating cut-out has a circular profile.

The radius of circular corners is to be not less than:

• 5% of the hatch width, where a continuous longitudinal deck girder is fitted below the hatch coaming

• 8% of the hatch width, where no continuous longitudi-nal deck girder is fitted below the hatch coaming.

Corner radiusing, in the case of the arrangement of two or more hatchways athwartship, is considered by the Society on a case by case basis.

6.2.2 For hatchways located in the positions specified in[6.2.1], insert plates are, in general, not required in way of corners where the plating cut-out has an elliptical or para-

bolic profile and the half axes of elliptical openings, or the half lengths of the parabolic arch, are not less than:

• 1/20 of the hatchway width or 600 mm, whichever is the lesser, in the transverse direction

• twice the transverse dimension, in the fore and aft direc-tion.

6.2.3 Where insert plates are required, their thickness is obtained, in mm, from the following formula:

without being taken less than t or greater than 1,6t

where:

: Width, in m, in way of the corner considered, of the cross deck strip between two consecutive hatchways, measured in the longitudinal direc-tion (see Fig 1)

b : Width, in m, of the hatchway considered, meas-ured in the transverse direction (see Fig 1)

tINS 0 8 0 4 b---,+,

t=

Pt B, Ch 4, Sec 6


t : Actual thickness, in mm, of the deck at the side of the hatchways.

For the extreme corners of end hatchways, the thickness of insert plates is to be 60% greater than the actual thickness of the adjacent deck plating. A lower thickness may be accepted by the Society on the basis of calculations show-ing that stresses at hatch corners are lower than permissible values.

6.2.4 Where insert plates are required, the arrangement shown in Ch 12, App 2, Tab 68 is to be complied with.

6.2.5 For hatchways located in positions other than those in[6.2.1], a reduction in the thickness of the insert plates in

way of corners may be considered by the Society on a case by case basis.

7 Openings in decks other than the strength deck

7.1 General

7.1.1 The requirements for such openings are similar to those in [6.1] for the strength deck. However, circular open-ings need not to be compensated.

7.1.2 Corners of hatchway openings are to be rounded, as specified in [6.2] for the strength deck; insert plates may be omitted, however, when deemed acceptable by the Society.

Pt B, Ch 4, Sec 7


SECTION 7 BULKHEAD STRUCTURE

1 General

1.1 Application

1.1.1 The requirements of this Section apply to longitudinalor transverse bulkhead structures which may be plane orcorrugated.

1.1.2 Bulkheads may be horizontally or vertically stiffened.

Horizontally framed bulkheads consist of horizontal ordi-nary stiffeners supported by vertical primary supportingmembers.

Vertically framed bulkheads consist of vertical ordinary stiff-eners which may be supported by horizontal girders.


1.2.1 The number and location of watertight bulkheads areto be in accordance with the relevant requirements given inCh 2, Sec 1.

1.2.2 For ships greater than 170 m in length, longitudinalcorrugated bulkheads are to have horizontal corrugationsand the upper and lower strakes of longitudinal corrugatedbulkheads are to be plane up to a distance of at least 0,1Dfrom deck and bottom.

Transverse corrugated bulkheads having horizontal corruga-tions are to be fitted with vertical primary supporting mem-bers of number and size sufficient to ensure the requiredvertical stiffness of the bulkhead.

1.2.3 Where an inner bottom terminates on a bulkhead, thelowest strake of the bulkhead forming the watertight floor ofthe double bottom is to extend at least 300 mm above theinner bottom.

1.2.4 Longitudinal bulkheads are to terminate at transversebulkheads and are to be effectively tapered to the adjoiningstructure at the ends and adequately extended in themachinery space, where applicable.

1.2.5 Where the longitudinal watertight bulkheads contrib-ute to longitudinal strength, the plating thickness is to beuniform for a distance of at least 0,1D from the deck andbottom.

1.2.6 The structural continuity of the bulkhead vertical andhorizontal primary supporting members with the surround-ing supporting structures is to be carefully ensured.

1.2.7 The height of vertical primary supporting members oflongitudinal bulkheads may be gradually tapered from bot-tom to deck. The maximum acceptable taper, however, is 8cm per metre.

1.3 Watertight bulkheads of trunks, tunnels, etc.

1.3.1 Watertight trunks, tunnels, duct keels and ventilatorsare to be of the same strength as watertight bulkheads atcorresponding levels. The means used for making themwatertight, and the arrangements adopted for closing open-ings in them, are to be to the satisfaction of the Society.

1.4 Openings in watertight bulkheads

1.4.1 Openings may not be cut in the collision bulkheadbelow the freeboard deck.

The number of openings in the collision bulkhead abovethe freeboard deck is to be kept to the minimum compatiblewith the design and proper working of the ship.

All such openings are to be fitted with means of closing toweathertight standards.

1.4.2 Certain openings below the freeboard deck are per-mitted in the other bulkheads, but these are to be kept to aminimum compatible with the design and proper workingof the ship and to be provided with watertight doors havingstrength such as to withstand the head of water to whichthey may be subjected.

1.5 Watertight doors

1.5.1 The net thickness of watertight doors is to be not lessthan that of the adjacent bulkhead plating, taking accountof their actual spacing.

1.5.2 Where vertical stiffeners are cut in way of watertightdoors, reinforced stiffeners are to be fitted on each side ofthe door and suitably overlapped; cross-bars are to be pro-vided to support the interrupted stiffeners.

1.5.3 Watertight doors required to be open at sea are to beof the sliding type and capable of being operated both atthe door itself, on both sides, and from an accessible posi-tion above the bulkhead deck.

Means are to be provided at the latter position to indicatewhether the door is open or closed, as well as arrows indi-cating the direction in which the operating gear is to beoperated.

1.5.4 Watertight doors may be of the hinged type if they arealways intended to be closed during navigation.

Such doors are to be framed and capable of being securedwatertight by handle-operated wedges which are suitablyspaced and operable at both sides.

Pt B, Ch 4, Sec 7


2 Plane bulkheads

2.1 General

2.1.1 Where a bulkhead does not extend up to the upper-most continuous deck (such as the after peak bulkhead),suitable strengthening is to be provided in the extension ofthe bulkhead.

2.1.2 Bulkheads are to be stiffened in way of deck girders.

2.1.3 The webs of vertical stiffeners on hopper and topsidetank watertight transverse bulkheads are generally to bealigned with the webs of longitudinal stiffeners on slopingplates of inner hull.

2.1.4 A primary supporting member is to be provided inway of any vertical knuckle in longitudinal bulkheads. Thedistance between the knuckle and the primary supportingmember is to be taken not greater than 70 mm.

2.1.5 Plate floors are to be fitted in the double bottom inway of plane transverse bulkheads.

2.1.6 A doubling plate of the same net thickness as thebulkhead plating is to be fitted on the after peak bulkheadin way of the sterntube, unless the net thickness of the bulk-head plating is increased by at least 60%.

2.2 End connections of ordinary stiffeners

2.2.1 The crossing of ordinary stiffeners through a water-tight bulkhead is to be watertight.

2.2.2 In general, end connections of ordinary stiffeners areto be bracketed (see [2.3]). However, stiffeners of watertightbulkheads in upper 'tweendecks may be sniped, providedthe scantlings of such stiffeners are modified accordingly.

2.2.3 Where hull lines do not enable compliance with therequirements of [2.2.2], sniped ends may be accepted, pro-vided the scantlings of stiffeners are modified accordingly.

2.2.4 Where sniped ordinary stiffeners are fitted, the snipeangle is to be not greater than 30° and their ends are to beextended, as far as practicable, to the boundary of the bulk-head.

2.3 Bracketed ordinary stiffeners

2.3.1 Where bracketed ordinary stiffeners are fitted, thearm lengths of end brackets of ordinary stiffeners, as shownin Fig 1 and Fig 2, are to be not less than the following val-ues, in mm:

• for arm length a:

- brackets of horizontal stiffeners and bottom bracketof vertical stiffeners:

a = 100

- upper bracket of vertical stiffeners:

a = 80

• for arm length b, the greater of:

where:

: Span, in m, of the stiffener measured betweensupports

w : Net section modulus, in cm3, of the stiffener

t : Net thickness, in mm, of the bracket

p : Design pressure, in kN/m2, calculated at mid-span


= 4,9 for tank bulkheads

= 3,6 for watertight bulkheads.

2.3.2 The connection between the stiffener and the bracketis to be such that the net section modulus of the connectionis not less than that of the stiffener.

Figure 1 : Bracket at upper end of ordinary stiffener on plane bulkhead

Figure 2 : Bracket at lower end of ordinary stiffeneron plane bulkhead

b 80 w 20+t

-----------------=

b pst

---------=

a

b

�

a

b

�

Pt B, Ch 4, Sec 7


3 Corrugated bulkheads

3.1 General

3.1.1 The main dimensions a, b, c and d of corrugatedbulkheads are defined in Fig 3.

3.1.2 Unless otherwise specified, the following require-ment is to be complied with:

Moreover, in some cases, the Society may prescribe anupper limit for the ratio b/t.

Figure 3 : Corrugated bulkhead

3.1.3 In general, the bending internal radius is to be notless than the following values, in mm:

• for normal strength steel:

Ri = 2,5 t

• for high tensile steel:

Ri = 3,0 t

where t is the net thickness, in mm, of the corrugated plate.

3.1.4 When welds in a direction parallel to the bend axisare provided in the zone of the bend, the welding proce-dures are to be submitted to the Society for approval, as afunction of the importance of the structural element.

Moreover, when the gross thickness of the bulkhead platingis greater than 20 mm, the Society may require the use ofsteel grade E or EH.

3.1.5 In general, where girders or vertical primary support-ing members are fitted on corrugated bulkheads, they are tobe arranged symmetrically.

3.2 Structural arrangement

3.2.1 The strength continuity of corrugated bulkheads is tobe ensured at ends of corrugations.

3.2.2 Where corrugated bulkheads are cut in way of primarymembers, attention is to be paid to ensure correct alignmentof corrugations on each side of the primary member.

3.2.3 The connection of the corrugated bulkhead with thedeck and the bottom is to be carefully designed and spe-cially considered by the Society.

3.2.4 In general, where vertically corrugated transversebulkheads are welded on the inner bottom, plate floors areto be fitted in way of the flanges of corrugations.

However, other arrangements ensuring adequate structuralcontinuity may be accepted by the Society.

3.2.5 In general, where vertically corrugated longitudinalbulkheads are welded on the inner bottom, girders are to befitted in way of the flanges of corrugations.

However, other arrangements ensuring adequate structuralcontinuity may be accepted by the Society.

3.2.6 In general, the upper and lower parts of horizontallycorrugated bulkheads are to be flat over a depth equal to0,1D.

3.2.7 Where stools are fitted at the lower part of transversebulkheads, the net thickness of adjacent plate floors is to benot less than that of the stool plating.

3.3 Bulkhead stool

3.3.1 In general, plate diaphragms or web frames are to befitted in bottom stools in way of the double bottom longitu-dinal girders or plate floors, as the case may be.

3.3.2 Brackets or deep webs are to be fitted to connect theupper stool to the deck transverses or hatch end beams, asthe case may be.

3.3.3 The continuity of the corrugated bulkhead with thestool plating is to be adequately ensured. In particular, theupper strake of the lower stool is to be of the same net thick-ness and yield stress as those of the lower strake of the bulk-head.

4 Non-tight bulkheads

4.1 Non-tight bulkheads not acting as pillars

4.1.1 Non-tight bulkheads not acting as pillars are to beprovided with vertical stiffeners with a maximum spacingequal to:

• 0,9 m, for transverse bulkheads

• two frame spacings, with a maximum of 1,5 m, for lon-gitudinal bulkheads.

4.2 Non-tight bulkheads acting as pillars

4.2.1 Non-tight bulkheads acting as pillars are to be pro-vided with vertical stiffeners with a maximum spacing equalto:

• two frame spacings, when the frame spacing does notexceed 0,75 m,

• one frame spacing, when the frame spacing is greaterthan 0,75 m.

4.2.2 Each vertical stiffener, in association with a width ofplating equal to 35 times the plating net thickness, is tocomply with the applicable requirements for pillars in Ch 7,Sec 3, the load supported being determined in accordancewith the same requirements.

a 1 2, d

b

c

d

a

t

Pt B, Ch 4, Sec 7


4.2.3 In the case of non-tight bulkheads supporting longitu-dinally framed decks, vertical girders are to be provided inway of deck transverses.

5 Wash bulkheads

5.1 General

5.1.1 The requirements in [5.2] apply to transverse and lon-gitudinal wash bulkheads whose main purpose is to reducethe liquid motions in partly filled tanks.

5.2 Openings

5.2.1 The total area of openings in a transverse wash bulk-head is generally to be between 10% and 30% of the totalbulkhead area.In the upper, central and lower portions of the bulkhead(the depth of each portion being 1/3 of the bulkhead

height), the areas of openings, expressed as percentages ofthe corresponding areas of these portions, are to be withinthe limits given in Tab 1.

5.2.2 In any case, the distribution of openings is to fulfil thestrength requirements specified in [4.2].

5.2.3 In general, openings may not be cut within 0,15Dfrom bottom and from deck.

Table 1 : Areas of openings in transversewash bulkheads

Bulkhead portion Lower limit Upper limit

Upper 10 % 15 %

Central 10 % 50 %

Lower 2 % 10 %

Chapter 5 Design Loads

Symbols

n, n1 :

Navigation coefficients, defined in Pt B, Ch 5, Sec 1, [2.6],

F :

Froude's number:

V :

Maximum ahead service speed, in knots,

T1 :

Draught, in m, defined in Pt B, Ch 5, Sec 1, [2.4.3] or Pt B, Ch 5, Sec 1, [2.5.3], as the case

may be,

g :

Gravity acceleration, in m/s2:

g = 9,81 m/s2,

x, y, z :

X, Y and Z co-ordinates, in m, of the calculation point with respect to the reference

co-ordinate system defined in Pt B, Ch 1, Sec 2, [4].

Pt B, Ch 5, Sec 1


SECTION 1 GENERAL

1 Definitions

1.1 Still water loads

1.1.1 Still water loads are those acting on the ship at rest incalm water.

1.2 Wave loads

1.2.1 Wave loads are those due to wave pressures and shipmotions, which can be assumed to have the same waveencounter period.

1.3 Dynamic loads

1.3.1 Dynamic loads are those that have a duration muchshorter than the period of the wave loads.

1.4 Local loads

1.4.1 Local loads are pressures and forces which aredirectly applied to the individual structural members: plat-ing panels, ordinary stiffeners and primary supporting mem-bers.

• Still water local loads are constituted by the hydrostaticexternal sea pressures and the static pressures andforces induced by the weights carried in the ship spaces.

• Wave local loads are constituted by the external seapressures due to waves and the inertial pressures andforces induced by the ship accelerations applied to theweights carried in the ship spaces.

• Dynamic local loads are constituted by the impact andsloshing pressures.

1.4.2 For the structures which constitute the boundary ofspaces not intended to carry liquids and which do notbelong to the outer shell, the still water and wave pressuresin flooding conditions are also to be considered.

1.5 Hull girder loads

1.5.1 Hull girder loads are (still water, wave and dynamic)forces and moments which result as effects of local loadsacting on the ship as a whole and considered as a beam.

1.6 Loading condition

1.6.1 A loading condition is a distribution of weights car-ried in the ship spaces arranged for their storage.

1.7 Load case

1.7.1 A load case is a state of the ship structures subjectedto a combination of hull girder and local loads.

2 Application criteria

2.1 Fields of application

2.1.1 General

The wave induced and dynamic loads defined in this Chap-ter corresponds to an operating life of the ship equal to20 years.

2.1.2 Requirements applicable to all types of ships

The still water, wave induced and dynamic loads defined inthis Chapter are to be used for the determination of the hullgirder strength and structural scantlings in the central part(see Ch 1, Sec 1) of ships equal to or greater than 65 m inlength, according to the requirements in Part B, Chapter 6and Part B, Chapter 7.

The design loads to be used for the determination of the hullgirder strength and structural scantlings in the central part(see Ch 1, Sec 1) of ships less than 65 m in length are speci-fied in Part B, Chapter 8.

2.1.3 Requirements applicable to specific ship types

The design loads applicable to specific ship types are to bedefined in accordance with the requirements in Part D.

2.1.4 Load direct calculation

As an alternative to the formulae in Ch 5, Sec 2 and Ch 5,Sec 3, the Society may accept the values of wave inducedloads and dynamic loads derived from direct calculations,when justified on the basis of the ship’s characteristics andintended service. The calculations are to be submitted tothe Society for approval.


2.2.1 The still water, wave and dynamic hull girder loads tobe used for the determination of:

• the hull girder strength, according to the requirementsof Part B, Chapter 6, and

• the structural scantling of plating, ordinary stiffeners andprimary supporting members contributing to the hullgirder strength, in combination with the local loadsgiven in Ch 5, Sec 5 and Ch 5, Sec 6, according to therequirements in Part B, Chapter 7,

are specified in Ch 5, Sec 2.

Pt B, Ch 5, Sec 1


2.3 Local loads

2.3.1 Load cases

The local loads defined in [1.4] are to be calculated in eachof the mutually exclusive load cases described in Ch 5, Sec 4.

Dynamic loads are to be taken into account and calculatedaccording to the criteria specified in Ch 5, Sec 5 and Ch 5,Sec 6.

2.3.2 Ship motions and accelerations

The wave local loads are to be calculated on the basis of thereference values of ship motions and accelerations specifiedin Ch 5, Sec 3.

2.3.3 Calculation and application of local loads

The criteria for calculating:

• still water local loads

• wave local loads on the basis of the reference values ofship motions and accelerations

are specified in Ch 5, Sec 5 for sea pressures and in Ch 5,Sec 6 for internal pressures and forces.

2.3.4 Flooding conditions

The still water and wave pressures in flooding conditionsare specified in Ch 5, Sec 6, [9]. The pressures in floodingconditions applicable to specific ship types are to bedefined in accordance with the requirements in Part D.

2.4 Load definition criteria to be adopted in structural analyses based on plate or isolated beam structural models

2.4.1 Application

The requirements of this sub-article apply for the definitionof local loads to be used in the scantling checks of:

• plating, according to Ch 7, Sec 1

• ordinary stiffeners, according to Ch 7, Sec 2

• primary supporting members for which a three dimen-sional structural model is not required, according to Ch7, Sec 3, [3].

2.4.2 Cargo and ballast distributions

When calculating the local loads for the structural scantlingof an element which separates two adjacent compartments,the latter may not be considered simultaneously loaded.The local loads to be used are those obtained consideringthe two compartments individually loaded.

For elements of the outer shell, the local loads are to be cal-culated considering separately:

• the still water and wave external sea pressures, consid-ered as acting alone without any counteraction from theship interior

• the still water and wave differential pressures (internalpressure minus external sea pressure) considering thecompartment adjacent to the outer shell as being loaded.

2.4.3 Draught associated with each cargo and ballast distribution

Local loads are to be calculated on the basis of the ship’sdraught T1 corresponding to the cargo or ballast distributionconsidered according to the criteria in [2.4.2]. The shipdraught is to be taken as the distance measured verticallyon the hull transverse section at the middle of the length L,from the moulded base line to the waterline in:

• full load condition, when:

- one or more cargo compartments (e.g. oil tank, drycargo hold, vehicle space, passenger space) are con-sidered as being loaded and the ballast tanks areconsidered as being empty

- the still water and wave external pressures are con-sidered as acting alone without any counteractionfrom the ship’s interior

• light ballast condition, when one or more ballast tanksare considered as being loaded and the cargo compart-ments are considered as being empty. In the absence ofmore precise information, the ship’s draught in light bal-last condition may be obtained, in m, from the follow-ing formulae:

- TB = 0,03 L 7,5 m in general

- TB = 2 + 0,02 L for ships with one of the servicenotations bulk carrier ESP, ore carrier ESP, combi-nation carrier ESP or oil tanker ESP.

2.5 Load definition criteria to be adopted in structural analyses based on three dimensional structural models

2.5.1 Application

The requirements of this sub-article apply for the definitionof local loads to be used in the scantling checks of primarysupporting members for which a three dimensional struc-tural model is required, according to Ch 7, Sec 3, [4].

2.5.2 Loading conditions

For all ship types for which analyses based on three dimen-sional models are required according to Ch 7, Sec 3, [4],the most severe loading conditions for the structural ele-ments under investigation are to be considered. These load-ing conditions are to be selected among those envisaged inthe ship loading manual.

For ships with the service notation general cargo ship orbulk carrier ESP completed by the additional service fea-tures BC-A or nonhomload, the loading conditions to beconsidered are to include the cases where the selectedholds are empty at draught T, according to the indicationsspecified in the ship notation.

Further criteria applicable to specific ship types are speci-fied in Part D.

Pt B, Ch 5, Sec 1


2.5.3 Draught associated with each loading condition

Local loads are to be calculated on the basis of the ship’sdraught T1 corresponding to the loading condition consid-ered according to the criteria in [2.5.2].

2.6 Navigation coefficients

2.6.1 The navigation coefficients, which appear in the for-mulae of this Chapter for the definition of wave hull girderand local loads, are defined in Tab 1 depending on theassigned navigation notation.

Table 1 : Navigation coefficients

Navigation notation Navigation coefficient n

Navigation coefficient n1

Unrestricted navigation 1,00 1,00

Summer zone 0,90 0,95

Tropical zone 0,80 0,90

Coastal area 0,80 0,90

Sheltered area 0,65 0,80

Pt B, Ch 5, Sec 2


SECTION 2 HULL GIRDER LOADS

Symbols

For symbols not defined in this Section, refer to the list atthe beginning of this Chapter.

C : Wave parameter:

H : Wave parameter:

without being taken greater than 8,13

1 General

1.1 Application

1.1.1 The requirements of this Section apply to ships hav-ing the following characteristics:

• L < 500 m

• L / B > 5

• B / D < 2,5

• CB 0,6

Ships not having one or more of these characteristics, shipsintended for the carriage of heated cargoes and ships ofunusual type or design will be considered by the Society ona case by case basis.

1.2 Sign conventions of vertical bending moments and shear forces

1.2.1 The sign conventions of bending moments and shearforces at any ship transverse section are as shown in Fig 1,namely:

• the vertical bending moment M is positive when itinduces tensile stresses in the strength deck (hoggingbending moment); it is negative in the opposite case(sagging bending moment)

• the vertical shear force Q is positive in the case ofdownward resulting forces preceding and upwardresulting forces following the ship transverse sectionunder consideration; it is negative in the opposite case.

2 Still water loads

2.1 General

2.1.1 Still water load calculation

For all ships, the longitudinal distributions of still waterbending moment and shear force are to be calculated, foreach of the loading conditions in [2.1.2], on the basis ofrealistic data related to the amount of cargo, ballast, fuel,lubricating oil and fresh water.

Where the amount and disposition of consumables at anyintermediate stage of the voyage are considered moresevere, calculations for such intermediate conditions are tobe submitted in addition to those for departure and arrivalconditions. Also, where any ballasting and/or deballasting isintended during voyage, calculations of the intermediatecondition just before and just after ballasting and/or debal-lasting any ballast tank are to be submitted and, whereapproved, included in the loading manual for guidance.

The actual hull lines and lightweight distribution are to betaken into account in the calculations. The lightweight distribu-tion may be replaced, if the actual values are not available, bya statistical distribution of weights accepted by the Society.

The designer is to supply the data necessary to verify thecalculations of still water loads.

For ships with the service notation container ship, thetorque due to non-uniform distribution of cargo, consuma-ble liquids and ballast is also to be considered, as specifiedin Pt D, Ch 2, Sec 2.

Figure 1 : Sign conventions for shear forces Q and bending moments M

C 118 0 36L,– L1000-------------= for 65m L 90m

C 10 75 300 L–100

-------------------

1 5,

–,= for 90m L 300m

C 10 75,= for 300m L 350m

C 10 75 L 350–150

-------------------

1 5,

–,= for L 350m

H 8 13, 250 0 7L,–125

----------------------------

3

–=

Q :

M :

Aft Fore

(+)

(+)

Pt B, Ch 5, Sec 2


2.1.2 Loading conditions

Still water loads are to be calculated for all the design load-ing conditions (cargo and ballast) subdivided into departureand arrival conditions, on which the approval of hull struc-tural scantlings is based.

For all ships, the following loading conditions are to be con-sidered:

• homogeneous loading conditions at maximum draught

• ballast conditions

Ballast loading conditions involving partially filled peakand/or other ballast tanks at departure, arrival or duringintermediate conditions are not permitted to be used asdesign conditions unless:

- the allowable stress limits defined in Ch 6, Sec 2, [3]are satisfied for all filling levels between empty andfull and

- for ships with the service notation bulk carrier ESP,the requirements in Pt D, Ch 4, Sec 3, [5.1], asapplicable, are complied with all filling levelsbetween empty and full.

To demonstrate compliance with all filling levelsbetween empty and full, it is acceptable if, in each con-dition at departure, arrival and where required in [2.1.1]any intermediate condition, the tanks intended to bepartially filled are assumed to be:

- empty

- full

- partially filled at intended level.

Where multiple tanks are intended to be partially filled,all combinations of empty, full or partially filled atintended level for those tanks are to be investigated.

However, for conventional ore carriers with large wingwater ballast tanks in cargo area, where empty or fullballast water filling levels of one or maximum two pairsof these tanks lead to the ship’s trim exceeding one ofthe following conditions, it is sufficient to demonstratecompliance with maximum, minimum and intendedpartial filling levels of these one or maximum two pairsof ballast tanks such that the ship’s condition does notexceed any of these trim limits. Filling levels of all otherwing ballast tanks are to be considered between emptyand full. The trim conditions mentioned above are:

- trim by stern of 3% of the ship’s length, or

- trim by bow of 1,5% of the ship’s length, or

- any trim that cannot maintain propeller immersion(l/D) not less than 25%, where:

l : Distance, in m, from propeller centerlineto the waterline

D : Propeller diameter, in m.

The maximum and minimum filling levels of the abovementioned pairs of side ballast tanks are to be indicatedin the loading manual.

• cargo loading conditions

For cargo loading conditions involving partially filledpeak and/or other ballast tanks, the requirements speci-fied in bullet item before apply to the peak tanks only

• sequential ballast water exchange

The requirements concerning the partially filled ballasttanks in ballast loading conditions and the partiallyfilled ballast tanks in cargo loading conditions (refer tothe two previous bullet items) are not applicable to bal-last water exchange using the sequential method

• special loadings (e.g. light load conditions at less thanthe maximum draught, deck cargo conditions, etc.,where applicable)

• short voyage or harbour conditions, where applicable

• loading and unloading transitory conditions, whereapplicable

• docking condition afloat

• ballast exchange at sea, if applicable.

For ships with the service notation general cargo ship com-pleted by the additional service feature nonhomload, theloading conditions to be considered are to include the caseswhere the selected holds are empty at draught T, accordingto the indications specified in the ship notation.

Part D specifies other loading conditions which are to beconsidered depending on the ship type.

2.2 Still water bending moments

2.2.1 The design still water bending moments MSW,H andMSW,S at any hull transverse section are the maximum stillwater bending moments calculated, in hogging and saggingconditions, respectively, at that hull transverse section forthe loading conditions specified in [2.1.2].

Where no sagging bending moments act in the hull sectionconsidered, the value of MSW,S is to be taken as specified inPart B, Chapter 6 and Part B, Chapter 7.

2.2.2 If the design still water bending moments are notdefined, at a preliminary design stage, at any hull transversesection, the longitudinal distributions shown in Fig 2 maybe considered.

In Fig 2, MSW is the design still water bending momentamidships, in hogging or sagging conditions, whose abso-lute values are to be taken not less than those obtained, inkN.m, from the following formulae:

• hogging conditions:

• sagging conditions:

where MWV,H, MWV,S are the vertical wave bending moments,in kN.m, defined in [3.1].

MSWM H, 175n1CL2B CB 0 7,+ 10 3– MWV H,–=

MSWM S, 175n1CL2B CB 0 7,+ 10 3– MWV S,+=

Pt B, Ch 5, Sec 2


Figure 2 : Preliminary still water bending momentdistribution

2.3 Still water shear force

2.3.1 The design still water shear force QSW at any hulltransverse section is the maximum positive or negativeshear force calculated, at that hull transverse section, for theloading conditions specified in [2.1.2].

3 Wave loads

3.1 Vertical wave bending moments

3.1.1 The vertical wave bending moments at any hull trans-verse section are obtained, in kN.m, from the following for-mulae:

• hogging conditions:

MWV,H = 190 FM n C L2 B CB 103

• sagging conditions:

MWV,S = 110 FM n C L2 B (CB + 0,7) 103

where:

FM : Distribution factor defined in Tab 1 (see also Fig3).

Table 1 : Distribution factor FM

Figure 3 : Distribution factor FM

3.1.2 The effects of bow flare impact are to be taken intoaccount, for the cases specified in [4.1.1], according to[4.2.1].

3.2 Horizontal wave bending moment

3.2.1 The horizontal wave bending moment at any hulltransverse section is obtained, in kN.m, from the followingformula:

MWH = 0,42 FM n H L2 T CB

where FM is the distribution factor defined in [3.1.1].

3.3 Wave torque

3.3.1 The wave torque at any hull transverse section is tobe calculated considering the ship in two different condi-tions:

• condition 1: ship direction forming an angle of 60o withthe prevailing sea direction

• condition 2: ship direction forming an angle of 120o

with the prevailing sea direction.

The values of the wave torques in these conditions, calcu-lated with respect to the section centre of torsion, areobtained, in kN.m, from the following formula:

where:

FTM, FTQ : Distribution factors defined in Tab 2 for shipconditions 1 and 2 (see also Fig 4 and Fig 5)

CM : Wave torque coefficient:

CM = 0,45 B2 CW2

CQ : Horizontal wave shear coefficient:

CQ = 5 T CB

CW : Waterplane coefficient, to be taken not greaterthan the value obtained from the following for-mula:

CW = 0,165 + 0,95 CB

where CB is to be assumed not less than 0,6. Inthe absence of more precise determination, CW

may be taken equal to the value provided by theabove formula.

d : Vertical distance, in m, from the centre of tor-sion to a point located 0,6 T above the baseline.

Table 2 : Distribution factors FTM and FTQ

Hull transverse section location Distribution factor FM

0 x < 0,4 L

0,4 L x 0,65 L 1

065 L < x L

Still waterbending moment

Msw

0,2Msw

AE0,0 0,50,3 0,7 1,0 FE

xL

2 5xL---,

2 86 1 xL---–

,

FM

0,4 0,65AE0,0

1,0

1,0 FExL

Shipcondition

Distribution factor FTM

Distribution factor FTQ

1

2

MWTHL4

--------n FTMCM FTQCQd+ =

1 2xL

----------cos– 2xL

----------sin

1 2 L x– L

------------------------cos– 2 L x– L

------------------------sin

Pt B, Ch 5, Sec 2


Figure 4 : Ship condition 1Distribution factors FTM and FTQ

Figure 5 : Ship condition 2Distribution factors FTM and FTQ

3.4 Vertical wave shear force

3.4.1 The vertical wave shear force at any hull transversesection is obtained, in kN, from the following formula:

QWV = 30 FQ n C L B (CB + 0,7) 102

where:FQ : Distribution factor defined in Tab 3 for positive

and negative shear forces (see also Fig 6).

Figure 6 : Distribution factor FQ

4 Dynamic loads due to bow flare impact

4.1 Application

4.1.1 The effects of bow flare impact are to be consideredwhere all the following conditions occur:

• 120 mL 200 m

• V 17,5 knots

•

where:

AS : Twice the shaded area shown in Fig 7, which isto be obtained, in m2, from the following for-mula:

AS = b a0 + 0,1 L (a0 + 2 a1 + a2)

b, a0, a1, a2: Distances, in m, shown in Fig 7.

Table 3 : Distribution factor FQ

FTM, FTQ

0,5

AE0,0

0,25-0,5

-1,0

1,0

1,5

2,0

0,50 0,75xLFE

FTM

FTQ

0 1

FTM, FTQ

0,5

0,0

-0,5

-1,0

1,0

1,5

2,0

0 1

0,25 0,50 0,75xLFE

FTM

FTQ

AE

Negative waveshear force

Positive waveshear force

0,2 0,3 0,4 0,6 0,7 0,85 1,0 FE

xLAE

0,0

1,0190 CB0,92

110(CB+0,7)

0,7

FQ

-0,7190 CB-

110(CB+0,7)0,92

100FAS

LB------------------- 1

Hull transverse section locationDistribution factor FQ

Positive wave shear force Negative wave shear force

0x 0,2 L

0,2 Lx 0,3 L 0,92 A 0,92

0,3 L < x < 0,4 L

0,4 Lx 0,6 L 0,7 0,7

0,6 L < x < 0,7 L

0,7 Lx 0,85 L 1 A

0,85 Lx L

Note 1:

4 6AxL---, 4– 6x

L---,

9 2A, 7– 0 4, xL---–

0 7,+ 2– 2 0 4, xL---–

0 7,–,

3 xL--- 0 6,– 0 7,+ 10A 7– – x

L--- 0 6,– 0 7,–

6 67 1 xL---–

, 6– 67A 1 xL---–

,

A190CB

110 CB 0 7,+ ------------------------------------=

Pt B, Ch 5, Sec 2


For multideck ships, the upper deck shown in Fig 7 is to betaken as the deck (including superstructures) which extendsup to the extreme forward end of the ship and has the larg-est breadth forward of 0,2L from the fore end.

Figure 7 : Area AS

4.1.2 When the effects of bow flare impact are to be con-sidered, according to [4.1.1], the sagging wave bendingmoment is to be increased as specified in [4.2.1] and[4.2.2].

4.1.3 The Society may require the effects of bow flareimpact to be considered also when one of the conditions in[4.1.1] does not occur, if deemed necessary on the basis ofthe ship’s characteristics.

In such cases, the increase in sagging wave bendingmoment is defined on a case by case basis.

4.2 Increase in sagging wave bending moment

4.2.1 GeneralThe sagging wave bending moment at any hull transversesection, defined in [3.1], is to be multiplied by the coeffi-cient FD obtained from the formulae in Tab 4, which takesinto account the dynamic effects of bow flare impact.

Where at least one of the conditions in [4.1.1] does notoccur, the coefficient FD may be taken equal to 1.

Table 4 : Coefficient FD

4.2.2 Direct calculationsAs an alternative to the formulae in [4.2.1], the Society mayaccept the evaluation of the effects of bow flare impact fromdirect calculations, when justified on the basis of the ship’scharacteristics and intended service. The calculations are tobe submitted to the Society for approval.

AS/2

Upper deck (includingsuperstructures, if any)a2

a1

Waterline at thecalculation draught

FE

b0,1L0,2L

a0 Hull transverse section location Coefficient FD

0 x < 0,4 L 1

0,4 L x < 0,5 L

0,5 L x L CD

Note 1:

AS : Area, in m2, defined in [4.1.1].

1 10 CD 1– xL--- 0 4– +

CD 262 5AS

CLB CB 0 7+ --------------------------------------- 0 6–= with 1 0 CD 1 2, ,

Pt B, Ch 5, Sec 3


SECTION 3 SHIP MOTIONS AND ACCELERATIONS

Symbols

For the symbols not defined in this Section, refer to the listat the beginning of this Chapter.

aB : Motion and acceleration parameter:

hW : Wave parameter, in m:

aSU : Surge acceleration, in m/s2, defined in [2.1]

aSW : Sway acceleration, in m/s2, defined in [2.2]

aH : Heave acceleration, in m/s2, defined in [2.3]

R : Roll acceleration, in rad/s2, defined in [2.4]

P : Pitch acceleration, in rad/s2, defined in [2.5]

Y : Yaw acceleration, in rad/s2, defined in [2.6]

TSW : Sway period, in s, defined in [2.2]

TR : Roll period, in s, defined in [2.4]

TP : Pitch period, in s, defined in [2.5]

AR : Roll amplitude, in rad, defined in [2.4]

AP : Pitch amplitude, in rad, defined in [2.5].

1 General

1.1

1.1.1 Ship motions and accelerations are defined, withtheir signs, according to the reference co-ordinate system inCh 1, Sec 2, [4].

1.1.2 Ship motions and accelerations are assumed to beperiodic. The motion amplitudes, defined by the formulaein this Section, are half of the crest to through amplitudes.

1.1.3 As an alternative to the formulae in this Section, theSociety may accept the values of ship motions and acceler-ations derived from direct calculations or obtained frommodel tests, when justified on the basis of the ship’s charac-teristics and intended service. In general, the values of shipmotions and accelerations to be determined are thosewhich can be reached with a probability level of 105. Inany case, the model tests or the calculations, including theassumed sea scatter diagrams and spectra, are to be submit-ted to the Society for approval.

2 Ship absolute motions and accelerations

2.1 Surge

2.1.1 The surge acceleration aSU is to be taken equal to0,5 m/s2.

2.2 Sway

2.2.1 The sway period and acceleration are obtained fromthe formulae in Tab 1.

Table 1 : Sway period and acceleration

2.3 Heave

2.3.1 The heave acceleration is obtained, in m/s2, from thefollowing formula:

aH = aB g

2.4 Roll

2.4.1 The roll amplitude, period and acceleration areobtained from the formulae in Tab 2.

Table 2 : Roll amplitude, period and acceleration

The meaning of symbols in Tab 2 is as follows:

GM : Distance, in m, from the ship’s centre of gravityto the transverse metacentre, for the loadingconsidered; when GM is not known, the valuesgiven in Tab 3 may be assumed

aB n 0 76F, 1 875hW

L-------,+

=

hW 11 44, L 250–110

-------------------3

–= for L 350m

hW200

L----------= for L 350m

Period TSW, in s Acceleration aSW, in m/s2

0,775 aB g

Amplitude AR ,in rad

Period TR ,in s

Acceleration R ,in rad/s2


0 8 L,1 22F, 1+-------------------------

aB E2 2,

GM-------------- AR

2TR-------

2

E 1 39GM2

----------B to be taken not less than 1,0,=

Pt B, Ch 5, Sec 3


Table 3 : Values of GM

: Roll radius of gyration, in m, for the loadingconsidered; when is not known, the followingvalues may be assumed, in full load and ballastconditions:

= 0,35 B in general

= 0,30 B for ships with the service notationore carrier ESP.

2.5 Pitch

2.5.1 The pitch amplitude, period and acceleration areobtained from the formulae in Tab 4.

Table 4 : Pitch amplitude, period and acceleration

2.6 Yaw

2.6.1 The yaw acceleration is obtained, in rad/s2, from thefollowing formula:

3 Ship relative motions and accelerations

3.1 Definitions

3.1.1 Ship relative motions

The ship relative motions are the vertical oscillating transla-tions of the sea waterline on the ship side. They are meas-ured, with their sign, from the waterline at draught T1.

3.1.2 Accelerations

At any point, the accelerations in X, Y and Z direction arethe acceleration components which result from the shipmotions defined in [2.1] to [2.6].

3.2 Ship conditions

3.2.1 General

Ship relative motions and accelerations are to be calculatedconsidering the ship in the following conditions:

• upright ship condition

• inclined ship condition.

3.2.2 Upright ship condition

In this condition, the ship encounters waves which produceship motions in the X-Z plane, i.e. surge, heave and pitch.

3.2.3 Inclined ship condition

In this condition, the ship encounters waves which produceship motions in the X-Y and Y-Z planes, i.e. sway, roll, yawand heave.

3.3 Ship relative motions

3.3.1 The reference value of the relative motion in theupright ship condition is obtained, at any hull transversesection, from the formulae in Tab 5.

Table 5 : Reference value of the relative motion h1

in the upright ship condition

3.3.2 The reference value, in m, of the relative motion inthe inclined ship condition is obtained, at any hull trans-verse section, from the following formula:

where:

h1 : Reference value, in m, of the relative motion inthe upright ship, calculated according to [3.3.1]

Service notation Full load Ballast

oil tanker ESP 0,12 B heavy ballast: 0,18 Blight ballast: 0,24 B

bulk carrier ESP 0,12 B heavy ballast: 0,18 Blight ballast: 0,24 B

ore carrier ESP 0,16 B heavy ballast: 0,18 Blight ballast: 0,24 B

Other 0,07 B 0,18 B

Amplitude AP, in radPeriod TP,

in sAcceleration P, in rad/s2

0 328, aB 1 32,hW

L-------–

0 6,CB--------

0 75,

0 575, L Ap2Tp-------

2

Y 1 581, aBgL

--------=

LocationReference value of the relative motion h1

in the upright ship condition, in m

x = 0

0 < x < 0,3 L

0,3 L x 0,7 L0,42 n C (CB + 0,7)without being taken greater than the mini-mum of T1 and D 0,9 T

0,7 L < x < L

x = L

Note 1:C : Wave parameter defined in Ch 5, Sec 2h1,AE : Reference value h1 calculated for x = 0h1,M : Reference value h1 calculated for x = 0,5 Lh1,FE : Reference value h1 calculated for x = L

0 7, 4 35,CB

----------- 3 25,– h1 M, if CB 0 875

h1 M, if CB 0 875

h1 AE,h1 AE, h1 M,–

0 3,---------------------------x

L---–

h1 M,h1 FE, h1 M,–

0 3,--------------------------- x

L--- 0 7,– +

4 35,CB

----------- 3 25,– h1 M,

h2 0 5h1, ARBW

2-------+=

Pt B, Ch 5, Sec 3


h2 : Reference value, in m, without being takengreater than the minimum of T1 and D 0,9 T

BW : Moulded breadth, in m, measured at the water-line at draught T1 at the hull transverse sectionconsidered.

3.4 Accelerations

3.4.1 The reference values of the longitudinal, transverseand vertical accelerations at any point are obtained fromthe formulae in Tab 6 for upright and inclined ship condi-tions.

Table 6 : Reference values of the accelerations aX, aY and aZ

Direction Upright ship condition Inclined ship condition

X - LongitudinalaX1 and aX2 in m/s2

ax2 = 0

Y - TransverseaY1 and aY2 in m/s2

aY1 = 0

Z - VerticalaZ1 and aZ2 in m/s2

Note 1:

aX1 aSU2 APg p z T1– + 2+=

aY2 aSW2 ARg R z T1– + 2 Y

2KXL2+ +=

aZ1 aH2 p

2KXL2+= aZ2 0 25aH2 R

2y2+=

KX 1 2 xL---

2

, 1 1xL---, 0 2 without being taken less than 0,018,+–=

Pt B, Ch 5, Sec 4


SECTION 4 LOAD CASES

Symbols

h1 : Reference value of the ship relative motion inthe upright ship condition, defined in Ch 5, Sec3, [3.3]

h : Reference value of the ship relative motion inthe inclined ship condition, defined in Ch 5,Sec 3, [3.3]

aX1,aY1,aZ1: Reference values of the accelerations in theupright ship condition, defined in Ch 5, Sec 3,[3.4]

aX2,aY2,aZ2: Reference values of the accelerations in theinclined ship condition, defined in Ch 5, Sec 3,[3.4]

MWV : Reference value of the vertical wave bendingmoment, defined in Ch 5, Sec 2, [3.1]

MWH : Reference value of the horizontal wave bendingmoment, defined in Ch 5, Sec 2, [3.2]

MT : Reference value of the wave torque, defined inCh 5, Sec 2, [3.3]

QWV : Reference value of the vertical wave shearforce, defined in Ch 5, Sec 2, [3.4].

1 General

1.1 Load cases for structural analyses based on partial ship models

1.1.1 The load cases described in this section are those tobe used for structural element analyses which do notrequire complete ship modelling. They are:

• the analyses of plating (see Ch 7, Sec 1)

• the analyses of ordinary stiffeners (see Ch 7, Sec 2)

• the analyses of primary supporting members analysedthrough isolated beam structural models or three dimen-sional structural models (see Ch 7, Sec 3)

• the fatigue analysis of the structural details of the aboveelements (see Ch 7, Sec 4).

1.1.2 These load cases are the mutually exclusive loadcases “a”, “b”, “c” and “d” described in [2].

Load cases “a” and “b” refer to the ship in upright condi-tions (see Ch 5, Sec 3, [3.2]), i.e. at rest or having surge,heave and pitch motions.

Load cases “c” and “d” refer to the ship in inclined condi-tions (see Ch 5, Sec 3, [3.2]), i.e. having sway, roll and yawmotions.

1.2 Load cases for structural analyses based on complete ship models

1.2.1 When primary supporting members are to be ana-lysed through complete ship models, according to Ch 7,Sec 3, [1.1.2], specific load cases are to be considered.

These load cases are to be defined considering the ship assailing in regular waves with different length, height andheading angle, each wave being selected in order to max-imise a design load parameter. The procedure for the deter-mination of these load cases is specified in Ch 7, App 3.

2 Load cases

2.1 Upright ship conditions (load cases “a” and “b”)

2.1.1 Ship condition

The ship is considered to encounter a wave which produces(see Fig 1 for load case “a” and Fig 2 for load case “b”) a rel-ative motion of the sea waterline (both positive and nega-tive) symmetric on the ship sides and induces wave verticalbending moment and shear force in the hull girder. In loadcase “b”, the wave is also considered to induce heave andpitch motions.

2.1.2 Local loads

The external pressure is obtained by adding to or subtract-ing from the still water head a wave head corresponding tothe relative motion.

The internal loads are the still water loads induced by theweights carried, including those carried on decks. For loadcase “b”, those induced by the accelerations are also to betaken into account.

2.1.3 Hull girder loads

The hull girder loads are:

• the vertical still water bending moment and shear force

• the vertical wave bending moment and the shear force.

Pt B, Ch 5, Sec 4


Figure 1 : Wave loads in load case “a”

Figure 2 : Wave loads in load case “b”

2.2 Inclined ship conditions (load cases “c” and “d”)

2.2.1 Ship condition

The ship is considered to encounter a wave which produces(see Fig 3 for load case “c” and Fig 4 for load case “d”):

• sway, roll and yaw motions

• a relative motion of the sea waterline anti-symmetric onthe ship sides

and induces:

• vertical wave bending moment and shear force in thehull girder

• horizontal wave bending moment in the hull girder

• in load case “c”, torque in the hull girder.

Figure 3 : Wave loads in load case “c”

Figure 4 : Wave loads in load case “d”

2.2.2 Local loads

The external pressure is obtained by adding or subtractingfrom the still water head a wave head linearly variable frompositive values on one side of the ship to negative values onthe other.

The internal loads are the still water loads induced by theweights carried, including those carried on decks, and thewave loads induced by the accelerations.

2.2.3 Hull girder loads

The hull girder loads are:

• the still water bending moment and shear force

• the vertical wave bending moment and shear force

• the horizontal wave bending moment

• the wave torque (for load case “c”).

2.3 Summary of load cases

2.3.1 The wave local and hull girder loads to be consideredin each load case are summarised in Tab 1 and Tab 2,respectively.

These loads are obtained by multiplying, for each load case,the reference value of each wave load by the relevant com-bination factor.

Positive h1

Z

Y

0,625Qwv 0,625MwvT1

h1

Negative h1

Z

Y

0,625Qwv 0,625Mwv T1

h1

Y

Z

Y

0,625Qwv az 0,625Mwv

0,5h1

T1

�

�

��

��

��

��

��

��

0,5

0,5

0,25M

WV0,25Q

Z

Y1,0aWV

2h

WH0,625M

Y

1T

h 2

Pt B, Ch 5, Sec 4


Table 1 : Wave local loads in each load case

Table 2 : Wave hull girder loads in each load case

Ship condition Load caseRelative motions Accelerations aX, aY, aZ

Reference value Combination factor Reference value Combination factor

Upright “a” h1 1,0 aX1; 0; aZ1 0,0

“b” (1) h1 0,5 aX1; 0; aZ1 1,0

Inclined “c” (2) h2 1,0 0; aY2; aZ2 0,7

“d” (2) h2 0,5 0; aY2; aZ2 1,0

(1) For a ship moving with a positive heave motion: • h1 is positive• the cargo acceleration aX1 is directed towards the positive part of the X axis• the cargo acceleration aZ1 is directed towards the negative part of the Z axis

(2) For a ship rolling with a negative roll angle: • h2 is positive for the points located in the positive part of the Y axis and, vice-versa, it is negative for the points located in the

negative part of the Y axis• the cargo acceleration aY2 is directed towards the positive part of the Y axis• the cargo acceleration aZ2 is directed towards the negative part of the Z axis for the points located in the positive part of the Y

axis and, vice-versa, it is directed towards the positive part of the Z axis for the points located in the negative part of the Y axis.

Shipcondition

Load case

Vertical bending moment

Vertical shear forceHorizontal bending

momentTorque

Reference value

Comb. factor

Reference value

Comb. factor

Reference value

Comb. factor

Reference value

Comb. factor

Upright “a” 0,625 MWV 1,0 0,625 QWV 1,0 0,625 MWH 0,0 0,625 MT 0,0

“b” 0,625 MWV 1,0 0,625 QWV 1,0 0,625 MWH 0,0 0,625 MT 0,0

Inclined “c” 0,625 MWV 0,4 0,625 QWV 0,4 0,625 MWH 1,0 0,625 MT 1,0

“d” 0,625 MWV 0,4 0,625 QWV 0,4 0,625 MWH 1,0 0,625 MT 0,0

Note 1: The sign of the hull girder loads, to be considered in association with the wave local loads for the scantling of plating, ordi-nary stiffeners and primary supporting members contributing to the hull girder longitudinal strength, is defined in Part B, Chapter 7.

Pt B, Ch 5, Sec 5


SECTION 5 SEA PRESSURES

Symbols

For the symbols not defined in this Section, refer to the listat the beginning of this Chapter.

: Sea water density, taken equal to 1,025 t/m3

h1 : Reference values of the ship relative motions inthe upright ship condition, defined in Ch 5, Sec3, [3.3]

h2 : Reference values of the ship relative motions inthe inclined ship conditions, defined in Ch 5,Sec 3, [3.3].

1 Still water pressure

1.1 Pressure on sides and bottom

1.1.1 The still water pressure at any point of the hull isobtained from the formulae in Tab 1 (see also Fig 1).

Table 1 : Still water pressure

Figure 1 : Still water pressure

1.2 Pressure on exposed decks

1.2.1 On exposed decks, the pressure due to the load carriedis to be considered. This pressure is to be defined by theDesigner and, in general, it may not be taken less than10 kN/m2, where is defined in Tab 2, and in Tab 4.

The Society may accept pressure values lower than10 kN/m2, when considered appropriate on the basisof the intended use of the deck.

Table 2 : Coefficient for pressure on exposed decks

2 Wave pressure

2.1 Upright ship conditions (load cases “a” and “b”)

2.1.1 Pressure on sides and bottomThe wave pressure at any point of the sides and bottom isobtained from the formulae in Tab 3 (see also Fig 2 for loadcase “a” and Fig 3 for load case “b”).

Figure 2 : Wave pressure in load case “a”

LocationStill water pressure pS,

in kN/m2

Points at and below the waterline(z T1)

g (T1 z)

Points above the waterline(z >T1)

0

T1

T1

Exposed deck location 1

Freeboard deck 1,00

Superstructure deck 0,75

1st tier of deckhouse 0,56

2nd tier of deckhouse 0,42

3rd tier of deckhouse 0,32

4th tier of deckhouse 0,25



7th tier of deckhouse and above 0,10

Positive h1

Negative h1

T1

h1

T1

Pt B, Ch 5, Sec 5


Figure 3 : Wave pressure in load case “b” 2.1.2 Pressure on exposed decksThe wave pressure on exposed decks is to be considered forload cases “a, crest” and “b”. This pressure is obtained fromthe formulae in Tab 4.

2.2 Inclined ship conditions (load cases “c” and “d”)

2.2.1 The wave pressure at any point of the sides and bot-tom is obtained from the formulae in Tab 5 (see also Fig 4for load case “c” and Fig 5 for load case “d”).

2.2.2 The wave pressure on exposed decks is to be consid-ered for load cases “c” and “d”. This pressure is obtainedfrom the formulae in Tab 5.

Table 3 : Wave pressure on sides and bottom in upright ship conditions (load cases “a” and “b”)

Table 4 : Wave pressure on exposed decks in upright ship conditions (load cases “a” and “b”)

T1

0,5h1

LocationWave pressure pW, in kN/m2

Crest Trough

Bottom and sides below the waterline(z T1) without being taken less than g (z T1)

Sides above the waterline(z > T1)

g (T1 + h z)without being taken, for case “a” only, less than 0,15 L

0,0

Note 1:h = CF1 h1

CF1 : Combination factor, to be taken equal to:• CF1 = 1,0 for load case “a”• CF1 = 0,5 for load case “b”.


Crest Through

0 x 0,5 L 0

0,5 L < x < 0,75 L 0

0,75 L x L 0

Note 1:

1 : Coefficient defined in Tab 22 : Coefficient taken equal to:

• 2 = 1 if L 120 m• 2 = L/120 if L < 120 m

HF : Value of H calculated at x = 0,75 LCF1 : Combination factor, to be taken equal to:

• CF1 = 1,0 for load case “a”• CF1 = 0,5 for load case “b”

V : Maximum ahead service speed, in knots, to be taken not less than 13 knots.

ghe2 T1 z– –

L------------------------------ – ghe

2 T1 z– –L

------------------------------

17 5n12,

17 5, 19 6 HF 17 5,–0 25,

------------------------------------------ xL--- 0 5,– +

n12

19 6n12 H,

H CF1 2 66 xL--- 0 7,–

2

0 14,+, VLCB

------- z T1– without being taken less than 0,8–=

Pt B, Ch 5, Sec 5


Figure 4 : Wave pressure in load case “c” Figure 5 : Wave pressure in load case “d”

Table 5 : Wave pressure on sides, bottom and exposed decks in inclined ship conditions (load cases “c” and “d”)

h2

T1

Z

Y

0,5h2

T1

Z

Y

LocationWave pressure pW, in kN/m2 (negative roll angle) (1)

y 0 y < 0



without being taken, for case “c” only, less than 0,15 L

0

Exposed decks

without being taken, for case “c” only, less than 0,15 12 L

0

(1) In the formulae giving the wave pressure pW, the ratio (y / BW) is not to be taken greater than 0,5.Note 1:1 : Coefficient defined in Tab 22 : Coefficient defined in Tab 4CF2 : Combination factor, to be taken equal to:

• CF2 = 1,0 for load case “c”• CF2 = 0,5 for load case “d”

BW : Moulded breadth, in m, measured at the waterline at draught T1 , at the hull transverse section considered

AR : Roll amplitude, defined in Ch 5, Sec 3, [2.4.1].

CF2g yBW

-------h1e2 T1 z– –

L------------------------------

ARye T1 z– –

L---------------------------

+CF2g y

BW

-------h1e2 T1 z– –

L------------------------------

ARye T1 z– –

L---------------------------

+

g T1 CF2y

BW

-------h1 ARy+ z–+

0 4, g T1 CF2y

BW

-------h1 ARy+ z–+

Pt B, Ch 5, Sec 6


SECTION 6 INTERNAL PRESSURES AND FORCES

Symbols

For the symbols not defined in this Section, refer to the list at the beginning of this Chapter.

ρL : Density, in t/m3, of the liquid carried

ρB : Density, in t/m3, of the dry bulk cargo carried; in certain cases, such as spoils, the water held by capillarity is to be taken into account

zTOP : Z co-ordinate, in m, of the highest point of the tank in the z direction

zL : Z co-ordinate, in m, of the highest point of the liquid:

zL = zTOP + 0,5 (zAP − zTOP)

zAP : Z co-ordinate, in m, of the top of air pipe, to be taken not less than zTOP

pPV : Setting pressure, in bar, of safety valves

M : Mass, in t, of a dry unit cargo carried

aX1,aY1,aZ1: Reference values of the accelerations in the upright ship condition, defined in Ch 5, Sec 3, [3.4], calculated in way of:

• the centre of gravity of the compartment, in general

• the centre of gravity of any dry unit cargo, in the case of this type of cargo

aX2,aY2,aZ2: Reference values of the accelerations in the inclined ship condition, defined in Ch 5, Sec 3, [3.4], calculated in way of:

• the centre of gravity of the compartment, in general

• the centre of gravity of any dry unit cargo, in the case of this type of cargo

CFA : Combination factor, to be taken equal to:

• CFA = 0,7 for load case “c”

• CFA = 1,0 for load case “d”

H : Height, in m, of a tank, to be taken as the verti-cal distance from the bottom to the top of the tank, excluding any small hatchways

dF : Filling level, in m, of a tank, to be taken as the vertical distance, measured with the ship at rest, from the bottom of the tank to the free surface of the liquid

C : Longitudinal distance, in m, between transverse watertight bulkheads or transverse wash bulk-heads, if any, or between a transverse watertight bulkhead and the adjacent transverse wash bulkhead; to this end, wash bulkheads are those satisfying the requirements in Ch 4, Sec 7, [5]

bC : Transverse distance, in m, between longitudinal watertight bulkheads or longitudinal wash bulk-heads, if any, or between a longitudinal water-tight bulkhead and the adjacent longitudinal wash bulkhead; to this end, wash bulkheads are those satisfying the requirements in Ch 4, Sec 7, [5]

dTB : Vertical distance, in m, from the baseline to the tank bottom

dAP : Distance from the top of air pipe to the top of compartment, in m

d0 : Distance, in m, to be taken equal to:

d0 = 0,02 L for 90 m ≤ L < 120 m

d0 = 2,4 for L ≥ 120 m.

1 Liquids

1.1 Watertight bulkheads

1.1.1 Still water pressure

The still water pressure to be used in combination with the inertial pressure in [1.1.2] is the greater of the values obtained, in kN/m2, from the following formulae:

pS = ρL g (zL − z)

pS = ρL g (zTOP − z) + 100 pPV

In no case is it to be taken, in kN/m2, less than:

1.1.2 Inertial pressure

The inertial pressure is obtained from the formulae in Tab 1or in Ch 5, App 1 for typical tank arrangements. Moreover, the inertial pressure pW is to be taken such that:

pS + pW ≥ 0

where pS is defined in [1.1.1].

pS ρLg0 8L1,

420 L1–--------------------- =

Pt B, Ch 5, Sec 6


Table 1 : Watertight bulkheads of liquid compartments - Inertial pressure

Figure 1 : Upright ship conditions - Distance B

1.1.3 Total acceleration vector

The total acceleration vector is the vector obtained from the following formula:

where:

A : Acceleration vector whose absolute values of X, Y and Z components are the longitudinal, trans-verse and vertical accelerations defined in Ch 5, Sec 3, [3.4]

G : Gravity acceleration vector.

Table 2 : Inclined ship conditionsY and Z components of the total acceleration vector

and angle Φ it forms with the z direction

The Y and Z components of the total acceleration vector and the angle it forms with the z direction are defined in Tab 2.

1.1.4 Highest point of the tank in the direction of the total acceleration vector

The highest point of the tank in the direction of the total acceleration vector AT, defined in [1.1.3], is the point of the tank boundary whose projection on the direction forming the angle Φ with the vertical direction is located at the greatest distance from the tank’s centre of gravity. It is to be determined for the inclined ship condition, as indicated inFig 2, where A and G are the vectors defined in [1.1.3] and C is the tank’s centre of gravity.

Figure 2 : Inclined ship conditionsHighest point H of the tank in the direction

of the total acceleration vector

1.2 Swash bulkheads

1.2.1 Still water and inertial pressures

The still water and inertial pressures transmitted to the swash bulkhead structures are obtained, in kN/m2, as speci-fied in Tab 3.

Ship condition Load case Inertial pressure pW , in kN/m2

Upright “a” No inertial pressure

“b”

Inclined(negative roll angle)

“c”

“d”

Note 1:B : Longitudinal distance, in m, between the transverse tank boundaries, without taking into account small recesses in the

lower part of the tank (see Fig 1)aTY, aTZ : Y and Z components, in m/s2, of the total acceleration vector defined in [1.1.3] for load case “c” and load case “d”yH, zH : Y and Z co-ordinates, in m, of the highest point of the tank in the direction of the total acceleration vector, defined in

[1.1.4] for load case “c” and load case “d”.

ρL 0 5a, X1B aZ1 zTOP z–( )+[ ]

ρL aTY y yH–( ) aTZ z zH–( ) g z zTOP–( )+ +[ ]

Components (negative roll angle)Angle Φ, in rad

aTY , in m/s2 aTZ , in m/s2

0,7 CFA aY2 − 0,7 CFA aZ2 − g

Z

X

�B

AT A G+=

aTY

aTZ-------atan

Φ H

Z90˚

H

A C

G

AT

Y

Pt B, Ch 5, Sec 6


Table 3 : Swash bulkheads in liquid compartmentsStill water and inertial pressures

2 Partly filled tanks intended for the carriage of liquid cargoes or ballast

2.1 Application

2.1.1 Membrane tanks of liquefied gas carriers

Sloshing pressure in membrane tanks of ships having the service notation liquefied gas carrier is defined in Pt D, Ch 9, Sec 4, [2.2].

2.1.2 Other tanks

Sloshing assessment in tanks other than membrane tanks of ships having the service notation liquefied gas carrier is to be carried out as specified in [2.2] to [2.5].

2.2 Evaluation of the risk of resonance

2.2.1 Where tanks are partly filled at a level dF such as 0,1H ≤ dF ≤ 0,95H, the risk of resonance between:

• the ship pitch motion and the longitudinal motion of the liquid inside the tank, for upright ship condition

• the ship roll motion and the transverse motion of the liq-uid inside the tank, for inclined ship condition,

is to be evaluated on the basis of the criteria specified in Tab 4,

where:

Table 4 : Criteria for the evaluationof the risk of resonance

TX : Natural period, in s, of the liquid motion in the longitudinal direction:

TY : Natural period, in s, of the liquid motion in the transverse direction:

S : Length, in m, of the free surface of the liquid, measured horizontally with the ship at rest and depending on the filling level dF, as shown inFig 3; in this figure, wash bulkheads are those satisfying the requirements in Ch 4, Sec 7, [5]

bS : Breadth, in m, of the free surface of the liquid, measured horizontally with the ship at rest and depending on the filling level dF, as shown inFig 4 for ships without longitudinal watertight or wash bulkheads; for ships fitted with longitudi-nal watertight or wash bulkheads (see Fig 5), bS

is delimited by these bulkheads (to this end, wash bulkheads are those satisfying the require-ments in Ch 4, Sec 7, [5])

TP : Pitch period, in s, defined in Ch 5, Sec 3, [2]

TR : Roll period, in s, defined in Ch 5, Sec 3, [2].

Figure 3 : Length S of the free surface of the liquid

Swash bulkheadStill water pressure pS and

inertial pressure pW , in kN/m2

Transverse bulkhead pS = 2,2 ρL C (1 − α) Ap

without being less than 0,4 g d0

pW = 2,2 ρL C (1 − α) Ap


Longitudinal bulkhead pS = 2,2 ρL bC (1 − α) sin AR


pW = 2,2 ρL bC (1 − α) sin AR


Note 1:α : Ratio of lightening hole area to the bulkhead

area, not to be taken greater than 0,3.

Shipcondition

Risk of resonance if: Resonance due to:

Upright Pitch

Inclined Roll

0 6,TX

TP----- 1 3 and,

dF

C----- 0 1,>< <

0 8,TY

TR----- 1 2 and,

dF

bC------ 0 1,>< <

TX4πS

g πdF

S

---------tanh-------------------------=

TY4πbS

g πdF

bS

---------tanh-------------------------=

�S

�S

dF

dF

watertight or wash transverse bulkheads

watertight or wash transversebulkheads

Pt B, Ch 5, Sec 6


Figure 4 : Breadth bS of the free surface of the liquid, for ships without longitudinal bulkheads

Figure 5 : Breadth bS of the free surface of the liquid, for ships with longitudinal bulkheads

2.2.2 The Society may accept that the risk of resonance is evaluated on the basis of dynamic calculation procedures, where deemed necessary in relation to the tank’s dimen-sions and the ship’s characteristics. The calculations are to be submitted to the Society for approval.

2.3 Still water pressure

2.3.1 Still water pressure to be used in combination with the dynamic sloshing pressure

The still water pressure to be used in combination with the dynamic sloshing pressure defined in [2.4] is to be obtained, in kN/m2, from the following formulae:

• pS = ρL g (dF + dTB − z) + 100 pPV for z < dF + dTB

• pS = 100 pPV for z ≥ dF + dTB

2.3.2 Still water pressure to be used in combination with the dynamic impact pressure

The still water pressure to be used in combination with the dynamic impact pressure defined in [2.5] is to be obtained, in kN/m2, from the following formulae:

• pS = ρL g (0,7 H + dTB − z) + 100 pPV for z < 0,7 H + dTB

• pS = 100 pPV for z ≥ 0,7 H + dTB.

2.4 Dynamic sloshing pressure


Where there is a risk of resonance in upright ship condition for a filling level dF, the dynamic sloshing pressure pSL cal-culated according to [2.4.3] is to be considered as acting on transverse bulkheads which form tank boundaries, in the area extended vertically 0,2 dF above and below dF (see Fig 6).

However, the dynamic sloshing pressure may not be con-sidered where there is a risk of resonance for filling levels dF

lower than 0,5 H.

Where tank bottom transverses or wash transverse bulk-heads are fitted, the sloshing pressure calculated according to [2.4.4] is to be considered as acting on them.

The Society may also require the dynamic sloshing pressure to be considered when there is no risk of resonance, but the tank arrangement is such that C / L > 0,15.


Where there is a risk of resonance in inclined ship condi-tion for a filling level dF, the dynamic sloshing pressure pSL

calculated according to [2.4.3] is to be considered as acting on longitudinal bulkheads, inner sides or sides which, as the case may be, form tank boundaries, in the area extended vertically 0,2 dF above and below dF (see Fig 6).

However, the dynamic sloshing pressure may not be con-sidered where there is a risk of resonance for filling levels dF

lower than 0,5 H.

If sloped longitudinal topsides are fitted, they are to be con-sidered as subjected to the sloshing pressure if their height is less than 0,3 H.

dF

dF

bS/2

bS/2

dF

dF

bS/2

bS/2

dF

bS/2

bS/2

dF

bS

dF

bS/2

bS/2bS

bS

dF

Watertight or wash longitudinal bulkheads

Watertight or wash longitudinal bulkheads

Pt B, Ch 5, Sec 6


2.4.3 Sloshing pressure

Where there is a risk of resonance for a filling level dF, the sloshing pressure is obtained, in kN/m2, from the following formulae (see Fig 6):

Figure 6 : Sloshing pressure pSL

where:

p0 : Reference pressure defined in Tab 5 for upright and inclined ship conditions

α : Coefficient taken equal to (see Fig 7):

Figure 7 : Coefficient α

Table 5 : Reference pressure for calculation of sloshing pressures

dF

dF

H

H

0,2dF

0,2dF

0,2dF

0,2dF

α p0

α p0

pSL 0= for z 0 8d, F dTB+≤

pSL 5z dTB–

dF

---------------- 4– αp0 = for 0 8d, F dTB+ z< dF dTB+≤

pSL 6 5– z dTB–dF

---------------- αp0 = for dF dTB+ z 1 2d, F dTB+< <

pSL 0= for z 1 2d, F dTB+≥

α dF

0 6H,-------------= for dF 0 6H,<

α 1= for 0 6H, dF 0 7H,≤ ≤

α H dF–0 3H,----------------= for dF 0 7H,>

0,7H

0,6H

H

1 α

Shipcondition

Reference pressure p0 ,in kN/m2

Meaning of symbols used in the definition of p0

Upright

ϕU : Coefficient defined as follows:ϕU = 1,0 in the case of smooth tanks or tanks with bottom transverses whose height, in m, measured from the tank bottom, is less than 0,1 HϕU = 0,4 in the case of tanks with bottom transverses whose height, in m, measured from the tank bottom, is not less than 0,1 H

S : Coefficient defined as follows:S = 1 + 0,02 L if L ≤ 200 mS = 3 + 0,01 L if L > 200 m

AP : Pitch amplitude, in rad, defined in Ch 5, Sec 3, [2].

Inclined

ϕI : Coefficient defined as follows:• if bC / B ≤ 0,3: ϕI = 0 • if bC / B > 0,3:

ϕI = 1,0 in the case of smooth tanks or tanks with bottom girders whose height, in m, measured from the tank bottom, is less than 0,1 H ϕI = 0,4 in the case of tanks with bottom girders whose height, in m, measured from the tank bottom, is not less than 0,1 H

AR : Roll amplitude, in rad, defined in Ch 5, Sec 3, [2].

0 84ϕU, ρLgSCAP

1 93ϕIρLgbCAR B 1 0 3 BbC------,–

,

Pt B, Ch 5, Sec 6


2.4.4 Sloshing pressure on tank bottom transverses in the case of resonance in upright ship condition

Where there is a risk of resonance in upright ship condition, the sloshing pressure to be considered as acting on tank bottom transverses is obtained, in kN/m2, from the follow-ing formula:

where n is the number of bottom transverses in the tank.

2.4.5 Alternative methods

The Society may accept that the dynamic sloshing pressure is evaluated on the basis of dynamic calculation proce-dures, where deemed necessary in relation to the tank’s dimensions and the ship’s characteristics. The calculations are to be submitted to the Society for verification.

2.5 Dynamic impact pressure


Where there is a risk of resonance in upright ship condition, the dynamic impact pressure due to the liquid motions is to be considered as acting on:

• transverse bulkheads which form tank boundaries, in the area extended vertically 0,15 H from the tank top

• the tank top in the area extended longitudinally 0,3 C

from the above transverse bulkheads.

However, the dynamic impact pressure may not be consid-ered where there is a risk of resonance for filling levels dF

lower than 0,5H.

The Society may also require the impact pressure to be con-sidered as acting on the above structures when there is no risk of resonance, but the tank arrangement is such that C/L > 0,15.

Where the upper part of a transverse bulkhead is sloped, the impact pressure is to be considered as acting on the sloped part of the transverse bulkhead and the tank top (as the case may be) in the area extended longitudinally 0,3 C from the transverse bulkhead.

The impact pressure is obtained, in kN/m2, from the follow-ing formula:

where:

ϕU : Coefficient defined in Tab 5

AP : Pitch amplitude, in rad, defined in Ch 5, Sec 3, [2].

Where the upper part of a transverse bulkhead is sloped, the pressure pI,U may be multiplied by the coefficient φ obtained from the following formula:

to be taken not less than zero,

where hT is the height, in m, of the sloped part of the trans-verse bulkhead.


Where there is a risk of resonance in inclined ship condi-tion, the dynamic impact pressure due to the liquid motions is to be considered as acting on:

• longitudinal bulkheads, inner sides or sides which, as the case may be, form tank boundaries, in the area extended vertically 0,15 H from the tank top

• the tank top in the area extended transversely 0,3bC

from the above longitudinal bulkheads, inner sides or sides.

However, the dynamic impact pressure may not be consid-ered where there is a risk of resonance for filling levels dF

lower than 0,5H.

Where the upper part of a longitudinal bulkhead, inner side or side is sloped, the impact pressure is to be considered as acting on this sloped part and the tank top (as the case may be) in the area extended transversely 0,3 bC from the longi-tudinal bulkhead, inner side or side.

The impact pressure is obtained, in kN/m2, from the follow-ing formula:

where:

ϕI : Coefficient defined in Tab 5.

Where the upper part of a longitudinal bulkhead, inner side or side is sloped, the pressure pI,I may be multiplied by the coefficient φ obtained from the following formula:

to be taken not less than zero,

where hT is the height, in m, of the sloped part of the longi-tudinal bulkhead, inner side or side.

2.5.3 Alternative methods

The Society may accept that the dynamic impact pressure is evaluated on the basis of dynamic calculation procedures, where deemed necessary in relation to the tank’s dimen-sions and the ship’s characteristics. The calculations are to be submitted to the Society for verification.

3 Dry bulk cargoes

3.1 Still water and inertial pressures

3.1.1 Pressures transmitted to the hull structures

The still water and inertial pressures (excluding those acting on the sloping plates of topside tanks, which may be taken equal to zero) are obtained, in kN/m2, as specified in Tab 6.

pSL W, 0 84ρL, g 1 95, 0 12n,–( ) z dTB–( )=

pI U, ϕUρLgCAP 0 9, C

L-----+

5 0 015L,+( )=

φ 1 hT

0 3, H-------------–=

pI I, 0 61ϕ, IρLg 0 75B, 8–( )bCAR=

φ 1 hT

0 3, H-------------–=

Pt B, Ch 5, Sec 6


Table 6 : Dry bulk cargoes - Still water and inertial pressures

3.1.2 Rated upper surface of the bulk cargoThe Z co-ordinate of the rated upper surface of the bulk cargo is obtained, in m, from the following formula (see Fig 8):

Figure 8 : Rated upper surface of the bulk cargo

where:

MC : Mass of cargo, in t, in the hold considered

H : Length, in m, of the hold, to be taken as the lon-gitudinal distance between the transverse bulk-heads which form boundaries of the hold considered

VLS : Volume, in m3, of the transverse bulkhead lower stool (above the inner bottom), to be taken equal to zero in the case of bulkheads fitted without lower stool

hHT : Height, in m, of the hopper tank, to be taken as the vertical distance from the baseline to the top of the hopper tank

hDB : Height, in m, of the double bottom, to be taken as the vertical distance from the baseline to the inner bottom

bHT : Breadth, in m, of the hopper tank, to be taken as the transverse distance from the outermost dou-ble bottom girder to the outermost point of the hopper tank

yHT : Half breadth, in m, of the hold, measured at the middle of H and at a vertical level correspond-ing to the top of the hopper tank.

4 Dry uniform cargoes


4.1.1 General

The still water and inertial pressures are obtained, in kN/m2, as specified in Tab 7.

Ship condition Load case Still water pressure pS and inertial pressure pW, in kN/m2

Still water

Upright “a” No inertial pressure

“b”

Inclined “c” The inertial pressure transmitted to the hull structures in inclined condition may gen-erally be disregarded. Specific cases in which this simplification is not deemed per-missible by the Society are considered individually.“d”

Note 1:zB : Z co-ordinate, in m, of the rated upper surface of the bulk cargo (horizontal ideal plane of the volume filled by the

cargo); see [3.1.2]α : Angle, in degrees, between the horizontal plane and the surface of the hull structure to which the calculation point belongsϕ : Angle of repose, in degrees, of the bulk cargo (considered drained and removed); in the absence of more precise evalu-

ation, the following values may be taken:• ϕ = 30° in general• ϕ = 35° for iron ore• ϕ = 25° for cement.

pS ρBg zB z–( ) αsin( )2 45o ϕ2---–

tan2

αcos( )2+

=

pW ρBaZ1 zB z–( ) αsin( )2 45o ϕ2---–

tan2

αcos( )2+

=

zB

MC

ρBH

----------- VLS

H

-------- hHT hDB–( )bHT+ +

2yHT

---------------------------------------------------------------------- hDB+=

ZB

ZB

yHT

hHT

bHT

hDB

�H

Pt B, Ch 5, Sec 6


Table 7 : Dry uniform cargoesStill water and inertial pressures

4.1.2 General cargo ships with the service notation completed with the additional service feature heavycargo

For ships with the service notation general cargo ship com-pleted by the additional service feature heavycargo [AREA1, X1 kN/m2 -AREA2, X2 kN/m2 - ....] (see Pt A, Ch 1, Sec 2, [4.2.2]), the values of pS, in kN/m2, are to be speci-fied by the Designer for each AREAi, according to [4.1.1], and introduced as Xi values in the above service feature.

5 Dry unit cargoes

5.1 Still water and inertial forces

5.1.1 The still water and inertial forces transmitted to the hull structures are to be determined on the basis of the forces obtained, in kN, as specified in Tab 8, taking into account the elastic characteristics of the lashing arrange-ment and/or the structure which contains the cargo.

Table 8 : Dry unit cargoesStill water and inertial forces

6 Wheeled cargoes

6.1 Still water and inertial forces

6.1.1 GeneralCaterpillar trucks and unusual vehicles are considered by the Society on a case by case basis.

The load supported by the crutches of semi-trailers, han-dling machines and platforms is considered by the Society on a case by case basis.

Harbour conditions are to be taken into account only for fork-lift trucks and vehicles on external ramps.

6.1.2 Tyred vehiclesThe forces transmitted through the tyres are comparable to pressure uniformly distributed on the tyre print, whose dimensions are to be indicated by the Designer together with information concerning the arrangement of wheels on axles, the load per axles and the tyre pressures.

With the exception of dimensioning of plating, such forces may be considered as concentrated in the tyre print centre.

The still water and inertial forces transmitted to the hull structures are to be determined on the basis of the forces obtained, in kN, as specified in Tab 9.

6.1.3 Non-tyred vehiclesThe requirements of [6.1.2] also apply to tracked vehicles; in this case the print to be considered is that below each wheel or wheelwork.

For vehicles on rails, all the forces transmitted are to be con-sidered as concentrated at the contact area centre.

Table 9 : Wheeled cargoesStill water and inertial forces

Shipcondition

Load case

Still water pressure pS

and inertial pressure pW, in kN/m2

Still water

The value of pS is generally specified by the Designer; in any case, it may not be taken less than 10 kN/m2.When the value of pS is not specified by the Designer, it may be taken, in kN/m2, equal to 6,9 hTD , where hTD is the com-partment ‘tweendeck height at side, in m.

Upright (positive heave motion)

“a” No inertial pressure

“b”

Inclined (negative roll angle)

“c”

“d”

Shipcondition

Load case

Still water force FS

and inertial force FW, in kN

Still water FS = M g


“a” No inertial force

“b” FW,X = M aX1 in x directionFW,Z = M aZ1 in z direction

Inclined (negative roll angle)

“c” FW,Y = M CFA aY2 in y directionFW,Z = M CFA aZ2 in z direction“d”

pW Z, pSaZ1

g-------= in z direction

pW Y, pSCFAaY2

g-----------------= in y direction

pW Z, pS

CFAaZ2

g-----------------= in z direction

Shipcondition

Load case

Still water force FS

and inertial force FW , in kN

Still water (1) (2) FS = M g

Upright (positive heave motion) (1)

“a” No inertial force

“b” FW,Z = α M aZ1 in z direction

Inclined (nega-tive roll angle) (2)

“c” FW,Y = M CFA aY2 in y directionFW,Z = α M CFA aZ2 in z direction“d”

Harbour FW,X = 0,035 M g in x directionFW,Y = 0,087 M g in y directionFW,Z = 0,100 M g in z direction

(1) This condition defines the force, applied by one wheel, to be considered for the determination of scantlings of plating, ordinary stiffeners and primary supporting members, as defined in Part B, Chapter 7, where:α : Coefficient taken equal to:

• 0,4 in general• 1,0 for landing gears of trailers

M : Mass, in t, taken equal to

QA : Axle load, in t. For fork-lift trucks, the value of QA is to be taken equal to the total mass of the vehicle, including that of the cargo handled, applied to one axle only.

nW : Number of wheels for the axle considered.(2) This condition is to be considered for the racking analy-

sis of ships with the service notation ro-ro cargo ship or ro-ro passenger ship, as defined in Ch 7, App 1, with M taken equal to the mass, in t, of wheeled loads located on the structural member under consideration.

M QA

nW

-------=

Pt B, Ch 5, Sec 6


7 Accommodation


7.1.1 The still water and inertial pressures transmitted to the deck structures are obtained, in kN/m2, as specified in Tab 10.

Table 10 : AccommodationStill water and inertial pressures

Table 11 : Still water deck pressurein accommodation compartments

8 Machinery


8.1.1 The still water and inertial pressures transmitted to the deck structures are obtained, in kN/m2, as specified in Tab 12.

9 Flooding


9.1.1 Ships for which damage stability calculations are required

Unless otherwise specified, the still water pressure pSF, in kN/m2, and the inertial pressure pWF, in kN/m2, to be con-sidered as acting on structural elements located below the deepest equilibrium waterline (excluding bottom and side

shell structural elements) which constitute boundaries of compartments not intended to carry liquids are obtained from the following formulae:

• pSF = ρ g dF without being taken less than 0,4 g d0

• pWF = 0,6 ρ aZ1 dF without being taken less than 0,4 g d0

where:

dF : Distance, in m, from the calculation point to the deepest equilibrium waterline.

The deepest equilibrium waterlines are to be provided by the Designer under his own responsibility.

Table 12 : MachineryStill water and inertial pressures

9.1.2 Ships for which damage stability calculations are not required

Unless otherwise specified, the still water and inertial pres-sures to be considered as acting on structural elements (excluding bottom and side shell structural elements) which constitute boundaries of compartments not intended to carry liquids are obtained, in kN/m2, from the formulae in Tab 13.

Table 13 : Flooding - Still water and inertial pressures for ships for which damage stability calculations are

not required

Shipcondition

Load case



Still water

The value of pS is defined in Tab 11depending on the type of the accommo-dation compartment.



“b”

Inclined “c”

The inertial pressure transmitted to the deck structures in inclined condition may generally be disregarded. Specific cases in which this simplification is not deemed permissible by the Society are considered individually.

“d”

Type of accommodation compartment pS , in kN/m2

Large public spaces, such as:restaurants, halls, cinemas, lounges

5,0

Large rooms, such as:• rooms with fixed furniture• games and hobbies rooms, hospitals

3,0

Cabins 3,0

Other compartments 2,5

pW pSaZ1

g-------= Ship

conditionLoad case


and inertial pressure pW , in kN/m2

Still water pS = 10



“b”

Inclined “c” The inertial pressure transmitted to the deck structures in inclined condition may generally be disregarded. Specific cases in which this simplification is not deemed permissible by the Society are considered individually.

“d”

Still water pressure pSF ,in kN/m2

Inertial pressure pWF ,in kN/m2

• Compartment located below bulkhead deck: ρ g (zF − z) without being taken less than 0,4 g d0

• Compartment located below bulkhead deck:0,6 ρ aZ1 (zF − z)without being taken less than 0,4 g d0

• Compartment located immediately above the bulkhead deck:0,32 g d0

• Compartment located immediately above the bulkhead deck:0,32 g d0

Note 1:zF : Z co-ordinate, in m, of the bulkhead deck.

pW pSaZ1

g-------=

Pt B, Ch 5, Sec 6


10 Testing

10.1 Still water pressures

10.1.1 The still water pressure to be considered as acting on plates and stiffeners subject to tank testing is obtained, in kN/m2, from the formulae in Tab 14.No inertial pressure is to be considered as acting on plates and stiffeners subject to tank testing.

Table 14 : Testing - Still water pressures

Compartment orstructure to be tested

Still water pressure pST , in kN/m2

Double bottom tanks The greater of the following:pST = 10 [(zTOP − z) + dAP]pST = 10 (zml − z)where:zml : Z co-ordinate, in m,

of the margin line

Double side tanks, fore and after peaks used as tank, cofferdams

The greater of the following:pST = 10 [(zTOP − z) + dAP]pST = 10 [(zTOP − z) + 2,4]

Tank bulkheads, deep tanks, fuel oil bunkers

The greater of the following:pST = 10 [(zTOP − z) + dAP]pST = 10 [(zTOP − z) + 2,4]pST = 10 [(zTOP − z) + 10 pPV]

Ballast holds of ships with service notation bulk carrier

The greater of the following:pST = 10 [(zTOP − z) + dAP]pST = 10 [(zh − z) + 0,9]where:zh : Z co-ordinate, in m,

of the top of hatch

Fore peak not used as tank

The greater of the following:pST = 10 (zF − z)pST = 10 (zml − z)where:zF : As defined in Tab 13zml : Z co-ordinate, in m,

of the margin line

Watertight doors below freeboard or bulkhead deck

pST = 10 (zbd − z)where:zbd : Z co-ordinate, in m,

of the bulkhead deck

Watertight hatch covers of tanks in ships with service notation combination carrier

The greater of the following:pST = 10 [(zh − z) + 2,4]pST = 10 [(zh − z) + 10 pPV]where:zh : Z co-ordinate, in m,

of the top of hatch

Chain locker (if aft of collision bulkhead)

pST = 10 (zTOP − z)

Independent tanks The greater of the following:pST = 10 [(zTOP − z) + dAP]pST = 10 [(zTOP − z) + 0,9]

Ballast ducts Ballast pump maximum pressure

Pt B, Ch 5, App 1


APPENDIX 1 INERTIAL PRESSURE FOR TYPICAL TANK ARRANGEMENT

1 Liquid cargoes and ballast - Inertial pressure

1.1 Introduction

1.1.1 Ch 5, Sec 6, [1] defines the criteria to calculate theinertial pressure pW induced by liquid cargoes and ballast inany type of tank. The relevant formulae are specified in Ch5, Sec 6, Tab 1 and entail the definition of the highest pointof the tank in the direction of the total acceleration vector.As specified in Ch 5, Sec 6, [1.2], this point depends on thegeometry of the tank and the values of the acceleration. Fortypical tank arrangements, the highest point of the tank inthe direction of the total acceleration vector can easily be

identified and the relevant formulae written using the tankgeometric characteristics.

1.1.2 This Appendix provides the formulae for calculatingthe inertial pressure pW in the case of typical tank arrange-ments.

1.2 Formulae for the inertial pressure calcu-lation

1.2.1 For typical tank arrangements, the inertial pressuretransmitted to the hull structures at the calculation point Pin inclined ship condition may be obtained from the formu-lae in Tab 1, obtained by applying to those tanks the generalformula in Ch 5, Sec 6, Tab 1.

Table 1 : Liquid cargoes and ballast - Inertial pressure for typical tank arrangements

Figure 1 : Distances bL and dH Figure 2 : Distances bL and dH

Ship condition Load case Inertial pressure pW , in kN/m2

Inclined(negative roll angle)

“c”

“d”

Note 1:CFA : Combination factor, to be taken equal to:

• CFA = 0,7 for load case “c”• CFA = 1,0 for load case “d”

L : Density, in t/m3, of the liquid cargo carriedaY2, aZ2 : Reference values of the acceleration in the inclined ship condition, defined in Ch 5, Sec 3, [3.4], calculated in way of

the centre of gravity of the tankbL, dH : Transverse and vertical distances, in m, to be taken as indicated in Fig 1 to Fig 6 for various types of tanks; for the cases

in Fig 1 to Fig 4, where the central cargo area is divided into two or more tanks by longitudinal bulkheads, bL and dH forcalculation points inside each tank are to be taken as indicated in Fig 5 for the double side. The angle which appearsin Fig 3 and Fig 4 is defined in Ch 5, Sec 6, Tab 2.

0 7CFAL aY2bL aZ2dH+

At calculation point P

dH

bT

dCT

P bL = 0,5bT+dCT

At calculation point PbL = 0,5bT+dCT

dCT

bT

P

dH

Pt B, Ch 5, App 1


Figure 3 : Distances bL and dH




At calculation point PbL = 0,5bT+dCT

dCT

P

dH

H

bT

Φ

Φ

��

�

�

��

��

��

��

��

��

��

�

��

��

��

��

��

��

��

�

��

��

��

��

��

��

��

��

��

��

� ��

� ��

Pt B, Ch 5, App 1


Chapter 6 Hull Girder Strength

Symbols

E :

Young's modulus, in N/mm2, to be taken equal to:

• for steels in general: E = 2,06.105 N/mm

2

• for stainless steels: E = 1,95.105 N/mm

2

• for aluminium alloys: E = 7,0.104 N/mm

2

MSW :

Still water bending moment, in kN.m:

• in hogging conditions: MSW = MSW,H

• in sagging conditions: MSW = MSW,S

MSW,H :

Design still water bending moment, in kN.m, in hogging condition, at the hull transverse

section considered, defined in Pt B, Ch 5, Sec 2, [2.2],

MSW,S :

Design still water bending moment, in kN.m, in sagging condition, at the hull transverse

section considered, defined in Pt B, Ch 5, Sec 2, [2.2], when the ship in still water is always

in hogging condition, MSW,S is to be taken equal to 0,

MWV :

Vertical wave bending moment, in kN.m:

• in hogging conditions: MWV = MWV,H

• in sagging conditions: MWV = MWV,S

MWV,H :

Vertical wave bending moment, in kN.m, in hogging condition, at the hull transverse section

considered, defined in Pt B, Ch 5, Sec 2, [3.1],

MWV,S :

Vertical wave bending moment, in kN.m, in sagging condition, at the hull transverse section


g :

Gravity acceleration, in m/s2: g = 9,81 m/s

2.

Pt B, Ch 6, Sec 1


SECTION 1 STRENGTH CHARACTERISTICS OF THE HULL GIRDER TRANSVERSE SECTIONS

Symbols


1 Application

1.1

1.1.1 This Section specifies the criteria for calculating thehull girder strength characteristics to be used for the checksin Ch 6, Sec 2 and Ch 6, Sec 3, in association with the hullgirder loads specified in Ch 5, Sec 2.

2 Calculation of the strength characteristics of hull girder transverse sections

2.1 Hull girder transverse sections

2.1.1 GeneralHull girder transverse sections are to be considered as beingconstituted by the members contributing to the hull girderlongitudinal strength, i.e. all continuous longitudinal mem-bers below the strength deck defined in [2.2], taking intoaccount the requirements in [2.1.2] to [2.1.9].

These members are to be considered as having (see also Ch4, Sec 2):• gross scantlings, when the hull girder strength character-

istics to be calculated are used for the yielding checks inCh 6, Sec 2

• net scantlings, when the hull girder strength characteris-tics to be calculated are used for the ultimate strengthchecks in Ch 6, Sec 3 and for calculating the hull girderstresses for the strength checks of plating, ordinary stiff-eners and primary supporting members in Part B, Chap-ter 7.

2.1.2 Continuous trunks and continuous longitudinal hatch coamings

Continuous trunks and continuous longitudinal hatch com-mons may be included in the hull girder transverse sections,provided they are effectively supported by longitudinalbulkheads or primary supporting members.

2.1.3 Longitudinal ordinary stiffeners or girders welded above the decks

Longitudinal ordinary stiffeners or girders welded above thedecks (including the deck of any trunk fitted as specified in[2.1.2]) may be included in the hull girder transverse sec-tions.

2.1.4 Longitudinal girders between hatchways

Where longitudinal girders are fitted between hatchways,the sectional area that can be included in the hull girdertransverse sections is obtained, in m2, from the followingformula:

AEFF = ALG a

where:

ALG : Sectional area, in m2, of longitudinal girders

a : Coefficient:

• for longitudinal girders effectively supportedby longitudinal bulkheads or primary sup-porting members:

a = 1

• for longitudinal girders not effectively sup-ported by longitudinal bulkheads or primarysupporting members and having dimensionsand scantlings such that 0 / r 60:

• for longitudinal girders not effectively sup-ported by longitudinal bulkheads or primarysupporting members and having dimensionsand scantlings such that 0 / r > 60:

a = 0

0 : Span, in m, of longitudinal girders, to be takenas shown in Fig 1

r : Minimum radius of gyration, in m, of the longi-tudinal girder transverse section

s, b1 : Dimensions, in m, defined in Fig 1.

Figure 1 : Longitudinal girders between hatchways

a 0 6 sb1

----- 0 15,+

0 5,

,=

�0

b1

ss b1

Pt B, Ch 6, Sec 1


2.1.5 Longitudinal bulkheads with vertical corrugations

Longitudinal bulkheads with vertical corrugations may notbe included in the hull girder transverse sections.

2.1.6 Members in materials other than steel

Where a member contributing to the longitudinal strength ismade in material other than steel with a Young’s modulus Eequal to 2,06 105 N/mm2, the steel equivalent sectionalarea that may be included in the hull girder transverse sec-tions is obtained, in m2, from the following formula:

where:

AM : Sectional area, in m2, of the member under con-sideration.

2.1.7 Large openings

Large openings are:

• elliptical openings exceeding 2,5 m in length or 1,2 min breadth

• circular openings exceeding 0,9 m in diameter.

Large openings and scallops, where scallop welding isapplied, are always to be deducted from the sectional areasincluded in the hull girder transverse sections.

2.1.8 Small openings

Smaller openings than those in [2.1.7] in one transversesection in the strength deck or bottom area need not bededucted from the sectional areas included in the hullgirder transverse sections, provided that:

bS 0,06 (B b)

where:

bS : Total breadth of small openings, in m, in thestrength deck or bottom area at the transversesection considered, determined as indicated inFig 2

b : Total breadth of large openings, in m, at thetransverse section considered, determined asindicated in Fig 2

Where the total breadth of small openings bS does not ful-fil the above criteria, only the excess of breadth is to bededucted from the sectional areas included in the hullgirder transverse sections.

2.1.9 Lightening holes, draining holes and single scallops

Lightening holes, draining holes and single scallops in lon-gitudinals need not be deducted if their height is less than0,25 hW , without being greater than 75 mm, where hW isthe web height, in mm, defined in Ch 4, Sec 3.

Otherwise, the excess is to be deducted from the sectionalarea or compensated.

Figure 2 : Calculation of b and bS

2.2 Strength deck

2.2.1 The strength deck is, in general, the uppermost con-tinuous deck.

In the case of a superstructure or deckhouses contributingto the longitudinal strength, the strength deck is the deck ofthe superstructure or the deck of the uppermost deckhouse.

2.2.2 A superstructure extending at least 0,15 L within 0,4L amidships may generally be considered as contributing tothe longitudinal strength. For other superstructures and fordeckhouses, their contribution to the longitudinal strengthis to be assessed on a case by case basis, through a finiteelement analysis of the whole ship, which takes intoaccount the general arrangement of the longitudinal ele-ments (side, decks, bulkheads).

The presence of openings in the side shell and longitudinalbulkheads is to be taken into account in the analysis. Thismay be done in two ways:

• by including these openings in the finite element model

• by assigning to the plate panel between the side framesbeside each opening an equivalent thickness, in mm,obtained from the following formula:

where (see Fig 3):

P : Longitudinal distance, in m, between theframes beside the opening

h : Height, in m, of openings

IJ : Moment of inertia, in m4, of the openingjamb about the transverse axis y-y

AJ : Shear area, in m2, of the opening jamb inthe direction of the longitudinal axis x-x

ASEE

2 06,105,----------------------AM=

30°

30°

Hull transverse sectionunder consideration

b1

b2

b1 and b2 included in Σb and Σbs

tEQ 103P

Gh2

12EIJ

------------- 1AJ

-----+

1–

=

Pt B, Ch 6, Sec 1


Figure 3 : Side openings

G : Coulomb’s modulus, in N/mm2, of the mate-rial used for the opening jamb, to be takenequal to:

• for steels:

G = 8,0.104 N/mm2

• for aluminium alloys:

G = 2,7.104 N/mm2.

2.3 Section modulus

2.3.1 The section modulus at any point of a hull transversesection is obtained, in m3, from the following formula:

where:

IY : Moment of inertia, in m4, of the hull transversesection defined in [2.1], about its horizontalneutral axis

z : Z co-ordinate, in m, of the calculation pointwith respect to the reference co-ordinate systemdefined in Ch 1, Sec 2, [4]

N : Z co-ordinate, in m, of the centre of gravity ofthe hull transverse section defined in [2.1], withrespect to the reference co-ordinate systemdefined in Ch 1, Sec 2, [4].

2.3.2 The section moduli at bottom and at deck areobtained, in m3, from the following formulae:

• at bottom:

• at deck:

where:

IY, N : Defined in [2.3.1]

VD : Vertical distance, in m:

• in general:

VD = zD N

where:

zD : Z co-ordinate, in m, of strengthdeck, defined in [2.2], withrespect to the reference co-ordi-nate system defined in Ch 1, Sec2, [4]

• if continuous trunks or hatch coamings aretaken into account in the calculation of IY ,as specified in [2.1.2]:

where:

yT, zT : Y and Z co-ordinates, in m, ofthe top of continuous trunk orhatch coaming with respect tothe reference co-ordinate systemdefined in Ch 1, Sec 2, [4]; yT

and zT are to be measured forthe point which maximises thevalue of VD

• if longitudinal ordinary stiffeners or girderswelded above the strength deck are takeninto account in the calculation of IY , asspecified in [2.1.3], VD is to be obtainedfrom the formula given above for continu-ous trunks and hatch coamings. In this case,yT and zT are the Y and Z co-ordinates, in m,of the top of the longitudinal stiffeners orgirders with respect to the reference co-ordi-nate system defined in Ch 1, Sec 2, [4].

2.4 Moments of inertia

2.4.1 The moments of inertia IY and IZ , in m4, are those,calculated about the horizontal and vertical neutral axes,respectively, of the hull transverse sections defined in [2.1].

2.5 First moment

2.5.1 The first moment S, in m3, at a level z above the base-line is that, calculated with respect to the horizontal neutralaxis, of the portion of the hull transverse sections defined in[2.1] located above the z level.

2.6 Structural models for the calculation of normal warping stresses and shear stresses

2.6.1 The structural models that can be used for the calcu-lation of normal warping stresses, induced by torque, andshear stresses, induced by shear forces or torque, are:

• three dimensional finite element models

• thin walled beam models

representing the members which constitute the hull girdertransverse sections according to [2.1].

�p

Side frames

h

y

y

x x

Cross section ofthe opening jamb

ZAIY

z N–----------------=

ZABIY

N----=

ZADIY

VD

------=

VD zT N– 0 9, 0 2yT

B-----,+

zD N–=

Pt B, Ch 6, Sec 2


SECTION 2 YIELDING CHECKS

Symbols

For symbols not defined in this Section, refer to the list at the beginning of this Chapter.

MWH : Horizontal wave bending moment, in kN.m, defined in Ch 5, Sec 2, [3.2]

MWT : Wave torque, in kN.m, defined in Ch 5, Sec 2, [3.3]

QSW : Design still water shear force, in kN, defined inCh 5, Sec 2, [2.3]

QWV : Vertical wave shear force, to be calculated according to Ch 5, Sec 2, [3.4]:

• if QSW ≥ 0, QWV is the positive wave shear force

• if QSW < 0, QWV is the negative wave shear force

k : Material factor, as defined in Ch 4, Sec 1, [2.3]

x : X co-ordinate, in m, of the calculation point with respect to the reference co-ordinate system defined in Ch 1, Sec 2, [4]

IY : Moment of inertia, in m4, of the hull transverse section about its horizontal neutral axis, to be calculated according to Ch 6, Sec 1, [2.4]

IZ : Moment of inertia, in m4, of the hull transverse section about its vertical neutral axis, to be cal-culated according to Ch 6, Sec 1, [2.4]

S : First moment, in m3, of the hull transverse sec-tion, to be calculated according to Ch 6, Sec 1, [2.5]

ZA : Gross section modulus, in m3, at any point of the hull transverse section, to be calculated according to Ch 6, Sec 1, [2.3.1]

ZAB, ZAD : Gross section moduli, in m3, at bottom and deck, respectively, to be calculated according toCh 6, Sec 1, [2.3.2]

n1 : Navigation coefficient defined in Ch 5, Sec 1, Tab 1

C : Wave parameter defined in Ch 5, Sec 2

σ1,ALL : Allowable normal stress, in N/mm2, defined in[3.1.1]

τ1,ALL : Allowable shear stress, in N/mm2, defined in[3.2.1].

1 Application

1.1

1.1.1 The requirements of this Section apply to ships hav-ing the following characteristics:

• L < 500 m

• L / B > 5

• B / D < 2,5

• CB ≥ 0,6

Ships not having one or more of these characteristics, ships intended for the carriage of heated cargoes and ships of unusual type or design are considered by the Society on a case by case basis.

2 Hull girder stresses

2.1 Normal stresses induced by vertical bending moments

2.1.1 The normal stresses induced by vertical bending moments are obtained, in N/mm2, from the following for-mulae:

• at any point of the hull transverse section:

• at bottom:

• at deck:

2.1.2 The normal stresses in a member made in material other than steel with a Young’s modulus E equal to 2,06 105

N/mm2, included in the hull girder transverse sections as specified in Ch 6, Sec 1, [2.1.6], are obtained from the fol-lowing formula:

where:

σ1S : Normal stress, in N/mm2, in the member under consideration, calculated according to [2.1.1]considering this member as having the steel equivalent sectional area ASE defined in Ch 6, Sec 1, [2.1.6].

σ1MSW MWV+

ZA-----------------------------10 3–=

σ1MSW MWV+

ZAB-----------------------------10 3–=

σ1MSW MWV+

ZAD-----------------------------10 3–=

σ1E

2 06 10⋅ 5,-------------------------σ1S=

Pt B, Ch 6, Sec 2


Table 1 : Torque and bending moments

Figure 1 : Ships with large openings

2.2 Normal stresses induced by torque and bending moments

2.2.1 Ships having large openings in the strength deck

The normal stresses induced by torque and bending moments are to be considered for ships having large open-ings in the strength decks, i.e. ships for which at least one of the three following conditions occur:

• b / B0 > 0,7

• A / 0 > 0,89

• b / B0 > 0,6 and A / 0 > 0,7

where b, B0 , A and 0 are the dimensions defined in Fig 1. In the case of two or more openings in the same hull trans-verse section, b is to be taken as the sum of the breadth b1

of each opening.

2.2.2 Normal stresses

The normal stresses are to be calculated for the load case constituted by the hull girder loads specified in Tab 1together with their combination factors. They are to be obtained, in N/mm2, from the following formula:

where:σΩ : Warping stress, in N/mm2, induced by the

torque MWT and obtained through direct calcu-lation analyses based on a structural model in accordance with Ch 6, Sec 1, [2.6]; for ships with the service notation container ship, it includes the contribution due to the still water torque MT,SW defined in Pt D, Ch 2, Sec 2, [4.1]

y : Y co-ordinate, in m, of the calculation point with respect to the reference co-ordinate system defined in Ch 1, Sec 2, [4].

2.3 Shear stresses

2.3.1 The shear stresses induced by shear forces and torque are obtained through direct calculation analyses based on a structural model in accordance with Ch 6, Sec 1, [2.6].The shear force corrections ΔQC and ΔQ are to be taken into account, in accordance with [2.4.1] and [2.4.2], respectively.

2.3.2 The hull girder loads to be considered in these analy-ses are: • for all ships, the vertical shear forces QSW and QWV

• for ships having large openings in the strength decks, also the torques MT and MT,SW as specified in [2.2].

When deemed necessary by the Society on the basis of the ship’s characteristics and intended service, the horizontal shear force is also to be calculated, using direct calculations, and taken into account in the calculation of shear stresses.

2.3.3 As an alternative to the above procedure, the shear stresses induced by the vertical shear forces QSW and QWV

may be obtained through the simplified procedure in [2.4].

2.4 Simplified calculation of shear stresses induced by vertical shear forces

2.4.1 Ships without effective longitudinal bulkheads or with one effective longitudinal bulkhead

In this context, effective longitudinal bulkhead means a bulkhead extending from the bottom to the strength deck.

The shear stresses induced by the vertical shear forces in the calculation point are obtained, in N/mm2, from the follow-ing formula:

Still water loads Wave loads

Torque (1) Vertical bending moment Torque Vertical bending

momentHorizontal bending

moment

Reference value

Comb. factor

Reference value

Comb. factor

Reference value

Comb. factor

Reference value

Comb. factor

Reference value

Comb. factor

MT,SW (2) 1,0 MSW 1,0 MWT 1,0 MWV 0,4 MWH 1,0

(1) To be considered only for ships with the service notation container ship.(2) MT,SW : Still water torque defined in Pt D, Ch 2, Sec 2, [4.1].

�A

�0

B0

B0

b 1b 1

b

σ1MSW

ZA

----------- 0,4MWV

ZA

-------------------- MWH

IZ

------------+ + y

= 10 3– σΩ+

Pt B, Ch 6, Sec 2


where:

t : Minimum thickness, in mm, of side, inner side and longitudinal bulkhead plating, as applica-ble according to Tab 2

δ : Shear distribution coefficient defined in Tab 2

ε = sgn(QSW)

ΔQC : Shear force correction (see Fig 2), which takes into account, when applicable, the portion of loads transmitted by the double bottom girders to the transverse bulkheads:

• for ships with double bottom in alternate loading conditions:

• for other ships:

ΔQC = 0

with:

0 , b0 : Length and breadth, respectively, in m, of the flat portion of the double bottom in way of the hold consid-ered; b0 is to be measured on the

hull transverse section at the middle of the hold

P : Total mass of cargo, in t, in the holdρ : Sea water density, in t/m3:

ρ = 1,025 t/m3

T1 : Draught, in m, measured vertically on the hull transverse section at the middle of the hold considered, from the moulded baseline to the water-line in the loading condition con-sidered.

BH : Ship’s breadth, in m, measured on the hull transverse section at the middle of the hold considered

C : Length, in m, of the hold consid-ered, measured between transverse bulkheads

Figure 2 : Shear force correction ΔQC

Table 2 : Shear stresses induced by vertical shear forces

τ1 QSW QWV εΔQC–+( ) SIYt------δ=

ΔQC α PBHC

------------ ρT1–=

α g0b0

2 ϕ 0

b0

-----+-------------------=

ϕ 1 38, 1 550

b0

----- 3 7,≤,+=

Full hold Empty hold

Correctedshear force

ΔQc

ΔQc = pαT1

Shear force obtained asspecified in Ch 5, Sec 2

Ship typology Location t, in mm δ Meaning of symbols used in the definition of δ

Single side ships without effective longitudinal bulkheadsSee Fig 3 (a)

Sides tS 0,5

Double side ships without effective longitudinal bulkheadsSee Fig 3 (b)

Sides tS (1 − Φ) / 2Φ = 0,275 + 0,25 α α = tISM / tSM

Inner sides tIS Φ / 2

Double side ships with one effective longitudinal bulkheadSee Fig 3 (c)

Sides tS (1 − Φ)Ψ / 2Φ = 0,275 + 0,25 α α = tISM / tSM

Inner sides tIS ΦΨ / 2

Longitudinal bulkhead tB 1 − χ

Note 1:tS, tIS, tB : Minimum thicknesses, in mm, of side, inner side and longitudinal bulkhead plating, respectivelytSM, tISM, tBM : Mean thicknesses, in mm, over all the strakes of side, inner side and longitudinal bulkhead plating, respectively. They

are calculated as Σ(i ti) / Σi, where i and ti are the length, in m, and the thickness, in mm, of the ith strake of side, inner side and longitudinal bulkhead.

Ψ 1 9β γ 2δ 1 1α0------+ +

0 17,–,= χ Ψ0 85, 0 17α,+----------------------------------=

α00 5tBM,

tSM tISM+----------------------= β 0 75,

3δ α0 1+ +----------------------------=

γ 2δ 1+

4δ 1 1α0------+ +

-----------------------------= δ B2D--------=

Pt B, Ch 6, Sec 2


Figure 3 : Ship typologies (with reference to Tab 2)

2.4.2 Ships with two effective longitudinal bulkheads

In this context, effective longitudinal bulkhead means a bulkhead extending from the bottom to the strength deck.

The shear stresses induced by the vertical shear force in the calculation point are obtained, in N/mm2, from the follow-ing formula:

where:δ : Shear distribution coefficient defined in Tab 3

with : QF, QA : Value of QSW, in kN, in way of the forward and aft transverse bulkhead, respectively, of the hold considered

C : Length, in m, of the hold consid-ered, measured between transverse bulkheads


ΔQ : Shear force correction, in kN, which takes into account the redistribution of shear force between sides and longitudinal bulkheads due to possible transverse non-uniform distribution of cargo:• in sides:

• in longitudinal bulkheads:

with:

ε = sgn(QSW)

pC : Pressure, in kN/m2, acting on the inner bottom in way of the centre hold in the loading condition con-sidered

pW : Pressure, in kN/m2, acting on the inner bottom in way of the wing hold in the loading condition considered, to be taken not greater than pC

bC : Breadth, in m, of the centre hold, measured between longitudinal bulkheads

n : Number of floors in way of the cen-tre hold

Φ : Coefficient defined in Tab 3.

Figure 4 : Ship typologies (with reference to Tab 3)

Table 3 : Shear stresses induced by vertical shear forces

(a) (b) (c)

τ1 QSW QWV+( )δ εQΔQ+[ ] SIYt------=

εQQF QA–

C

-------------------- sgn=

ΔQgε pC pW–( )CbC

4------------------------------------------ n

3 n 1+( )--------------------- 1 Φ–( )–=

ΔQgε pC pW–( )CbC

4------------------------------------------ 2n

3 n 1+( )--------------------- Φ–=

(a) (b)

Ship typology Location t, in mm δMeaning of symbols used

in the definition of δ

Single side ships with two effectivelongitudinal bulkheads - see Fig 4 (a)

Sides tS (1 − Φ) / 2 Φ = 0,3 + 0,21 αα = tBM / tSMLongitudinal bulkheads tB Φ / 2

Double side ships with two effective longitudinal bulkheads - see Fig 4 (b)

Sides tS (1 − Φ) / 4 Φ = 0,275 + 0,25 α

Inner sides tIS (1 − Φ) / 4

Longitudinal bulkheads tB Φ / 2

Note 1:tS, tIS, tB : Minimum thicknesses, in mm, of side, inner side and longitudinal bulkhead plating, respectivelytSM, tISM, tBM : Mean thicknesses, in mm, over all the strakes of side, inner side and longitudinal bulkhead plating, respectively. They

are calculated as Σ(i ti) / Σi, where i and ti are the length, in m, and the thickness, in mm, of the ith strake of side, inner side and longitudinal bulkheads.

α tBM

tSM tISM+----------------------=

Pt B, Ch 6, Sec 2


3 Checking criteria

3.1 Normal stresses induced by vertical bending moments

3.1.1 It is to be checked that the normal stresses σ1 calcu-lated according to [2.1] and, when applicable, [2.2] are in compliance with the following formula:

σ1 ≤ σ1,ALL

where:

σ1,ALL : Allowable normal stress, in N/mm2, obtained from the following formulae:

3.2 Shear stresses

3.2.1 It is to be checked that the shear stresses τ1 calculated according to [2.3] are in compliance with the following for-mula:

τ1 ≤ τ1,ALL

where:

τ1,ALL : Allowable shear stress, in N/mm2: τ1,ALL = 110/k

4 Section modulus and moment of inertia

4.1 General

4.1.1 The requirements in [4.2] to [4.5] provide the mini-mum hull girder section modulus, complying with the checking criteria indicated in [3], and the midship section moment of inertia required to ensure sufficient hull girder rigidity.

4.1.2 The k material factors are to be defined with respect to the materials used for the bottom and deck members contributing to the longitudinal strength according to Ch 6, Sec 1, [2]. When material factors for higher strength steels are used, the requirements in [4.5] apply.

4.2 Section modulus within 0,4L amidships

4.2.1 For ships with CB greater than 0,8, the gross section moduli ZAB and ZAD within 0,4L amidships are to be not less than the greater value obtained, in m3, from the following formulae:

• ZR,MIN = n1 C L2 B (CB + 0,7) k 10−6

•

4.2.2 For ships with CB less than or equal to 0,8, the gross section moduli ZAB and ZAD at the midship section are to be not less than the value obtained, in m3, from the following formula:

ZR,MIN = n1 C L2 B (CB + 0,7) k 10−6

In addition, the gross section moduli ZAB and ZAD within 0,4L amidships are to be not less than the value obtained, in m3, from the following formula:

4.2.3 Where the total breadth ΣbS of small openings, as defined in Ch 6, Sec 1, [2.1.8], is deducted from the sec-tional areas included in the hull girder transverse sections, the values ZR and ZR,MIN defined in [4.2.1] or [4.2.2] may be reduced by 3%.

4.2.4 Scantlings of members contributing to the longitudi-nal strength (see Ch 6, Sec 1, [2]) are to be maintained within 0,4 L amidships.

4.3 Section modulus outside 0,4L amidships

4.3.1 The gross section moduli ZAB and ZAD outside 0,4 L amidships are to be not less than the value obtained, in m3, from the following formula:

4.3.2 Scantlings of members contributing to the hull girder longitudinal strength (see Ch 6, Sec 1, [2]) may be gradually reduced, outside 0,4L amidships, to the minimum required for local strength purposes at fore and aft parts, as specified in Part B, Chapter 9.

4.4 Midship section moment of inertia

4.4.1 The gross midship section moment of inertia about its horizontal neutral axis is to be not less than the value obtained, in m4, from the following formula:

IYR = 3 Z’R,MIN L 10−2

where Z’R,MIN is the required midship section modulus ZR,MIN, in m3, calculated as specified in [4.2.1] or [4.2.2], but assuming k = 1.

4.5 Extent of higher strength steel

4.5.1 When a material factor for higher strength steel is used in calculating the required section modulus at bottom or deck according to [4.2] or [4.3], the relevant higher strength steel is to be adopted for all members contributing to the lon-gitudinal strength (see Ch 6, Sec 1, [2]), at least up to a verti-cal distance, in m, obtained from the following formulae:

• above the baseline (for section modulus at bottom):

σ1 ALL,119

k----------= for x

L--- 0 1,≤

σ1 ALL,175

k---------- 1400

k------------- x

L--- 0 3,–

2

–= for 0 1, xL--- 0 3,< <

σ1 ALL,175

k----------= for 0 3, x

L--- 0 7,≤ ≤

σ1 ALL,175

k---------- 1400

k------------- x

L--- 0 7,–

2

–= for 0 7, xL--- 0 9,< <

σ1 ALL,119

k----------= for x

L--- 0 9,≥

ZRMSW MWV+

σ1 ALL,-----------------------------10 3–=

ZRMSW MWV+

σ1 ALL,-----------------------------10 3–=

ZRMSW MWV+

σ1 ALL,-----------------------------10 3–=

VHBσ1B kσ1 ALL,–

σ1B σ1D+-------------------------------zD=

Pt B, Ch 6, Sec 2


• below a horizontal line located at a distance VD (see Ch 6, Sec 1, [2.3.2]) above the neutral axis of the hull trans-verse section (for section modulus at deck):

where:

σ1B, σ1D : Normal stresses, in N/mm2, at bottom and deck, respectively, calculated according to [2.1.1]

zD : Z co-ordinate, in m, of the strength deck, defined in Ch 6, Sec 1, [2.2], with respect to the reference co-ordinate system defined in Ch 1, Sec 2, [4]

N : Z co-ordinate, in m, of the centre of gravity of the hull transverse section defined in Ch 6, Sec 1, [2.3.1], with respect to the reference co-ordi-nate system defined in Ch 1, Sec 2, [4]

VD : Vertical distance, in m, defined in Ch 6, Sec 1, [2.3.2].

4.5.2 The higher strength steel is to extend in length at least throughout 0,4 L amidships where it is required for strength purposes according to the provisions of Part B.

5 Permissible still water bending moment and shear force during navigation

5.1 Permissible still water bending moment

5.1.1 The permissible still water bending moment at any hull transverse section during navigation, in hogging or sagging conditions, is the value MSW considered in the hull girder sec-tion modulus calculation according to [4.2] and [4.3].

In the case of structural discontinuities in the hull transverse sections, the distribution of permissible still water bending moments is considered on a case by case basis.

5.2 Permissible still water shear force

5.2.1 Direct calculations

Where the shear stresses are obtained through calculation analyses according to [2.3], the permissible positive or neg-ative still water shear force at any hull transverse section is obtained, in kN, from the following formula:

QP = ε |QT| − QWV

where:

ε = sgn(QSW)

QT : Shear force, in kN, which produces a shear stress τ = 110/k N/mm2 in the most stressed point of the hull transverse section, taking into account the shear force correction ΔQC and ΔQ in accord-ance with [2.4.1] and [2.4.2], respectively.

5.2.2 Ships without effective longitudinal bulkeads or with one effective longitudinal bulkhead

Where the shear stresses are obtained through the simpli-fied procedure in [2.4.1], the permissible positive or nega-

tive still water shear force at any hull transverse section is obtained, in kN, from the following formula:

where:

ε = sgn(QSW)



ΔQC : Shear force correction defined in [2.4.1].

5.2.3 Ships with two effective longitudinal bulkeads

Where the shear stresses are obtained through the simpli-fied procedure in [2.4.2], the permissible positive or nega-tive still water shear force at any hull transverse section is obtained, in kN, from the following formula:

where:


ε = sgn(QSW)


εQ : Defined in [2.4.2]

ΔQ : Shear force correction defined in [2.4.2].

6 Permissible still water bending moment and shear force in harbour conditions

6.1 Permissible still water bending moment

6.1.1 The permissible still water bending moment at any hull transverse section in harbour conditions, in hogging or sagging conditions, is obtained, in kN.m, from the following formula:

where ZA,M is the lesser of ZAB and ZAD defined in [4.2.1] or[4.2.2].

6.2 Permissible shear force

6.2.1 The permissible positive or negative still water shear force at any hull transverse section, in harbour conditions, is obtained, in kN, from the following formula:

QP,H = ε QP + 0,7 QWV

where:

ε = sgn(QSW)

QP : Permissible still water shear force during naviga-tion, in kN, to be calculated according to [5.2].

VHDσ1D kσ1 ALL,–

σ1B σ1D+-------------------------------- N VD+( )=

QP ε 110kδ

---------- IYtS------⋅ ΔQC+

QWV–=

QP1δ--- ε110

k---------- IYt

S------⋅ εQΔQ–

QWV–=

MP H,130

k----------ZA M, 103=

Pt B, Ch 6, Sec 3


SECTION 3 ULTIMATE STRENGTH CHECK

Symbols


1 Application

1.1

1.1.1 The requirements of this Section apply to ships equalto or greater than 170 m in length.

2 General

2.1 Net scantlings

2.1.1 As specified in Ch 4, Sec 2, [1], the ultimate strengthof the hull girder is to be checked on the basis of the netstrength characteristics of the transverse section which is tobe calculated according to Ch 4, Sec 2, [2].

2.2 Partial safety factors

2.2.1 The partial safety factors to be considered for check-ing the ultimate strength of the hull girder are specified inTab 1.

Table 1 : Partial safety factors

3 Hull girder ultimate strength check


3.1.1 Bending moments in navigationThe bending moment in navigation, in sagging and hoggingconditions, to be considered in the ultimate strength checkof the hull girder, is to be obtained, in kN.m, from the fol-lowing formula:

M = S1 MSW + W1 MWV

3.1.2 Bending moments in harbour conditionsThe bending moment in harbour conditions, in sagging andhogging conditions, to be considered in the ultimatestrength check of the hull girder, is to be obtained, in kN.m,from the following formula:

MH = S1 MP,H + 0,1 W1 MWV

where MP,H is the permissible still water bending moment inharbour conditions, defined in Ch 6, Sec 2, [6.1.1].

3.2 Hull girder ultimate bending moment capacities

3.2.1 Curve M-

The ultimate bending moment capacities of a hull girdertransverse section, in hogging and sagging conditions, aredefined as the maximum values of the curve of bendingmoment capacity M versus the curvature of the transversesection considered (see Fig 1).

The curvature is positive for hogging condition and nega-tive for sagging condition.

The curve M- is to be obtained through an incremental-iterative procedure according to the criteria specified in Ch6, App 1.

Figure 1 : Curve bending moment capacity Mversus curvature

3.2.2 Hull girder transverse sections

The hull girder transverse sections are constituted by theelements contributing to the hull girder longitudinalstrength, considered with their net scantlings, according toCh 6, Sec 1, [2].

3.3 Checking criteria

3.3.1 It is to be checked that the hull girder ultimate bend-ing capacity at any hull transverse section is in compliancewith the following formulae:

Partial safety factor coveringuncertainties on:

Symbol Value

Still water hull girder loads S1 1,00

Wave induced hull girder loads W1 1,10

Material m 1,02

Resistance R 1,03

M

MUHHogging condition

MUSSagging condition

χF

- χF χ

MU

Rm

---------- M

MU

Rm

---------- MH

Pt B, Ch 6, Sec 3


where:

MU : Ultimate bending moment capacity of the hulltransverse section considered, in kN.m:

• in hogging conditions:

MU = MUH

• in sagging conditions:

MU = MUS

MUH : Ultimate bending moment capacity in hoggingconditions, defined in [3.2.1]

MUS : Ultimate bending moment capacity in saggingconditions, defined in [3.2.1]

M : Bending moment in navigation, in kN.m,defined in [3.1.1]

MH : Bending moment in harbour conditions, inkN.m, defined in [3.1.2].

Pt B, Ch 6, App 1


APPENDIX 1 HULL GIRDER ULTIMATE STRENGTH

Symbols

For symbols not defined in this Appendix, refer to the list atthe beginning of this Chapter.

ReH : Minimum upper yield stress, in N/mm2, of thematerial

IY : Moment of inertia, in m4, of the hull transversesection around its horizontal neutral axis, to becalculated according to Ch 6, Sec 1, [2.4]

ZAB ,ZAD : Section moduli, in cm3, at bottom and deck,respectively, defined in Ch 6, Sec 1, [2.3.2]

s : Spacing, in m, of ordinary stiffeners

: Span, in m, of ordinary stiffeners, measuredbetween the supporting members (see Ch 4, Sec3, Fig 2 to Ch 4, Sec 3, Fig 5)

hw : Web height, in mm, of an ordinary stiffener

tw : Web net thickness, in mm, of an ordinary stiff-ener

bf : Face plate width, in mm, of an ordinary stiffener

tf : Face plate net thickness, in mm, of an ordinarystiffener

AS : Net sectional area, in cm2, of an ordinary stiff-ener

tp : Net thickness, in mm, of the plating attached toan ordinary stiffener.

1 Hull girder ultimate strength check

1.1 Introduction

1.1.1 Ch 6, Sec 3, [2] defines the criteria for calculatingthe ultimate bending moment capacities in hogging condi-tion MUH and sagging condition MUS of a hull girder trans-verse section.

As specified in Ch 6, Sec 3, [2], the ultimate bendingmoment capacities are defined as the maximum values ofthe curve of bending moment capacity M versus the curva-ture of the transverse section considered (see Fig 1).

1.1.2 This Appendix provides the criteria for obtaining thecurve M-.

1.2 Criteria for the calculation of the curve M-

1.2.1 Procedure

The curve M- is to be obtained by means of an incremen-tal-iterative approach, summarised in the flow chart in Fig 2.

Figure 1 : Curve bending moment capacity Mversus curvature

Each step of the incremental procedure is represented bythe calculation of the bending moment Mi which acts onthe hull transverse section as the effect of an imposed cur-vature i

For each step, the value i is to be obtained by summing anincrement of curvature to the value relevant to the previ-ous step i-1.This increment of curvature corresponds to anincrement of the rotation angle of the hull girder transversesection around its horizontal neutral axis.

This rotation increment induces axial strains in each hullstructural element, whose value depends on the position ofthe element. In hogging condition, the structural elementsabove the neutral axis are lengthened, while the elementsbelow the neutral axis are shortened. Vice-versa in saggingcondition.

The stress induced in each structural element by the strain is to be obtained from the load-end shortening curve -of the element, which takes into account the behaviour ofthe element in the non-linear elasto-plastic domain.

The distribution of the stresses induced in all the elementscomposing the hull transverse section determines, for eachstep, a variation of the neutral axis position, since the rela-tionship - is non-linear. The new position of the neutralaxis relevant to the step considered is to be obtained bymeans of an iterative process, imposing the equilibriumamong the stresses acting in all the hull elements.

Once the position of the neutral axis is known and the rele-vant stress distribution in the section structural elements isobtained, the bending moment of the section Mi around thenew position of the neutral axis, which corresponds to thecurvature i imposed in the step considered, is to beobtained by summing the contribution given by each ele-ment stress.

M

MUH Hogging condition

MUSSagging condition

χF

- χF χ

Pt B, Ch 6, App 1


Figure 2 : Flow chart of the procedure for the evaluation of the curve M-

Start

First step

Calculation of the position of the neutral axis Ni-1

χi-1= 0

Increment of the curvature

χi = χi-1+ Δχ

Calculation of the strain ε induced on eachstructural element by the curvature χi

for the neutral axis position Ni-1

For each structural element; calculationof the stress σ relevant to the strain ε Curve σ-ε

Ni-1 = Ni

χi-1 = χi

Calculation of the new position of theneutral axis Ni ,imposing the equilibrium

on the stress resultant F

NO

NO

YES

YES

NO

YES

End

χ > χF

F = δ1 δ1 δ2 = specified tolerance on zero value

Check on the positionof the neutral axis

Ni - Ni-1 < δ2

Calculation of the bending moments Mirelevant to the curvature χi summing the

contribution of each structural element stressCurve M - χ

Pt B, Ch 6, App 1


1.2.2 AssumptionIn applying the procedure described in [1.2.1], the follow-ing assumptions are generally to be made:

• The ultimate strength is calculated at hull transverse sec-tions between two adjacent reinforced rings.

• The hull girder transverse section remains plane duringeach curvature increment.

• The hull material has an elasto-plastic behaviour.

• The hull girder transverse section is divided into a set ofelements, which are considered to act independently.These elements are:

- transversely framed plating panels and/or ordinarystiffeners with attached plating, whose structuralbehaviour is described in [1.3.1]

- hard corners, constituted by plating crossing, whosestructural behaviour is described in [1.3.2].

• According to the iterative procedure, the bendingmoment Mi acting on the transverse section at each cur-vature value i is obtained by summing the contributiongiven by the stress acting on each element. The stress, corresponding to the element strain , is to beobtained for each curvature increment from the non-lin-ear load-end shortening curves - of the element.

These curves are to be calculated, for the failure mecha-nisms of the element, from the formulae specified in[1.3]. The stress is selected as the lowest among thevalues obtained from each of the considered load-endshortening curves -

• The procedure is to be repeated for each step, until thevalue of the imposed curvature reaches the value F, inm1, in hogging and sagging condition, obtained fromthe following formula:

where:

MY : The lesser of the values MY1 and MY2 , inkN.m:

MY1 = 103 ReH ZAB

MY2 = 103 ReH ZAD

If the value F is not sufficient to evaluate the peaks ofthe curve M-the procedure is to be repeated until thevalue of the imposed curvature permits the calculationof the maximum bending moments of the curve.

1.3 Load-end shortening curves -

1.3.1 Plating panels and ordinary stiffenersPlating panels and ordinary stiffeners composing the hullgirder transverse sections may collapse following one of themodes of failure specified in Tab 1.

1.3.2 Hard cornersHard corners are sturdier elements composing the hullgirder transverse section, which collapse mainly accordingto an elasto-plastic mode of failure. The relevant load-endshortening curve - is to be obtained for lengthened andshortened hard corners according to [1.3.3].

Table 1 : Modes of failure of plate panelsand ordinary stiffeners

1.3.3 Elasto-plastic collapse

The equation describing the load-end shortening curve -for the elasto-plastic collapse of structural elements com-posing the hull girder transverse section is to be obtainedfrom the following formula, valid for both positive (shorten-ing) and negative (lengthening) strains (see Fig 3):

= ReH

where:

: Edge function:

= 1 for < 1

= for 1 < < 1

= 1 for > 1

: Relative strain:

E : Element strain

Y : Strain inducing yield stress in the element:

Figure 3 : Load-end shortening curve -for elasto-plastic collapse

F 0 003MY

EIY

-------,=

Element Mode of failureCurve defined in

Lengthened plate panel or ordinary stiffener

Elasto-plasticcollapse

[1.3.3]

Shortened ordinarystiffener

Beam columnbuckling

[1.3.4]

Torsional buckling [1.3.5]

Web local buckling of flanged profiles

[1.3.6]

Web local buckling of flat bars

[1.3.7]

Shortened transversely framed plate panel

Plate buckling [1.3.8]

Shortened transversely framed curved plate panel

Curved plate buckling

[1.3.9]

E

Y

-----=

YReH

E--------=

- ReH

ReH

σ

ε

Pt B, Ch 6, App 1


1.3.4 Beam column buckling

The equation describing the load-end shortening curveCR1- for the beam column buckling of ordinary stiffenerscomposing the hull girder transverse section is to beobtained from the following formula (see Fig 4):

where:

: Edge function defined in [1.3.3]

C1 : Critical stress, in N/mm2:

: Relative strain defined in [1.3.3]

E1 : Euler column buckling stress, in N/mm2:

IE : Net moment of inertia of ordinary stiffeners, incm4, with attached shell plating of width bE

AE : Net sectional area, in cm2, of ordinary stiffenerswith attached shell plating of width bE

bE : Width, in m, of the attached shell plating:

E : Generalized slenderness parameter:

Figure 4 : Load-end shortening curve CR1-for beam column buckling

1.3.5 Torsional buckling

The equation describing the load-end shortening curveCR2- for the lateral-flexural buckling of ordinary stiffenerscomposing the hull girder transverse section is to beobtained according to the following formula (see Fig 5):

where:


C2 : Critical stress, in N/mm2:

E2 : Euler torsional buckling stress, in N/mm2,defined in Ch 7, Sec 2, [4.3.3]

: Relative strain defined in [1.3.3]

CP : Buckling stress of the attached plating, inN/mm2:

E : Coefficient defined in [1.3.4].

Figure 5 : Load-end shortening curve CR2-for flexural-torsional buckling

1.3.6 Web local buckling of flanged ordinary stiffeners

The equation describing the load-end shortening curveCR3- for the web local buckling of flanged ordinary stiffen-ers composing the hull girder transverse section is to beobtained from the following formula:

where:


bE : Width, in m, of the attached shell plating,defined in [1.3.4]

hWE : Effective height, in mm, of the web:

: Relative strain defined in [1.3.3].

CR1 C1AS 10bEtP+AS 10stP+-----------------------------=

C1E1

-------= for E1

ReH

2--------

C1 ReH 1ReH4E1

-----------– = for E1

ReH

2--------

E1 2EIE

AE2-----------10 4–=

bE2 25,E

----------- 1 25,E

2-----------–

s= for E 1 25,

bE s= for E 1 25,

E 103 stp

--- ReH

E-----------=

σCR1

ε

σC1

CR2 ASC2 10stPCP+

AS 10stP+-------------------------------------------=

C2E2

-------= for E2

ReH

2--------

C2 ReH 1ReH4E2

-----------– = for E2

ReH

2--------

CP2 25,E

----------- 1 25,E

2-----------–

ReH= for E 1 25,

CP ReH= for E 1 25,

σCR2

ε

σC2

CR3 ReH103bEtP hWEtW bFtF+ +103stP hWtW bFtF+ +

--------------------------------------------------------=

hWE2 25,W

----------- 1 25,W

2-----------–

hW= for W 1 25,

hWE hW= for W 1 25,

WhW

tW

------- ReH

E-----------=

Pt B, Ch 6, App 1


1.3.7 Web local buckling of flat bar ordinary stiffeners

The equation describing the load-end shortening curveCR4- for the web local buckling of flat bar ordinary stiffen-ers composing the hull girder transverse section is to beobtained from the following formula (see Fig 6):

where: : Edge function defined in [1.3.3]CP : Buckling stress of the attached plating, in

N/mm2, defined in [1.3.5]C4 : Critical stress, in N/mm2:

E4 : Local Euler buckling stress, in N/mm2:

: Relative strain defined in [1.3.3].

Figure 6 : Load-end shortening curve CR4-for web local buckling of flat bars

1.3.8 Plate buckling

The equation describing the load-end shortening curveCR5- for the buckling of transversely stiffened panels com-posing the hull girder transverse section is to be obtainedfrom the following formula:

where:

E : Coefficient defined in [1.3.4].

1.3.9 Transversely stiffened curved panels

The equation describing the load-end shortening curveCR6 for the buckling of transversely stiffened curvedpanels is to be obtained from the following formulae:

where:

EC : Euler buckling stress, to be obtained, in N/mm2,from the following formula:

b : Width of curved panel, in m, measured on arcbetween two adjacent supports

K3 : Buckling factor to be taken equal to:

r : Radius of curvature, in m.

CR4 10stPCP ASC4+

AS 10stP+-------------------------------------------=

C4E4

-------= for E4

ReH

2--------

C4 ReH 1ReH4E4

-----------– = for E4

ReH

2--------

E4 160000tW

hW

-------

2

=

σCR4

ε

σC4

CR5 minReH

ReHs-- 2 25,

E

----------- 1 25,E

2-----------–

0 1 1 s--–

1 1E

2-----+

2

,+

=

CR6EC

-------------= for EC

ReH

2--------

CR6 ReH 1ReH4EC

------------– = for EC

ReH

2--------

EC2E

12 1 2– -------------------------- t

b---

2

K310 6–=

K3 2 1 1 12 1 2– 4

-------------------------- b4

r2t2--------106++

=

Chapter 7 Hull Scantlings

Symbols

L1, L2 :

Lengths, in m, defined in Pt B, Ch 1, Sec 2, [2.1.1],

E :

Young's modulus, in N/mm2, to be taken equal to:

• for steels in general: E = 2,06.105 N/mm

2

• for stainless steels: E = 1,95.105 N/mm

2

• for aluminium alloys: E = 7,0.104 N/mm2

ν :

Poisson's ratio. Unless otherwise specified, a value of 0,3 is to be taken into account,

k :

Material factor, defined in:

• Pt B, Ch 4, Sec 1, [2.3], for steel,

• Pt B, Ch 4, Sec 1, [4.4], for aluminium alloys,

Ry :

Minimum yield stress, in N/mm2, of the material, to be taken equal to 235/k N/mm

2, unless

otherwise specified,

tc :

Corrosion addition, in mm, defined in Pt B, Ch 4, Sec 2, Tab 2,

IY :

Net moment of inertia, in m4, of the hull transverse section around its horizontal neutral axis,

to be calculated according to Pt B, Ch 6, Sec 1, [2.4] considering the members contributing to

the hull girder longitudinal strength as having their net scantlings,

IZ :

Net moment of inertia, in m4, of the hull transverse section around its vertical neutral axis, to

be calculated according to Pt B, Ch 6, Sec 1, [2.4] considering the members contributing to

the hull girder longitudinal strength as having their net scantlings,

x, y, z :

X, Y and Z co-ordinates, in m, of the calculation point with respect to the reference co-ordinate system defined in Pt B, Ch 1, Sec 2, [4],

N :

Z co-ordinate, in m, with respect to the reference co-ordinate system defined in Pt B, Ch 1,

Sec 2, [4], of the centre of gravity of the hull transverse section constituted by members

contributing to the hull girder longitudinal strength considered as having their net scantlings

(see Pt B, Ch 6, Sec 1, [2]),

MSW,H :

Design still water bending moment, in kN.m, in hogging condition, at the hull transverse


MSW,S :

Design still water bending moment, in kN.m, in sagging condition, at the hull transverse


MSW,Hmin :

Minimum still water bending moment, in kN.m, in hogging condition, at the hull transverse

section considered, without being taken greater than 0,3MWV,S,

MWV,H :

Vertical wave bending moment, in kN.m, in hogging condition, at the hull transverse section


MWV,S :

Vertical wave bending moment, in kN.m, in sagging condition, at the hull transverse section


MWH :

Horizontal wave bending moment, in kN.m, at the hull transverse section considered, defined

in Pt B, Ch 5, Sec 2, [3.2],

MWT :

Wave torque, in kN.m, at the hull transverse section considered, defined in Pt B, Ch 5, Sec 2,

[3.3].

Pt B, Ch 7, Sec 1


SECTION 1 PLATING

Symbols


pS : Still water pressure, in kN/m2, see [3.2.2]

pW : Wave pressure and, if necessary, dynamic pres-sures, according to the criteria in Ch 5, Sec 5, [2] and Ch 5, Sec 6, [2], in kN/m2 (see [3.2.2])

pSF, pWF : Still water and wave pressure, in kN/m2, in flooding conditions, defined in Ch 5, Sec 6, [9](see [3.2.3])

FS : Still water wheeled force, in kN, see [4.2.2]

FW,Z : Inertial wheeled force, in kN, see [4.2.2]

σX1 : In-plane hull girder normal stress, in N/mm2, defined in:

• [3.2.5] for the strength check of plating sub-jected to lateral pressure

• [5.2.2] for the buckling check of plating

τ1 : In-plane hull girder shear stress, in N/mm2, defined in [3.2.6]

ReH : Minimum yield stress, in N/mm2, of the plating material, defined in Ch 4, Sec 1, [2]

: Length, in m, of the longer side of the plate panel

s : Length, in m, of the shorter side of the plate panel

a, b : Lengths, in m, of the sides of the plate panel, as shown in Fig 2 to Fig 4

ca : Aspect ratio of the plate panel, equal to:

to be taken not greater than 1,0cr : Coefficient of curvature of the panel, equal to:

cr = 1 − 0,5 s / r

to be taken not less than 0,5r : Radius of curvature, in mt : Net thickness, in mm, of a plate panel.

1 General

1.1 Net thicknesses

1.1.1 As specified in Ch 4, Sec 2, [1], all thicknesses referred to in this Section are net, i.e. they do not include any margin for corrosion.The gross thicknesses are obtained as specified in Ch 4, Sec 2.


1.2.1 The partial safety factors to be considered for the checking of the plating are specified in Tab 1.

1.3 Elementary plate panel

1.3.1 The elementary plate panel is the smallest unstiffened part of plating.

Table 1 : Plating - Partial safety factors

ca 1= 21 1 0 33 s--

2

,+, 0 69s--,–

Partial safety factorscovering uncertainties

regarding:Symbol

Strength check of plating subjected to lateral pressureBuckling

checkGeneralSloshing pressure

Impact pressure

Watertight bulkheadplating (1)

Testing check

see [3.2], [3.3.1], [3.4.1], [3.5.1] and [4]

see [3.3.2], [3.4.2]and [3.5.2]

see [3.3.3], [3.4.3], [3.5.3]

see [5]

Still water hull girder loads γS1 1,00 0 0 1,00 N.A. 1,00

Wave hull girder loads γW1 1,15 0 0 1,15 N.A. 1,15

Still water pressure γS2 1,00 1,00 1,00 1,00 1,00 N.A.

Wave pressure γW2 1,20 1,05 1,20 1,20 N.A. N.A.

Material γm 1,02 1,02 1,02 1,02 1,02 1,02

Resistance γR 1,20 1,10 1,02 1,05 (2) 1,05 1,10

(1) Applies also to plating of bulkheads or inner side which constitute boundary of compartments not intended to carry liquids.(2) For plating of the collision bulkhead, γR =1,25Note 1: N.A. = not applicable

Pt B, Ch 7, Sec 1


1.4 Load point

1.4.1 Unless otherwise specified, lateral pressure and hull girder stresses are to be calculated:

• for longitudinal framing, at the lower edge of the ele-mentary plate panel or, in the case of horizontal plating, at the point of minimum y-value among those of the ele-mentary plate panel considered

• for transverse framing, at the lower edge of the strake.

2 General requirements

2.1 General

2.1.1 The requirements in [2.2] to [2.6] are to be applied to plating in addition of those in [3] to [5].

2.2 Minimum net thicknesses

2.2.1 The net thickness of plating is to be not less than the values given in Tab 2.

2.3 Bilge plating

2.3.1 The net thickness of the longitudinally framed bilge plating, in mm, is to be not less than the greater of:

• value obtained from [3.3.1]

• value obtained from [5], to be checked as curved panel.

2.3.2 The net thickness of the transversely framed bilge plating, in mm, is to be not less than the greater of:

• t = 0,7 [ γR γm (γS2 pS + γW2 pW) sb ]0,4 R0,6 k1/2

where:

R : Bilge radius, in m

sb : Spacing of floors or transverse bilge brack-ets, in m

• value obtained from [5], to be checked as curved panel.

2.3.3 The net thickness bilge plating is to be not less than the actual thicknesses of the adjacent bottom or side plat-ing, whichever is the greater.

2.4 Inner bottom of cargo holds intended to carry dry cargo

2.4.1 For ships with one of the following service notations:

• general cargo ship, intended to carry dry bulk cargo in holds

• bulk carrier ESP

• ore carrier ESP

• combination carrier ESP

the inner bottom net thickness is to be increased by 2 mm unless it is protected by a continuous wooden ceiling.

Table 2 : Minimum net thickness of plating (in mm)

Plating Minimum net thicknessKeel 3,8 + 0,040 L k1/2 + 4,5 sBottom• longitudinal framing 1,9 + 0,032 L k1/2 + 4,5 s• transverse framing 2,8 + 0,032 L k1/2 + 4,5 sInner bottom• outside the engine room (1) 1,9 + 0,024 L k1/2 + 4,5 s• engine room 3,0 + 0,024 L k1/2 + 4,5 sSide• below freeboard deck (1) 2,1 + 0,031 L k1/2 + 4,5 s• between freeboard deck and

strength deck2,1 + 0,013 L k1/2 + 4,5 s

Inner side• L < 120 m 1,7 + 0,013 L k1/2+ 4,5 s• L ≥ 120 m 3,6 + 2,20 k1/2 + sWeather strength deck and trunk deck, if any (2)• area within 0,4 L amidships

- longitudinal framing 1,6 + 0,032 L k1/2 + 4,5 s- transverse framing 1,6 + 0,040 L k1/2 + 4,5 s

• area outside 0,4 L amidships (3)• between hatchways 2,1 + 0,013 L k1/2 + 4,5 s• at fore and aft part 2,1 + 0,013 L k1/2 + 4,5 sCargo deck• general 8 s k1/2

• wheeled load only 4,5Accommodation deck• L < 120 m 1,3 + 0,004 L k1/2 + 4,5 s• L ≥ 120 m 2,1 + 2,20 k1/2 + sPlatform in engine room• L < 120 m 1,7 + 0,013 L k1/2 + 4,5 s• L ≥ 120 m 3,6 + 2,20 k1/2 + sTransv. watertight bulkhead (4)• L < 120 m 1,3 + 0,004 L k1/2 + 4,5 s• L ≥ 120 m 2,1 + 2,20 k1/2 + sLongitud. watertight bulkhead (4)• L < 120 m 1,7 + 0,013 L k1/2 + 4,5 s• L ≥ 120 m 3,6 + 2,20 k1/2 + sTank and wash bulkheads (4)• L < 120 m 1,7 + 0,013 L k1/2 + 4,5 s• L ≥ 120 m 3,6 + 2,20 k1/2 + s(1) Not applicable to ships with one of the service nota-

tions passenger ship and ro-ro passenger ship. For such ships, refer to the applicable requirements of Part D.

(2) Not applicable to ships with one of the following serv-ice notations (for such ships, refer to the applicable requirements of Part D):• ro-ro cargo ship• liquefied gas carrier• passenger ship• ro-ro passenger ship.

(3) The minimum net thickness is to be obtained by linearly interpolating between that required for the area within 0,4 L amidships and that at the fore and aft part.

(4) Not applicable to ships with the service notation lique-fied gas carrier.

Pt B, Ch 7, Sec 1


2.5 Sheerstrake

2.5.1 Welded sheerstrake

The net thickness of a welded sheerstrake is to be not less than that of the adjacent side plating, taking into account higher strength steel corrections if needed.

In general, the required net thickness of the adjacent side plating is to be taken as a reference. In specific case, depending on its actual net thickness, this latter may be required to be considered when deemed necessary by the Society.

2.5.2 Rounded sheerstrake

The net thickness of a rounded sheerstrake is to be not less than the actual net thickness of the adjacent deck plating.

2.5.3 Net thickness of the sheerstrake in way of breaks of long superstructures

The net thickness of the sheerstrake is to be increased in way of breaks of long superstructures occurring within 0,5L amidships, over a length of about one sixth of the ship’s breadth on each side of the superstructure end.

This increase in net thickness is to be equal to 40%, but need not exceed 4,5 mm.

Where the breaks of superstructures occur outside 0,5L amidships, the increase in net thickness may be reduced to 30%, but need not exceed 2,5 mm.

2.5.4 Net thickness of the sheerstrake in way of breaks of short superstructures

The net thickness of the sheerstrake is to be increased in way of breaks of short superstructures occurring within 0,6L amidships, over a length of about one sixth of the ship’s breadth on each side of the superstructure end.


2.6 Stringer plate

2.6.1 General

The net thickness of the stringer plate is to be not less than the actual net thickness of the adjacent deck plating.

2.6.2 Net thickness of the stringer plate in way of breaks of long superstructures

The net thickness of the stringer plate is to be increased in way of breaks of long superstructures occurring within 0,5L amidships, over a length of about one sixth of the ship’s breadth on each side of the superstructure end.


Where the breaks of superstructures occur outside 0,5 L amidships, the increase in net thickness may be reduced to 30%, but need not exceed 2,5 mm.

2.6.3 Net thickness of the stringer plate in way of breaks of short superstructures

The net thickness of the stringer plate is to be increased in way of breaks of short superstructures occurring within 0,6L amidships, over a length of about one sixth of the ship breadth on each side of the superstructure end.


2.7 Deck plating protected by wood sheath-ing or deck composition

2.7.1 The net thickness of deck plating protected by wood sheathing, deck composition or other arrangements deemed suitable by the Society may be reduced on a case by case basis. In any case this net thickness is to be not less than the minimum value given in Tab 2.

2.7.2 The sheathing is to be secured to the deck to the satis-faction of the Society.

2.8 Corrugated bulkhead

2.8.1 Unless otherwise specified, the net plating thickness of a corrugated bulkhead is to be not less than that obtained from [3] and [5] with s equal to the greater of b and c, where b and c are defined in Ch 4, Sec 7, Fig 3.

3 Strength check of plating subjected to lateral pressure

3.1 General

3.1.1 The requirements of this Article apply for the strength check of plating subjected to lateral pressure and, for plat-ing contributing to the longitudinal strength, to in-plane hull girder normal and shear stresses.

3.2 Load model

3.2.1 General

The still water and wave lateral pressures induced by the sea and the various types of cargoes and ballast in intact conditions are to be considered, depending on the location of the plating under consideration and the type of the com-partments adjacent to it, in accordance with Ch 5, Sec 1, [2.4].

The plating which constitute the boundary of compartments not intended to carry liquid (excluding bottom and side shell platings) is to be subjected to lateral pressure in flood-ing conditions.

The wave lateral pressures and hull girder loads are to be calculated in the mutually exclusive load cases “a”, “b”, “c” and “d” in Ch 5, Sec 4.

Pt B, Ch 7, Sec 1


Table 3 : Hull girder normal stresses

3.2.2 Lateral pressure in intact conditions

The lateral pressure in intact conditions is constituted by still water pressure and wave pressure.

Still water pressure (pS) includes:

• the still water sea pressure, defined in Ch 5, Sec 5, [1]

• the still water internal pressure, defined in Ch 5, Sec 6for the various types of cargoes and for ballast.

Wave pressure (pW) includes:

• the wave pressure, defined in Ch 5, Sec 5, [2] for each load case “a”, “b”, “c” and “d”

• the inertial pressure, defined in Ch 5, Sec 6 for the vari-ous types of cargoes and for ballast, and for each load case “a”, “b”, “c” and “d”

• the dynamic pressures, according to the criteria in Ch 5, Sec 6, [2].

Sloshing and impact pressures are to be applied to plating of tank structures, when such tanks are partly filled and if a risk of resonance exists (see Ch 5, Sec 6, [2]).

3.2.3 Lateral pressure in flooding conditions

The lateral pressure in flooding conditions is constituted by the still water pressure pSF and wave pressure pWF defined inCh 5, Sec 6, [9].

3.2.4 Lateral pressure in testing conditions

The lateral pressure (pT) in testing conditions is taken equal to:

• pST − pS for bottom shell plating and side shell plating

• pST otherwise,

where pS is the still water sea pressure defined in Ch 5, Sec 5, [1.1.1] for the draught T1 at which the testing is carried out.

If the draught T1 is not defined by the Designer, it may be taken equal to the light ballast draught TB defined in Ch 5, Sec 1, [2.4.3].

3.2.5 In-plane hull girder normal stresses

The in-plane hull girder normal stresses to be considered for the strength check of plating are obtained, in N/mm2, from the following formulae:

• for plating contributing to the hull girder longitudinal strength:

• for plating not contributing to the hull girder longitudi-nal strength:

σX1 = 0

where:

σS1, σWV1, σWH1 : Hull girder normal stresses, in N/mm2, defined in Tab 3

σΩ : Absolute value of the warping stress, in N/mm2, induced by the torque 0,625 MWT and obtained through direct calculation analyses based on a structural model in accordance with Ch 6, Sec 1, [2.6]

CFV, CFH, CFΩ : Combination factors defined in Tab 4.

Table 4 : Combination factors CFV, CFH and CFΩ

3.2.6 In-plane hull girder shear stressesThe in-plane hull girder shear stresses to be considered for the strength check of plating, subjected to lateral loads, which contributes to the longitudinal strength are obtained, in N/mm2, from the following formula:

where:

CFV : Combination factor defined in Tab 4

τS1 : Absolute value of the hull girder shear stresses, in N/mm2, induced by the maximum still water hull girder vertical shear force in the section considered

τW1 : Absolute value of the hull girder shear stresses, in N/mm2, induced by the maximum wave hull girder vertical shear force in the section consid-ered.

τS1 and τW1 are to be taken not less than the values indicated in Tab 5.

Condition σS1 , in N/mm2 (1) σWV1 , in N/mm2 σWH1 , in N/mm2

(1) When the ship in still water is always in hogging condition, MSW,S is to be taken equal to 0.Note 1:FD : Coefficient defined in Ch 5, Sec 2, [4].

γS1MSW S, 0 625γ, W1CFVMWV S,+γS1MSW H, 0 625γW1, CFVMWV H,+------------------------------------------------------------------------------ 1≥

MSW S,

IY-------------- z N–( ) 10 3– 0 625FDM, WV S,

IY------------------------------------- z N–( ) 10 3–

0 625MWH,IZ

---------------------------y 10 3–

γS1MSW S, 0 625γ, W1CFVMWV S,+γS1MSW H, 0 625γW1, CFVMWV H,+------------------------------------------------------------------------------ 1<

MSW H,

IY--------------- z N–( ) 10 3– 0 625M, WV H,

IY-------------------------------- z N–( ) 10 3–

Load case CFV CFH CFΩ

“a” 1,0 0 0

“b” 1,0 0 0

“c” 0,4 1,0 1,0

“d” 0,4 1,0 0

σX1 γS1σS1 γW1 CFVσWV1 CFHσWH1 CFΩσΩ+ +( )+=

τ1 γS1τS1 0 625CFVγW1τW1,+=

Pt B, Ch 7, Sec 1


Table 5 : Hull girder shear stresses

3.3 Longitudinally framed plating contribut-ing to the hull girder longitudinal strength

3.3.1 General

The net thickness of laterally loaded plate panels subjected to in-plane normal stress acting on the shorter sides is to be not less than the value obtained, in mm, from the following formula:

where:

• for bottom, inner bottom and decks (excluding possible longitudinal sloping plates):

• for bilge, side, inner side and longitudinal bulkheads (including possible longitudinal sloping plates):


The plating which constitute the boundary of compartments not intended to carry liquids (excluding bottom and side shell platings) is to be checked in flooding conditions. To this end, its net thickness is to be not less than the value obtained, in mm, from the following formula:

where λL is defined in [3.3.1].

3.3.3 Testing conditionsThe plating of compartments or structures as defined in Ch 5, Sec 6, Tab 14 is to be checked in testing conditions. To this end, its net thickness is to be not less than the value obtained, in mm, from the following formula:

3.4 Transversely framed plating contributing to the hull girder longitudinal strength

3.4.1 GeneralThe net thickness of laterally loaded plate panels subjected to in-plane normal stress acting on the longer sides is to be not less than the value obtained, in mm, from the following formula:

where:

• for bottom, inner bottom and decks (excluding possible longitudinal sloping plates):

• for side, inner side and longitudinal bulkheads (includ-ing possible longitudinal sloping plates):

3.4.2 Flooding conditionsThe plating which constitutes the boundary of compart-ments not intended to carry liquids (excluding bottom and side shell platings) is to be checked in flooding conditions. To this end, its net thickness is to be not less than the value obtained, in mm, from the following formula:

where λT is defined in [3.4.1].

3.4.3 Testing conditionsThe plating of compartments or structures as defined in Ch 5, Sec 6, Tab 14 is to be checked in testing conditions. To this end, its net thickness is to be not less than the value obtained, in mm, from the following formula:

3.5 Plating not contributing to the hull girder longitudinal strength

3.5.1 GeneralThe net thickness of plate panels subjected to lateral pres-sure is to be not less than the value obtained, in mm, from the following formula:

Structural element τS1, τW1 in N/mm2

Bottom, inner bottom and decks (excluding possible longitudinal sloping plates)

0

Bilge, side, inner side and longitudinal bulkheads (including possible longitudi-nal sloping plates):

• 0 ≤ z ≤ 0,25 D

• 0,25 D < z ≤ 0,75 D τ0

• 0,75 D < z ≤ D

Note 1:

τ0 0 5, 2 zD----+

τ0 2 5, 2 zD----–

τ047k

------ 1 6 3,L1

---------–

N/mm²=

t 14 9, cacrs γRγmγS2pS γW2pW+

λLRy

----------------------------------=

λL 1 0 95 γmσx1

Ry

-------

2

,– 0 225γm, σx1

Ry

-------–=

λL 1 3 γmτ1

Ry

-----

2

0 95 γmσx1

Ry

-------

2

,–– 0 225γm, σx1

Ry

-------–=

t 14 9, cacrs γRγmγS2pSF γW2pWF+

λLRy

--------------------------------------=

t 14 9, cacrs γRγmγS2pT

Ry

------------=


λTRy

----------------------------------=

λT 1 0 89γm, σx1

Ry

-------–=

λT 1 3 γmτ1

Ry

-----

2

– 0 89γm, σx1

Ry

-------–=


λTRy

--------------------------------------=


Ry

------------=


Ry

----------------------------------=

Pt B, Ch 7, Sec 1



The plating which constitute the boundary of compartments not intended to carry liquids (excluding bottom and side shell platings) is to be checked in flooding conditions. To this end, its net thickness is to be not less than the value obtained, in mm, from the following formula:

3.5.3 Testing conditions

The plating of compartments or structures as defined in Ch 5, Sec 6, Tab 14 is to be checked in testing conditions. To this end, its net thickness is to be not less than the value obtained, in mm, from the following formula:

4 Strength check of plating subjected to wheeled loads

4.1 General

4.1.1 The requirements of this Article apply for the strength check of plating subjected to wheeled loads.

4.2 Load model

4.2.1 General

The still water and inertial forces induced by the sea and the various types of wheeled vehicles are to be considered, depending on the location of the plating.

The inertial forces induced by the sea are to be calculated in load case “b”, as defined in Ch 5, Sec 4.

4.2.2 Wheeled forces

The wheeled force applied by one wheel is constituted by still water force and inertial force.

Still water force is the vertical force (FS) defined in Ch 5, Sec 6, [6.1].

Inertial force is the vertical force (FW,Z) defined in Ch 5, Sec 6, [6.1], for load case “b”.

4.3 Plating

4.3.1 The net thickness of plate panels subjected to wheeled loads is to be not less than the value obtained, in mm, from the following formula:

where:

CWL : Coefficient to be taken equal to:

where /s is to be taken not greater than 3

AT : Tyre print area, in m2. In the case of double or triple wheels, the area is that corresponding to the group of wheels

AT is not to be taken less than the value given in [4.3.2]

, s : Lengths, in m, of, respectively, the longer and the shorter sides of the plate panel

n : Number of wheels on the plate panel, taken equal to:

• 1 in the case of a single wheel

• the number of wheels in a group of wheels in the case of double or triple wheels

P0 : Wheeled force, in kN, taken equal to:

4.3.2 When the tyre print area is not known, it may be taken equal to:

where:

n : Number of wheels on the plate panel, defined in [4.3.1]

QA : Axle load, in t

nW : Number of wheels for the axle considered

pT : Tyre pressure, in kN/m2. When the tyre pressure is not indicated by the designer, it may be taken as defined in Tab 6.

Table 6 : Tyre pressures pT for vehicles

4.3.3 For vehicles with the four wheels of the axle located on a plate panel as shown in Fig 1, the net thickness of deck plating is to be not less than the greater of the values obtained, in mm, from the following formulae:

t = t1

t = t2 (1 + β2 + β3 + β4)0,5

where:

t1 : Net thickness obtained, in mm, from [4.3.1] for n = 2, considering one group of two wheels located on the plate panel

t2 : Net thickness obtained, in mm, from [4.3.1] for n = 1, considering one wheel located on the plate panel


Ry

--------------------------------------=


Ry

------------=

t CWL nP0k( )0 5, tc–=

CWL 2 15, 0 05,s

---------------– 0 02 4 s--–

α0 5,, 1 75α0 25,,–+=

Vehicle typeTyre pressure pT , in kN/m2

Pneumatic tyres Solid rubber tyres

Private cars 250 Not applicable

Vans 600 Not applicable

Trucks and trailers 800 Not applicable

Handling machines 1100 1600

α AT

s------=

P0 γS2FS γW2FW Z,+=

AT 9 81nQA

nWpT

-------------,=

Pt B, Ch 7, Sec 1


β2, β3, β4: Coefficients obtained from the following for-mula, by replacing i by 2, 3 and 4, respectively (see Fig 1): • for xi / b < 2:

βi = 0,8 (1,2 − 2,02 αi + 1,17 αi2 − 0,23 αi

3)

• for xi / b ≥ 2:

βi = 0

xi : Distance, in m, from the wheel considered to the reference wheel (see Fig 1)

b : Dimension, in m, of the plate panel side per-pendicular to the axle

Figure 1 : Four wheel axle located on a plate panel

5 Buckling check

5.1 General

5.1.1 Application

The requirements of this Article apply for the buckling check of plating subjected to in-plane compression stresses, acting on one or two sides, or to shear stress.

Rectangular plate panels are considered as being simply supported. For specific designs, other boundary conditions may be considered, at the Society’s discretion, provided that the necessary information is submitted for review.

5.1.2 Compression and bending with or without shear

For plate panels subjected to compression and bending along one side, with or without shear, as shown in Fig 2, side “b” is to be taken as the loaded side. In such case, the compression stress varies linearly from σ1 to σ2 = ψ σ1

(ψ ≤ 1) along edge “b”.

5.1.3 Shear

For plate panels subjected to shear, as shown in Fig 3, side “b” may be taken as either the longer or the shorter side of the panel.

Figure 2 : Buckling of a simply supported rectangular plate panel subjected to compression and bending,with and without shear

Figure 3 : Buckling of a simply supportedrectangular plate panel subjected to shear

Figure 4 : Buckling of a simply supported rectangular plate panel subjected to

bi-axial compression and shear

αixi

b---- =

X2 X3

X4

2 1 3 4

a

b

σ1 σ1 σ1 σ1

σ2σ2σ2σ2

b b

a a

τ

a or b

τ a or

b

τ

τ

τ

σ a a

b

σb

Primarysupportingmembers

Ordinarystiffeners

Pt B, Ch 7, Sec 1


5.1.4 Bi-axial compression and shear

For plate panels subjected to bi-axial compression along sides “a” and “b”, and to shear, as shown in Fig 4, side “a” is to be taken as the side in the direction of the primary sup-porting members.

5.2 Load model

5.2.1 Sign convention for normal stresses

The sign convention for normal stresses is as follows:

• tension: positive

• compression: negative.

5.2.2 In-plane hull girder compression normal stresses

The in-plane hull girder compression normal stresses to be considered for the buckling check of plating contributing to the longitudinal strength are obtained, in N/mm2, from the following formula:

where:


σΩ : Compression warping stress, in N/mm2, induced by the torque 0,625MWT and obtained through direct calculation analyses based on a structural model in accordance with Ch 6, Sec 1, [2.6]

CFV, CFH, CFΩ :Combination factors defined in Tab 4.

σX1 is to be taken as the maximum compression stress on the plate panel considered.

In no case may σX1 be taken less than 30/k N/mm2.

When the ship in still water is always in hogging condition, σX1 may be evaluated by means of direct calculations when justified on the basis of the ship’s characteristics and intended service. The calculations are to be submitted to the Society for approval.

Where deemed necessary, the buckling check is to be car-ried out in harbour conditions by considering a reduced wave bending moment equal to 0,1MWV given in Ch 5, Sec 2, [3.1].

5.2.3 In-plane hull girder shear stressesThe in-plane hull girder shear stresses to be considered for the buckling check of plating are obtained as specified in[3.2.6] for the strength check of plating subjected to lateral pressure, which contributes to the longitudinal strength.

5.2.4 Combined in-plane hull girder and local compression normal stresses

The combined in-plane compression normal stresses to be considered for the buckling check of plating are to take into account the hull girder stresses and the local stresses result-ing from the bending of the primary supporting members. These local stresses are to be obtained from a direct struc-tural analysis using the design loads given in Part B, Chapter 5.

With respect to the reference co-ordinate system defined inCh 1, Sec 2, [4.1], the combined stresses in x and y direc-tion are obtained, in N/mm2, from the following formulae:

where:σX1 : Compression normal stress, in N/mm2, induced

by the hull girder still water and wave loads, defined in [5.2.2]

σX2,S,σY2,S: Compression normal stress in x and y direction, respectively, in N/mm2, induced by the local bending of the primary supporting members and obtained from a direct structural analysis using the still water design loads given in Part B, Chapter 5

σX2,W,σY2,W: Compression normal stress in x and y direction, respectively, in N/mm2, induced by the local bending of the primary supporting members and obtained from a direct structural analysis using the wave design loads given in Part B, Chapter 5.

5.2.5 Combined in-plane hull girder and local shear stresses

The combined in-plane shear stresses to be considered for the buckling check of plating are to take into account the hull girder stresses and the local stresses resulting from the bending of the primary supporting members. These local stresses are to be obtained from a direct structural analysis using the design loads given in Part B, Chapter 5.

Table 7 : Hull girder normal compression stresses

σX1 γS1σS1 γW1 CFVσWV1 CFHσWH1 CFΩσΩ+ +( )+=

σX σX1 γS2σX2 S, γW2σX2 W,+ +=σY γS2σY2 S, γW2σY2 W,+=

Condition σS1 in N/mm2 (1) σWV1 in N/mm2 σWH1 in N/mm2

z ≥ N

z < N

(1) When the ship in still water is always in hogging condition, σS1 for z ≥ N is to be obtained, in N/mm2, from the following for-mula, unless σX1 is evaluated by means of direct calculations (see [5.2.2]):

Note 1:FD : Coefficient defined in Ch 5, Sec 2, [4].

MSW S,

IY-------------- z N–( )10 3– 0 625FDM, WV S,

IY------------------------------------- z N–( )10 3–

0 625MWH,IZ

---------------------------y– 10 3–

MSW H,

IY--------------- z N–( )10 3– 0 625M, WV H,

IY-------------------------------- z N–( )10 3–

σS1MSW Hmin,

IY---------------------- z N–( )10 3–=

Pt B, Ch 7, Sec 1


The combined stresses are obtained, in N/mm2, from the following formula:

where:

τ1 : Shear stress, in N/mm2, induced by the hull girder still water and wave loads, defined in[5.2.3]

τ2,S : Shear stress, in N/mm2, induced by the local bending of the primary supporting members and obtained from a direct structural analysis using the still water design loads given in Part B, Chapter 5

τ2,W : Shear stress, in N/mm2, induced by the local bending of the primary supporting members and obtained from a direct structural analysis using the wave design loads given in Part B, Chapter 5.

5.3 Critical stresses

5.3.1 Compression and bending for plane panelThe critical buckling stress is to be obtained, in N/mm2, from the following formulae:

where:

σE : Euler buckling stress, to be obtained, in N/mm2, from the following formula:

K1 : Buckling factor defined in Tab 8

ε : Coefficient to be taken equal to:

• ε = 1,00 for α ≥ 1• ε = 1,05 for α < 1 and side “b” stiffened by

flat bar• ε = 1,10 for α < 1 and side “b” stiffened by

bulb section• ε = 1,21 for α < 1 and side “b” stiffened by

angle or T-section

• ε = 1,30 for α < 1 and side “b” stiffened by primary supporting members.

with α = a / b.

5.3.2 Shear for plane panelThe critical shear buckling stress is to be obtained, in N/mm2, from the following formulae:

where:τE : Euler shear buckling stress, to be obtained, in

N/mm2, from the following formula:


α : Coefficient defined in [5.3.1].

Table 8 : Buckling factor K1 for plane panels

τ τ1 γS2τ2 S, γW2τ2 W,+ +=

σc σE= for σEReH

2--------≤

σc ReH 1 ReH

4σE

---------– = for σE

ReH

2-------->

σEπ2E

12 1 ν2–( )-------------------------- t

b---

2

K1ε10 6–=

τc τE= for τEReH

2 3-----------≤

τcReH

3-------- 1 ReH

4 3τE

----------------– = for τE

ReH

2 3----------->

τEπ2E

12 1 ν2–( )-------------------------- t

b---

2

K210 6–=

K2 5= 34, 4α2------+ for α 1>

K25 34,

α2-----------= 4+ for α 1≤

Load pattern Aspect ratio Buckling factor K1

0 ≤ ψ ≤ 1

α ≥ 1

α < 1

− 1 < ψ < 0

ψ ≤ − 1

Note 1:

K1′ : Value of K1 calculated for ψ = 0

K1″ : Value of K1 calculated for ψ = − 1

8 4,ψ 1 1,+-------------------

α 1α---+

2 2 1,ψ 1 1,+-------------------

1 ψ+( )K1′ ψK1

″ 10ψ 1 ψ+( )+–

α1 ψ–2

------------- 23---≥ 23 9 1 ψ–

2-------------

2

,

α1 ψ–2

------------- 23---< 15 87, 1 87,

α1 ψ–2

-------------

2------------------------- 8 6 α1 ψ–

2-------------

2

,+ +

1 ψ–2

-------------

2

ψ σ2

σ1

-----=

Pt B, Ch 7, Sec 1


5.3.3 Bi-axial compression and shear for plane panelThe critical buckling stress σc,a for compression on side “a” of the panel is to be obtained, in N/mm2, from the following formula:

where:β : Slenderness of the panel, to be taken equal to:

without being taken less than 1,25.The critical buckling stress σc,b for compression on side “b” of the panel is to be obtained, in N/mm2, from the formulae in [5.3.1].

The critical shear buckling stress is to be obtained, in N/mm2, from the formulae in [5.3.2].

5.3.4 Compression and shear for curved panelsThe critical buckling stress of curved panels subjected to compression perpendicular to curved edges is to be obtained, in N/mm2, from the following formulae:

where:σE : Euler buckling stress, to be obtained, in N/mm2,

from the following formula:

b : Width of curved panel, in m, measured on arc between two adjacent supports


r : Radius of curvature, in m.The critical shear buckling stress is to be obtained, in N/mm2, from the following formulae:

where:τE : Euler shear buckling stress, to be obtained, in

N/mm2, from the following formula:


b, r : Defined above.

5.3.5 Compression for corrugation flanges

The critical buckling stress is to be obtained, in N/mm2, from the following formulae:

where:

σE : Euler buckling stress, to be obtained, in N/mm2, from the following formula:


• for the first flange of the corrugation con-nected to a bulkhead plating or similar

K5 = 4

• for the other flanges of the corrugation

tf : Net thickness, in mm, of the corrugation flange

tw : Net thickness, in mm, of the corrugation web

V, V’ : Dimensions of a corrugation, in m, shown in Fig 5.

Figure 5 : Dimensions of a corrugation


5.4.1 Acceptance of results

The net thickness of plate panels is to be such as to satisfy the buckling check, as indicated in [5.4.2] to [5.4.5]depending on the type of stresses acting on the plate panel considered. When the buckling criteria is exceeded, the scantlings may still be considered as acceptable, provided that the stiffeners located on the plate panel satisfy the buckling and the ultimate strength checks as specified in Ch 7, Sec 2, [4] and Ch 7, Sec 2, [5].

σc a,2 25,

β----------- 1 25,

β2-----------–

ReH=

β 103= at--- ReH

E--------

σc σE= for σEReH

2--------≤

σc ReH 1 ReH

4σE

---------– = for σE

ReH

2-------->

σEπ2E

12 1 ν2–( )-------------------------- t

b---

2

K310 6–=

K3 2 1 1 12 1 ν2–( )π4

-------------------------- b4

r2t2--------106++

=

τc τE= for τEReH

2 3-----------≤

τcReH

3-------- 1 ReH

4 3τE

----------------– = for τE

ReH

2 3----------->

τEπ2E

12 1 ν2–( )-------------------------- t

b---

2

K410 6–=

K412 1 ν2–( )

π2--------------------------= 5 b2

rt-----102+

σc σE= for σEReH

2--------≤

σc ReH 1 ReH

4σE

---------– = for σE

ReH

2-------->

σEπ2E

12 1 ν2–( )-------------------------- tf

V----

2

K510 6–=

K5 1 tw

tf

----+ = 3 0 5V ′

V-----, 0 33 V ′

V-----

2

,–+

Vσ

V'

tw tf

Pt B, Ch 7, Sec 1


5.4.2 Compression and bending

For plate panels subjected to compression and bending on one side, the critical buckling stress is to comply with the following formula:

where:

σc : Critical buckling stress, in N/mm2, defined in [5.3.1], [5.3.4] or [5.3.5], as the case may be

σb : Compression stress, in N/mm2, acting on side “b” of the plate panel, to be calculated, as spec-ified in [5.2.2] or [5.2.4], as the case may be.

In equivalence to the previous criteria on the critical buck-ling stress, the net thickness, in mm, is to comply with the following formulae:

where:

Ki = K1 , defined in [5.3.1] for a plane panel

Ki = K3 , defined in [5.3.4] for a curved panel.

5.4.3 Shear

For plate panels subjected to shear, the critical shear buck-ling stress is to comply with the following formula:

where:

τc : Critical shear buckling stress, in N/mm2, defined in [5.3.2] or [5.3.4], as the case may be

τb : Shear stress, in N/mm2, acting on the plate panel, to be calculated as specified in [5.2.3] or[5.2.5], as the case may be.

In equivalence to the previous criteria on the critical shear buckling stress, the net thickness, in mm, is to comply with the following formulae:

where:

Ki = K2 , defined in [5.3.2] for a plane panel

Ki = K4 , defined in [5.3.4] for a curved panel.

5.4.4 Compression, bending and shear

For plate panels subjected to compression, bending and shear, the combined critical stress is to comply with the fol-lowing formulae:

where:

σE : Euler buckling stress, in N/mm2, defined in[5.3.1], [5.3.4] or [5.3.5] as the case may be

τE : Euler shear buckling stress, in N/mm2, defined in [5.3.2] or [5.3.4], as the case may be

σ1, σ2 and τ are defined in Fig 2 and are to be calculated, in N/mm2, as specified in [5.2].

5.4.5 Bi-axial compression, taking account of shear stress

For plate panels subjected to bi-axial compression and shear, the critical buckling stresses are to comply with the following formula:

where:

σc,a : Critical buckling stress for compression on side “a”, in N/mm2, defined in [5.3.3]

σc,b : Critical buckling stress for compression on side “b”, in N/mm2, defined in [5.3.3]

σa : Compression stress acting on side “a”, in N/mm2, to be calculated as specified in [5.2.2]or [5.2.4], as the case may be

σb : Compression stress acting on side “b”, in N/mm2, to be calculated as specified in [5.2.2]or [5.2.4], as the case may be

α = a / b

τ : Shear stress, in N/mm2, to be calculated as specified in [5.2.3] or [5.2.5], as the case may be

τc : Critical shear buckling stress, in N/mm2, defined in [5.3.2].

σc

γRγm

---------- σb≥

t bπ--- 12γRγm σb 1-ν2( )

EKiε--------------------------------------------103= for σE

ReH

2--------≤

t bπ--- 3ReH

2 1-ν2( )EKiε ReH-γRγm σb( )------------------------------------------------103= for σE

ReH

2-------->

τc

γRγm

---------- τb≥

t bπ--- 12γRγm τb 1-ν2( )

EKi

-------------------------------------------103= for τEReH

2 3-----------≤

t bπ--- ReH

2 1-ν2( )

EKiReH

3---------γRγm τb

---------------------------------------------103= for τEReH

2 3----------->

F 1≤ forσcomb

F------------- ReH

2γRγm

--------------≤

F4σcomb

ReH γRγm⁄----------------------- 1 σcomb

ReH γRγm⁄-----------------------–

≤ forσcomb

F------------- ReH

2γRγm

-------------->

σcomb σ12 3τ2+=

F γRγm1 ψ+

4------------- σ1

σE

-------- 3 ψ–4

-------------

2 σ1

σE

-----

2 ττE

----

2

++=

ψ σ2

σ1

-----=

γRγmσa

σc a,-----------------

1 9, γRγmσb

σc b,-----------------

1,9 γRγmττc

--------------1,9

+ + 1≤

Pt B, Ch 7, Sec 2


SECTION 2 ORDINARY STIFFENERS

Symbols


pS : Still water pressure, in kN/m2, see [3.3.2] and[5.3.2]

pW : Wave pressure and, if necessary, dynamic pres-sures, according to the criteria in Ch 5, Sec 5, [2] and Ch 5, Sec 6, [2], in kN/m2 (see [3.3.2]and [5.3.2])

pSF, pWF : Still water and wave pressures, in kN/m2, in flooding conditions, defined in Ch 5, Sec 6, [9]

FS : Still water wheeled force, in kN, see [3.3.5]

FW,Z : Inertial wheeled force, in kN, see [3.3.5]

σX1 : Hull girder normal stress, in N/mm2, defined in:

• [3.3.6] for the yielding check of ordinary stiffeners

• [4.2.2] for the buckling check of ordinary stiffeners

• [5.3.3] for the ultimate strength check of ordinary stiffeners

ReH,P : Minimum yield stress, in N/mm2, of the plating material, defined in Ch 4, Sec 1, [2]

ReH,S : Minimum yield stress, in N/mm2, of the stiffener material, defined in Ch 4, Sec 1, [2]


: Span, in m, of ordinary stiffeners, measured between the supporting members, see Ch 4, Sec 3, [3.2]

hw : Web height, in mm

tw : Net web thickness, in mm

bf : Face plate width, in mm

tf : Net face plate thickness, in mm

bp : Width, in m, of the plating attached to the stiff-ener, for the yielding check, defined in Ch 4, Sec 3, [3.3.1]

be : Width, in m, of the plating attached to the stiff-ener, for the buckling check, defined in [4.1]

bU : Width, in m, of the plating attached to the stiff-ener, for the ultimate strength check, defined in[5.2]

tp : Net thickness, in mm, of the attached plating

w : Net section modulus, in cm3, of the stiffener, with an attached plating of width bp , to be cal-culated as specified in Ch 4, Sec 3, [3.4]

A : Net sectional area, in cm2, of the stiffener with-out attached plating

AS : Net sectional area, in cm2, of the stiffener with attached plating of width s

Ae : Net sectional area, in cm2, of the stiffener with attached plating of width be

AU : Net sectional area, in cm2, of the stiffener with attached plating of width bU

ASh : Net shear sectional area, in cm2, of the stiffener, to be calculated as specified in Ch 4, Sec 3, [3.4]

I : Net moment of inertia, in cm4, of the stiffener without attached plating, about its neutral axis parallel to the plating (see Ch 4, Sec 3, Fig 4 and Ch 4, Sec 3, Fig 5)

IS : Net moment of inertia, in cm4, of the stiffener with attached shell plating of width s, about its neutral axis parallel to the plating

Ie : Net moment of inertia, in cm4, of the stiffener with attached shell plating of width be , about its neutral axis parallel to the plating

IU : Net moment of inertia, in cm4, of the stiffener with attached shell plating of width bU , about its neutral axis parallel to the plating

ρS : Radius of gyration, in cm, of the stiffener with attached plating of width s

ρU : Radius of gyration, in cm, of the stiffener with attached plating of width bU .

1 General

1.1 Net scantlings

1.1.1 As specified in Ch 4, Sec 2, [1], all scantlings referred to in this Section are net, i.e. they do not include any mar-gin for corrosion.

The gross scantlings are obtained as specified in Ch 4, Sec 2.


1.2.1 The partial safety factors to be considered for the checking of ordinary stiffeners are specified in Tab 1.

1.3 Load point

1.3.1 Lateral pressure

Unless otherwise specified, lateral pressure is to be calcu-lated at mid-span of the ordinary stiffener considered.

Pt B, Ch 7, Sec 2


Table 1 : Ordinary stiffeners - Partial safety factors

1.3.2 Hull girder stressesFor longitudinal ordinary stiffeners contributing to the hull girder longitudinal strength, the hull girder normal stresses are to be calculated in way of the attached plating of the stiffener considered.

1.4 Net dimensions of ordinary stiffeners

1.4.1 The requirements relative to the net dimensions of ordinary stiffeners, as indicated in [1.4.2] to [1.4.3], are applicable when the buckling assessment is not carried out for such stiffeners in accordance with [4].

1.4.2 Flat barThe net dimensions of a flat bar ordinary stiffener (see Fig 1) are to comply with the following requirement:

1.4.3 T-sectionThe net dimensions of a T-section ordinary stiffener (see Fig 2) are to comply with the following requirements:

1.4.4 AngleThe net dimensions of an angle ordinary stiffener (see Fig 3) are to comply with the following requirements:

Figure 1 : Net dimensions of a flat bar

Figure 2 : Net dimensions of a T-section

Figure 3 : Net dimensions of an angle


regarding:Symbol

Yielding check

Buckling check

Ultimate strength checkGeneral

Sloshing pressure

Impact pressure

Watertight bulk-head ordinary stiffeners (1)

Testing check

(see [3.3] to [3.7]) (see [3.8]) (see [3.9]) (see [4]) (see [5])

Still water hull girder loads γS1 1,00 0 0 1,00 N.A. 1,00 1,00

Wave hull girder loads γW1 1,15 0 0 1,15 N.A. 1,15 1,30

Still water pressure γS2 1,00 1,00 1,00 1,00 1,00 N.A. 1,00

Wave pressure γW2 1,20 1,10 1,00 1,05 N.A. N.A. 1,40

Material γm 1,02 1,02 1,02 1,02 1,02 1,02 1,02

Resistance γR 1,02 1,02 1,02 1,02 (2) 1,20 1,10 1,02

(1) Applies also to ordinary stiffeners of bulkheads or inner side which constitute boundary of compartments not intended to carry liquids.

(2) For ordinary stiffeners of the collision bulkhead, γR =1,25.Note 1: N.A. = Not applicable.

hw

tw

------ 20 k≤

hw

tw

------ 55 k≤

bf

tf

---- 33 k ≤

bftfhwtw

6-----------≥

hw

tw

------ 55 k≤

bf

tf

---- 16 5 k,≤

bftfhwtw

6-----------≥

twh w

tw

h w

tf

bf

tw

h w

bf

tf

Pt B, Ch 7, Sec 2



2.1 General

2.1.1 The requirements in [2.2] and [2.3] are to be applied to ordinary stiffeners in addition of those in [3] to [5].

2.2 Minimum net thicknesses

2.2.1 The net thickness of the web of ordinary stiffeners is to be not less than the lesser of:

• the value obtained, in mm, from the following formulae:

tMIN = 0,8 + 0,004 L k1/2 + 4,5 s for L < 120 m

tMIN = 1,6 + 2,2 k1/2 + s for L ≥ 120 m

• the net as built thickness of the attached plating.

2.3 Struts connecting ordinary stiffeners

2.3.1 The sectional area ASR, in cm2, and the moment of inertia ISR about the main axes, in cm4, of struts connecting ordinary stiffeners are to be not less than the values obtained from the following formulae:

where:

pSR : Pressure to be taken equal to the greater of the values obtained, in kN/m2, from the following formulae:

pSR = 0,5 (pSR1 + pSR2)

pSR = pSR3

pSR1 : External pressure in way of the strut, in kN/m2, acting on one side, outside the compartment in which the strut is located, equal to:

pSR1 = γS2 pS + γW2 pW

pSR2 : External pressure in way of the strut, in kN/m2, acting on the opposite side, outside the com-partment in which the strut is located, equal to:


pSR3 : Internal pressure at mid-span of the strut, in kN/m2, in the compartment in which the strut is located, equal to:


: Span, in m, of ordinary stiffeners connected by the strut (see Ch 4, Sec 3, [3.2.2])

SR : Length, in m, of the strut

AASR : Actual net sectional area, in cm2, of the strut.

2.4 Corrugated bulkhead

2.4.1 Unless otherwise specified, the net section modulus and the net shear sectional area of a corrugation are to be not less than those obtained from [3] to [5] with s equal to the greater of (a + b), where a and b are defined in Ch 4, Sec 7, Fig 3.

2.5 Deck ordinary stiffeners in way of launching appliances used for survival craft or rescue boat

2.5.1 The scantlings of deck ordinary stiffeners are to be determined by direct calculations.

2.5.2 The loads exerted by launching appliance are to cor-respond to the SWL of the launching appliance.

2.5.3 The combined stress, in N/mm2, is not to exceed the smaller of:

where Rm is the ultimate minimum tensile strength of the stiffener material, in N/mm2.

3 Yielding check

3.1 General

3.1.1 The requirements of this Article apply for the yielding check of ordinary stiffeners subjected to lateral pressure or to wheeled loads and, for ordinary stiffeners contributing to the hull girder longitudinal strength, to hull girder normal stresses.

3.1.2 When tanks are partly filled and if a risk of resonance exists, the yielding check of vertical ordinary stiffeners of tank structures subjected to sloshing and impact pressures is to be carried out by direct calculation.

3.1.3 The yielding check is also to be carried out for ordi-nary stiffeners subjected to specific loads, such as concen-trated loads.

3.2 Structural model

3.2.1 Boundary conditionsThe requirements in [3.4], [3.7.3], [3.7.4] and [3.8] apply to stiffeners considered as clamped at both ends, whose end connections comply with the requirements in [3.2.2].

The requirements in [3.5] and [3.7.5] apply to stiffeners considered as simply supported at both ends. Other bound-ary conditions may be considered by the Society on a case by case basis, depending on the distribution of wheeled loads.

For other boundary conditions, the yielding check is to be considered on a case by case basis.

3.2.2 Bracket arrangement The requirements of this Article apply to ordinary stiffeners without end brackets, with a bracket at one end or with two end brackets, where the bracket length is not greater than 0,2 .

In the case of ordinary stiffeners with end brackets of length greater than 0,2 , the determination of normal and shear stresses due to design loads and the required section modu-lus and shear sectional area are considered by the Society on a case by case basis.

ASRpSRs

20-------------=

ISR0 75s pSR1 pSR2+( )AASRSR

2,47 2AASR, s pSR1 pSR2+( )–--------------------------------------------------------------------=

100235----------ReH and 54

235----------Rm

Pt B, Ch 7, Sec 2


3.3 Load model

3.3.1 General

The still water and wave lateral loads induced by the sea and the various types of cargoes and ballast in intact condi-tions are to be considered, depending on the location of the ordinary stiffener under consideration and the type of com-partments adjacent to it, in accordance with Ch 5, Sec 1, [2.4].

Ordinary stiffeners located on platings which constitute the boundary of compartments not intended to carry liquids (excluding those on bottom and side shell platings) are to be subjected to the lateral pressure in flooding conditions.

The wave lateral loads and hull girder loads are to be calcu-lated in the mutually exclusive load cases “a”, “b”, “c” and “d” in Ch 5, Sec 4.


The lateral pressure in intact conditions is constituted by still water pressure and wave pressure.






• the inertial pressure, defined in Ch 5, Sec 6 for the vari-ous types of cargoes and for ballast, and for each load case “a”, “b”, “c” and “d”

• the dynamic pressures, according to the criteria in Ch 5, Sec 6, [2].

Sloshing and impact pressures are to be applied to ordinary stiffeners of tank structures, when such tanks are partly filled and if a risk of resonance exists (see Ch 5, Sec 6, [2]).


The lateral pressure in flooding conditions is constituted by the still water pressure pSF and wave pressure pWF defined inCh 5, Sec 6, [9].

3.3.4 Lateral pressure in testing conditions

The lateral pressure (pT) in testing conditions is taken equal to:

• pST − pS for bottom shell plating and side shell plating

• pST otherwise,

where pS is the still water sea pressure defined in Ch 5, Sec 5, [1.1.1] for the draught T1 at which the testing is carried out.

If the draught T1 is not defined by the Designer, it may be taken equal to the light ballast draught TB defined in Ch 5, Sec 1, [2.4.3].

3.3.5 Wheeled forces

The wheeled force applied by one wheel is constituted by still water force and inertial force:

• Still water force is the vertical force (FS) defined in Ch 5, Sec 6, [6.1]

• Inertial force is the vertical force (FW,Z) defined in Ch 5, Sec 6, [6.1], for load case “b”.

3.3.6 Hull girder normal stresses

The hull girder normal stresses to be considered for the yielding check of ordinary stiffeners are obtained, in N/mm2, from the following formulae:

• for longitudinal stiffeners contributing to the hull girder longitudinal strength and subjected to lateral pressure:

σX1 = γS1 σS1 + γW1 (CFV σWV1 + CFH σWH1 + CFΩ σΩ)

to be taken not less than 60/k

• for longitudinal stiffeners contributing to the hull girder longitudinal strength and subjected to wheeled loads:

σX1,Wh = Max (σX1H ; σX1S)

to be taken not less than 60/k

• for longitudinal stiffeners not contributing to the hull girder longitudinal strength:

σX1 = 0

• for transverse stiffeners:

σX1 = 0

where:


σΩ : Absolute value of the warping stress, in N/mm2, induced by the torque 0,625 MWT and obtained through direct calculation analyses based on a structural model in accordance with Ch 6, Sec 1, [2.6]

σX1H, σX1S: Hull girder normal stresses, in N/mm2, respec-tively in hogging and in sagging, defined in Tab 3


3.4 Normal and shear stresses due to lateral pressure in intact conditions

3.4.1 General

Normal and shear stresses, induced by lateral pressures, in ordinary stiffeners are to be obtained from the formulae in:

• [3.4.2] in the case of single span longitudinal and trans-verse stiffeners

• [3.4.3] in the case of single span vertical stiffeners

• [3.4.4] in the case of multispan stiffeners.

Pt B, Ch 7, Sec 2


Table 2 : Hull girder normal stresses - Ordinary stiffeners subjected to lateral pressure

Table 3 : Hull girder normal stresses - Ordinary stiffeners subjected to wheeled loads

Table 4 : Combination factors CFV , CFH and CFΩ

Table 5 : Coefficients βb and βs

3.4.2 Single span longitudinal and transverse ordinary stiffeners

The maximum normal stress σ and shear stress τ are to be obtained, in N/mm2, from the following formulae:

where:

βb ; βs : Coefficients defined in Tab 5.

3.4.3 Single span vertical ordinary stiffenersThe maximum normal stress σ and shear stress τ are to be obtained, in N/mm2, from the following formulae:

where:βb, βs : Coefficients defined in [3.4.2]

λb : Coefficient taken equal to the greater of the fol-lowing values:

Condition σS1 , in N/mm2 (1) σWV1 , in N/mm2 σWH1 , in N/mm2

Lateral pressure applied on the side opposite to the ordinary stiffener, with respect to the plating:

• z ≥ N

• z < N

Lateral pressure applied on the same side as the ordinary stiffener:

• z ≥ N

• z < N


Condition Hull girder normal stresses, in N/mm2

• Hogging

• Sagging (1)


0 625MWH,IZ

---------------------------y 10 3–

MSW S,

IY-------------- z N–( ) 10 3– 0 625FDM, WV S,

IY------------------------------------- z N–( ) 10 3–

MSW H,

IY--------------- z N–( ) 10 3– 0 625M, WV H,

IY-------------------------------- z N–( ) 10 3–

MSW H,

IY--------------- z N–( ) 10 3– 0 625M, WV H,

IY-------------------------------- z N–( ) 10 3–

MSW S,

IY-------------- z N–( ) 10 3– 0 625FDM, WV S,

IY------------------------------------- z N–( ) 10 3–

σX1H γS1MSW H,

IY--------------- z N–( )10 3– γW1 CFV

0 625M, WV H,

IY-------------------------------- z N–( )10 3– CFH

0 625MWH,IZ

----------------------------y10 3– CFΩσΩ+ + +=

σX1S γS1MSW S,

IY-------------- z N–( )10 3– γW1 CFV

0 625FDM, WV S,

IY------------------------------------- z N–( )10 3– CFH

0 625MWH,IZ

----------------------------y10 3– CFΩσΩ+ + +=


“a” 1,0 0 0

“b” 1,0 0 0

“c” 0,4 1,0 1,0

“d” 0,4 1,0 0

Brackets at ends

Bracket lengths

βb βs

0 − 1 1

1 b

2 b1 ; b2

1b

2------–

2

1b

2------–

1b1

2------- b2

2-------––

2

1b1

2------- b2

2-------––

σ βbγS2pS γW2pW+

12w---------------------------------- 1 s

2------–

s2103 σX1+=

τ 5βsγS2pS γW2pW+

ASh

---------------------------------- 1 s2------–

s=

σ λbβbγS2pS γW2pW+

12w---------------------------------- 1 s

2------–

s2103=

τ 5λsβsγS2pS γW2pW+

ASh

---------------------------------- 1 s2------–

s=

λb 1 0 2γS2 pSd pSu–( ) γW2 pWd pWu–( )+γS2 pSd pSu+( ) γW2 pWd pWu+( )+------------------------------------------------------------------------------,+=

λb 1 0 2,– γS2 pSd pSu–( ) γW2 pWd pWu–( )+γS2 pSd pSu+( ) γW2 pWd pWu+( )+------------------------------------------------------------------------------=

Pt B, Ch 7, Sec 2


λs : Coefficient taken equal to the greater of the fol-lowing values:

pSd : Still water pressure, in kN/m2, at the lower end of the ordinary stiffener considered

pSu : Still water pressure, in kN/m2, at the upper end of the ordinary stiffener considered

pWd : Wave pressure, in kN/m2, at the lower end of the ordinary stiffener considered

pWu : Wave pressure, in kN/m2, at the upper end of the ordinary stiffener considered.

3.4.4 Multispan ordinary stiffeners

The maximum normal stress σ and shear stress τ in a multi-span ordinary stiffener are to be determined by a direct cal-culation taking into account:

• the distribution of still water and wave pressure and forces, to be determined on the basis of the criteria specified in Ch 5, Sec 5 and Ch 5, Sec 6

• the number and position of intermediate supports (decks, girders, etc.)

• the condition of fixity at the ends of the stiffener and at intermediate supports

• the geometrical characteristics of the stiffener on the intermediate spans.

3.5 Normal and shear stresses due to wheeled loads

3.5.1 General

Normal and shear stresses, induced by the wheeled loads, in ordinary stiffeners are to be obtained from the formulae in:

• [3.5.2] in the case of single span longitudinal and trans-verse stiffeners

• [3.5.3]in the case of multispan stiffeners.

3.5.2 Single span longitudinal and transverse ordinary stiffeners subjected to wheeled loads

The maximum normal stress σ and shear stress τ are to be obtained, in N/mm2, from the following formulae:

where:

P0 : Wheeled force, in kN, taken equal to:

P0 = γS2 FS + γW2 FW,Z

αw : Coefficient taking account of the number of wheels per axle considered as acting on the stiffener, defined in Tab 6

KS , KT : Coefficients taking account of the number of axles considered as acting on the stiffener, defined in Tab 7.

Table 6 : Wheeled loads - Coefficient αW

Table 7 : Wheeled loads - Coefficients KS and KT

λs 1 0 4γS2 pSd pSu–( ) γW2 pWd pWu–( )+γS2 pSd pSu+( ) γW2 pWd pWu+( )+------------------------------------------------------------------------------,+=

λs 1 0 4,– γS2 pSd pSu–( ) γW2 pWd pWu–( )+γS2 pSd pSu+( ) γW2 pWd pWu+( )+------------------------------------------------------------------------------=

σ αWKSP0

6w--------103 σX1 Wh,+=

τ αWKT10P0

ASh

------------=

Configuration αW

Single wheel

1

Double wheels

Triple wheels

Note 1:y : Distance, in m, from the external wheel of a

group of wheels to the stiffener under considera-tion, to be taken equal to the distance from the external wheel to the centre of the group of wheels.

CoefficientConfiguration

Single axle Double axles

KS 1

•

•

KT 1

Note 1:d : Distance, in m, between two axles (see Fig 4).

y

s

2 1 ys---–

s

y

3 2ys---–

if d 3⁄≤

17281

---------- 4d3-------– d2

2

-----– d4

4

-----+

if d 3⁄>

43--- 4d

3-------– 3d2

2

--------- 8d3

33---------–+

2 d2------– 3d2

22---------– d3

3

-----+

Pt B, Ch 7, Sec 2


Figure 4 : Wheeled load on stiffeners - Double axles

3.5.3 Multispan ordinary stiffeners subjected to wheeled loads

The maximum normal stress σ and shear stress τ in a multi-span ordinary stiffener are to be determined by a direct cal-culation taking into account:

• the distribution of still water forces and inertial forces applying on the stiffener, to be determined according to[3.3.5]

• the number and position of intermediate supports (gird-ers, bulkheads, etc.)

• the condition of fixity at the ends of the stiffener and at intermediate supports

• the geometrical characteristics of the stiffener on the intermediate spans.


3.6.1 General It is to be checked that the normal stress σ and the shear stress τ, calculated according to [3.4] and [3.5], are in com-pliance with the following formulae:

3.7 Net section modulus and net shear sectional area of ordinary stiffeners, complying with the checking criteria

3.7.1 GeneralThe requirements in [3.7.3] and [3.7.4] provide the mini-mum net section modulus and net shear sectional area of single span ordinary stiffeners subjected to lateral pressure in intact conditions, complying with the checking criteria indicated in [3.6].

The requirements in [3.7.5] provide the minimum net sec-tion modulus and net shear sectional area of single span ordinary stiffeners subjected to wheeled loads, complying with the checking criteria indicated in [3.6].

The requirements in [3.7.6] provide the minimum net sec-tion modulus and net shear sectional area of multispan ordinary stiffeners subjected to lateral pressure in intact condition or to wheeled loads, complying with the check-ing criteria indicated in [3.6].

3.7.2 Groups of equal ordinary stiffeners

Where a group of equal ordinary stiffeners is fitted, it is acceptable that the minimum net section modulus in [3.7.1]is calculated as the average of the values required for all the stiffeners of the same group, but this average is to be taken not less than 90% of the maximum required value.

The same applies for the minimum net shear sectional area.

3.7.3 Single span longitudinal and transverse ordinary stiffeners subjected to lateral pressure

The net section modulus w, in cm3, and the net shear sec-tional area ASh , in cm2, of longitudinal or transverse ordi-nary stiffeners subjected to lateral pressure are to be not less than the values obtained from the following formulae:

where:

βb, βs : Coefficients defined in [3.4.2].

3.7.4 Single span vertical ordinary stiffeners subjected to lateral pressure

The net section modulus w, in cm3, and the net shear sec-tional area ASh , in cm2, of vertical ordinary stiffeners sub-jected to lateral pressure are to be not less than the values obtained from the following formulae:

where:

βb, βs : Coefficients defined in [3.4.2]

λb, λs : Coefficients defined in [3.4.3].

3.7.5 Single span ordinary stiffeners subjected to wheeled loads

The net section modulus w, in cm3, and the net shear sec-tional area ASh , in cm2, of ordinary stiffeners subjected to wheeled loads are to be not less than the values obtained from the following formulae:

where:

P0 : Wheeled force, in kN, defined in [3.5.2]

αW, KS, KT: Coefficients defined in [3.5.2].


The minimum net section modulus and the net shear sec-tional area of multispan ordinary stiffeners are to be obtained from [3.4.4] or [3.5.3], as applicable, taking account of the checking criteria indicated in [3.6].

�

d

Ry

γRγm

---------- σ≥

0 5Ry

γRγm

----------, τ≥

w γRγmβbγS2pS γW2pW+

12 Ry γRγmσX1–( )------------------------------------------- 1 s

2------–

s2103=

ASh 10γRγmβsγS2pS γW2pW+

Ry

---------------------------------- 1 s2------–

s=

w γRγmλbβbγS2pS γW2pW+

12Ry

---------------------------------- 1 s2------–

s2103=

ASh 10γRγmλsβsγS2pS γW2pW+

Ry

---------------------------------- 1 s2------–

s=

w γRγmαWKSP0

6 Ry γRγmσX1 Wh,–( )-----------------------------------------------103=

ASh 20γRγmαWKTP0

Ry

-------------------=

Pt B, Ch 7, Sec 2


3.8 Net section modulus and net shear sectional area of ordinary stiffeners subjected to lateral pressure in flooding conditions

3.8.1 General

The requirements in [3.8.3] to [3.8.5] provide the minimum net section modulus and net shear sectional area of ordi-nary stiffeners located on platings which constitute the boundary of compartments not intended to carry liquids (excluding stiffeners on bottom and side shell platings) in flooding conditions.





The net section modulus w, in cm3, and the net shear sec-tional area ASh , in cm2, of longitudinal or transverse ordi-nary stiffeners are to be not less than the values obtained from the following formulae:

where:

βb , βs : Coefficients defined in [3.4.2].

3.8.4 Single span vertical ordinary stiffeners

The net section modulus w, in cm3, and the net shear sec-tional area ASh , in cm2, of vertical ordinary stiffeners are to be not less than the values obtained from the following for-mulae:

where:

βb , βs : Coefficients defined in [3.4.2]

λb : Coefficient taken equal to the greater of the fol-lowing values:


pSFd : Still water pressure, in kN/m2, in flooding con-ditions, at the lower end of the ordinary stiffener considered

pSFu : Still water pressure, in kN/m2, in flooding con-ditions, at the upper end of the ordinary stiffener considered

pWFd : Wave pressure, in kN/m2, in flooding condi-tions, at the lower end of the ordinary stiffener considered

pWFu : Wave pressure, in kN/m2, in flooding condi-tions, at the upper end of the ordinary stiffener considered.


The minimum net section modulus and the net shear sec-tional area of multispan ordinary stiffeners are to be obtained from [3.4.4], considering the still water pressure pSF and the wave pressure pWF in flooding conditions, and taking account of the checking criteria indicated in [3.6].

3.9 Net section modulus and net shear sectional area of ordinary stiffeners subjected to lateral pressure in testing conditions

3.9.1 General

The requirements in [3.9.3] to [3.9.5] provide the minimum net section modulus and net shear sectional area of ordinary stiffeners of compartments subject to testing conditions.





The net section modulus w, in cm3, and the net shear sec-tional area ASh , in cm2, of longitudinal or transverse ordi-nary stiffeners are to be not less than the values obtained from the following formulae:

where:

βb , βs : Coefficients defined in [3.4.2].

w γRγmβbγS2pSF γW2pWF+

12 Ry γRγmσX1–( )------------------------------------------- 1 s

2------–

s2103=

ASh 10γRγmβsγS2pSF γW2pWF+

Ry

-------------------------------------- 1 s2------–

s=

w γRγmλbβbγS2pSF γW2pWF+

12Ry

-------------------------------------- 1 s2------–

s2103=

ASh 10γRγmλsβsγS2pSF γW2pWF+

Ry

-------------------------------------- 1 s2------–

s=

λb 1 0 2γS2 pSFd pSFu–( ) γW2 pWFd pWFu–( )+γS2 pSFd pSFu+( ) γW2 pWFd pWFu+( )+--------------------------------------------------------------------------------------,+=

λb 1 0 2γS2 pSFd pSFu–( ) γW2 pWFd pWFu–( )+γS2 pSFd pSFu+( ) γW2 pWFd pWFu+( )+--------------------------------------------------------------------------------------,–=

λs 1 0 4γS2 pSFd pSFu–( ) γW2 pWFd pWFu–( )+γS2 pSFd pSFu+( ) γW2 pWFd pWFu+( )+--------------------------------------------------------------------------------------,+=

λs 1 0 4γS2 pSFd pSFu–( ) γW2 pWFd pWFu–( )+γS2 pSFd pSFu+( ) γW2 pWFd pWFu+( )+--------------------------------------------------------------------------------------,–=

w γRγmβbγS2pT

12Ry

------------ 1 s2------–

s2103=

ASh 10γRγmβsγS2pT

Ry

------------ 1 s2------–

s=

Pt B, Ch 7, Sec 2


3.9.4 Single span vertical ordinary stiffenersThe net section modulus w, in cm3, and the net shear sec-tional area ASh , in cm2, of vertical ordinary stiffeners are to be not less than the values obtained from the following for-mulae:

where:βb , βs : Coefficients defined in [3.4.2]λb : Coefficient taken equal to the greater of the fol-

lowing values:


pTd : Still water pressure, in kN/m2, in testing condi-tions, at the lower end of the ordinary stiffener considered

pTu : Still water pressure, in kN/m2, in testing condi-tions, at the upper end of the ordinary stiffener considered.

3.9.5 Multispan ordinary stiffenersThe minimum net section modulus and the net shear sec-tional area of multispan ordinary stiffeners are to be obtained from [3.4.4], considering the pressure in testing conditions and taking account of the checking criteria indi-cated in [3.6].

4 Buckling check


4.1.1 The width of the attached plating to be considered for the buckling check of ordinary stiffeners is to be obtained, in m, from the following formulae:• where no local buckling occurs on the attached plating

(see Ch 7, Sec 1, [5.4.1]):be = s

• where local buckling occurs on the attached plating (seeCh 7, Sec 1, [5.4.1]):

to be taken not greater than s

where:

σb : Compression stress σX or σY, in N/mm2, acting on the plate panel, defined in Ch 7, Sec 1, [5.2.4], according to the direction x or y considered.

4.2 Load model

4.2.1 Sign convention for normal stressesThe sign convention for normal stresses is as follows:

• tension: positive

• compression: negative.

4.2.2 Hull girder compression normal stressesThe hull girder compression normal stresses to be consid-ered for the buckling check of ordinary stiffeners contribut-ing to the hull girder longitudinal strength are obtained, in N/mm2, from the following formula:

σX1 = γS1 σS1 + γW1 (CFV σWV1 + CFH σWH1 + CFΩ σΩ)

where:


σΩ : Compression warping stress, in N/mm2, induced by the torque 0,625MWT and obtained through direct calculation analyses based on a structural model in accordance with Ch 6, Sec 1, [2.6]


For longitudinal stiffeners, σX1 is to be taken as the maxi-mum compression stress on the stiffener considered.

In no case may σX1 be taken less than 30/k N/mm2.

When the ship in still water is always in hogging condition, σX1 may be evaluated by means of direct calculations when justified on the basis of the ship’s characteristics and intended service. The calculations are to be submitted to the Society for approval.

Where deemed necessary, the buckling check is to be car-ried out in harbour conditions by considering a reduced wave bending moment equal to 0,1MWV given in Ch 5, Sec 2, [3.1]

4.2.3 Combined hull girder and local compression normal stresses

The combined compression normal stresses to be consid-ered for the buckling check of ordinary stiffeners are to take into account the hull girder stresses and the local stresses resulting from the bending of the primary supporting mem-bers. These local stresses are to be obtained from a direct structural analysis using the design loads as given in Part B, Chapter 5.

With respect to the reference co-ordinate system defined inCh 1, Sec 2, [4.1], the combined stresses in x and y direc-tion are obtained, in N/mm2, from the following formulae:

σX = σX1 + γS2 σX2, S + γW2 σX2, W

σY = γS2 σY2, S + γW2 σY2, W

where:

σX1 : Compression normal stress, in N/mm2, induced by the hull girder still water and wave loads, defined in [4.2.2]

w γRγmλbβbγS2pT

12Ry

------------ 1 s2------–

s2103=

ASh 10γRγmλsβsγS2pT

Ry

------------ 1 s2------–

s=

λb 1 0 2pTd pTu–pTd pTu+---------------------,+=

λb 1 0 2pTd pTu–pTd pTu+---------------------,–=

λs 1 0 4pTd pTu–pTd pTu+---------------------,+=

λs 1 0 4pTd pTu–pTd pTu+---------------------,–=

be2 25,

βe

----------- 1 25,βe

2-----------–

s=

βestp

--- σb

E-----103=

Pt B, Ch 7, Sec 2


Table 8 : Hull girder normal compression stresses

σX2,S, σY2,S: Compression normal stress in x and y direction, respectively, in N/mm2, induced by the local bending of the primary supporting members and obtained from a direct structural analysis using the still water design loads as given in Part B, Chapter 5

σX2,W, σY2,W: Compression normal stress in x and y direction, respectively, in N/mm2, induced by the local bending of the primary supporting members and obtained from a direct structural analysis using the wave design loads as given in Part B, Chapter 5.

4.3 Critical stress

4.3.1 General

The critical buckling stress is to be obtained, in N/mm2, from the following formulae:

where:

σE = Min (σE1, σE2, σE3)

σE1 : Euler column buckling stress, in N/mm2, given in [4.3.2]

σE2 : Euler torsional buckling stress, in N/mm2, given in [4.3.3]

σE3 : Euler web buckling stress, in N/mm2, given in[4.3.4].

4.3.2 Column buckling of axially loaded stiffeners

The Euler column buckling stress is obtained, in N/mm2, from the following formula:

4.3.3 Torsional buckling of axially loaded stiffeners

The Euler torsional buckling stresses is obtained, in N/mm2, from the following formula:

where:

Iw : Net sectorial moment of inertia, in cm6, of the stiffener about its connection to the attached plating:

• for flat bars:

• for T-sections:

• for angles and bulb sections:

Ip : Net polar moment of inertia, in cm4, of the stiff-ener about its connection to the attached plating:

• for flat bars:

• for stiffeners with face plate:

It : St. Venant’s net moment of inertia, in cm4, of the stiffener without attached plating:

• for flat bars:


Condition σS1 in N/mm2 (1) σWV1 in N/mm2 σWH1 in N/mm2

z ≥ N

z < N

(1) When the ship in still water is always in hogging condition, σS1 for z ≥ N is to be obtained, in N/mm2, from the following for-mula, unless σX1 is evaluated by means of direct calculations (see [4.2.2]):

Note 1:FD : Coefficient defined in Ch 5, Sec 2, [4].

MSW S,

IY-------------- z N–( )10 3– 0 625FDM, WV S,

IY------------------------------------- z N–( )10 3–

0 625MWH,IZ

---------------------------y– 10 3–

MSW H,

IY--------------- z N–( )10 3– 0 625M, WV H,

IY-------------------------------- z N–( )10 3–

σS1MSW Hmin,

IY---------------------- z N–( )10 3–=

σc σE= for σEReH S,

2-----------≤

σc ReH S, 1 ReH S,

4σE

-----------– = for σE

ReH S,

2----------->

σE π2EIe

Ae2

-----------10 4–=

σEπ2EIw

104Ip2

------------------ KC

m2------- m2+ 0 385, E

It

Ip

---+=

Iwhw

3 tw3

36------------10 6–=

Iwtfbf

3hw2

12----------------10 6–=

Iwbf

3hw2

12 bf hw+( )2------------------------------- [tf bf

2 2bfhw 4hw2+ +( )=

+ 3twbfhw] 10 6–

Iphw

3 tw

3-----------10 4–=

Iphw

3 tw

3----------- hw

2 bftf+ 10 4–=

Ithwtw

3

3-----------10 4–=

It13--- hwtw

3 bftf3 1 0 63, tf

bf

----– + 10 4–=

Pt B, Ch 7, Sec 2


m : Number of half waves, to be taken equal to the integer number such that (see also Tab 9):

C0 : Spring stiffness of the attached plating:

Table 9 : Torsional buckling ofaxially loaded stiffeners - Number m of half waves

4.3.4 Web buckling of axially loaded stiffeners

The Euler buckling stress of the stiffener web is obtained, in N/mm2, from the following formulae:

• for flat bars:



4.4.1 Stiffeners parallel to the direction of compression

The critical buckling stress of the ordinary stiffener is to comply with the following formula:

where:

σc : Critical buckling stress, in N/mm2, as calculated in [4.3.1]

σb : Compression stress σxb or σyb , in N/mm2, in the stiffener, as calculated in [4.2.2] or [4.2.3].

Figure 5 : Buckling of stiffeners parallel tothe direction of compression

4.4.2 Stiffeners perpendicular to the direction of compression

The net moment of inertia of stiffeners, in cm4, is to be not less than the greatest value obtained from the following for-mulae:

• I = 360 2

• for σ ≤ ReH,P / 2:

• for σ > ReH,P / 2:

Figure 6 : Buckling of stiffeners perpendicularto the direction of compression

where:

/s : Ratio to be taken not less than 1,41 σE,0 : Euler buckling stress, in N/mm2, of the unstiff-

ened plate taken equal to:

K1,0 : Coefficient defined in Ch 7, Sec 1, Tab 8 for:

0 ≤ Ψ ≤ 1 and α = a /

ε : Coefficient defined in Ch 7, Sec 1, [5.3.1]σE,1 : Euler buckling stress, in N/mm2, of the plate

panel taken equal to:

K1,1 : Coefficient defined in Ch 7, Sec 1, Tab 8 for:

0 ≤ Ψ ≤ 1 and α = s / .

Where intercostal stiffeners are fitted, as shown in Fig 7, the check of the moment of inertia of stiffeners perpendicular to the direction of compression is to be carried out with the equivalent net thickness teq,net , in mm, obtained from the following formula:

where 1 is to be taken not less than s.

KC 0 ≤ KC < 4 4 ≤ KC < 36 36 ≤ KC < 144

m 1 2 3

m2 m 1–( )2 KC≤ m2 m 1+( )2<

KCC0

4

π4EIw

--------------106=

C0Etp

3

2 73, s--------------10 3–=

σE 16tW

hW

-------

2

104=

σE 78tW

hW

-------

2

104=

σc

γRγm

---------- σb≥

σσ

a

s

b

Istp

3

485----------

s--

4

4–

σE 1, σE 0,–----------------------- σ σE 0,–( )=

Istp

3

485----------

s--

4

4–

σE 1, σE 0,–----------------------- ReH P,

4 1 σReH P,-----------–

------------------------------ σE 0,–=

�

σσ

a

s

σE 0,π2E

12 1 ν2–( )-------------------------- tp

---

2

εK1 0, 10 6–=

σE 1,π2E

12 1 ν2–( )-------------------------- tp

---

2

εK1 1, 10 6–=

teq net,

1 s1

----

2

+

1 s--

2

+---------------------- tnet=

Pt B, Ch 7, Sec 2


Figure 7 : Buckling of stiffeners perpendicular tothe direction of compression (intercostal stiffeners)

5 Ultimate strength check of ordinary stiffeners contributing to the hull girder longitudinal strength

5.1 Application

5.1.1 The requirements of this Article apply to ships equal to or greater than 170 m in length. For such ships, the ulti-mate strength of stiffeners subjected to lateral pressure and to hull girder normal stresses is to be checked.


5.2.1 The width of the attached plating to be considered for the ultimate strength check of ordinary stiffeners is to be obtained, in m, from the following formulae:• if βU ≤ 1,25:

bU = s

• if βU > 1,25:

where:

σX1E : Stress defined in Tab 10.

5.3 Load model

5.3.1 GeneralThe still water and wave lateral pressures induced by the sea and the various types of cargoes and ballast in intact conditions are to be considered, depending on the location of the ordinary stiffener under consideration and the type of compartments adjacent to it, in accordance with Ch 5, Sec 1, [2.4].

The wave lateral pressures and hull girder loads are to be calculated in the mutually exclusive load cases “a”, “b”, “c” and “d” in Ch 5, Sec 4.


Lateral pressure is constituted by still water pressure and wave pressure.

Still water pressure (pS ) includes:



Wave induced pressure (pW) includes:


• the inertial pressure, defined in Ch 5, Sec 6 for the vari-ous types of cargoes and for ballast, and for each load case “a”, “b”, “c” and “d”.

5.3.3 Hull girder compression normal stresses

The hull girder compression normal stresses σX1 to be con-sidered for the ultimate strength check of stiffeners contrib-uting to the longitudinal strength are those given in [4.2.2], where the partial safety factors are those specified in Tab 1for the ultimate strength check.

5.4 Ultimate strength stress

5.4.1 The ultimate strength stress σU is to be obtained, in N/mm2, from the formulae in Tab 10, for resultant lateral pressure acting either on the side opposite to the ordinary stiffener, with respect to the plating, or on the same side as the ordinary stiffener.


5.5.1 The ultimate strength stress of the ordinary stiffener is to comply with the following formula:

where:

σU : Ultimate strength stress, in N/mm2, as calcu-lated in [5.4.1]

σX1 : Compression stress, in N/mm2, as calculated in[5.3.3].

�

� 1

σσ

a

s

bU2 25,βU

----------- 1 25,βU

2-----------–

s=

βUstp

--- σX1E

E----------103=

σU

γRγm

---------- σX1≥

Pt B, Ch 7, Sec 2


Table 10 : Ultimate strength stress

SymbolResultant load pressure acting on the side opposite to theordinary stiffener, with respect to the plating, in N/mm2

Resultant load pressure acting on the same side as the ordinary stiffener, in N/mm2

σU ReH,S f

f

ζ

μ

η

ηP 0

λU

Note 1:dP,U : Distance, in cm, between the neutral axis of the cross-section of the stiffener with attached plating of width bU and the

fibre at half-thickness of the platingdF,S : Distance, in cm, between the neutral axis of the cross-section of the stiffener with attached plating of width s and the

fibre at half-thickness of the face plate of the stiffenerdP : Distance, in cm, between the neutral axis of the ordinary stiffener without attached plating and the fibre at half-thickness

of the attached platingp : Lateral pressure acting on the stiffener, equal to: p = γ S2 pS + γW2U pW

δ0 : Pre-deformation, in cm, of the ordinary stiffener, to be assumed, in the absence of more accurate evaluation: δ0 = 0,2 ET : Structural tangent modulus, equal to:

σX1E : Stress to be obtained, in N/mm2, from the following formulae:

σX1 : Compression stress, in N/mm2, acting on the stiffener, as defined in [5.3.3].

fAU

AS

------ 1 s10bU

-------------– ReH P,

ζ2--- ζ2

4----- 1 μ–

1 ηP+( )λU2

---------------------------––

1 μ–1 ηP+--------------- 1 ηP η+ +

1 ηP+( )λU2

---------------------------+

125ps2dP U,

ReH P, IU 1 s10bU

-------------–

--------------------------------------------- 41 7ps2, dF S,

ReH S, IS

---------------------------------

δ013ps4

ETIS

------------------104+ dP U,

ρU2

--------- 0 577δ, 01 5ps4,

ETIS

---------------------104+ dF S,

ρS2

--------

dPA 1AU

------ 1AS

-----– dP U,

ρU2

---------

31 8,ρU

--------------- ReH P,

ET

----------- 1 s10bU

-------------– 18 4,

ρS

--------------- ReH S,

ET

-----------

ET 4EσX1E

ReH P,----------- 1 σX1E

ReH P,-----------–

= for σX1E 0 5ReH P,,>

ET E= for σX1E 0 5ReH P,,≤

σX1E

22 5stP,α

-------------------– 22 5s, tP

α-------------------

2

4A A 10stP+( ) σX112 5s, tP

α2-------------------+++

2A----------------------------------------------------------------------------------------------------------------------------------------------------

2

= if α 1 25,σX1

--------------->

σX1E σX1= if α 1 25,σX1

---------------≤

α 1000 stP E-----------=

Pt B, Ch 7, Sec 3


SECTION 3 PRIMARY SUPPORTING MEMBERS

Symbols


pS : Still water pressure, in kN/m2, see [3.4.2] and[3.4.4]

pW : Wave pressure, in kN/m2, see [3.4.2] and[3.4.4]

pSF, pWF : Still water and wave pressures, in kN/m2, inflooding conditions, defined in Ch 5, Sec 6, [9]

X1 : Hull girder normal stress, in N/mm2, defined in[3.4.5]

s : Spacing, in m, of primary supporting members

: Span, in m, of primary supporting members,measured between the supporting elements, seeCh 4, Sec 3, [4.1]

bp : Width, in m, of the plating attached to the pri-mary supporting member, for the yieldingcheck, defined in Ch 4, Sec 3, [4.2]

w : Net section modulus, in cm3, of the primarysupporting member, with an attached plating ofwidth bp , to be calculated as specified in Ch 4,Sec 3, [4.3]

ASh : Net shear sectional area, in cm2, of the primarysupporting member, to be calculated as speci-fied in Ch 4, Sec 3, [4.3]

m : Boundary coefficient, to be taken equal to:

• m = 10 in general

• m = 12 for bottom and side primary sup-porting members

I : Net moment of inertia, in cm4, of the primarysupporting member without attached plating,about its neutral axis parallel to the plating.

1 General

1.1 Application

1.1.1 Analysis criteria

The requirements of this Section apply for the yielding andbuckling checks of primary supporting members.

1.1.2 Structural models

Depending on the service notation and structural arrange-ment, primary structural models are to be modelled as spec-ified in Tab 1.

Table 1 : Selection of structural models

1.1.3 Yielding check

The yielding check is to be carried out according to:

• [3] for primary supporting members analysed throughisolated beam models

• [4] for primary supporting members analysed throughthree dimensional beam or finite element models

• [5] for primary supporting members analysed throughcomplete ship models.

1.1.4 Buckling check

The buckling check is to be carried out according to [6], onthe basis of the stresses in primary supporting members cal-culated according to [3], [4] or [5], depending on the struc-tural model adopted.

1.1.5 Minimum net thicknesses

In addition to the above, the scantlings of primary support-ing members are to comply with the requirements in [2].

Service notationShip length,

in mCalculation model

Ro-ro cargo shipRo-ro passenger ship

L 120 Isolated beam model, or three dimensional beam model for gril-lage or complex arrangement

120 < L 200 Three dimensional beam model

L > 200 Complete ship model

Passenger shipContainer shipGeneral cargo ship with large deck openings

L 120 Isolated beam model, or three dimensional beam model for gril-lage or complex arrangement


L > 170 Complete ship model

Other ships L 120 Isolated beam model, or three dimensional beam model for gril-lage or complex arrangement


L > 170 Three dimensional finite element model

Pt B, Ch 7, Sec 3


1.2 Analysis documentation

1.2.1 The following documents are to be submitted to theSociety for review of the three dimensional beam or finiteelement structural analyses:• reference to the calculation program used with identifi-

cation of the version number and results of the valida-tion text, if the results of the program have not beenalready submitted to the Society approval

• extent of the model, element types and properties,material properties and boundary conditions

• loads given in print-out or suitable electronic format. Inparticular, the method used to take into account theinteraction between the overall, primary and local load-ings is to be described. The direction and intensity ofpressure loads, concentrated loads, inertia and weightloads are to be provided

• stresses given in print-out or suitable electronic format• buckling checks as required in [6]• fatigue checks of structural details, as required in Ch 7,

Sec 4• identification of the critical areas, where the results of

the checkings exceed 97,5% of the permissible rule cri-teria in [4.3] or [5.3] and [6].

1.2.2 According to the results of the submitted calcula-tions, the Society may request additional runs of the modelwith structural modifications or local mesh refinements inhighly stressed areas.

1.3 Net scantlings

1.3.1 As specified in Ch 4, Sec 2, [1], all scantlings referredto in this Section are net, i.e. they do not include any mar-gin for corrosion.

The gross scantlings are obtained as specified in Ch 4, Sec2.


1.4.1 The partial safety factors to be considered for check-ing primary supporting members are specified in:

• Tab 2 for analyses based on isolated beam models

• Tab 3 for analyses based on three dimensional models

• Tab 4 for analyses based on complete ship models.

Table 2 : Primary supporting members analysed through isolated beam models - Partial safety factors

Table 3 : Primary supporting members analysed through three dimensional models - Partial safety factors


regarding:Symbol

Yielding check Buckling check

General(see [3.4] to [3.7])

Watertight bulkheadprimary supporting

members (1) (see [3.8])

Plate panels(see [6.1])

Pillars(see [6.2] and [6.3])

Still water hull girder loads S1 1,00 1,00 1,00 1,00

Wave hull girder loads W1 1,15 1,15 1,15 1,15

Still water pressure S2 1,00 1,00 1,00 1,00

Wave pressure W2 1,20 1,05 1,20 1,20

Material m 1,02 1,02 1,02 1,02

Resistance R 1,02 in general1,15 for bottom and side girders

1,02 (2) 1,10 for [6.2]: see Tab 13 for [6.3]: 1,15

(1) Applies also to primary supporting members of bulkheads or inner side which constitute boundary of compartments notintended to carry liquids.

(2) For primary supporting members of the collision bulkhead, R = 1,25


regarding:Symbol

Yielding check (see [4]) Buckling check

GeneralWatertight bulkhead primary supporting

members (1)

Plate panels(see [6.1])

Pillars(see [6.2] and [6.3])

Still water hull girder loads S1 1,00 1,00 1,00 1,00

Wave hull girder loads W1 1,05 1,05 1,05 1,05

Still water pressure S2 1,00 1,00 1,00 1,00

Wave pressure W2 1,10 1,10 1,10 1,10

Material m 1,02 1,02 1,02 1,02

Resistance R defined in Tab 5 defined in Tab 5 1,02 (2) for [6.2]: see Tab 13 for [6.3]: 1,15

(1) Applies also to primary supporting members of bulkheads or inner side which constitute boundary of compartments notintended to carry liquids.

(2) For corrugated bulkhead platings, R = 1,10.Note 1: For primary supporting members of the collision bulkhead, R = 1,25

Pt B, Ch 7, Sec 3


Table 4 : Primary supporting members analysed through complete ship models - Partial safety factors

Table 5 : Primary supporting members analysed through three dimensional or complete ship models

Resistance partial safety factor

Table 6 : Minimum net thicknesses of websof double bottom primary supporting members

Table 7 : Minimum net thicknesses of webs and flanges of single bottom primary supporting members


2.1 Minimum thicknesses

2.1.1 General

The net thickness of plating which forms the webs of pri-mary supporting members is to be not less than the valueobtained, in mm, from the following formulae:

tMIN = 3,7 + 0,015 L k1/2 for L < 120 m

tMIN = 3,7 + 1,8 k1/2 for L 120 m

2.1.2 Double bottom

In addition to the requirements in [2.1], the net thickness ofplating which forms the webs of primary supporting mem-bers of the double bottom is to be not less than the valuesgiven in Tab 6.

2.1.3 Single bottom

In addition to the requirements in [2.1], the net thickness ofplating which forms the webs and the flanges of primarysupporting members of the single bottom is to be not lessthan the values given in Tab 7.

2.2 Deck ordinary stiffeners in way of launching appliances used for survival craft or rescue boat

2.2.1 The scantlings of deck ordinary stiffeners are to bedetermined by direct calculations.

2.2.2 The loads exerted by launching appliance are to cor-respond to the SWL of the launching appliance.

2.2.3 The combined stress, in N/mm2, is not to exceed thesmaller of:

where Rm is the ultimate minimum tensile strength of thestiffener material, in N/mm2.

Partial safety factors covering uncertainties regarding:

SymbolYielding check

(see [5])

Buckling check

Plate panels (see [6.1]) Pillars (see [6.2] and [6.3])

Still water hull girder loads S1 1,00 1,00 1,00

Wave hull girder loads W1 1,10 1,10 1,10

Still water pressure S2 1,00 1,00 1,00

Wave pressure W2 1,10 1,10 1,10

Material m 1,02 1,02 1,02

Resistance R defined in Tab 5 1,02 (1) for [6.2]: see Tab 13 for [6.3]: 1,15

(1) For corrugated bulkhead platings, R = 1,10.

Type of threedimensional model(see Ch 7, App 1)

Resistance partial safety factor R

(see [4.3] and [5.3])

GeneralWatertight bulkhead pri-

mary supporting members

Beam model 1,20 1,02

Coarse mesh finite element model

1,20 1,02

Fine mesh finite element model

1,05 1,02

Primary supporting member

Minimum net thickness, in mm

Area within0,4L amidships

Area outside0,4L amidships

Centre girder 2,0 L1/3 k1/6 1,7 L1/3 k1/6

Side girders 1,4 L1/3 k1/6 1,4 L1/3 k1/6

Floors 1,5 L1/3 k1/6 1,5 L1/3 k1/6

Girder bounding a duct keel (1)

1,5 + 0,8 L1/2 k1/4 1,5 + 0,8 L1/2 k1/4

Margin plate L1/2 k1/4 0,9 L1/2 k1/4

(1) The minimum net thickness is to be taken not less than that required for the centre girder.


Minimum net thickness, in mm

Area within0,4L amidships

Area outside0,4L amidships

Centre girder 6,0 + 0,05 L2 k1/2 4,5 + 0,05 L2 k1/2

Floors and side girders 5,0 + 0,05 L2 k1/2 3,5 + 0,05 L2 k1/2

100235----------ReH and 54

235----------Rm

Pt B, Ch 7, Sec 3


3 Yielding check of primary supporting members analysed through an isolated beam structural model

3.1 General

3.1.1 The requirements of this Article apply for the yieldingcheck of primary supporting members subjected to lateralpressure or to wheeled loads and, for those contributing tothe hull girder longitudinal strength, to hull girder normalstresses, which may be analysed through an isolated beammodel, according to [1.1.2].

3.1.2 The yielding check is also to be carried out for pri-mary supporting members subjected to specific loads, suchas concentrated loads.

3.2 Bracket arrangement

3.2.1 The requirements of this Article apply to primary sup-porting members with brackets at both ends of length notgreater than 0,2 .

In the case of a significantly different bracket arrangement,the determination of normal and shear stresses due todesign loads and the required section modulus and shearsectional area are considered by the Society on a case bycase basis.

3.3 Load point


Unless otherwise specified, lateral pressure is to be calcu-lated at mid-span of the primary supporting member con-sidered.


For longitudinal primary supporting members contributingto the hull girder longitudinal strength, the hull girder nor-mal stresses are to be calculated in way of the neutral axisof the primary supporting member with attached plating.

3.4 Load model

3.4.1 General

The still water and wave lateral pressures induced by thesea and the various types of cargoes and ballast in intactconditions are to be considered, depending on the locationof the primary supporting member under consideration andthe type of compartments adjacent to it, in accordance withCh 5, Sec 1, [2.4].

Primary supporting members of bulkheads or inner sidewhich constitute the boundary of compartments notintended to carry liquids are to be subjected to the lateralpressure in flooding conditions.

The wave lateral pressures and hull girder loads are to becalculated in the mutually exclusive load cases “a”, “b”, “c”and “d” in Ch 5, Sec 4.


The lateral pressure in intact conditions is constituted bystill water pressure and wave pressure.





• the wave pressure, defined in Ch 5, Sec 5, [2] for eachload case “a”, “b”, “c” and “d”

• the inertial pressure, defined in Ch 5, Sec 6 for the vari-ous types of cargoes and for ballast, and for each loadcase “a”, “b”, “c” and “d”.


The lateral pressure in flooding conditions is constituted bythe still water pressure pSF and the wave pressure pWF

defined in Ch 5, Sec 6, [9].

3.4.4 Wheeled loads

For primary supporting members subjected to wheeledloads, the yielding check may be carried out according to[3.5] to [3.7] considering uniform pressures equivalent tothe distribution of vertical concentrated forces, when suchforces are closely located.

For the determination of the equivalent uniform pressures,the most unfavourable case, i.e. where the maximumnumber of axles is located on the same primary supportingmember according to Fig 1 to Fig 3, is to be considered.

The equivalent still water pressure and inertial pressure areindicated in Tab 8.

For arrangements different from those shown in Fig 1 to Fig3, the yielding check of primary supporting members is tobe carried out by a direct calculation, taking into accountthe distribution of concentrated loads induced by vehiclewheels.

Figure 1 : Wheeled loads - Distribution of vehicleson a primary supporting member

�

Pt B, Ch 7, Sec 3


Table 8 : Wheeled loadsEquivalent uniform still water and inertial pressures

Figure 2 : Wheeled loadsDistance between two consecutive axles

Figure 3 : Wheeled loadsDistance between axles of two consecutive vehicles


The hull girder normal stresses to be considered for theyielding check of primary supporting members areobtained, in N/mm2, from the following formulae:

• for longitudinal primary supporting members contribut-ing to the hull girder longitudinal strength:

X1 = S1 S1 + W1 (CFV WV1 + CFH WH1 + CF )

• for longitudinal primary supporting members not con-tributing to the hull girder longitudinal strength:

X1 = 0

• for transverse primary supporting members:

X1 = 0

where:

S1, WV1, WH1 : Hull girder normal stresses, in N/mm2,defined in:

• Tab 9 for primary supporting members sub-jected to lateral pressure

• Tab 10 for primary supporting members sub-jected to wheeled loads

: absolute value of the warping stress, in N/mm2,induced by the torque 0,625MWT and obtainedin accordance with Ch 6, Sec 1, [2.6]

CFV, CFH, CF : Combination factors defined in Tab 11.

Table 9 : Hull girder normal stresses - Primary supporting members subjected to lateral pressure

Ship conditionLoad case



Still water condition pS = peq

Upright condition “a” No inertial pressure

“b” pW = peq aZ1 / g

Inclined condition “c” The inertial pressure may be disregarded

“d” pW = peq aZ2 / g

Note 1:

nV : Maximum number of vehicles possible locatedon the primary supporting member

QA : Maximum axle load, in t, defined in Ch 5, Sec 6,Tab 9

X1 : Minimum distance, in m, between two consecu-tive axles (see Fig 2 and Fig 3)

X2 : Minimum distance, in m, between axles of twoconsecutive vehicles (see Fig 3)

: Coefficient taken equal to 0,4.

peq 10nVQA

s-------------- 3

X1 X2+s

------------------– =

s X1

X1 X2

Condition S1 , in N/mm2 (1) WV1 , in N/mm2 WH1 , in N/mm2

Lateral pressure applied onthe side opposite to the pri-mary supporting member,with respect to the plating:

z N

z < N

Lateral pressure applied onthe same side as the primarysupporting member:

z N

z < N


MSW S,

IY-------------- z N– 10 3– 0 625FDM, WV S,

IY------------------------------------- z N– 10 3–

0 625MWH,IZ

---------------------------y 10 3–

MSW H,

IY--------------- z N– 10 3– 0 625M, WV H,

IY-------------------------------- z N– 10 3–

MSW H,

IY--------------- z N– 10 3– 0 625M, WV H,

IY-------------------------------- z N– 10 3–

MSW S,

IY-------------- z N– 10 3– 0 625FDM, WV S,

IY------------------------------------- z N– 10 3–

Pt B, Ch 7, Sec 3


Table 10 : Hull girder normal stresses - Primary supporting members subjected to wheeled loads

Table 11 : Combination factors CFV, CFH and CF

3.5 Normal and shear stresses due to lateral pressure in intact conditions

3.5.1 General

Normal and shear stresses, induced by lateral pressures, inprimary supporting members are to be determined from theformulae given in:

• [3.5.2] in the case of longitudinal and transverse stiffen-ers

• [3.5.3] in the case of vertical stiffeners.

3.5.2 Longitudinal and transverse primary supporting members

The maximum normal stress and shear stress are to beobtained, in N/mm2, from the following formulae:

where:

b1 , b2 : Lengths of the brackets at ends, in m.

3.5.3 Vertical primary supporting members

The maximum normal stress and shear stress are to beobtained, in N/mm2, from the following formulae:

where:

b, s : Coefficients defined in [3.5.2]

b : Coefficient taken equal to the greater of the fol-lowing values:

s : Coefficient taken equal to the greater of the fol-lowing values:

pSd : Still water pressure, in kN/m2, at the lower endof the primary supporting member considered

pSu : Still water pressure, in kN/m2, at the upper endof the primary supporting member considered

pWd : Wave pressure, in kN/m2, at the lower end ofthe primary supporting member considered

pWu : Wave pressure, in kN/m2, at the upper end ofthe primary supporting member considered

A : Axial stress, to be obtained, in N/mm2, from thefollowing formula:

FA : Axial load (still water and wave) transmitted tothe vertical primary supporting members by thestructures above. For multideck ships, the crite-ria in [6.2.1] for pillars are to be adopted

A : Net sectional area, in cm2, of the vertical pri-mary supporting members with attached platingof width bP.

Condition S1 in N/mm2 (1) WV1 in N/mm2 WH1 in N/mm2

z N

z < N


MSW H,

IY

--------------- z N– 10 3– 0 625M, WV H,

IY

-------------------------------- z N– 10 3–

0 625MWH,IZ

---------------------------y 10 3–

MSW S,

IY-------------- z N– 10 3– 0 625FDM, WV S,

IY------------------------------------- z N– 10 3–

Load case CFV CFH CF

“a” 1,0 0 0

“b” 1,0 0 0

“c” 0,4 1,0 1,0

“d” 0,4 1,0 0

bS2pS W2pW+

mw----------------------------------s2103 X1+=

5sS2pS W2pW+

ASh

----------------------------------s=

b 1b1

2------- b2

2-------––

2

=

s 1b1

2------- b2

2-------––=

bbS2pS W2pW+

mw----------------------------------s2103 A+=

5ssS2pS W2pW+

ASh

----------------------------------s=

b 1 0 2S2 pSd pSu– W2 pWd pWu– +S2 pSd pSu+ W2 pWd pWu+ +------------------------------------------------------------------------------,+=

b 1 0 2S2 pSd pSu– W2 pWd pWu– +S2 pSd pSu+ W2 pWd pWu+ +------------------------------------------------------------------------------–=

s 1 0 4S2 pSd pSu– W2 pWd pWu– +S2 pSd pSu+ W2 pWd pWu+ +------------------------------------------------------------------------------,+=

s 1 0 4S2 pSd pSu– W2 pWd pWu– +S2 pSd pSu+ W2 pWd pWu+ +------------------------------------------------------------------------------–=

A 10FA

A-----=

Pt B, Ch 7, Sec 3



3.6.1 General

It is to be checked that the normal stress and the shearstress , calculated according to [3.5], are in compliancewith the following formulae:

3.7 Net section modulus and net sectional shear area complying with the checking criteria

3.7.1 General

The requirements in [3.7.2] and [3.7.3] provide the mini-mum net section modulus and net shear sectional area ofprimary supporting members subjected to lateral pressure inintact conditions, complying with the checking criteria indi-cated in [3.6].


The net section modulus w, in cm3, and the net shear sec-tional area ASh , in cm2, of longitudinal or transverse primarysupporting members are to be not less than the valuesobtained from the following formulae:

where b ands are the coefficients defined in [3.5.2].


The net section modulus w, in cm3, and the net shear sec-tional area ASh , in cm2, of vertical primary supporting mem-bers are to be not less than the values obtained from thefollowing formulae:

where:



A : Defined in [3.5.3].

3.8 Net section modulus and net shear sectional area of primary supporting members subjected to lateral pressure in flooding conditions

3.8.1 General

The requirements in [3.8.2] and [3.8.3] provide the mini-mum net section modulus and net shear sectional area of

primary supporting members of bulkheads or inner sidewhich constitute the boundary of compartments notintended to carry liquids, in flooding conditions.


The net section modulus w, in cm3, and the net shear sec-tional area ASh , in cm2, of longitudinal or transverse primarysupporting members are to be not less than the valuesobtained from the following formulae:

where:

b, s : Coefficients defined in [3.5.2].


The net section modulus w, in cm3, and the net shear sec-tional area ASh , in cm2, of vertical primary supporting mem-bers are to be not less than the values obtained from thefollowing formulae:

where:


b : Coefficient taken equal to the greater of the fol-lowing values:

s : Coefficient taken equal to the greater of the fol-lowing values:

pSFd : Still water pressure, in kN/m2, in flooding con-ditions, at the lower end of the primary support-ing member considered

pSFu : Still water pressure, in kN/m2, in flooding con-ditions, at the upper end of the primary support-ing member considered

pWFd : Wave pressure, in kN/m2, in flooding condi-tions, at the lower end of the primary supportingmember considered

pWFu : Wave pressure, in kN/m2, in flooding condi-tions, at the upper end of the primary support-ing member considered.

Ry

Rm

----------

0 5Ry

Rm

----------,

w RmbS2pS W2pW+

m Ry RmX1– -----------------------------------------s2103=

ASh 10RmsS2pS W2pW+

Ry

----------------------------------s=

w RmbbS2pS W2pW+

m Ry RmA– ---------------------------------------s2103=

ASh 10RmssS2pS W2pW+

Ry

----------------------------------s=

w RmbS2pSF W2pWF+m Ry mX1– --------------------------------------s2103=

ASh 10RmsS2pSF W2pWF+

Ry

--------------------------------------s=

w RmbbS2pSF W2pWF+

mRy

--------------------------------------s2103=

ASh 10RmssS2pSF W2pWF+

Ry

--------------------------------------s=

b 1 0 2S2 pSFd pSFu– W2 pWFd pWFu– +S2 pSFd pSFu+ W2 pWFd pWFu+ +--------------------------------------------------------------------------------------,+=

b 1 0 2S2 pSFd pSFu– W2 pWFd pWFu– +S2 pSFd pSFu+ W2 pWFd pWFu+ +--------------------------------------------------------------------------------------–=

s 1 0 4S2 pSFd pSFu– W2 pWFd pWFu– +S2 pSFd pSFu+ W2 pWFd pWFu+ +--------------------------------------------------------------------------------------,+=

s 1 0 4S2 pSFd pSFu– W2 pWFd pWFu– +S2 pSFd pSFu+ W2 pWFd pWFu+ +--------------------------------------------------------------------------------------–=

Pt B, Ch 7, Sec 3


4 Yielding check of primary supporting members analysed through a three dimensional structural model

4.1 General

4.1.1 The requirements of this Article apply for the yieldingcheck of primary supporting members subjected to lateralpressure or to wheeled loads and, for those contributing tothe hull girder longitudinal strength, to hull girder normalstresses, which are to be analysed through a three dimen-sional structural model.

4.1.2 The yielding check is also to be carried out for pri-mary supporting members subjected to specific loads, suchas concentrated loads.

4.2 Analysis criteria

4.2.1 The analysis of primary supporting members based onthree dimensional models is to be carried out according to:

• the requirements in Ch 7, App 1 for primary supportingmembers subjected to lateral pressure

• the requirements in Ch 7, App 2 for primary supportingmembers subjected to wheeled loads.

These requirements apply for:

• the structural modelling

• the load modelling

• the stress calculation.


4.3.1 General

For all types of analysis (see Ch 7, App 1, [2]), it is to bechecked that the equivalent stress VM , calculated accord-ing to Ch 7, App 1, [5] is in compliance with the followingformula:

4.3.2 Additional criteria for analyses based on fine mesh finite element models

Fine mesh finite element models are defined with referenceto Ch 7, App 1, [3.4].

For all the elements of the fine mesh models, it is to bechecked that the normal stresses 1 and 2 and the shearstress 12, calculated according to Ch 7, App 1, [5], are incompliance with the following formulae:

4.3.3 Specific case of primary supporting members subjected to wheeled loads

For all types of analysis (see Ch 7, App 2, [2]), it is to bechecked that the equivalent stress VM, calculated accordingto Ch 7, App 2, [5] is in compliance with the following for-mula:

5 Yielding check of primary supporting members analysed through a complete ship structural model

5.1 General

5.1.1 The requirements of this Article apply for the yieldingcheck of primary supporting members which are to be ana-lysed through a complete ship structural model.

5.1.2 A complete ship structural model is to be carried out,when deemed necessary by the Society, to analyse primarysupporting members of ships with one or more of the fol-lowing characteristics:• ships having large deck openings• ships having large space arrangements • multideck ships having series of openings in side or lon-

gitudinal bulkheads, when the stresses due to the differ-ent contribution of each deck to the hull girder strengthare to be taken into account.

5.1.3 Based on the criteria in [5.1.2], analyses based oncomplete ship models may be required, in general, for thefollowing ship types:• ships with the service notation general cargo ship, hav-

ing large deck openings• ships with the service notation container ship• ships with the service notation ro-ro cargo ship• ships with the service notation passenger ship• ships with the service notation ro-ro passenger ship.


5.2.1 The analysis of primary supporting members basedon complete ship models is to be carried out according toCh 7, App 3. These requirements apply for:• the structural modelling• the load modelling• the stress calculation.


5.3.1 General It is to be checked that the equivalent stress VM , calculatedaccording to Ch 7, App 3, [4] is in compliance with the fol-lowing formula:

Ry

Rm

---------- VM

Ry

Rm

---------- max 1 2,( )

0 5Ry

Rm

----------, 12

Ry

Rm

---------- VM

Ry

Rm

---------- VM

Pt B, Ch 7, Sec 3


5.3.2 Additional criteria for elements modelled with fine meshes

Fine meshes are defined with reference to Ch 7, App 3,[2.4].

For all the elements modelled with fine meshes, it is to bechecked that the normal stresses 1 and 2 and the shearstress 12 , calculated according to Ch 7, App 3, [4], are incompliance with the following formulae:

6 Buckling check

6.1 Local buckling of plate panels

6.1.1 A local buckling check is to be carried out, for platepanels which constitute primary supporting membersand/or corrugated bulkheads, according to:• Ch 7, App 1, [6] in case of buckling check based on a

fine mesh element model• Ch 7, Sec 1, [5] in other cases, calculating the stresses

in the plate panels according to [3] or [5], depending onthe structural model.

6.2 Buckling of pillars subjected to compression axial load

6.2.1 Compression axial loadWhere pillars are in line, the compression axial load in apillar is obtained, in kN, from the following formula:

where:AD : Area, in m2, of the portion of the deck or plat-

form supported by the pillar consideredri : Coefficient which depends on the relative posi-

tion of each pillar above the one considered, tobe taken equal to:• ri = 0,9 for the pillar immediately above that

considered (i = 1)

• ri = 0,9i for the ith pillar of the line above thepillar considered, to be taken not less than0,478

Qi,S , Qi,W : Still water and wave loads, respectively, in kN,from the ith pillar of the line above the pillarconsidered.

6.2.2 Critical column buckling stress of pillarsThe critical column buckling stress of pillars is to beobtained, in N/mm2, from the following formulae:

where:

E1 : Euler column buckling stress, to be obtained, inN/mm2, from the following formula:

I : Minimum net moment of inertia, in cm4, of thepillar

A : Net cross-sectional area, in cm2, of the pillar

: Span, in m, of the pillar

f : Coefficient, to be obtained from Tab 12.

Table 12 : Coefficient f

6.2.3 Critical torsional buckling stress of built-up pillars

The critical torsional buckling stress of built-up pillars is tobe obtained, in N/mm2, from the following formulae:

where:

E2 : Euler torsional buckling stress, to be obtained,in N/mm2, from the following formula:

Ry

Rm

---------- max 1 , 2( )

0 5Ry

Rm

----------, 12

FA AD S2pS W2pW+ ri

i 1=

N

S2Qi S, W2Qi W,+ +=

cB E1= for E1ReH

2--------

cB ReH 1ReH

4E1

-----------– = for E1

ReH

2--------

Boundary conditions of the pillar f

Both ends fixed

0,5

One end fixed, one end pinned

Both ends pinned

1

E1 2E IA f 2----------------10 4–=

22

-------

cT E2= for E2ReH

2--------

cT ReH 1ReH

4E2

-----------– = for E2

ReH

2--------

E22EIw

104Ip2

------------------ 0 41, EIt

Ip

---+=

Pt B, Ch 7, Sec 3


Iw : Net sectorial moment of inertia of the pillar, tobe obtained, in cm6, from the following for-mula:

hW : Web height of built-up section, in mm

tW : Net web thickness of built-up section, in mm

bF : Face plate width of built-up section, in mm

tF : Net face plate thickness of built-up section, inmm

Ip : Net polar moment of inertia of the pillar, to beobtained, in cm4, from the following formula:

Ip = IXX + IYY

IXX : Net moment of inertia about the XX axis of thepillar section (see Fig 4)

IYY : Net moment of inertia about the YY axis of thepillar section (see Fig 4)

It : St. Venant’s net moment of inertia of the pillar, tobe obtained, in cm4, from the following formula:

Figure 4 : Reference axes for the calculationof the moments of inertia of a built-up section

6.2.4 Critical local buckling stress of built-up pillars

The critical local buckling stress of built-up pillars is to beobtained, in N/mm2, from the following formulae:

where:

E3 : Euler local buckling stress, to be taken equal tothe lesser of the values obtained, in N/mm2,from the following formulae:

•

•

tW, hW, tF, bF : Dimensions, in mm, of the built-up section,defined in [6.2.3].

6.2.5 Critical local buckling stress of pillars having hollow rectangular section

The critical local buckling stress of pillars having hollowrectangular section is to be obtained, in N/mm2, from thefollowing formulae:

where:

E4 : Euler local buckling stress, to be taken equal tothe lesser of the values obtained, in N/mm2,from the following formulae:

•

•

b : Length, in mm, of the shorter side of the section

t2 : Net web thickness, in mm, of the shorter side ofthe section

h : Length, in mm, of the longer side of the section

t1 : Net web thickness, in mm, of the longer side ofthe section.

6.2.6 Checking criteria

The net scantlings of the pillar loaded by the compressionaxial stress FA defined in [6.2.1] are to comply with the for-mulae in Tab 13.

6.3 Buckling of pillars subjected to compression axial load and bending moments

6.3.1 Checking criteria

In addition to the requirements in [6.2], the net scantlings ofthe pillar loaded by the compression axial load and bend-ing moments are to comply with the following formula:

where:

F : Compression load, in kN, acting on the pillar

A : Net cross-sectional area, in cm2, of the pillar

e : Eccentricity, in cm, of the compression loadwith respect to the centre of gravity of the cross-section

Iwtfbf

3hw2

24----------------10 6–=

It13--- hwtw

3 2bftf3+ 10 4–=

Y

Y

X X

cL E3= for E3ReH

2--------

cL ReH 1ReH

4E3

-----------– = for E3

ReH

2--------

E3 78tW

hW

-------

2

104=

E3 32tF

bF

-----

2

104=

cL E4= for E4ReH

2--------

cL ReH 1ReH

4E4

-----------– = for E4

ReH

2--------

E4 78t2

b---

2

104=

E4 78t1

h---

2

104=

10F 1A---- e

wP

--------+ 103Mmax

wP

------------ + ReH

Rm

----------

1

1 10FE1A------------–

---------------------=

Pt B, Ch 7, Sec 3


E1 : Euler column buckling stress, in N/mm2,defined in [6.2.2]

wP : Minimum net section modulus, in cm3, of thecross-section of the pillar

Mmax : Max (M1, M2, M0)

M1 : Bending moment, in kN.m, at the upper end ofthe pillar

M2 : Bending moment, in kN.m, at the lower end ofthe pillar

Table 13 : Buckling check of pillars subject to compression axial load

M00 5 1 t2+ , M1 M2+

u cos----------------------------------------------------------=

u 0 5, 10FE1A------------=

t 1u tan

----------------- M2 M1–M2 M1+--------------------- =

provided that:

utan2– M2 M1–M2 M1+--------------------- utan2

Pillarcross-section

Columnbuckling check

Torsionalbuckling check

Localbuckling check

Geometriccondition

Built-up

•

Hollow tubular

Not required Not required•

• t 5,5 mm

Hollow rectangular

Not required

•

•

• t1 5,5 mm• t2 5,5 mm

Note 1:cB : Critical column buckling stress, in N/mm2, defined in [6.2.2]cT : Critical torsional buckling stress, in N/mm2, defined in [6.2.3]cL : Critical local buckling stress, in N/mm2, defined in [6.2.4] for built-up section or in [6.2.5] for hollow rectangular sec-

tionR : Resistance partial safety factor, equal to:

• 1,15 for column buckling• 1,05 for torsional and local buckling

FA : Compression axial load in the pillar, in kN, defined in [6.2.1]A : Net sectional area, in cm2, of the pillar.

bF

hW tW

tF

cB

Rm

---------- 10FA

A-----

cT

Rm

---------- 10FA

A-----

cL

Rm

---------- 10FA

A-----

bF

tF

----- 40

t

d

cB

Rm

---------- 10FA

A-----

dt--- 55

b

t2t1

h

cB

Rm

---------- 10FA

A-----

cL

Rm

---------- 10FA

A-----

bt2

--- 55

ht1

--- 55

Pt B, Ch 7, Sec 4


SECTION 4 FATIGUE CHECK OF STRUCTURAL DETAILS

Symbols


pS : Still water pressure, in kN/m2, see [2.2]pW : Wave pressure, in kN/m2, see [2.2]i : Index which denotes the load case “a”, “b”, “c”

or “d”j : Index which denotes the loading condition

“Full load” or “Ballast”

Kh, K : Stress concentration factors, defined in Ch 12, Sec 2 for the special structural details there specified

KF : Fatigue notch factor, defined in [4.3.1]Km : Stress concentration factor, taking account of

misalignment, defined in [4.3.1]KS : Coefficient taking account of the stiffener sec-

tion geometry, defined in [6.2.2]T1 : Draught, in m, corresponding to the loading

condition considered.

1 General

1.1 Application

1.1.1 GeneralThe requirements of this Section apply to ships equal to or greater than 170 m in length.

1.1.2 Structural details to be checkedThe requirements of this Section apply for the fatigue check of special structural details defined in Ch 12, Sec 2, depending on the ship type and on the hull area where the detail are located.

The Society may require other details to be checked, when deemed necessary on the basis of the detail geometry and stress level.

In case of a hot spot located in a plate edge without any welded joint, the SN curve to be used is to be considered on a case by case basis by the Society.

1.1.3 Categorisation of detailsWith respect to the method to be adopted to calculate the stresses acting on structural members, the details for which the fatigue check is to be carried out may be grouped as fol-lows:• details where the stresses are to be calculated through a

three dimensional structural model (e.g. connections between primary supporting members)

• details located at ends of ordinary stiffeners, for which an isolated structural model can be adopted.

1.1.4 Details where the stresses are to be calculated through a three dimensional structural model

The requirements of Ch 7, App 1, [7] apply, in addition of those of [1] to [5] of this Section.

1.1.5 Details located at ends of ordinary stiffenersThe requirements of [1] to [6] of this Section apply.

1.1.6 Other detailsIn general, for details other than those in [1.1.3], the stresses are to be calculated through a method agreed by the Soci-ety on a case by case basis, using the load model defined in[2].

The checking criteria in [5] is generally to be applied.

1.2 Net scantlings

1.2.1 As specified in Ch 4, Sec 2, [1], all scantlings referred to in this Section are net, i.e. they do not include any mar-gin for corrosion.

The gross scantlings are obtained as specified in Ch 4, Sec 2.

1.3 Sign conventions

1.3.1 Bending momentsThe sign conventions of bending moments at any ship trans-verse section are the following ones:

• the vertical bending moment is positive when it induces tensile stresses in the strength deck (hogging bending moment); it is negative in the opposite case (sagging bending moment)

• the horizontal bending moment is positive.

1.3.2 StressesThe sign conventions of stresses are the following ones:

• tensile stresses are positive

• compressive stresses are negative.

1.4 Definitions

1.4.1 Hot spotsHot spots are the locations where fatigue cracking may occur. They are indicated in the relevant figures of special structural details in Ch 12, Sec 2 (see [1.1.2]).

1.4.2 Nominal stressNominal stress is the stress in a structural component taking into account macro-geometric effects but disregarding the stress concentration due to structural discontinuities and to the presence of welds (see Fig 1).

Pt B, Ch 7, Sec 4


Figure 1 : Nominal, hot spot and notch stresses

1.4.3 Hot spot stress

Hot spot stress is a local stress at the hot spot taking into account the influence of structural discontinuities due to the geometry of the detail, but excluding the effects of welds (see Fig 1).

1.4.4 Notch stress

Notch stress is a peak stress in a notch such as the root of a weld or the edge of a cut-out. This peak stress takes into account the stress concentrations due to the presence of notches (see Fig 1).

1.4.5 Elementary stress range

Elementary stress range is the stress range determined for one of the load cases “a”, “b”, “c” or “d” (see Ch 5, Sec 4, [2]) and for either of the loading conditions (see Ch 5, Sec 1, [2.4] and Ch 5, Sec 1, [2.5]).


1.5.1 The partial safety factors to be considered for the fatigue check of structural details are specified in Tab 1.

Table 1 : Fatigue check - Partial safety factors

2 Load model

2.1 General

2.1.1 Load point

Unless otherwise specified, design loads are to be deter-mined at points defined in:

• Ch 7, Sec 2, [1.3] for ordinary stiffeners

• Ch 7, Sec 3, [1] for primary supporting members.

2.1.2 Local and hull girder loads

The fatigue check is based on the stress range induced at the hot spot by the time variation of the local pressures and hull girder loads in each load case “a”, “b”, “c” and “d” defined in [2.2] for the loading conditions defined in [2.1.4] and[2.1.3] (see Fig 2).

For the purpose of fatigue check, each load case “a”, “b”, “c” and “d” is divided in two cases “-max” and “-min” for which the local pressures and corresponding hull girder loads are defined in [2.2] and [2.3] respectively.

Figure 2 : Stress range

2.1.3 Loading conditions for details where the stresses are to be calculated through a three dimensional structural model

The most severe full load and ballast conditions for the detail concerned are to be considered in accordance withCh 5, Sec 1, [2.5].

2.1.4 Loading conditions for details located at ends of ordinary stiffeners

The cargo and ballast distribution is to be considered in accordance with Ch 5, Sec 1, [2.4].

2.1.5 Spectral fatigue analysis

For ships with non-conventional shapes or with restricted navigation, the Society may require a spectral fatigue analy-sis to be carried out.

In this analysis, the loads and stresses are to be evaluated through long-term stochastic analysis taking into account the characteristics of the ship and the navigation notation.

The load calculations and fatigue analysis are to be submit-ted to the Society for approval.

Partial safety factors covering uncertainties

regarding:Symbol

Value

GeneralDetails at

ends of ordi-nary stiffeners

Still water hull girder loads

γS1 1,00 1,00

Wave hull girder loads γW1 1,05 1,15

Still water pressure γS2 1,00 1,00

Wave pressure γW2 1,10 1,20

Resistance γR 1,02 1,02

notchstress

hot spotstress

nominalstress

hot spot t

0,5 t

1,5 t

σmax

σ

σmin

Δσ

time

Pt B, Ch 7, Sec 4


2.2 Local lateral pressures

2.2.1 General

The still water and wave lateral pressures induced by the sea and various types of cargoes and ballast are to be con-sidered.

Lateral pressure is constituted by still water pressure and wave pressure.

2.2.2 Load cases “a-max” and “a-min”, in upright ship condition

The still water sea pressure (pS) is defined in Ch 5, Sec 5, [1.1.1].

The wave pressure (pW) is defined in Tab 2.

No internal inertial pressures are considered.

2.2.3 Load cases “b-max” and “b-min”, in upright ship condition


• the still water sea pressure defined in Ch 5, Sec 5, [1]


Dynamic pressure (pW) is constituted by internal inertial pressures defined in Tab 4.

No sea wave dynamic pressures are considered.

2.2.4 Load cases “c-max” and “c-min”, in inclined ship condition





• the wave pressure obtained from Tab 3

• the inertial pressure obtained from Tab 4 for the various types of cargoes and ballast.

Table 2 : Wave pressure in load case a

Table 3 : Wave pressure in inclined ship conditions (load cases “c” and “d”)


a-max a-min

Bottom and sides below the waterline(z ≤ T1)


0,0

Note 1:α = T1 /T


c-max / d-max c-min / d-min

Bottom and sides below the waterline(z ≤ T1)


0,0

(1) In the formulae giving the wave pressure pW, the ratio (y / BW) is not to be taken greater than 0,5.Note 1:α = T1 /TCF2 : Combination factor, to be taken equal to:


BW : Moulded breadth, in m, measured at the waterline at draught T1 , at the hull transverse section consideredh2 : Reference value, in m, of the relative motion in the inclined ship condition, defined in Ch 5, Sec 3, [3.3.2] and not to be

taken greater than the minimum of T1 and D − 0,9 T1.

α1 4⁄ ρgh1

2------------ T1 z+

T1---------------

α– 1 4⁄ ρgh1

2------------ T1 z+

T1---------------

without being taken less than γS

γW------ρg z T1–( )

ρg T1 α1 4⁄ h1 z–+( )

CF2α1 4⁄ ρgh2y

BW

------- T1 z+T1

--------------C– F2α1 4⁄ ρgh2

yBW

------- T1 z+T1

--------------

without being taken less than γS

γW

------ρg z T1–( )

ρg T1 2CF2α1 4⁄ yBW

-------h2 z–+

Pt B, Ch 7, Sec 4


Table 4 : Inertial pressures

2.2.5 Load cases “d-max” and “d-min”, in inclined ship condition





• the wave pressure obtained from Tab 3

• the inertial pressure obtained from Tab 4 for the various types of cargoes and ballast.

2.3 Nominal hull girder normal stresses

2.3.1 The nominal hull girder normal stresses are obtained, in N/mm2, from the following formulae:

• for members contributing to the hull girder longitudinal strength:

• for members not contributing to the hull girder longitu-dinal strength:

σh = 0

where:

σSW : Still water hull girder normal stresses, in N/mm2, taken equal to:

MSW : Still water bending moment for the loading con-dition considered

σWV, σWV, σWH: Hull girder normal stresses, in N/mm2, defined in Tab 5

σΩ : Warping stresses, in N/mm2, induced by the torque 0,625MWT and obtained through direct calculation analyses based on a structural model in accordance with Ch 6, Sec 1, [2.6]

CFV, CFH, CFΩ: Combination factors defined in Tab 6.

Table 5 : Nominal hull girder normal stresses

Table 6 : Combination factors CFV, CFH and CFΩ

Cargo Load case Inertial pressures, in kN/m2 (1)

Liquids b-max

b-min

c-max d-max

c-mind-min

Dry bulk cargoesb-max

b-min

c-max and c-mind-max and d-min

The inertial pressure transmitted to the hull structures in inclined condition may gen-erally be disregarded. Specific cases in which this simplification is not deemed per-missible by the Society are considered individually.

(1) The symbols used in the formulae of inertial pressures are defined in Ch 5, Sec 6.Note 1:CFA : Combination factor, to be taken equal to:

• CFA = 0,7 for load case “c”• CFA = 1,0 for load case “d”.

pW ρL 0 5a, X1– B aZ1– zTOP z–( )[ ]=

pW ρL= 0 5a, X1B aZ1 zTOP z–( )+[ ]

pW ρL 0 7C, FAaY2 y yH–( ) 0 7C, FAa– Z2 g–( ) z zH–( ) g z zTOP–( )+ +[ ]=

pW ρL 0 7C, FAaY2 y yH–( )– 0 7C, FAaZ2 g–( ) z zH–( ) g z zTOP–( )+ +[ ]=

pW ρ– BaZ1 zB z–( ) αsin( )2 45o ϕ2---–

tan2

αcos( )2+

=

pW ρBaZ1 zB z–( ) αsin( )2 45o ϕ2---–

tan2

αcos( )2+

=

σh γS1σSW γW1 CFVσWV CFHσWH CFΩσΩ+ +( )+=

σSWMSW

IY

----------- z N–( )10 3–=

Load case

σWV, in N/mm2 σWH, in N/mm2

a-max 0

a-min 0

b-maxb-min

0 0

c-maxd-max

0

c-mind-min

0


“a” 1,0 0 0

“b” 1,0 0 0

“c” 0,4 1,0 1,0

“d” 0,4 1,0 0

0 625M, WV H,

IY

------------------------------- z N–( )10 3–

0 625M, WV S,

IY

------------------------------ z N–( )10 3–

0 625M, WH

IZ

---------------------------– y10 3–

0 625M, WH

IZ

---------------------------y10 3–

Pt B, Ch 7, Sec 4


3 Fatigue damage ratio

3.1 General

3.1.1 Elementary fatigue damage ratio

The elementary fatigue damage ratio is to be obtained from the following formula:

where:

ΔσN,ij : Elementary notch stress range, in N/mm2, defined in [4.3.1]

T1 : Draught, in m, corresponding to the loading condition “Full load” or “Ballast”

CFL : • in general: CFL = 1

• when the additional class notation VeriS-TAR- HULL DFL xx years is assigned, xx being equal to TFL:

t : Net thickness, in mm, of the element under consideration not being taken less than 22 mm

Nt : Number of cycles, to be taken equal to:

α0 : Sailing factor, taken equal to 0,85

TA : Average period, in seconds, to be taken equal to:

TA = 4 log L

TFL : Increased design fatigue life, in years, having a value between 25 and 40

pR = 10−5

ΓN[X+1,νij]: Incomplete Gamma function, calculated for X = 3 / ξ or X = 5 / ξ and equal to:

Values of ΓN[X+1,νij] are also indicated in Tab 7. For intermediate values of X and νij, ΓN may be obtained by linear interpolation

ΓC[X+1] : Complete Gamma function, calculated for X = 3 / ξ, equal to:

Values of ΓC[X+1] are also indicated in Tab 8. For intermediate values of X, ΓC may be obtained by linear interpolation.

3.1.2 Cumulative damage ratio

The cumulative damage ratio is to be obtained from the fol-lowing formula:

where:

α : Part of the ship’s life in full load condition, given in Tab 9 for various ship types

βIF : Fatigue life improvement factor for improve-ment tehnique, if any, as defined in:

• [3.1.3] in case of grinding

• [3.1.4] for improvement techniques other than grinding

DF : Cumulative damage ratio for ship in “Full load” condition, taken equal to:

DB : Cumulative damage ratio for ship in “Ballast” condition, taken equal to:

DaF, DbF, DcF, DdF: Elementary damage ratios for load cases “a”, “b”, “c” and ”d”, respectively, in “Full load” condition, defined in [3.1.1]

DaB, DbB, DcB: Elementary damage ratios for load cases “a”, “b”, and “c”, respectively, in “Ballast” condi-tion, defined in [3.1.1]

Kcor : Corrosion factor, taken equal to:

• Kcor = 1,5 for cargo oil tanks

• Kcor = 1,1 for ballast tanks having an effec-tive coating protection.

DijNt

Kp

----- ΔσN ij,( )3

pRln–( )3 ξ⁄-------------------------- μi j ΓC

3ξ--- 1+=

μij 1ΓN

3ξ--- 1 νi j,+ ΓN

5ξ--- 1 νij,+ νij

2 ξ⁄––

ΓC3ξ--- 1+

---------------------------------------------------------------------------------------–=

ξ ξ0 1 04, 0 14z T1–D T1–-----------------,–

without being less than 0,9 ξ0=

ξ073 0 07L,–

60----------------------------CFL without being less than 0,85=

CFL0 2 NtFL( )log,[ ]log0 2 Nt( )log,[ ]log

-----------------------------------------------=

νijSq

ΔσN ij,--------------

ξ

– pRln=

Sq Kp10 7–( )1 3⁄=

Kp 5 802 22t

------

0 9,

1012,=

Nt631α0

TA

----------------106=

NtFL31 55α0TFL,

TA

------------------------------106=

ΓN X 1 νij,+[ ] tXe t– td0

νi j

=

ΓC X 1+[ ] tXe t– td0

500

=

DKcor

βIF

--------- αDF 1 α–( )DB+[ ]=

DF16---DaF

16---DbF+ 1

3---DcF

13---DdF+ +=

DB13---DaB

13---DbB+ 1

3---DcB+=

Pt B, Ch 7, Sec 4


Table 7 : Function ΓN [X+1, νij]

XValue of νij

1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 5,5 6,0 6,5 7,0 7,5 8,0

2,5 0,38 0,73 1,13 1,53 1,90 2,22 2,48 2,70 2,86 2,99 3,08 3,15 3,20 3,24

2,6 0,38 0,75 1,19 1,63 2,04 2,41 2,71 2,96 3,16 3,31 3,42 3,51 3,57 3,61

2,7 0,39 0,78 1,25 1,73 2,20 2,62 2,97 3,26 3,49 3,67 3,81 3,91 3,99 4,04

2,8 0,39 0,80 1,31 1,85 2,38 2,85 3,26 3,60 3,87 4,09 4,25 4,37 4,46 4,53

2,9 0,39 0,83 1,38 1,98 2,57 3,11 3,58 3,98 4,30 4,56 4,75 4,90 5,01 5,10

3,0 0,39 0,86 1,45 2,12 2,78 3,40 3,95 4,41 4,79 5,09 5,33 5,51 5,65 5,75

3,1 0,40 0,89 1,54 2,27 3,01 3,72 4,35 4,89 5,34 5,70 5,99 6,21 6,37 6,49

3,2 0,40 0,92 1,62 2,43 3,27 4,08 4,81 5,44 5,97 6,40 6,74 7,01 7,21 7,36

3,3 0,41 0,95 1,72 2,61 3,56 4,48 5,32 6,06 6,68 7,20 7,61 7,93 8,17 8,36

3,4 0,41 0,99 1,82 2,81 3,87 4,92 5,90 6,76 7,50 8,11 8,60 8,99 9,29 9,51

3,5 0,42 1,03 1,93 3,03 4,22 5,42 6,55 7,55 8,42 9,15 9,74 10,21 10,57 10,85

3,6 0,42 1,07 2,04 3,26 4,60 5,97 7,27 8,45 9,48 10,34 11,05 11,62 12,06 12,41

3,7 0,43 1,12 2,17 3,52 5,03 6,59 8,09 9,47 10,68 11,71 12,56 13,25 13,79 14,21

3,8 0,43 1,16 2,31 3,80 5,50 7,28 9,02 10,63 12,06 13,28 14,30 15,13 15,80 16,31

3,9 0,44 1,21 2,45 4,10 6,02 8,05 10,06 11,94 13,63 15,09 16,31 17,32 18,12 18,76

4,0 0,45 1,26 2,61 4,43 6,59 8,91 11,23 13,43 15,42 17,16 18,63 19,85 20,83 21,61

4,1 0,45 1,32 2,78 4,80 7,22 9,87 12,55 15,12 17,47 19,54 21,31 22,78 22,98 24,94

4,2 0,46 1,38 2,96 5,20 7,93 10,95 14,05 17,05 19,82 22,29 24,41 26,19 27,65 28,83

4,3 0,47 1,44 3,16 5,63 8,70 12,15 15,73 19,24 22,51 25,45 28,00 30,16 31,93 33,38

4,4 0,48 1,51 3,37 6,11 9,56 13,50 17,64 21,74 25,60 29,10 32,16 34,77 36,94 38,71

4,5 0,49 1,57 3,60 6,63 10,52 15,01 19,79 24,58 29,14 33,31 36,99 40,15 42,79 44,96

4,6 0,49 1,65 3,85 7,20 11,57 16,70 22,23 27,82 33,20 38,17 42,59 46,41 49,63 52,29

4,7 0,50 1,73 4,12 7,82 12,75 18,59 24,98 31,53 37,88 43,79 49,10 53,72 57,65 60,91

4,8 0,52 1,81 4,40 8,50 14,04 20,72 28,11 35,75 43,25 50,29 56,66 62,26 67,05 71,05

4,9 0,52 1,90 4,71 9,25 15,49 23,11 31,64 40,57 49,42 57,81 65,47 72,24 78,08 82,98

5,0 0,53 1,99 5,04 10,07 17,09 25,78 35,65 46,08 56,53 66,52 75,72 83,92 91,03 97,05

5,1 0,55 2,09 5,40 10,97 18,86 28,79 40,19 52,39 64,71 76,61 87,66 97,58 106,3 113,6

5,2 0,56 2,19 5,79 11,95 20,84 32,17 45,34 59,60 74,15 88,32 101,6 113,6 124,2 133,2

5,3 0,57 2,30 6,21 13,03 23,03 35,96 51,19 67,85 85,02 101,9 117,8 132,4 145,3 156,4

5,4 0,58 2,41 6,66 14,21 25,46 40,23 57,83 77,29 97,56 117,7 136,8 154,4 170,1 183,8

5,5 0,59 2,54 7,14 15,50 28,17 45,03 65,37 88,11 112,0 136,0 159,0 180,3 199,4 216,2

5,6 0,61 2,67 7,67 16,92 31,18 50,42 73,93 100,5 128,8 157,3 184,9 210,7 234,0 254,6

5,7 0,62 2,80 8,23 18,48 34,53 56,49 83,66 114,7 148,1 182,0 215,2 246,4 274,8 300,1

5,8 0,64 2,95 8,84 20,19 38,25 63,33 94,73 131,0 170,4 210,9 250,7 288,4 323,1 354,1

5,9 0,65 3,10 9,50 22,07 42,39 71,02 107,3 149,8 196,2 244,4 292,2 337,9 380,2 418,2

6,0 0,67 3,26 10,21 24,13 47,00 79,69 121,6 171,2 226,1 283,5 340,9 396,2 447,7 494,4

6,1 0,68 3,44 10,98 26,39 52,14 89,45 138,0 195,9 260,6 329,0 398,0 464,9 527,7 585,0

6,2 0,70 3,62 11,82 28,87 57,86 100,5 156,5 224,2 300,6 382,1 464,9 546,0 622,5 692,8

6,3 0,72 3,81 12,71 31,60 64,24 112,9 177,7 256,8 347,0 444,0 543,5 641,6 734,9 821,1

6,4 0,73 4,02 13,68 34,60 71,34 126,9 201,7 294,3 400,7 516,3 635,8 754,5 868,3 974,0

6,5 0,75 4,23 14,73 37,90 79,25 142,6 229,2 337,3 463,0 600,6 744,2 887,9 1026,6 1156,3

6,6 0,77 4,46 15,87 41,52 88,07 160,4 260,5 386,9 535,2 699,2 871,6 1045,5 1214,6 1373,8

Pt B, Ch 7, Sec 4


Table 8 : Function ΓC [X+1]

Table 9 : Part of the ship’s life in full load condition

3.1.3 Grinding of welds

In principle, grinding technique for improving fatigue life is applicable only to full penetration welds; applicability is indicated in Tab 11 depending on the weld configuration. For welds other than full penetration welds, grinding may be considered on a case by case basis.

When applicable, grinding of welds is to be regarded as an exceptional measure considered case by case, and only when the design fatigue life cannot be achieved by the design (such as improvement of the shape of cut-outs, sof-tening of bracket toes and local increase in thickness) and geometry of the structural detail.

In such a case:

• the information "grinding of welds", with indication of the toe to be ground, is to be specified by the designer on drawings

• the relevant grinding procedure, according to Ch 12, Sec 2, [3], is to be submitted to the Society by the designer for review

• the fatigue life improvement factor for grinding βIF may, generally, be taken equal to 2,2 provided that a perma-nent protective coating is applied on the ground weld. Otherwise, the value of βIF may be considered by the Society on a case by case basis.

3.1.4 Improvement techniques other than grinding of welds

Improving fatigue life by using improvement techniques other than grinding is to be regarded as an exceptional measure. Such improvement techniques may be considered

by the Society on a case by case basis. In such a case, the fatigue life improvement factor βIF is to be duly justified by the designer.

4 Stress range

4.1 General

4.1.1 Calculation point

Unless otherwise specified, stresses are to be determined at the hot spots indicated, for each detail, in the relevant fig-ures in Ch 12, Sec 2.

4.1.2 Stress components

For the details in [1.1.3], the stresses to be used in the fatigue check are the normal stresses in the directions indicated, for each detail, in the relevant figures in Ch 12, Sec 2.

Where the fatigue check is required for details other than those in [1.1.3], the stresses to be used are the principal stresses at the hot spots which form the smallest angle with the crack rising surface.

4.2 Hot spot stress range

4.2.1 Elementary hot spot stress range

The elementary hot spot stress range ΔσG,ij is to be obtained, in N/mm2, in accordance with:

• Ch 7, App 1, [7] for details where the stresses are to be calculated through a three dimensional structural models

• [6.2] for details located at ends of ordinary stiffeners.

4.3 Notch stress range

4.3.1 Elementary notch stress range

The elementary notch stress range is to be obtained, in N/mm2, from the following formula:

ΔσN,ij = KC,ij ΔσN0,ij

with:

ΔσN0,ij = 0,7 KF Km ΔσG,ij

where:

KF : Fatigue notch factor, equal to:

for flame-cut edges, KF may be taken equal to the values defined in Tab 12, depending on the cut-ting quality, post treatment and control quality

λ : Coefficient depending on the weld configura-tion, and given in Tab 11

θ : Mean weld toe angle, in degrees, without being taken less than 30°. Unless otherwise specified, θ may be taken equal to:

• 30° for butt joints

• 45° for T joints or cruciform joints

X ΓC [X+1] X ΓC [X+1]

2,5 3,323 3,3 8,855

2,6 3,717 3,4 10,136

2,7 4,171 3,5 11,632

2,8 4,694 3,6 13,381

2,9 5,299 3,7 15,431

3,0 6,000 3,8 17,838

3,1 6,813 3,9 20,667

3,2 7,757 4,0 24,000

Service notation Coefficient α

Oil tanker ESPChemical tanker ESPLiquefied gas carrierTankerBulk carrier ESPOre carrier ESPCombination carrier ESP

0,60

Others 0,75

KF λ θ30------=

Pt B, Ch 7, Sec 4


Table 10 : Stress concentration factor Km for misalignment

Geometry Km (1)

Axial misalignment between flat plates

Axial misalignment between flat plates of different thicknesses

Axial misalignment in fillet welded cruciform joints

(1) When the actual misalignment m is lower than the permissible misalignment m0, Km is to be taken equal to 1.Note 1:m : Actual misalignment between two abutting membersm0 : Permissible misalignment for the detail considered, given in Ch 12, Sec 2.

mt1

3 m m0–( )t

--------------------------+

mt2 t1

16 m m0–( )

t1-------------------------- t1

3 2⁄

t13 2⁄ t2

3 2⁄+-----------------------+

m

h

t

1m m0–

t h+------------------+

Pt B, Ch 7, Sec 4


Table 11 : Weld coefficient λ

Weld configurationCoefficient λ Grinding

applicableType Description Stress direction Figure

Butt weld

Parallel to the weld 2,10 yes

Perpendicular tothe weld

2,40 yes

Fillet weld

Continuous

Parallel to the weld 1,80 yes

Perpendicular tothe weld (1)

2,15 yes

Well contoured endPerpendicular to

the weld2,15 yes

Not continuous Parallel to the weld 2,90 yes

Lap weld(root cracking)

Axial loadingout of plane andperpendicular to

the weld

4,50 no

Cruciform joint

Full penetrationPerpendicular to

the weld2,10 yes

Partial penetrationPerpendicular to

the weld

Toe cracking: 2,10

yes

Root cracking: 4,50

no

(1) This case includes the hot spots indicated in the sheets of special structural details in Ch 12, Sec 2 relevant to the connections of longitudinal ordinary stiffeners with transverse primary supporting members.

Pt B, Ch 7, Sec 4


Table 12 : KF values

Km : Stress concentration factor, taking account of misalignment, defined in Tab 10, and to be taken not less than 1,0

ΔσG,ij : Elementary hot spot stress range, defined in[4.2.1]

5 Checking criteria

5.1 Damage ratio

5.1.1 The cumulative damage ratio D calculated according to [3.1.2], is to comply with the following formula:

6 Structural details located at ends of ordinary stiffeners

6.1 General

6.1.1 For the fatigue check of connections located at ends of ordinary stiffeners, the elementary hot spot stress range ΔσG,ij may be calculated as indicated in [6.2].

6.2 Determination of elementary hot spot stress range

6.2.1 Nominal local stressFor each load case “a”, “b”, “c” and “d”, “-max” and “-min”, the nominal local stress σ applied to the ordinary stiffener, is to be obtained, in N/mm2, from the following formula:

where:

w : Net section modulus, in cm3, of the stiffener, with an attached plating of width bp , to be cal-culated as specified in Ch 4, Sec 3, [3.4]


: Span, in m, of ordinary stiffeners, measured between the supporting members, see Ch 4, Sec 3, [3.2].

6.2.2 Elementary hot spot stress rangeFor each load case “a”, “b”, “c” and “d”, the elementary hot spot stress range ΔσG,ij is to be obtained, in N/mm2, from the following formula:

ΔσG, ij = | σG (i-max) − σG (i-min) | + KΔσDEF, ij

where:

σG (i-max) = KN (Kh σh + K KS σ)(i-max)

σG (i-min) = KN (Kh σh + K KS σ)(i-min)

ΔσDEF, ij : Nominal stress range due to the local deflection of the ordinary stiffener to be obtained, in N/mm2, from the following formula:

σh : Nominal hull girder stress for the load case “i-max” or “i-min” considered, to be determined as indicated in [2.3.1]

σ : Nominal local stress for the load case “i-max” or “i-min” considered, to be determined as indi-cated in [6.2.1]

KN : Coefficient taking account of North Atlantic navigation, taken equal to 1,0

KS : Coefficient taking account of the stiffener sec-tion geometry, equal to:

without being taken less than 1,0a, b : Eccentricities of the stiffener, in mm, defined in

Fig 3Bulb sections are to be taken as equivalent to an angle profile, as defined in Ch 4, Sec 3, [3.1.2]with a = 0,75 bf and b = 0,25 bf

Figure 3 : Geometry of a stiffener section

tf : Face plate net thickness, in mmbf : Face plate width, in mmwA, wB : Net section moduli of the stiffener without

attached plating, in cm3, respectively in A and B (see Fig 3), about its neutral axis parallel to the stiffener web

Δδ : Local range of deflection, in mm, of the ordi-nary stiffener

I : Net moment of inertia, in cm4, of the ordinary stiffener with an attached plating of width bp , to be calculated as specified in Ch 4, Sec 3, [3.4].

Flame-cut edge description KF

Machine gas cut edges, with subsequent machining, dressing or grinding

1,4

Machine thermally cut edges, corners removed, no crack by inspection

1,6

Manually thermally cut edges, free from cracks and severe notches

2,0

Manually thermally cut edges, uncontrolled, no notch deeper than 0,5 mm

2,5

KC ij,0 4ReH,ΔσN0 ij,----------------- 0 6,+= with 0,8 KC ij, 1≤ ≤

D 1γR

----≤

σ

γS2pS γW2pW+12w

---------------------------------- 1 s2------–

s2103=

ΔσDEF ij,4 Δδ( )EI

w2

---------------------10 5–=

KS 1tf a2 b2–( )

2wB

------------------------ 1 ba b+------------ 1 wB

wA

-------+ – 10 3–+=

tf

AB

b a

Pt B, Ch 7, App 1


APPENDIX 1 ANALYSES BASED ON THREE DIMENSIONAL MODELS

Symbols

For symbols not defined in this Appendix, refer to the list atthe beginning of this Chapter.

: Sea water density, taken equal to 1,025 t/m3

g : Gravity acceleration, in m/s2:

g = 9,81 m/s2

h1 : Reference values of the ship relative motions inthe upright ship condition, defined in Ch 5, Sec3, [3.3]

h2 : Reference values of the ship relative motions inthe inclined ship conditions, defined in Ch 5,Sec 3, [3.3]

T1 : Draught, in m, corresponding to the loadingcondition considered

MSW : Still water bending moment, in kN.m, at thehull transverse section considered

MWV : Vertical wave bending moment, in kN.m, at thehull transverse section considered, defined inCh 5, Sec 2, [3.1], having the same sign as MSW

QSW : Still water shear force, in kN, at the hull trans-verse section considered

QWV : Vertical wave shear force, in kN, at the hulltransverse section considered, defined in Ch 5,Sec 2, [3.4], having sign:

• where MWV is positive (hogging condition):

positive for x < 0,5 L

negative for x 0,5 L

• where MWV is negative (sagging condition):

negative for x < 0,5 L

positive for x 0,5 L

S1, W1 : Partial safety factors, defined in Ch 7, Sec 3.

1 General

1.1 Application

1.1.1 The requirements of this Appendix apply for the anal-ysis criteria, structural modelling, load modelling and stresscalculation of primary supporting members which are to beanalysed through three dimensional structural models,according to Ch 7, Sec 3.

The analysis application procedure is shown graphically inFig 1.

Figure 1 : Application procedure of the analyses based on three dimensional models

1.1.2 This Appendix deals with that part of the structuralanalysis which aims at:• calculating the stresses in the primary supporting mem-

bers in the midship area and, when necessary, in otherareas, which are to be used in the yielding and bucklingchecks

• calculating the hot spot stress ranges in the structuraldetails which are to be used in the fatigue check.

1.1.3 The yielding and buckling checks of primary support-ing members are to be carried out according to Ch 7, Sec 3. The fatigue check of structural details is to be carried outaccording to Ch 7, Sec 4.

T1

T-----=

Demand Capability of thehull strucuture

3D modelLoading conditionsLoad cases

Light weightStill water loads

Wave loads

Boundary conditions

Calculation of :- deformations,- stresses.

Strenght criteria :- yielding,- buckling.

Adjustment ofscantlings

Yes

Calculation of hotspot stress ranges

Fatigue analysis

Adjustment oflocal details

Yes

ENDof

analysis

Pt B, Ch 7, App 1


2 Analysis criteria

2.1 General

2.1.1 All primary supporting members in the midshipregions are normally to be included in the three dimen-sional model, with the purpose of calculating their stresslevel and verifying their scantlings.

When the primary supporting member arrangement is suchthat the Society can accept that the results obtained for themidship region are extrapolated to other regions, no addi-tional analyses are required. Otherwise, analyses of theother regions are to be carried out.

2.2 Finite element model analyses

2.2.1 The analysis of primary supporting members is to becarried out on fine mesh models, as defined in [3.4.3].

2.2.2 Areas which appear, from the primary supportingmember analysis, to be highly stressed may be required tobe further analysed through appropriately meshed structuralmodels, as defined in [3.4.4].

2.3 Beam model analyses

2.3.1 Beam models may be adopted in cases specified inCh 7, Sec 3, [1.1.2], provided that:

• primary supporting members are not so stout that thebeam theory is deemed inapplicable by the Society

• their behaviour is not substantially influenced by thetransmission of shear stresses through the shell plating.

In any case, finite element models are to be adopted whendeemed necessary by the Society on the basis of the ship’sstructural arrangement.

2.4 Structural detail analysis

2.4.1 Structural details in Ch 7, Sec 4, [1.1.4], for which afatigue analysis is to be carried out, are to be modelled asspecified in [7].

3 Primary supporting members structural modelling

3.1 Model construction

3.1.1 Elements

The structural model is to represent the primary supportingmembers with the plating to which they are connected.

Ordinary stiffeners are also to be represented in the modelin order to reproduce the stiffness and inertia of the actualhull girder structure. The way ordinary stiffeners are repre-sented in the model depends on the type of model (beam orfinite element), as specified in [3.4] and [3.5].

3.1.2 Net scantlingsAll the elements in [3.1.1] are to be modelled with their netscantlings according to Ch 4, Sec 2. Therefore, also the hullgirder stiffness and inertia to be reproduced by the modelare those obtained by considering the net scantlings of thehull structures.

3.2 Model extension

3.2.1 The longitudinal extension of the structural model isto be such that:

• the hull girder stresses in the area to be analysed areproperly taken into account in the structural analysis

• the results in the areas to be analysed are not influencedby the unavoidable inaccuracy in the modelling of theboundary conditions.

3.2.2 In general, for multitank/hold ships more than 170 min length, the conditions in [3.2.1] are considered as beingsatisfied when the model is extended over at least threecargo tank/hold lengths.

For the analysis of the midship area, this model is to be suchthat its aft end corresponds to the first transverse bulkheadaft of the midship, as shown in Fig 2. The structure of thefore and aft transverse bulkheads located within the model,including the bulkhead plating, is to be modelled.

Figure 2 : Model longitudinal extensionShips more than 170 m in length

3.2.3 For ships less than 170 m in length, the model maybe limited to one cargo tank/hold length (one half cargotank/hold length on either side of the transverse bulkhead;see Fig 3).

However, larger models may need to be adopted whendeemed necessary by the Society on the basis of the ship’sstructural arrangement.

Figure 3 : Model longitudinal extensionShips less than 170 m in length

3.2.4 In the case of structural symmetry with respect to theship’s centreline longitudinal plane, the hull structures maybe modelled over half the ship’s breadth.

Length of the model

CL

Length of the model

CL

Pt B, Ch 7, App 1


3.3 Finite element modelling criteria

3.3.1 Modelling of primary supporting members

The analysis of primary supporting members based on finemesh models, as defined in [3.4.3], is to be carried out byapplying one of the following procedures (see Fig 4),depending on the computer resources:

• an analysis of the whole three dimensional model basedon a fine mesh

• an analysis of the whole three dimensional model basedon a coarse mesh, as defined in [3.4.2], from which thenodal displacements or forces are obtained to be usedas boundary conditions for analyses based on fine meshmodels of primary supporting members, e.g.:

- transverse rings

- double bottom girders

- side girders

- deck girders

- primary supporting members of transverse bulk-heads

- primary supporting members which appear from theanalysis of the whole model to be highly stressed.

Figure 4 : Finite element modelling criteria

3.3.2 Modelling of the most highly stressed areas

The areas which appear from the analyses based on finemesh models to be highly stressed may be required to befurther analysed, using the mesh accuracy specified in[3.4.4].

3.4 Finite element models

3.4.1 General

Finite element models are generally to be based on linearassumptions. The mesh is to be executed using membraneor shell elements, with or without mid-side nodes.

Meshing is to be carried out following uniformity criteriaamong the different elements.

Most of quadrilateral elements are to be such that the ratiobetween the longer side length and the shorter side lengthdoes not exceed 2. Some of them may have a ratio notexceeding 4. Their angles are to be greater than 60° and lessthan 120°. The triangular element angles are to be greaterthan 30° and less than 120°.

Further modelling criteria depend on the accuracy level ofthe mesh, as specified in [3.4.2] to [3.4.4].

3.4.2 Coarse mesh

The number of nodes and elements is to be such that thestiffness and inertia of the model properly represent those ofthe actual hull girder structure, and the distribution of loadsamong the various load carrying members is correctly takeninto account.

To this end, the structural model is to be built on the basis ofthe following criteria:

• ordinary stiffeners contributing to the hull girder longitu-dinal strength and which are not individually repre-sented in the model are to be modelled by rod elementsand grouped at regular intervals

• webs of primary supporting members may be modelledwith only one element on their height

• face plates may be simulated with bars having the samecross-section

• the plating between two primary supporting membersmay be modelled with one element stripe

• holes for the passage of ordinary stiffeners or small pipesmay be disregarded

• manholes (and similar discontinuities) in the webs ofprimary supporting members may be disregarded, butthe element thickness is to be reduced in proportion tothe hole height and the web height ratio.

In some specific cases, some of the above simplificationsmay not be deemed acceptable by the Society in relation tothe type of structural model and the analysis performed.

3.4.3 Fine mesh

The ship’s structure may be considered as finely meshedwhen each longitudinal ordinary stiffener is modelled; as aconsequence, the standard size of finite elements used isbased on the spacing of ordinary stiffeners.

Whole three dimensional modelFINE MESH

Whole three dimensional modelCOARSE MESH

Models of primary supportingmembers

FINE MESH

Application of boundaryconditions derived from coarse

mesh model analysis

- yielding check,- buckling check

Strength criteria :

of primary supporting members

(When necessary)

Mesh for the analysis ofhighly stressed areas

Boundary conditionsderived from fine mesh

model analysis

Strength criteria :yielding check of

highly stressed areas

Pt B, Ch 7, App 1


The structural model is to be built on the basis of the follow-ing criteria:

• webs of primary members are to be modelled with atleast three elements on their height

• the plating between two primary supporting members isto be modelled with at least two element stripes

• the ratio between the longer side and the shorter side ofelements is to be less than 3 in the areas expected to behighly stressed

• holes for the passage of ordinary stiffeners may be disre-garded.


3.4.4 Mesh for the analysis of structural details

The structural modelling is to be accurate; the mesh dimen-sions are to be such as to enable a faithful representation ofthe stress gradients. The use of membrane elements is onlyallowed when significant bending effects are not present; inother cases, elements with general behaviour are to beused.

3.5 Beam models

3.5.1 Beams representing primary supporting members

Primary supporting members are to be modelled by beamelements with shear strain, positioned on their neutral axes,whose inertia characteristics are to be calculated as speci-fied in Ch 4, Sec 3, [4].

3.5.2 Torsional moments of inertia

Whenever the torsional effects of the modelling beams areto be taken into account (e.g. for modelling the double bot-tom, hopper tanks and lower stools), their net torsionalmoments of inertia are obtained, in cm4, from the followingformulae:

• for open section beams (see Fig 5):

• for box-type section beams, e.g. those with which hop-per tanks and lower stools are modelled (see Fig 6):

• for beams of double skin structures (see Fig 7):

where:

i : Sum of all the profile segments that constitutethe beam section

ti , i : Net thickness and length, respectively, in mm,of the i-th profile segment of the beam section(see Fig 5 and Fig 6)

: Area, in mm2, of the section enclosed by thebeam box profile (see Fig 6)

t1 , t2 : Net thickness, in mm, of the inner and outerplating, respectively, (see Fig 7)

b1 , b2 : Distances, in mm, from the beam considered tothe two adjacent beams (see Fig 7)

HD : Height, in mm, of the double skin (see Fig 7).

Figure 5 : Open section beams

Figure 6 : Box-type section beams

Figure 7 : Beams of double skin structures

3.5.3 Variable cross-section primary supporting members

In the case of variable cross-section primary supportingmembers, the inertia characteristics of the modelling beamsmay be assumed as a constant and equal to their averagevalue along the length of the elements themselves.

3.5.4 Modelling of primary supporting members ends

The presence of end brackets may be disregarded; in suchcase their presence is also to be neglected for the evaluationof the beam inertia characteristics.

IT13--- ti

3i 10 4–

i

=

IT42

i

ti

---i

-----------10 4–=

ITt1t2 b1 b2+ HD

2

2 t1 t2+ ---------------------------------------10 4–=

�i

�i

Ω

�i�i

t2

t1

b1 b2

HD

Pt B, Ch 7, App 1


Rigid end beams are generally to be used to connect endsof the various primary supporting members, such as:

• floors and side vertical primary supporting members

• bottom girders and vertical primary supporting membersof transverse bulkheads

• cross ties and side/longitudinal bulkhead primary sup-porting members.

3.5.5 Beams representing hull girder characteristics

The stiffness and inertia of the hull girder are to be takeninto account by longitudinal beams positioned as follows:

• on deck and bottom in way of side shell and longitudi-nal bulkheads, if any, for modelling the hull girder bend-ing strength

• on deck, side shell, longitudinal bulkheads, if any, andbottom for modelling the hull girder shear strength.

3.6 Boundary conditions of the whole three dimensional model

3.6.1 Structural model extended over at least three cargo tank/hold lengths

The whole three dimensional model is assumed to be fixedat one end, while shear forces and bending moments areapplied at the other end to ensure equilibrium (see [4]).

At the free end section, rigid constraint conditions are to beapplied to all nodes located on longitudinal members, insuch a way that the transverse section remains plane afterdeformation.

When the hull structure is modelled over half the ship'sbreadth (see [3.2.4]), in way of the ship’s centreline longitu-dinal plane, symmetry or anti-symmetry boundary condi-tions as specified in Tab 1 are to be applied, depending onthe loads applied to the model (symmetrical or anti-sym-metrical, respectively).

Table 1 : Symmetry and anti-symmetry conditionsin way of the ship’s centreline longitudinal plane

3.6.2 Structural models extended over one cargo tank/hold length

Symmetry conditions are to be applied at the fore and aftends of the model, as specified in Tab 2.

Table 2 : Symmetry conditionsat the model fore and aft ends

When the hull structure is modelled over half the ship'sbreadth (see [3.2.4]), in way of the ship’s centreline longitu-dinal plane, symmetry or anti-symmetry boundary condi-tions as specified in Tab 1 are to be applied, depending onthe loads applied to the model (symmetrical or anti-sym-metrical, respectively).

Vertical supports are to be fitted at the nodes positioned inway of the connection of the transverse bulkheads with lon-gitudinal bulkheads, if any, or with sides.

4 Primary supporting members load model

4.1 General

4.1.1 Loading conditions and load cases in intact conditions

The still water and wave loads are to be calculated for themost severe loading conditions as given in the loading man-ual, with a view to maximising the stresses in the longitudi-nal structure and primary supporting members.

The following loading conditions are generally to be con-sidered:

• homogeneous loading conditions at draught T

• non-homogeneous loading conditions at draught T,when applicable

• partial loading conditions at the relevant draught

• ballast conditions at the relevant draught.

The wave local and hull girder loads are to be calculated inthe mutually exclusive load cases “a”, “b”, “c” and “d” inCh 5, Sec 4.

4.1.2 Loading conditions and load cases in flooding conditions

When applicable, the pressures in flooding conditions areto be calculated according to Ch 5, Sec 6, [9].

4.1.3 Lightweight

The structure weight of the modelled portion of the hull is tobe included in the static loads. In order to obtain the actuallongitudinal distribution of the still water bending moment,the lightweight is to be uniformly distributed over the lengthof the model.

Boundaryconditions

DISPLACEMENTS in directions (1)

X Y Z

Symmetry free fixed free

Anti-symmetry fixed free fixed

Boundaryconditions

ROTATION around axes (1)

X Y Z

Symmetry fixed free fixed

Anti-symmetry free fixed free

(1) X, Y and Z directions and axes are defined with respect to the reference co-ordinate system in Ch 1, Sec 2, [4].

DISPLACEMENTSin directions (1):

ROTATIONaround axes (1):

X Y Z X Y Z

fixed free free free fixed fixed


Pt B, Ch 7, App 1


4.1.4 Models extended over half ship’s breadthWhen the ship is symmetrical with respect to her centrelinelongitudinal plane and the hull structure is modelled overhalf the ship's breadth, non-symmetrical loads are to bebroken down into symmetrical and anti-symmetrical loadsand applied separately to the model with symmetry andanti-symmetry boundary conditions in way of the ship’scentreline longitudinal plane (see [3.6]).

4.2 Local loads

4.2.1 GeneralStill water loads include:• the still water sea pressure, defined in Ch 5, Sec 5, [1]• the still water internal loads, defined in Ch 5, Sec 6 for

the various types of cargoes and for ballast.

Wave loads include:• the wave pressure, defined in [4.2.2] for each load case

“a”, “b”, “c” and “d”• the inertial loads, defined in Ch 5, Sec 6 for the various

types of cargoes and for ballast, and for each load case“a”, “b”, “c” and “d”.

4.2.2 Wave loads

The wave pressure at any point of the model is obtainedfrom the formulae in Tab 3 for upright ship conditions (loadcases “a” and “b”) and in Tab 4 for inclined ship conditions(load cases “c” and “d”).

4.2.3 Distributed loads

Distributed loads are to be applied to the plating panels.

In the analyses carried out on the basis of membrane finiteelement models or beam models, the loads distributed per-pendicularly to the plating panels are to be applied on theordinary stiffeners proportionally to their areas of influence.When ordinary stiffeners are not modelled or are modelledwith rod elements (see [3.4]), the distributed loads are to beapplied to the primary supporting members actually sup-porting the ordinary stiffeners.

4.2.4 Concentrated loads

When the elements directly supporting the concentratedloads are not represented in the structural model, the loadsare to be distributed on the adjacent structures according tothe actual stiffness of the structures which transmit them.

Table 3 : Wave pressure in upright ship conditions (load cases “a” and “b”)

Table 4 : Wave pressure in inclined ship conditions (load cases “c” and “d”)


crest trough (1)


Sides above the waterline(z > T1) without being taken, for case “a” only, less than 0,15L

0,0

(1) The wave pressure for load case “b, trough” is to be used only for the fatigue check of structural details (see Ch 7, Sec 4).Note 1:CF1 : Combination factor, to be taken equal to:

• CF1 = 1,0 for load case “a”• CF1 = 0,5 for load case “b”.


y 0 y < 0



without being taken, for case “c” only, less than 0,15L

0,0

(1) In the formulae giving the wave pressure pW, the ratio (y / BW) is not to be taken greater than 0,5.Note 1:CF2 : Combination factor, to be taken equal to:


BW : Moulded breadth, in m, measured at the waterline at draught T1 , at the hull transverse section consideredAR : Roll amplitude, defined in Ch 5, Sec 3, [2.4.1].

CF11 4 gh1e

2 T1 z– –L

------------------------------ CF11 4 – gh1e

2 T1 z– –L

------------------------------

g T1 CF11 4 h1 z–+

CF21 4 g y

BW

-------h1e2 T1 z– –

L------------------------------

ARye T1 z– –

L---------------------------

+CF2

1 4 g yBW

-------h1e2 T1 z– –

L------------------------------

ARye T1 z– –

L---------------------------

+

g T1 CF21 4 y

BW

-------h1 ARy+ z–+

Pt B, Ch 7, App 1


In the analyses carried out on the basis of coarse mesh finiteelement models or beam models, concentrated loadsapplied in five or more points almost equally spaced insidethe same span may be applied as equivalent linearly distrib-uted loads.

4.2.5 Cargo in sacks, bales and similar packages

The vertical loads are comparable to distributed loads. Theloads on vertical walls may be disregarded.

4.2.6 Other cargoes

The modelling of cargoes other than those mentioned under[4.2.3] to [4.2.5] will be considered by the Society on acase by case basis.


4.3.1 Structural model extended over at least three cargo tank/hold lengths

The hull girder loads are constituted by:

• the still water and wave vertical bending moments

• the horizontal wave bending moment

• the still water and wave vertical shear forces,

and are to be applied at the model free end section. Theshear forces are to be distributed on the plating according tothe theory of bidimensional flow of shear stresses.

These loads are to be applied for the following two condi-tions:

• maximal bending moments at the middle of the centraltank/hold within 0,4 L amidships: the hull girder loadsapplied at the free end section are to be such that thevalues of the hull girder loads in Tab 5 are obtained

• maximal shear forces in way of the aft transverse bulk-head of the central tank/hold: the hull girder loadsapplied at the free end section are to be such that thevalues of the hull girder loads in Tab 6 are obtained.

4.3.2 Structural model extended over one cargo tank/hold length

The normal and shear stresses induced by the hull girderloads in Tab 7 are to be added to the stresses induced in theprimary supporting members by local loads.

4.4 Additional requirements for the load assignment to beam models

4.4.1 Vertical and transverse concentrated loads are to beapplied to the model, as shown in Fig 8, to compensate theportion of distributed loads which, due to the positioning ofbeams on their neutral axes, are not modelled.

In this figure, FY and FZ represent concentrated loads equiv-alent to the dashed portion of the distributed loads which isnot directly modelled.

Table 5 : Hull girder loads - Maximal bending moments at the middle of the central tank/hold

Table 6 : Hull girder loads - Maximal shear forces in way of the aft bulkhead of the central tank/hold

Shipcondition

Load case

Vertical bending moments at the middle of the central tank/hold

Horizontal wave bending moment at the middle of the

central tank/hold

Vertical shear forces at themiddle of the central tank/hold

Still water Wave Still water Wave

Upright “a” crest S1 MSW 0,625 W1 MWV,H 0 0 0

“a” trough S1 MSW 0,625 W1 MWV,S 0 0 0

“b” S1 MSW 0,625 W1 MWV,S 0 0 0

Inclined “c” S1 MSW 0,250 W1 MWV 0,625 W1 MWH 0 0

“d” S1 MSW 0,250 W1 MWV 0,625 W1 MWH 0 0

Note 1: Hull girder loads are to be calculated at the middle of the central tank/hold.

Ship condition Load case

Vertical bending moments in way ofthe aft bulkhead of the central tank/hold

Vertical shear forces in way ofthe aft bulkhead of the central tank/hold


Upright “a” crest S1 MSW 0,40 W1 MWV S1 QSW 0,625 W1 QWV

“a” trough S1 MSW 0,40 W1 MWV S1 QSW 0,625 W1 QWV

“b” S1 MSW 0,40 W1 MWV S1 QSW 0,625 W1 QWV

Inclined “c” S1 MSW 0,25 W1 MWV S1 QSW 0,250 W1 QWV

“d” S1 MSW 0,25 W1 MWV S1 QSW 0,250 W1 QWV

Note 1: Hull girder loads are to be calculated in way of the aft bulkhead of the central tank/hold.

Pt B, Ch 7, App 1


Table 7 : Hull girder loads for a structural model extended over one cargo tank/hold length

Figure 8 : Concentrated loadsequivalent to non-modelled distributed loads

5 Stress calculation

5.1 Analyses based on finite element models

5.1.1 Stresses induced by local and hull girder loads

When finite element models extend over at least three cargotank/hold lengths, both local and hull girder loads are to bedirectly applied to the model, as specified in [4.3.1]. In thiscase, the stresses calculated by the finite element programinclude the contribution of both local and hull girder loads.

When finite element models extend over one cargotank/hold length, only local loads are directly applied to thestructural model, as specified in [4.3.2]. In this case, thestresses calculated by the finite element program includethe contribution of local loads only. Hull girder stresses areto be calculated separately and added to the stressesinduced by local loads.


Stress components are generally identified with respect tothe element co-ordinate system, as shown, by way of exam-ple, in Fig 9. The orientation of the element co-ordinate sys-tem may or may not coincide with that of the reference co-ordinate system in Ch 1, Sec 2, [4].

Figure 9 : Reference and element co-ordinate systems

The following stress components are to be calculated at thecentroid of each element:

• the normal stresses 1 and 2 in the directions of the ele-ment co-ordinate system axes

• the shear stress 12 with respect to the element co-ordi-nate system axes

• the Von Mises equivalent stress, obtained from the fol-lowing formula:

5.1.3 Stress calculation points

Stresses are generally calculated by the computer programsfor each element. The values of these stresses are to be usedfor carrying out the checks required.

5.2 Analyses based on beam models

5.2.1 Stresses induced by local and hull girder loads

Since beam models generally extend over one cargotank/hold length (see [2.3.1] and [3.2.3]), only local loadsare directly applied to the structural model, as specified in[4.3.2]. Therefore, the stresses calculated by the beam pro-gram include the contribution of local loads only. Hullgirder stresses are to be calculated separately and added tothe stresses induced by local loads.

Shipcondition

Load case

Vertical bending moments at the middle of the model

Horizontal wave bending moment at the middle of

the model

Vertical shear forces at themiddle of the model


Upright “a” crest S1 MSW 0,625 W1 MWV,H 0 S1 QSW 0,625 W1 QWV

“a” trough S1 MSW 0,625 W1 MWV,S 0 S1 QSW 0,625 W1 QWV

“b” S1 MSW 0,625 W1 MWV,S 0 S1 QSW 0,625 W1 QWV

Inclined “c” S1 MSW 0,250 W1 MWV 0,625 W1 MWH S1 QSW 0,250 W1 QWV

“d” S1 MSW 0,250 W1 MWV 0,625 W1 MWH S1 QSW 0,250 W1 QWV

Note 1: Hull girder loads are to be calculated at the middle of the model.

Fy

Fz

X2

1

Z

Y

X, Y, Z :reference co-ordinate system

Element

VM 12 2

2 12 3122+–+=

Pt B, Ch 7, App 1



The following stress components are to be calculated:

• the normal stress 1 in the direction of the beam axis

• the shear stress 12 in the direction of the local loadsapplied to the beam



Stresses are to be calculated at least in the following pointsof each primary supporting member:

• in the primary supporting member span where the max-imum bending moment occurs

• at the connection of the primary supporting memberwith other structures, assuming as resistant section thatformed by the member, the bracket (if any and if repre-sented in the model) and the attached plating

• at the toe of the bracket (if any and if represented in themodel) assuming as resistant section that formed by themember and the attached plating.

The values of the stresses are to be used for carrying out thechecks required.

6 Buckling assessment based on fine mesh element model

6.1 Buckling panel properties

6.1.1 Yield stress

The buckling panel yield stress ReH is taken as the minimumvalue of the elements yield stresses.

6.1.2 ThicknessIn order to carry out the critical stresses according to Ch 7,Sec 1, [5.3], the net thickness of the buckling panel is to beobtained by deducting tC from the gross thickness.

Where the thickness is not constant across a buckling paneldefined by a number of finite plate elements, an equivalentaverage thickness is calculated according to the followingformula:

where:ti : Thickness, in mm, of the element iAi : Area, in mm2, of the element i.

6.2 Reference stresses

6.2.1 Where the buckling panel is meshed by several finiteplate elements, the stresses of the buckling panel areobtained by the following methodology:

• For each finite element, the stresses (x e, y e

, e)

expressed in the element co-ordinate system are pro-jected in the co-ordinate system of the buckling panel toobtained the stresses (x e , y e , e) (see Fig 10).

• For the buckling panel, the stresses are calculatedaccording to the following formulae:

Figure 10 : Definition of the buckling panel

VM 12 312

2+= tavr

Aiti

1

n

Ai

1

n

----------------=

x

Aix ei

i

n

Ai

i

n

---------------------- 0= y

Aiy ei

i

n

Ai

i

n

---------------------- 0=

Aiei

i

n

Ai

i

n

------------------ 0=

S

σy


Stiffeners

Co-ordinate system ofthe buckling panel

σ x

σy

σ x

Finite element

l

Pt B, Ch 7, App 1


Figure 11 : Buckling check criteria: types a) and b)

Type a) : Commpression according to Ch 7, Sec 1, [5.4.2]

Type b) : Shear according to Ch 7, Sec 1, [5.4.3]

Figure 12 : Buckling check criteria: types c) and d)

Type c) : Compresion and shear according to Ch 7, Sec 1, [5.4.4]

Type d) : Bi-axial compression taking into account of shear stress according to Ch 7, Sec 1, [5.4.5]

σ xPrimary

supportingmembers

Ordinarystiffeners

σy


Ordinarystiffenersσ x

σy


Ordinarystiffeners

τ

τ

a)

b)


Ordinarystiffeners


Ordinarystiffeners

σ x


Ordinarystiffeners

τ τ

τ τ

σy

σyσy

σy

σ x σ xσ x

τ

τ

c)

d)

Pt B, Ch 7, App 1


where:x ei , y ei : Stresses, in N/mm2, of the element i, taken

equal to 0 in case of tensile stress ei : Shear stress, in N/mm2, of the element iAi : Area, in mm2, of the element i.

6.2.2 The edge stress ratio for the stresses (x y) is equalto 1.


6.3.1 The buckling check is to be carried out for four typeof solicitations (see Fig 11 and Fig 12):

a) compression according to Ch 7, Sec 1, [5.4.2]

b) shear according to Ch 7, Sec 1, [5.4.3]

c) compression and shear according to Ch 7, Sec 1, [5.4.4]

d) bi-axial compression taking into account of shear stressaccording to Ch 7, Sec 1, [5.4.5].

7 Fatigue analysis

7.1 Elementary hot spot stress range calculation

7.1.1 GeneralThe requirements of this Article apply for calculating theelementary hot spot stress range for the fatigue check ofstructural details at the connections of primary supportingmembers analysed through a three dimensional structuralmodel. The fatigue check of these details is to be carried outin accordance with the general requirements of Ch 7, Sec 4,[1] to Ch 7, Sec 4, [5].

The definitions in Ch 7, Sec 4, [1.4] apply.

7.1.2 Net scantlingsThe three dimensional structural model is to be built con-sidering all the structures with their net scantlings accordingto Ch 4, Sec 2.

7.1.3 Hot spot stresses directly obtained through finite element analyses

Where the structural detail is analysed through a finite ele-ment analysis based on a very fine mesh, the elementaryhot spot stress range may be obtained as the differencebetween the maximum and minimum stresses induced bythe wave loads in the hot spot considered.

The requirements for:• the finite element modelling, and• the calculation of the hot spot stresses and the hot spot

stress range

are specified in [7.2].

7.1.4 Hot spot stresses directly obtained through the calculation of nominal stresses

Where the structural detail is analysed through a finite ele-ment analysis based on a mesh less fine than that in [7.1.3],the elementary hot spot stress range may be obtained bymultiplying the nominal stress range, obtained as the differ-ence between the maximum and minimum nominal

stresses induced by the wave loads in the vicinity of the hotspot considered, by the appropriate stress concentrationfactors.

The requirements for:

• the finite element modelling

• the calculation of the nominal stresses and the nominalstress range

• the stress concentration factors

• the calculation of the hot spot stresses and the hot spotstress range

are specified in [7.3].

7.2 Hot spot stresses directly obtained through finite element analyses

7.2.1 Finite element modelIn general, the determination of hot spot stresses necessi-tates carrying out a very fine mesh finite element analysis,further to a coarser mesh finite element analysis. Theboundary nodal displacements or forces obtained from thecoarser mesh model are applied to the very fine meshmodel as boundary conditions.

The model extension is to be such as to enable a faithfulrepresentation of the stress gradient in the vicinity of the hotspot and to avoid it being incorrectly affected by the appli-cation of the boundary conditions.

7.2.2 Finite element modelling criteriaThe finite element model is to be built according to the fol-lowing requirements:

• the detail may be considered as being realised with nomisalignment

• the size of finite elements located in the vicinity of thehot spot is to be about once to twice the thickness of thestructural member. Where the details is the connectionbetween two or more members of different thickness,the thickness to be considered is that of the thinnestmember

• the centre of the first element adjacent to a weld toe isto be located between the weld toe and 0,4 times thethickness of the thinnest structural member connectedby the weld

• plating, webs and face plates of primary and secondarymembers are to be modelled by 4-node thin shell or 8-node solid elements. In the case of a steep stress gradi-ent, 8-node thin shell elements or 20-node solid ele-ments are recommended

• when thin shell elements are used, the structure is to bemodelled at mid-face of the plates

• the aspect ratio of elements is to be not greater than 2.

7.2.3 Calculation of hot spot stressesWhen the detail is located at a structural discontinuitywhere a large stress gradient is expected the hot spotstresses are normally obtained by linear extrapolation. Thestress components must be evaluated at a distance of 0,5and 1,5 times the thickness of the plating from the weld toeand linearly extrapolated to the weld toe. The two evalua-tion points must be located in two different finite elements.

Pt B, Ch 7, App 1


In other cases or when extrapolation can not be used thehot spot stresses are to be calculated at the centroid of thefirst element adjacent to the hot spot. The size of this ele-ment has to be determined according to the requirements in[7.2.2].

Where the detail is the free edge of an opening (e.g. a cut-out for the passage of an ordinary stiffener through a pri-mary supporting member), the hot spot stresses have to becalculated at the free edge. The stresses can be obtained bylinear extrapolation or using fictitious truss elements withminimal stiffness fitted along the edge.

The stress components to be considered are those specifiedin Ch 7, Sec 4, [4.1.2]. They are to be calculated at the sur-face of the plate in order to take into account the platebending moment, where relevant.

7.2.4 Calculation of the elementary hot spot stress range

The elementary hot spot stress range is to be obtained, inN/mm2, from the following formula:

where:

S,ij,max ,S,ij,min: Maximum and minimum values of the hotspot stress, induced by the maximum and mini-mum loads, defined in Ch 7, Sec 4, [2.2] andCh 7, Sec 4, [2.3]

i : Denotes the load case

j : Denotes the loading condition.

7.3 Hot spot stresses obtained through the calculation of nominal stresses

7.3.1 Finite element modelA finite element is to be adopted, to be built according tothe requirements in [3.3] and [3.4]. The areas in the vicinityof the structural details are to be modelled with fine meshmodels, as defined in [3.4.3].

7.3.2 Calculation of the elementary nominal stress range

The elementary nominal stress range is to be obtained, inN/mm2, from the following formula:

where:n,ij,max, n,ij,min: Maximum and minimum values of the nom-

inal stress, induced by the maximum and mini-mum loads, defined in Ch 7, Sec 4, [2.2] andCh 7, Sec 4, [2.3]

i : Denotes the load casej : Denotes the loading condition.

7.3.3 Calculation of the elementary hot spot stress range

The elementary hot spot stress range is to be obtained, inN/mm2, from the following formula:

S,ij = KS n,ij

where:KS : Stress concentration factor, defined in Ch 12,

Sec 2, [2], for the relevant detail configurationn,ij : Elementary nominal stress range, defined in

[7.3.2].

S ij, S ij max,, S ij min,,–=

n ij, n ij max,, n ij min,,–=

Pt B, Ch 7, App 2


APPENDIX 2 ANALYSES OF PRIMARY SUPPORTING MEMBERS SUBJECTED TO WHEELED LOADS

1 General

1.1 Scope

1.1.1 The requirements of this Appendix apply to the anal-ysis criteria, structural modelling, load modelling and stresscalculation of primary supporting members subjected towheeled loads which are to be analysed through threedimensional structural models, according to Ch 7, Sec 3.

1.1.2 The purpose of these structural analyses is to deter-mine:

• the distribution of the forces induced by the verticalacceleration acting on wheeled cargoes, among the var-ious primary supporting members of decks, sides andpossible bulkheads

• the behaviour of the above primary supporting membersunder the racking effects due to the transverse forcesinduced by the transverse acceleration acting onwheeled cargoes, when the number or location of trans-verse bulkheads are not sufficient to avoid such effects,

and to calculate the stresses in primary supporting mem-bers.

The above calculated stresses are to be used in the yieldingand buckling checks.

In addition, the results of these analyses may be used,where deemed necessary by the Society, to determine theboundary conditions for finer mesh analyses of the mosthighly stressed areas.

1.1.3 When the behaviour of primary supporting membersunder the racking effects, due to the transverse forcesinduced by the transverse acceleration, is not to be deter-mined, the stresses in deck primary supporting membersmay be calculated according to the simplified analysis in[6], provided that the conditions for its application are ful-filled (see [6.1]).

1.1.4 The yielding and buckling checks of primary support-ing members are to be carried out according to Ch 7, Sec 3,[4.3].

1.2 Application

1.2.1 The requirements of this Appendix apply to shipswhose structural arrangement is such that the followingassumptions may be considered as being applicable:

• primary supporting members of side and possible bulk-heads may be considered fixed in way of the doublebottom (this is generally the case when the stiffness offloors is at least three times that of the side primary sup-porting members)

• under transverse inertial forces, decks behave as beamsloaded in their plane and supported at the ship ends;their effect on the ship transverse rings (side primarysupporting members and deck beams) may therefore besimulated by means of elastic supports in the transversedirection or transverse displacements assigned at thecentral point of each deck beam.

1.2.2 When the assumptions in [1.2.1] are considered bythe Society as not being applicable, the analysis criteria aredefined on a case by case basis, taking into account theship’s structural arrangement and loading conditions. Insuch cases, the analysis is generally to be carried out on thebasis of a finite element model of the whole ship, builtaccording to the requirements in Ch 7, App 1, as far asapplicable.

1.3 Information required

1.3.1 To perform these structural analyses, the followingcharacteristics of vehicles loaded are necessary:

• load per axle

• arrangement of wheels on axles

• tyre dimensions.

1.4 Lashing of vehicles

1.4.1 The presence of lashing for vehicles is generally to bedisregarded, but may be given consideration by the Society,on a case by case basis, at the request of the interested par-ties.

2 Analysis criteria

2.1 Finite element model analyses

2.1.1 For ships greater than 200 m in length, finite elementmodels, built according to Ch 7, App 1, [3.4], are generallyto be adopted.

The analysis of primary supporting members is to be carriedout on fine mesh models, as defined in Ch 7, App 1, [3.4.3].

2.1.2 Areas which appear, from the primary supportingmember analysis, to be highly stressed may be required tobe further analysed through appropriately meshed structuralmodels, as defined in Ch 7, App 1, [3.4.4].

Pt B, Ch 7, App 2


2.2 Beam model analyses

2.2.1 For ships less than 200 m in length, beam models,built according to Ch 7, App 1, [3.5], may be adopted inlieu of the finite element models in [2.1], provided that:

• primary supporting members are not so stout that thebeam theory is deemed inapplicable by the Society

• their behaviour is not substantially influenced by thetransmission of shear stresses through the shell plating.

2.2.2 In any case, finite element models may need to beadopted when deemed necessary by the Society on thebasis of the ship’s structural arrangement.

3 Primary supporting members structural modelling


3.1.1 ElementsThe structural model is to represent the primary supportingmembers with the plating to which they are connected. Inparticular, the following primary supporting members are tobe included in the model:

• deck beams

• side primary supporting members

• primary supporting members of longitudinal and trans-verse bulkheads, if any

• pillars

• deck beams, deck girders and pillars supporting rampsand deck openings, if any.

3.1.2 Net scantlingsAll the elements in [3.1.1] are to be modelled with their netscantlings according to Ch 4, Sec 2, [1].

3.2 Model extension

3.2.1 The structural model is to represent a hull portionwhich includes the zone under examination and which isrepeated along the hull. The non-modelled hull parts are tobe considered through boundary conditions as specified in[3.3].

In addition, the longitudinal extension of the structuralmodel is to be such that the results in the areas to be ana-lysed are not influenced by the unavoidable inaccuracy inthe modelling of the boundary conditions.

3.2.2 Double bottom structures are not required to beincluded in the model, based on the assumptions in [1.2.1].

3.3 Boundary conditions of the three dimen-sional model

3.3.1 Boundary conditions at the lower ends of the model

The lower ends of the model (i.e. the lower ends of primarysupporting members of side and possible bulkheads) are tobe considered as being clamped in way of the inner bottom.

3.3.2 Boundary conditions at the fore and aft ends of the model


Table 1 : Symmetry conditionsat the model fore and aft ends

3.3.3 Additional boundary conditions at the fore and aft ends of models subjected to transverse loads

When the model is subjected to transverse loads, i.e. whenthe loads in inclined ship conditions (as defined in Ch 5,Sec 4) are applied to the model, the transverse displace-ments of the deck beams are to be obtained by means of aracking analysis and applied at the fore and aft ends of themodel, in way of each deck beam.

For ships with a traditional arrangement of fore and aftparts, a simplified approximation may be adopted, whendeemed acceptable by the Society, defining the boundaryconditions without taking into account the racking calcula-tion and introducing springs, acting in the transverse direc-tion, at the fore and aft ends of the model, in way of eachdeck beam (see Fig 1). Each spring, which simulates theeffects of the deck in way of which it is modelled, has a stiff-ness obtained, in kN/m, from the following formula:

where:

JD : Net moment of inertia, in m4, of the averagecross-section of the deck, with the attached sideshell plating

Figure 1 : Springs at the fore and aft endsof models subjected to transverse loads

DISPLACEMENTSin directions (1):

ROTATIONaround axes (1):

X Y Z X Y Z

fixed free free free fixed fixed


RD24EJDsa103

2x4 4LDx3– LD2 x2 15 6

JD

AD

------,+ LD

3 x+ +-----------------------------------------------------------------------------------------------=

RDN

RD3

RD2

RD1

Pt B, Ch 7, App 2


AD : Net area, in m2, of the average cross-section ofdeck plating

sa : Spacing of side vertical primary supportingmembers, in m

x : Longitudinal distance, in m, measured from thetransverse section at mid-length of the model toany deck end

LD : Length of the deck, in m, to be taken equal tothe ship’s length. Special cases in which suchvalue may be reduced will be considered by theSociety on a case by case basis.

4 Load model

4.1 General

4.1.1 Hull girder and local loadsOnly local loads are to be directly applied to the structuralmodel.

The stresses induced by hull girder loads are to be calcu-lated separately and added to the stresses induced by localloads.

4.1.2 Loading conditions and load cases: wheeled cargoes

The still water and wave loads are to be calculated for themost severe loading conditions as given in the loading man-ual, with a view to maximising the stresses in primary sup-porting members.

The loads transmitted by vehicles are to be applied takinginto account the most severe axle positions for the shipstructures.

The wave local loads and hull girder loads are to be calcu-lated in the mutually exclusive load cases “b” and “d” inCh 5, Sec 4. Load cases “a” and “c” may be disregarded forthe purposes of the structural analyses dealt with in thisAppendix.

4.1.3 Loading conditions and load cases: dry uniform cargoes

When the ship’s decks are also designed to carry dry uni-form cargoes, the loading conditions which envisage thetransportation of such cargoes are also to be considered.The still water and wave loads induced by these cargoes areto be calculated for the most severe loading conditions,with a view to maximising the stresses in primary support-ing members.

The wave local loads and hull girder loads are to be calcu-lated in the mutually exclusive load cases “b” and “d” in Ch5, Sec 4. Load cases “a” and “c” may be disregarded for thepurposes of the structural analyses dealt with in this Appen-dix.

4.2 Local loads

4.2.1 GeneralStill water loads include:• the still water sea pressure, defined in Ch 5, Sec 5, [1]• the still water forces induced by wheeled cargoes,

defined in Ch 5, Sec 6, Tab 9.

Wave induced loads include:

• the wave pressure, defined in Ch 5, Sec 5, [2] for loadcases “b” and “d”

• the inertial forces defined in Ch 5, Sec 6, Tab 9 for loadcases “b” and “d”.

When the ship’s decks are also designed to carry dry uni-form cargoes, local loads also include the still water andinertial pressures defined in Ch 5, Sec 6, [4]. Inertial pres-sures are to be calculated for load cases “b” and “d”.

4.2.2 Tyred vehicles

For the purpose of primary supporting members analyses,the forces transmitted through the tyres may be consideredas concentrated loads in the tyre print centre.

The forces acting on primary supporting members are to bedetermined taking into account the area of influence ofeach member and the way ordinary stiffeners transfer theforces transmitted through the tyres.

4.2.3 Non-tyred vehicles

The requirements in [4.2.2] also apply to tracked vehicles.In this case, the print to be considered is that below eachwheel or wheelwork.

For vehicles on rails, the loads transmitted are to be appliedas concentrated loads.

4.2.4 Distributed loads

In the analyses carried out on the basis of beam models ormembrane finite element models, the loads distributed per-pendicularly to the plating panels are to be applied on theprimary supporting members proportionally to their areas ofinfluence.


4.3.1 The normal stresses induced by the hull girder loadsin Tab 2 are to be added to the stresses induced in the pri-mary supporting members by local loads.

Table 2 : Hull girder loads

Shipcondition

Load case

Vertical bending moments at the middle

of the model

Horizontal wave bending moment at the middle of the

modelStill

waterWave

Upright “b” MSW 0,625 MWV,S 0

Inclined “d” MSW 0,25 MWV 0,625 MWH

Note 1:MSW : Still water bending moment at the middle of the

model, for the loading condition considered MWV,S : Sagging wave bending moments at the middle

of the model, defined in Ch 5, Sec 2 MWV : Wave bending moment at the middle of the

model, defined in Ch 5, Sec 2, having the samesign as MSW

MWH : Horizontal wave bending moment at the middleof the model, defined in Ch 5, Sec 2.

Pt B, Ch 7, App 2



5.1 Stresses induced by local and hull girder loads

5.1.1 Only local loads are directly applied to the structuralmodel, as specified in [4.1.1]. Therefore, the stresses calcu-lated by the program include the contribution of local loadsonly. Hull girder stresses are to be calculated separately andadded to the stresses induced by local loads.

5.2 Analyses based on finite element models


Stress components are generally identified with respect tothe element co-ordinate system, as shown, by way of exam-ple, in Fig 2. The orientation of the element co-ordinate sys-tem may or may not coincide with that of the reference co-ordinate system in Ch 1, Sec 2, [4].



• the normal stresses 1 and 2 in the directions of ele-ment co-ordinate system axes




Stresses are generally calculated by the computer programsfor each element. The values of these stresses are to be usedfor carrying out the checks required.

5.3 Analyses based on beam models


The following stress components are to be calculated:

• the normal stress 1 in the direction of the beam axis

• the shear stress 12 in the direction of the local loadsapplied to the beam



Stresses are to be calculated at least in the following pointsof each primary supporting member:

• in the primary supporting member span where the max-imum bending moment occurs

• at the connection of the primary supporting memberwith other structures, assuming as resistant section thatformed by the member, the bracket (if any and if repre-sented in the model) and the attached plating

• at the toe of the bracket (if any and if represented in themodel) assuming as resistant section that formed by themember and the attached plating.

The values of the stresses calculated in the above points areto be used for carrying out the checks required.

6 Grillage analysis of primary supporting members of decks

6.1 Application

6.1.1 For the sole purpose of calculating the stresses indeck primary supporting members, due to the forcesinduced by the vertical accelerations acting on wheeledcargoes, these members may be subjected to the simplifiedtwo dimensional analysis described in [6.2].

This analysis is generally considered as being acceptable forusual structural typology, where there are neither pillarlines, nor longitudinal bulkheads.


6.2.1 Structural model

The structural model used to represent the deck primarysupporting members is a beam grillage model.

6.2.2 Model extension

The structural model is to represent a hull portion whichincludes the zone under examination and which is repeatedalong the hull. The non-modelled hull parts are to be con-sidered through boundary conditions as specified in [3.3].

6.3 Boundary conditions

6.3.1 Boundary conditions at the fore and aft ends of the model


X2

1

Z

Y


Element

VM 12 2

2 12 3122+–+=

VM 12 312

2+=

Pt B, Ch 7, App 2


6.3.2 Boundary conditions at the connections of deck beams with side vertical primary supporting members

Vertical supports are to be fitted at the nodes positioned inway of the connection of deck beams with side primarysupporting members.

The contribution of flexural stiffness supplied by the sideprimary supporting members to the deck beams is to besimulated by springs, applied at their connections, havingrotational stiffness, in the plane of the deck beam webs,obtained, in kN.m/rad, from the following formulae:

• for intermediate decks:

• for the uppermost deck:

where:

1, 2 : Height, in m, of the ‘tweendecks, respectivelybelow and above the deck under examination(see Fig 3)

J1, J2 : Net moments of inertia, in cm4, of side primarysupporting members with attached shell plating,relevant to the ‘tweendecks, respectively belowand above the deck under examination.

6.4 Load model

6.4.1 Hull girder and local loads are to be calculated andapplied to the model according to [4].Wave loads are to be calculated considering load case “b”only.

6.5 Stress calculation

6.5.1 Stress components are to be calculated according to[5.1] and [5.3].

Figure 3 : Heights of ‘tween-decks for grillage analysis of deck primary supporting members

RF3E J1 J2+ 1 2+

12

22

12–+-----------------------------------------------10 5–=

RF6EJ1

1

-----------10 5–= �2

�1

deck under examination

Pt B, Ch 7, App 3


APPENDIX 3 ANALYSES BASED ON COMPLETE SHIP MODELS

Symbols

g : Gravity acceleration, equal to 9,81 m/s2

: Moulded displacement in seawater, in t

B : Moulded breadth, in m

L : Rule length, in m

TR : Roll period, in s, defined in Ch 5, Sec 3, [2.4.1]

F : Froude’s number, defined in Part B, Chapter 5,calculated at the maximum service speed

S1 ,W1 ,S2 ,W2 : Partial safety factors defined in Ch 7, Sec 3

: Wave length, in m.

1 General

1.1 Application

1.1.1 The requirements of this Appendix apply for the anal-ysis criteria, structural modelling, load modelling and stresscalculation of primary supporting members which are to beanalysed through a complete ship model, according to Ch7, Sec 3.

1.1.2 This Appendix deals with that part of the structuralanalysis which aims at calculating the stresses in the pri-mary supporting members and also in the hull plating, to beused for yielding and buckling checks.

1.1.3 The yielding and buckling checks of primary support-ing members are to be carried out according to Ch 7, Sec 3.

2 Structural modelling


2.1.1 Elements

The structural model is to represent the primary supportingmembers with the plating to which they are connected.

Ordinary stiffeners are also to be represented in the modelin order to reproduce the stiffness and the inertia of theactual hull girder structure.

2.1.2 Net scantlings

All the elements in [2.1.1] are to be modelled with their netscantlings according to Ch 4, Sec 2. Therefore, also the hullgirder stiffness and inertia to be reproduced by the modelare those obtained by considering the net scantlings of thehull structures.

2.2 Model extension

2.2.1 The complete ship is to be modelled so that the cou-pling between torsion and horizontal bending is properlytaken into account in the structural analysis.

Superstructures are to be modelled in order to reproducethe correct lightweight distribution.

Long superstructures of ships with one of the service nota-tions passenger ship or ro-ro passenger ship are to be mod-elled in order to also reproduce the correct hull globalstrength, in particular the contribution of each superstruc-ture deck to the hull girder longitudinal strength.

2.2.2 In the case of structural symmetry with respect to theship’s centreline longitudinal plane, the hull structures maybe modelled over half the ship’s breadth.

2.3 Finite element modelling criteria

2.3.1 Modelling of primary supporting members

The analyses of primary supporting members are to be basedon fine mesh models, as defined in Ch 7, App 1, [3.4.3].

Such analyses may be carried out deriving the nodal dis-placements or forces, to be used as boundary conditions,from analyses of the complete ship based on coarsemeshes, as defined in Ch 7, App 1, [3.4.2].

The areas for which analyses based on fine mesh modelsare to be carried out are listed in Tab 1 for various types ofships.

Other areas may be required to be analysed through finemesh models, where deemed necessary by the Society,depending on the ship’s structural arrangement and loadingconditions as well as the results of the coarse mesh analysis.

2.3.2 Modelling of the most highly stressed areas

The areas which appear from the analyses based on finemesh models to be highly stressed may be required to befurther analysed, using the mesh accuracy specified in Ch 7,App 1, [3.4.4].

2.4 Finite element models

2.4.1 General

Finite element models are generally to be based on linearassumptions. The mesh is to be executed using membraneor shell elements, with or without mid-side nodes.

Meshing is to be carried out following uniformity criteriaamong the different elements.

Pt B, Ch 7, App 3


Table 1 : Areas to be analysedthrough fine mesh models

In general, for some of the most common elements, thequadrilateral elements are to be such that the ratio betweenthe longer side length and the shorter side length does notexceed 4 and, in any case, is less than 2 for most elements.Their angles are to be greater than 60° and less than 120°.The triangular element angles are to be greater than 30° andless than 120°.

Further modelling criteria depend on the accuracy level ofthe mesh, as specified in [2.4.2] to [2.4.4].

2.4.2 Coarse mesh

The number of nodes and elements is to be such that thestiffness and the inertia of the model represent properlythose of the actual hull girder structure, and the distributionof loads among the various load carrying members is cor-rectly taken into account.

To this end, the structural model is to be built on the basis ofthe following criteria:

• ordinary stiffeners contributing to the hull girder longitu-dinal strength and which are not individually repre-sented in the model are to be modelled by rod elementsand grouped at regular intervals

• webs of primary supporting members may be modelledwith only one element on their height

• face plates may be simulated with bars having the samecross-section

• the plating between two primary supporting membersmay be modelled with one element stripe

• holes for the passage of ordinary stiffeners or small pipesmay be disregarded

• manholes (and similar discontinuities) in the webs ofprimary supporting members may be disregarded, butthe element thickness is to be reduced in proportion tothe hole height and the web height ratio.


2.4.3 Fine mesh

The ship’s structure may be considered as finely meshedwhen each longitudinal secondary stiffener is modelled; asa consequence, the standard size of finite elements used isbased on the spacing of ordinary stiffeners.

The structural model is to be built on the basis of the follow-ing criteria:

• webs of primary members are to be modelled with atleast three elements on their height

• the plating between two primary supporting members isto be modelled with at least two element stripes

• the ratio between the longer side and the shorter side ofelements is to be less than 3 in the areas expected to behighly stressed

• holes for the passage of ordinary stiffeners may be disre-garded.


2.4.4 Mesh for the analysis of structural details

The structural modelling is to be accurate; the mesh dimen-sions are to be such as to enable a faithful representation ofthe stress gradients. The use of membrane elements is onlyallowed when significant bending effects are not present; inother cases, elements with bending behaviour are to beused.

2.5 Boundary conditions of the model

2.5.1 In order to prevent rigid body motions of the overallmodel, the constraints specified in Tab 2 are to be applied.

2.5.2 When the hull structure is modelled over half theship's breadth (see [2.2.2]), in way of the ship’s centrelinelongitudinal plane, symmetry or anti-symmetry boundaryconditions as specified in Tab 3 are to be applied, depend-ing on the loads applied to the model (respectively symmet-rical or anti-symmetrical).

Service notation Areas

Container ship • typical transverse reinforced frames• hatch corners and hatch coamings of

the strength deck• connection of the cross-deck box

beams to the longitudinal bulkheadsand hatch coamings

• connection of the longitudinal deckgirders to the transverse bulkheads

• end connections of hatch coamingsincluding connection with the forefront of the superstructures, if any

• cut-outs in the longitudinal bulkheads,longitudinal deck girders, hatch coam-ings, and cross-deck box beams.

Ro-ro cargo ship • typical reinforced transverse rings• typical deck girders• areas of structural discontinuity (e.g.

ramp areas).

Passenger ship • areas in way of typical side and deckopenings

• areas of significant discontinuity inprimary supporting member arrange-ments (e.g. in way of lounges, largepublic spaces, theatres).

Ro-ro passenger ship

• typical reinforced transverse rings• typical deck girders• areas of structural discontinuity (e.g.

ramp areas)• areas in way of typical side and deck

openings• areas of significant discontinuity in

primary supporting member arrange-ments (e.g. in way of lounges, largepublic spaces).

Pt B, Ch 7, App 3


Table 2 : Boundary conditionsto prevent rigid body motion of the model

Table 3 : Symmetry and anti-symmetry conditionsin way of the ship’s centreline longitudinal plane

3 Load model

3.1 General

3.1.1 Design wave method

The various load components which occur simultaneouslymay be combined by setting the characteristics of regularwaves that maximise the dominant load parameters given inCh 5.

Any other method may be used provided that relevant doc-umentation is submitted to the Society for review.

A recommended procedure to compute the characteristicsof the design wave is provided in [3.2].

3.1.2 Loads

Still water loads include:


• the still water internal loads, defined in Ch 5, Sec 6 forthe various types of cargoes and for ballast.

Wave loads, determined by mean of hydrodynamic calcula-tions according to [3.2], include:

• the wave pressure

• the inertial loads.

3.1.3 Lightweight

The lightweight of the ship is to be distributed over themodel length, in order to obtain the actual longitudinal dis-tribution of the still water bending moment.

3.1.4 Models extended over half ship’s breadth

When the ship is symmetrical with respect to her centrelinelongitudinal plane and the hull structure is modelled overhalf the ship's breadth, non-symmetrical loads are to bebroken down into symmetrical and anti-symmetrical loadsand applied separately to the model with symmetry andanti-symmetry boundary conditions in way of the ship’scentreline longitudinal plane (see [2.5.2]).

3.2 Procedure for the selection of design waves

3.2.1 Summary of the loading procedure

Applicable cargo loading conditions given in Part D areanalysed through:

• the computation of the characteristics of the finite ele-ment model under still water loads (see [3.3.1])

• the selection of the load cases critical for the strength ofthe resistant structural members (see [3.3.2]).

The determination of the design wave characteristics foreach load case includes the following steps:

• computation of the response operators (amplitude andphase) of the dominant load effect

• selection of the wave length and heading according tothe guidelines in [3.3]

• determination of the wave phase such that the dominantload effect reaches its maximum

• computation of the wave amplitude corresponding tothe design value of the dominant load effect.

3.2.2 Dominant load effects

Each critical load case maximises the value of one of thenine following load effects having a dominant influence onthe strength of some parts of the structure:

• vertical wave bending moment in hogging condition atmidship section

• vertical wave bending moment in sagging condition atmidship section

• vertical wave shear force on transverse bulkheads

Boundary conditions DISPLACEMENTSin directions (1)

X Y Z

One node on the fore end of the ship free fixed fixed

One node on the port side shell at aft end of the ship (2)

fixed free fixed

One node on the starboard side shell at aft end of the ship (2)

free fixed fixed

Boundary conditions ROTATIONaround axes (1)

X Y Z

One node on the fore end of the ship free free free

One node on the port side shell at aft end of the ship (2)

free free free

One node on the starboard side shell at aft end of the ship (2)

free free free

(1) X, Y and Z directions and axes are defined with respectto the reference co-ordinate system in Ch 1, Sec 2, [4].

(2) The nodes on the port side shell and that on the star-board side shell are to be symmetrical with respect tothe ship’s longitudinal plane of symmetry.

Boundaryconditions

DISPLACEMENTS in directions (1)

X Y Z

Symmetry free fixed free

Anti-symmetry fixed free fixed

Boundaryconditions

ROTATION around axes (1)

X Y Z

Symmetry fixed free fixed

Anti-symmetry free fixed free

(1) X, Y and Z directions and axes are defined with respectto the reference co-ordinate system in Ch 1, Sec 2, [4].

Pt B, Ch 7, App 3


• horizontal wave bending moment at midship section

• wave torque within cargo area of ships with large deckopenings

• vertical acceleration in midship and fore body sections

• transverse acceleration at deck at sides at midship sec-tion

• wave pressure at bottom at centreline in upright shipcondition, at midship section

• wave pressure at bottom at side in inclined ship condi-tion, at midship section.

3.2.3 Response Amplitude Operators

The Response Amplitude Operators (RAO’s) and associatedphase characteristics are to be computed for wave periodsbetween 4 and 22 seconds, using a seakeeping program, forthe following motions and load effects:

• heave, sway, pitch, roll and yaw motions

• vertical wave bending moment at 0,50L or at the longi-tudinal position where the bending moment RAO ismaximum

• vertical wave shear force at 0,25L and 0,50L

• horizontal wave bending moment at 0,50L

• wave torque at 0,25L, 0,50L and 0,75L (for ships withlarge deck openings).

The response amplitude operators are to be calculated forwave headings ranging from following seas (0 degree) tohead seas (180 degrees) by increment of 15 degrees, using aship speed of 60% of the maximum service speed.

The amplitude and phase of other dominant load effectsmay be computed at relevant wave period, using the RAO’slisted above.

3.2.4 Design waves

For each load case, the ship is considered to encounter aregular wave, defined by its parameters:

• wave length or period T

• heading angle (see Fig 1)

• wave height (double amplitude)

• wave phase (see Fig 1).

Figure 1 : Wave heading

The wave length and the wave period T are linked by thefollowing relation:

= g T2/ 2

The range of variation of design wave period is between T1and 22 seconds, where T1 is equal to:

The possible wave height H, in m, is limited by the maxi-mum wave steepness according to the relation (see Fig 2):

H = 0,02 g T2

Figure 2 : Allowable range of design waves

3.2.5 Design wave amplitudeThe amplitude of the design wave is obtained by dividingthe design value of the dominant load effect by the value ofthe response amplitude operator of this effect computed forthe relevant heading and wave length.

The design values of load effect, heading and wave lengthare given for each load case in [3.3.2].

When positioning the finite element model of the ship onthe design wave, the amplitude of the wave is to be cor-rected to obtain the design value of the dominant loadeffect in order to take into account the non linear effectsdue to the hull shape and to the pressure distribution abovethe mean water line given in [3.2.7].

The design wave phase is the phase of the dominant loadeffect.

3.2.6 Combined load casesFor the wave characteristics and crest position selectedaccording to [3.2.5], the value of the wave-inducedmotions, accelerations and other load effects is obtained bythe following formula:

Ei = RAOi a cos(d i)

where:Ei : Value of amplitude of the load component iRAOi : Response amplitude operator of the load com-

ponent i computed for the design heading andwave length

a : Design wave amplituded : Phase of the dominant load effecti : Phase of the load component i.

Y

Wave propagationdirectionα = 90˚

α = 0˚ α α = 180˚

X

Phase angle (degrees) = c . 360

F : center of rotation

CREST

CREST

λ

F

ξ

cξλ

T1 2 Bg

-------=

10

20

30

40

5 10 15 20 22

39 156 351 625 756 Wavelength (m)

Period (s)

Wave height (m)

DESIGNWAVE

ALLOWABLERANGE2√πB

g

0.02

gT

2

5

Pt B, Ch 7, App 3


As a rule, the amplitude of the load components computedabove are not to exceed their rule reference value by a fac-tor Cmax given in Tab 4.

Table 4 : Values of factor Cmax

3.2.7 Finite element model loading

The loads are applied to the finite element model accordingto the following indications:

a) For fatigue analysis of structural members located in thevicinity of the mean waterline, the sum of the wave andhydrostatic parts of the pressure is zero above thedeformed wave profile and varies linearly between themean waterline and the wave crest levels.

b) The fluid pressure in tanks is affected by the change ofdirection of the total acceleration vector defined in Ch5, Sec 6, [1.1.3].

c) For dry unit cargoes, the inertial forces are computed atthe centre of mass, taking into account the massmoment of inertia.

d) Inertial loads for structure weight and dry uniform cargoare computed using local accelerations calculated attheir location.

3.2.8 Equilibrium check

The finite element model is to be in equilibrium conditionwith all the still water and wave loads applied.

The unbalanced forces in the three axes are not to exceed2% of the displacement.

The unbalanced moments are not to exceed 2% of .Baround y and z axes and 0,2% of .B around x axis.

3.3 Load cases

3.3.1 Hydrostatic calculation

For each cargo loading condition given in the relevantchapter of Part E, the longitudinal distribution of still watershear force and bending moment is to be computed andchecked by reference to the approved loading manual (seeCh 11, Sec 2).

The convergence of the displacement, trim and verticalbending moment is deemed satisfactory if within the follow-ing tolerances:

• 2% of the displacement

• 0,1 degrees of the trim angle

• 10% of the still water wave bending moment.

3.3.2 Value of load effects

The wave length and heading which maximise each domi-nant load effect are specified in Tab 5. Where two values ofheading angle are indicated in the table, the angle whichcorresponds to the highest peak value of the load effect’sRAO is to be considered. The wave length and heading mayhave to be adjusted in order to fulfil the requirements givenin [3.3.2].

The design value of dominant load effects is specified in Tab6.


4.1 Stress components

4.1.1 Stress components are generally identified withrespect to the element co-ordinate system, as shown, byway of example, in Fig 3. The orientation of the element co-ordinate system may or may not coincide with that of thereference co-ordinate system in Ch 1, Sec 2, [4].


• the normal stresses 1 and 2 in the directions of ele-ment co-ordinate system axes




Load component Cmax

Wave bending moments and wave torque(see Ch 5, Sec 2, [3])

1,10

Wave shear forces(see Ch 5, Sec 2, [3])

1,40

Roll angle, vertical and horizontal accelerations(see Ch 5, Sec 3, [2])

1,10

Wave pressure(see Ch 7, App 1, [4.2.2])

1,20

VM 12 2

2 12 3122+–+=

X2

1

Z

Y


Element

Pt B, Ch 7, App 3


Table 5 : Load cases and load effect values

Load case

Dominant load effect

Wave parameters (1)

Location(s) Notes

Heading angle

1 Vertical wave bendingmoment in hoggingcondition

peak value of vertical wavebending moment RAO withoutbeing less than 0,9L

180° Midship section

2 Vertical wave bendingmoment in saggingcondition

same as load case 1 180° Midship section

3 Vertical wave shearforce

peak value of vertical waveshear force RAO:at 0,5L for 0,35L < x < 0,65Lat 0,25L elsewhere

0° or 180°

Each transversebulkhead

4 Horizontal wave bend-ing moment

peak value of horizontal wavebending moment RAO or 0,5L

120° or 135°

Midship section Select the heading such thatthe value of Cmax for verticalwave bending moment is notexceeded

5 Wave torque peak value of wave torque RAOor 0,5L

60° or 75°

Vicinity of 0,25 LMidship section

Select the heading such thatthe value of Cmax for verticalwave bending moment is notexceeded

6 Wave torque peak value of wave torque RAOwithin the allowable range

90° Midship section Wave amplitude may haveto be limited such that thevalue of Cmax for transverseacceleration and vertical rel-ative motion at sides are notexceeded

7 Wave torque same as load case 5 105° or 120 °

Vicinity of 0,75 LMidship section

Select the heading such thatthe value of Cmax for verticalwave bending moment is notexceeded

8 Vertical acceleration ininclined ship condition

where: C = 1,0 for 90° heading

1,15 for 105° headingCW : Waterplane coefficient at

load waterline

90° or 105°

Midship section

9 Vertical acceleration inupright ship condition

= 1,6 L (0,575 + 0,8 F)2 180° From forward endof cargo area to F.P.

10 Transverse acceleration = 1,35 g TR2 / (2)

without being taken greater than756 m


11 Wave pressure at bot-tom at centreline inupright ship condition

0,7 L 180° or 0°

Midship section may have to be increasedto keep the wave steepnessbelow wave breaking limit

12 Wave pressure at bot-tom at side in inclinedship condition

= 0,35 g TR2 / (2)

without being taken less than2,0B


(1) The forward ship speed is to be taken equal to 0,6 V.

12 3, C

BLCW----------------------=

Pt B, Ch 7, App 3


Table 6 : Dominant load effect values

Dominant load effect Design valueCombined load

componentsReferences

Vertical wave bending moment in hog-ging condition

0,625 W1 MWV ,H

MWV,H defined in Ch 5, Sec 2, [3.1.1]

Vertical wave bending moment in sag-ging condition 0,625 W1 FD MWV ,S

MWV,S defined in Ch 5, Sec 2, [3.1.1]FD defined in Ch 5, Sec 2, [4.2.1]

Vertical wave shear force 0,625 W1 QWV QWV defined in Ch 5, Sec 2, [3.4]

Horizontal wave bending moment 0,625 W1 MWH MWH defined in Ch 5, Sec 2, [3.2.1]

Wave torque (1) 0,625 W1 MWT Horizontal wave bending moment

MT defined in Ch 5, Sec 2, [3.3]

Vertical acceleration at centreline in upright ship condition

W2 aZ1Vertical relative motion at sides at F.E.

aZ1 defined in Ch 5, Sec 3, [3.4.1]

Vertical acceleration at deck at sides in inclined ship condition

W2 aZ2 aZ2 defined in Ch 5, Sec 3, [3.4.1]

Transverse acceleration at deck at sides W2 aY2 Roll angle aY2 defined in Ch 5, Sec 3, [3.4.1]

Wave pressure at bottom at centreline in upright ship condition

W2 pWVertical wave bending moment at midship

pW defined in Ch 7, App 1, Tab 3 for case “a”

Wave pressure at bottom at side in inclined ship condition

W2 pW pW defined in Ch 7, App 1, Tab 4 for case “c”

(1) This load effect is to be considered for ships with large deck openings only.

Pt B, Ch 12, Sec 1


SECTION 1 WELDING AND WELD CONNECTIONS

1 General

1.1 Application

1.1.1 The requirements of this Section apply for the prepa-ration, execution and inspection of welded connections in hull structures.

They are to be complemented by the criteria given in Ch 12, App 1, to which reference is made. These criteria being given as recommendations, minor departures may be accepted by the Society, on a case by case basis.

The general requirements relevant to fabrication by welding and qualification of welding procedures are given in NR216 Materials and Welding, Chapter 5.

1.1.2 Weld connections are to be executed according to the approved plans. A detail not specifically represented in the plans is, if any, to comply with the applicable require-ments.

1.1.3 It is understood that welding of the various types of steel is to be carried out by means of welding procedures approved for the purpose, even though an explicit indica-tion to this effect may not appear on the approved plans.

1.1.4 The quality standard adopted by the shipyard is to be submitted to the Society and applies to all constructions unless otherwise specified on a case by case basis.

1.2 Base material

1.2.1 The requirements of this Section apply for the weld-ing of hull structural steels or aluminium alloys of the types considered in NR216 Materials and Welding or other types accepted as equivalent by the Society.

1.2.2 The service temperature is intended to be the ambient temperature, unless otherwise stated.

1.3 Welding consumables and procedures

1.3.1 Approval of welding consumables and procedures

Welding consumables and welding procedures adopted are to be approved by the Society.

The requirements for the approval of welding consumables are given in NR216 Materials and Welding, Ch 5, Sec 2.

The requirements for the approval of welding procedures are given in NR216 Materials and Welding, Ch 5, Sec 1, NR216 Materials and Welding, Ch 5, Sec 4 and NR216 Materials and Welding, Ch 5, Sec 5.

1.3.2 Consumables

For welding of hull structural steels, the minimum consuma-ble grades to be adopted are specified in Tab 1 depending on the steel grade.

Consumables used for manual or semi-automatic welding (covered electrodes, flux-cored and flux-coated wires) of higher strength hull structural steels are to be at least of hydrogen-controlled grade H15 (H). Where the carbon equivalent Ceq is not more than 0,41% and the thickness is below 30 mm, any type of approved higher strength con-sumables may be used at the discretion of the Society.

Especially, welding consumables with hydrogen-controlled grade H15 (H) and H10 (HH) shall be used for welding hull steel forgings and castings of respectively ordinary strength level and higher strength level.

Table 1 : Consumable grades

1.4 Personnel and equipment

1.4.1 Welders

Welders for manual welding and for semi-automatic weld-ing processes are to be certified by the Society unless other-wise agreed for welders already certified in accordance with a recognised standard accepted by the Society.

Steel grade

Consumable minimum grade

Butt welding, partial and full T penetration welding

Fillet welding

A 1 1

B - D 2

E 3

AH32 - AH36DH32 - DH36

2Y 2Y

EH32 - EH36 3Y

FH32 - FH36 4Y

AH40 2Y40 2Y40

DH40 - EH40 3Y40

FH40 4Y40

Note 1: Welding consumables approved for welding higher strength steels (Y) may be used in lieu of those approved for welding normal strength steels having the same or a lower grade; welding consumables approved in grade Y40 may be used in lieu of those approved in grade Y having the same or a lower grade.Note 2: In the case of welded connections between two hull structural steels of different grades, as regards strength or notch toughness, welding consumables appropriate to one or the other steel are to be adopted.

Pt B, Ch 12, Sec 1


1.4.2 Automatic welding operators

Personnel manning automatic welding machines and equipment are to be competent and sufficiently trained.

1.4.3 Organisation

The internal organisation of the shipyard is to be such as to ensure compliance with the requirements in [1.4.1] and[1.4.2] and to provide for assistance and inspection of welding personnel, as necessary, by means of a suitable number of competent supervisors.

1.4.4 NDE operators

Non-destructive tests are to be carried out by qualified per-sonnel, certified by recognised bodies in compliance with appropriate standards.

The qualifications are to be appropriate to the specific applications.

1.4.5 Technical equipment and facilities

The welding equipment is to be appropriate to the adopted welding procedures, of adequate output power and such as to provide for stability of the arc in the different welding positions.

In particular, the welding equipment for special welding procedures is to be provided with adequate and duly cali-brated measuring instruments, enabling easy and accurate reading, and adequate devices for easy regulation and regu-lar feed.

Manual electrodes, wires and fluxes are to be stored in suit-able locations so as to ensure their preservation in proper condition. Especially, where consumables with hydrogen-controlled grade are to be used, proper precautions are to be taken to ensure that manufacturer’s instructions are fol-lowed to obtain (drying) and maintain (storage, maximum time exposed, re-backing, ...) hydrogen-controlled grade.

1.5 Documentation to be submitted

1.5.1 The structural plans to be submitted for approval, according to Ch 1, Sec 3, are to contain the necessary data relevant to the fabrication by welding of the structures and items represented as far as class is concerned.

For important structures, the main sequences of prefabrica-tion, assembly and welding and non-destructive examina-tion planned are also to be represented in the plans.

1.5.2 A plan showing the location of the various steel types is to be submitted at least for outer shell, deck and bulkhead structures.

1.6 Design

1.6.1 General

For the various structural details typical of welded construc-tion in shipbuilding and not dealt with in this Section, the rules of good practice, recognised standards and past expe-rience are to apply as agreed by the Society.

1.6.2 Plate orientationThe plates of the shell and strength deck are generally to be arranged with their length in the fore-aft direction. Possible exceptions to the above will be considered by the Society on a case-by-case basis; tests as deemed necessary (for example, transverse impact tests) may be required by the Society.

1.6.3 Overall arrangement Particular consideration is to be given to the overall arrange-ment and structural details of highly stressed parts of the hull.

Plans relevant to the special details specified in Ch 12, Sec 2 are to be submitted.

1.6.4 Prefabrication sequences Prefabrication sequences are to be arranged so as to facili-tate positioning and assembling as far as possible.

The amount of welding to be performed on board is to be limited to a minimum and restricted to easily accessible connections.

1.6.5 Distance between weldsWelds located too close to one another are to be avoided. The minimum distance between two adjacent welds is con-sidered on a case by case basis, taking into account the level of stresses acting on the connected elements.

In general, the distance between two adjacent butts in the same strake of shell or deck plating is to be greater than two frame spaces.

2 Type of connections and preparation

2.1 General

2.1.1 The type of connection and the edge preparation are to be appropriate to the welding procedure adopted, the structural elements to be connected and the stresses to which they are subjected.

2.2 Butt welding

2.2.1 General In general, butt connections of plating are to be full penetra-tion, welded on both sides except where special procedures or specific techniques, considered equivalent by the Soci-ety, are adopted.

Connections different from the above may be accepted by the Society on a case by case basis; in such cases, the rele-vant detail and workmanship specifications are to be approved.

2.2.2 Welding of plates with different thicknesses In the case of welding of plates with a difference in gross thickness equal to or greater than:

• 3 mm, if the thinner plate has a gross thickness equal to or less than 10 mm

• 4 mm, if the thinner plate has a gross thickness greater than 10 mm,

Pt B, Ch 12, Sec 1


a taper having a length of not less than 4 times the differ-ence in gross thickness is to be adopted for connections of plating perpendicular to the direction of main stresses. For connections of plating parallel to the direction of main stresses, the taper length may be reduced to 3 times the dif-ference in gross thickness.

When the difference in thickness is less than the above val-ues, it may be accommodated in the weld transition between plates.

2.2.3 Edge preparation, root gap

Typical edge preparations and gaps are indicated in Ch 12, App 1, [1.2].

The acceptable root gap is to be in accordance with the adopted welding procedure and relevant bevel preparation.

2.2.4 Butt welding on permanent backing

Butt welding on permanent backing, i.e. butt welding assembly of two plates backed by the flange or the face plate of a stiffener, may be accepted where back welding is not feasible or in specific cases deemed acceptable by the Society.

The type of bevel and the gap between the members to be assembled are to be such as to ensure a proper penetration of the weld on its backing and an adequate connection to the stiffener as required.

2.2.5 Section, bulbs and flat bars

When lengths of longitudinals of the shell plating and strength deck within 0,6 L amidships, or elements in general subject to high stresses, are to be connected together by butt joints, these are to be full penetration. Other solutions may be adopted if deemed acceptable by the Society on a case by case basis.

The work is to be done in accordance with an approved procedure; in particular, this requirement applies to work done on board or in conditions of difficult access to the welded connection. Special measures may be required by the Society.

Welding of bulbs without a doubler is to be performed by welders specifically certified by the Society for such type of welding.

2.3 Fillet welding

2.3.1 Fillet welding types

Fillet welding may be of the following types:

• continuous fillet welding, where the weld is constituted by a continuous fillet on each side of the abutting plate (see [2.3.2])

• intermittent fillet welding, which may be subdivided (see [2.3.3]) into:

- chain welding

- scallop welding

- staggered welding.

2.3.2 Continuous fillet welding

Continuous fillet welding is to be adopted:

• for watertight connections

• for connections of brackets, lugs and scallops

• at the ends of connections for a length of at least 75mm

• where intermittent welding is not allowed, according to[2.3.3].

Continuous fillet welding may also be adopted in lieu of intermittent welding wherever deemed suitable, and it is recommended where the spacing p, calculated according to [2.3.3], is low.

2.3.3 Intermittent welding

The spacing p and the length d, in mm, of an intermittent weld, shown in:

• Fig 1, for chain welding

• Fig 2, for scallop welding

• Fig 3, for staggered welding

are to be such that:

where the coefficient ϕ is defined in Tab 2 and Tab 3 for the different types of intermittent welding, depending on the type and location of the connection.

In general, staggered welding is not allowed for connec-tions subjected to high alternate stresses.

In addition, the following limitations are to be complied with:

• chain welding (see Fig 1):

d ≥ 75 mm

p − d ≤ 200 mm

Figure 1 : Intermittent chain welding

• scallop welding (see Fig 2):

d ≥ 75 mm

p − d ≤ 150 mm

v ≤ 0,25 b without being greater than 75 mm

Figure 2 : Intermittent scallop welding

pd--- ϕ≤

dp

dp

v b

Pt B, Ch 12, Sec 1


• staggered welding (see Fig 3):d ≥ 75 mmp − 2d ≤ 300 mm p ≤ 2d for connections subjected to high alternate stresses.

Figure 3 : Intermittent staggered welding

2.3.4 Throat thickness of fillet weld T connections The throat thickness of fillet weld T connections is to be obtained, in mm, from the following formula:

where:wF : Welding factor, defined in Tab 2 for the various

hull structural connections; for connections of primary supporting members belonging to sin-gle skin structures and not mentioned in Tab 2, wF is defined in Tab 3; for some connections of specific ship types, the values of wF specified inPart D for these ship types are to be used in lieu of the corresponding values in Tab 2 or Tab 3

t : Thickness, in mm, of the thinner plate in the considered assembly

p, d : Spacing and length, in mm, of an intermittent weld, defined in [2.3.3].

For continuous fillet welds, p/d is to be taken equal to 1.

Table 2 : Welding factors wF and coefficient ϕ for the various hull structural connections

dp

tT wFtpd---=

Hull areaConnection

wF (1)ϕ (2) (3) p1, in mm

(see [2.3.5]) (3)

of to CH SC ST

General, unless

otherwise specified

in the table

watertight plates boundaries 0,35webs of ordinarystiffeners

plating at ends (4) 0,13elsewhere 0,13 3,5 3,0 4,6 ST 260

face plate of fabricated stiffeners

at ends (4) 0,13elsewhere 0,13 3,5 3,0 4,6 ST 260

Bottomand

doublebottom

longitudinal ordinary stiffeners

bottom and inner bottom plating (6) 0,13 3,5 3,0 4,6 ST 260

centre girder keel 0,25 1,8 1,8 CH/SC 130inner bottom plating 0,20 2,2 2,2 CH/SC 160

side girders bottom and inner bottom plating 0,13 3,5 3,0 4,6 ST 260floors (interrupted girders) 0,20 2,2 CH 160

floors bottom and inner bottom plating

in general 0,13 3,5 3,0 4,6 ST 260at ends (20% of span) for longitudinally framed double bottom

0,25 1,8 CH 130

inner bottom plating in way of brackets of primary supporting members

0,25 1,8 CH 130

girders (interrupted floors) 0,20 2,2 CH 160side girders in way of hopper tanks 0,35

partial side girders floors 0,25 1,8 CH 130web stiffeners floor and girder webs 0,13 3,5 3,0 4,6 ST 260

Side and inner side

ordinary stiffeners side and inner side plating 0,13 3,5 3,0 4,6 ST 260girders and web frames in double side skin ships

side and inner side plating 0,35

Deck strength deck (5) side plating wF = 0,45 if t ≤ 15 mmPartial penetration welding if t>15mm

non-watertight decks side plating 0,20 2,2 CH 160ordinary stiffeners and intercostal girders

deck plating 0,13 3,5 3,0 4,6 ST 260

hatch coamings deck plating in general 0,35at corners of hatchways for 15% of the hatch length

0,45

web stiffeners coaming webs 0,13 3,5 3,0 4,6 ST 260

Pt B, Ch 12, Sec 1


Bulkheads tank bulkheadstructures

tank bottom plating and ordinary stiffeners(plane bulkheads)

0,45

vertical corrugations (corrugated bulkheads)

Full penetration welding, in general

boundaries other than tank bottom 0,35watertight bulkhead structures

boundaries 0,35

non-watertightbulkhead structures

boundaries wash bulkheads 0,20 2,2 2,2 CH/SC 160others 0,13 3,5 3,0 4,6 ST 260

ordinary stiffeners bulkheadplating

in general (6) 0,13 3,5 3,0 4,6 ST 260at ends (25% of span), where no end brackets are fitted

0,35

Structures located

forward of 0,75 L fromthe AE (7)

bottom longitudinal ordinary stiffeners

bottom plating 0,20 2,2 CH 160

floors and girders bottom and inner bottom plating 0,25 1,8 CH 130side frames in panting area

side plating 0,20 2,2 CH 160

webs of side girdersin single side skin structures

side plating and face plate

A < 65 cm2 (8) 0,25 1,8 1,8 CH/SC 130

A ≥ 65 cm2 (8) See Tab 3

After peak (7)

internal structures each other 0,20side ordinary stiffeners side plating 0,20floors bottom and inner bottom plating 0,20

Machinery space (7)

centre girder keel and inner bottom plating

in way of main engine foundations

0,45

in way of seating of auxiliary machinery and boilers

0,35

elsewhere 0,25 1,8 1,8 CH/SC 130side girders bottom and

inner bottom plating

in way of main engine foundations

0,45


0,35

elsewhere 0,20 2,2 2,2 CH/SC 160floors (except in wayof main enginefoundations)

bottom and inner bottom plating


0,35

elsewhere 0,20 2,2 2,2 CH/SC 160floors in way of main engine foundations

bottom plating 0,35foundation plates 0,45

floors centre girder single bottom 0,45double bottom 0,25 1,8 1,8 CH/SC 130

Super-structures

anddeckhouses

external bulkheads deck in general 0,35engine and boiler cas-ings at corners of open-ings (15% of opening length)

0,45

internal bulkheads deck 0,13 3,5 3,0 4,6 ST 260ordinary stiffeners external and internal bulkhead plating 0,13 3,5 3,0 4,6 ST 260

Hatch covers ordinary stiffener plating 0,13 3,5 3,0 4,6 ST 260

Hull areaConnection

wF (1)ϕ (2) (3) p1, in mm

(see [2.3.5]) (3)

of to CH SC ST

Pt B, Ch 12, Sec 1


The throat thickness of the fillet welds is not to be less than:

• 3,5 mm as a rule, whether the welds is continuous or intermittent

• 3,0 mm in the case of automatic or semi-automatic deep penetration weld.

For plating thickness of less than 6 mm, the throat thickness of the fillet welds is not to be less than:

• 3,0 mm as a rule, whether the welds is continuous or intermittent

• 2,5 mm in the case of automatic or semi-automatic deep penetration weld.

In the case of automatic or semi-automatic deep penetra-tion weld, the throat thickness may be reduced according to[2.3.8].

The throat thickness may be required by the Society to be increased, depending on the results of structural analyses.

The leg length of fillet weld T connections is to be not less than 1,4 times the required throat thickness.

2.3.5 Weld dimensions in a specific case

Where intermittent fillet welding is adopted with:

• length d = 75 mm

• throat thickness tT specified in Tab 4 depending on the thickness t defined in [2.3.4],

the weld spacing may be taken equal to the value p1

defined in Tab 2. The values of p1 in Tab 2 may be used when 8 ≤ t ≤ 16 mm.

For thicknesses t less than 8 mm, the values of p1 may be increased, with respect to those in Tab 2, by:

• 10 mm for chain or scallop welding

• 20 mm for staggered welding,

without exceeding the limits in [2.3.3].

For thicknesses t greater than 16 mm, the values of p1 are to be reduced, with respect to those in Tab 2, by:

• 10 mm for chain or scallop welding

• 20 mm for staggered welding.

2.3.6 Throat thickness of welds between cut-outs

The throat thickness of the welds between the cut-outs in primary supporting member webs for the passage of ordi-nary stiffeners is to be not less than the value obtained, in mm, from the following formula:

where:

tT : Throat thickness defined in [2.3.4]

ε, λ : Dimensions, in mm, to be taken as shown in:

• Fig 4 for continuous welding

• Fig 5 for intermittent scallop welding.

Pillars elements composing the pillar section

each other (fabricated pillars) 0,13

pillars deck pillars in compression 0,35pillars in tension Full penetration welding

Ventilators coamings deck 0,35Rudders horizontal and vertical

webs directly conected to solid parts

each other 0,45

other webs each other 0,20 2,2 SC 160webs plating in general 0,20 2,2 SC 160

top and bottom plates of rudder plating

0,35

solid parts or rudder stock According to Ch 10, Sec 1, [7.4] or Ch 10, Sec 1, [7.5]

(1) In connections for which wF ≥ 0,35, continuous fillet welding is to be adopted. (2) For coefficient ϕ, see [2.3.3]. In connections for which no ϕ value is specified for a certain type of intermittent welding, such

type is not permitted and continuous welding is to be adopted.(3) CH = chain welding, SC = scallop welding, ST = staggered welding. (4) The web at the end of intermittently welded girders or stiffeners is to be continuously welded to the plating or the flange plate,

as applicable, over a distance d at least equal to the depth h of the girder or stiffeners, with 300 mm ≥ d ≥ 75 mm. Where end brackets are fitted, ends means the area extended in way of brackets and at least 50 mm beyond the bracket toes.

(5) Fillet weld of 5 mm is acceptable for ships of less than 90 m in length if thicknesses of strength deck and shell plating are less than 10 mm and if shell plating extends over the strength deck by more than 50 mm.

(6) In tanks intended for the carriage of ballast or fresh water, continuous welding with wF = 0,35 is to be adopted.(7) For connections not mentioned, the requirements for the central part apply.(8) A is the face plate sectional area of the side girders, in cm2.

Hull areaConnection

wF (1)ϕ (2) (3) p1, in mm

(see [2.3.5]) (3)

of to CH SC ST

tTC tTελ---=

Pt B, Ch 12, Sec 1


Figure 4 : Continuous fillet weldingbetween cut-outs

Figure 5 : Intermittent scallop fillet weldingbetween cut-outs

Table 3 : Welding factors wF and coefficient ϕ for connections of primary supporting members

Throat thickness a

λε

λ1 λ2 λ3 λ=∑(λi)ε

Throat thickness a


ConnectionwF (1)

ϕ (2) (3) p1, in mm(see [2.3.5]) (3)of to CH SC ST

General (4) web, where A < 65 cm2

plating andface plate

at ends 0,20

elsewhere 0,15 3,0 3,0 CH/SC 210

web,where A ≥ 65 cm2

plating 0,35

face plate at ends 0,35


end brackets face plate 0,35

In tanks,where A < 65 cm2 (5)

web plating at ends 0,25


face plate at ends 0,20



In tanks,where A ≥ 65 cm2

web plating at ends 0,45

elsewhere 0,35

face plate 0,35


(1) In connections for which wF ≥ 0,35, continuous fillet welding is to be adopted. (2) For coefficient ϕ, see [2.3.3]. In connections for which no ϕ value is specified for a certain type of intermittent welding, such

type is not permitted.(3) CH = chain welding, SC = scallop welding, ST = staggered welding. (4) For cantilever deck beams, continuous welding is to be adopted.(5) For primary supporting members in tanks intended for the carriage of ballast or fresh water, continuous welding is to be

adopted.Note 1:A is the face plate sectional area of the primary supporting member, in cm2. Note 2:Ends of primary supporting members means the area extended 20% of the span from the span ends. Where end brackets are fitted, ends means the area extended in way of brackets and at least 100 mm beyond the bracket toes.

Pt B, Ch 12, Sec 1


Table 4 : Required throat thickness

2.3.7 Throat thickness of welds connecting ordinary stiffeners with primary supporting members

The throat thickness of fillet welds connecting ordinary stiff-eners and collar plates, if any, to the web of primary sup-porting members is to be not less than 0,35 tW, where tW is the web gross thickness, in mm. Further requirements are specified in Ch 12, Sec 2.

Where primary supporting member web stiffeners are welded to ordinary stiffener face plates, in certain cases the Society may require the above throat thickness to be obtained, in mm, from the following formula:

where:

k : Material factor of the steel used, defined in Ch 4, Sec 1, [2.3]

pS, pW : Still water and wave pressure, respectively, in kN/m2, acting on the ordinary stiffener, defined in Ch 7, Sec 2, [3.3.2]

γS2, γW2 : Partial safety factors defined in Ch 7, Sec 2, [1.2.1]

k1 : Coefficient depending on the connection of the primary supporting member web with the ordi-nary stiffener, taken equal to:

• k1 = 0, when there is no primary supporting member web stiffener in way of the ordinary stiffener

• the value defined in Ch 4, Sec 3, [4.7.2], when there is a primary supporting member web stiffener in way of the ordinary stiffener

b,c,d,u,v: Main dimensions, in mm, of the cut-out shown in Fig 6.

Figure 6 : End connection of ordinary stiffenerDimensions of the cut-out

2.3.8 Throat thickness of deep penetration fillet welding

When fillet welding is carried out with automatic welding procedures, the throat thickness required in [2.3.4] may be reduced up to 15%, depending on the properties of the electrodes and consumables. However, this reduction may not be greater than 1,5 mm.

The same reduction applies also for semi-automatic proce-dures where the welding is carried out in the downhand position.

2.4 Partial and full T penetration welding

2.4.1 GeneralPartial or full T penetration welding is to be adopted for connections subjected to high stresses for which fillet weld-ing is considered unacceptable by the Society.

Partial or full T penetration welding is required, in any event, where indicated for the connections specified in Part D depending on the ship type. Further requirements are specified in Ch 12, Sec 2.

Typical edge preparations are indicated in:

• for partial penetration welds: Fig 7 and Fig 8, in which f, in mm, is to be taken between 3 mm and t/3, and αbetween 45° and 60°

• for full penetration welds: Fig 9 and Fig 10, in which f, in mm, is to be taken between 0 and 3 mm, and αbetween 45° and 60°

Back gouging is generally required for full penetration welds.

Figure 7 : Partial penetration weld

t, in mm tT , in mm t, in mm tT , in mm

6 3,0 17 7,0

8 3,5 18 7,0

9 4,0 19 7,5

10 4,5 20 7,5

11 5,0 21 8,5

12 5,5 22 8,5

13 6,0 23 9,0

14 6,0 24 9,0

15 6,5 25 10,0

16 6,5 26 10,0

tT

4k γS2pS γW2pW+( )s 1 s2------–

1 k1–( )

u v c 0 2d,+b 0 2d,+---------------------- +

----------------------------------------------------------------------------------------------=

c

uv

d

c b

T

f

� �

Pt B, Ch 12, Sec 1


Figure 8 : Partial penetration weld

Figure 9 : Full penetration weld

Figure 10 : Full penetration weld

2.4.2 Lamellar tearing

Precautions are to be taken in order to avoid lamellar tears, which may be associated with:

• cold cracking when performing T connections between plates of considerable thickness or high restraint

• large fillet welding and full penetration welding on higher strength steels.

2.5 Lap-joint welding

2.5.1 General

Lap-joint welding may be adopted for:

• peripheral connection of doublers

• internal structural elements subjected to very low stresses.

Elsewhere, lap-joint welding may be allowed by the Society on a case by case basis, if deemed necessary under specific conditions.

Continuous welding is generally to be adopted.

2.5.2 GapThe surfaces of lap-joints are to be in sufficiently close con-tact.

2.5.3 Dimensions The dimensions of the lap-joint are to be specified and are considered on a case by case basis. Typical details are given in Ch 12, App 1, [1.3].

2.6 Slot welding

2.6.1 GeneralSlot welding may be adopted in very specific cases subject to the special agreement of the Society, e.g. for doublers according to Ch 4, Sec 3, [2.1].

In general, slot welding of doublers on the outer shell and strength deck is not permitted within 0,6L amidships. Beyond this zone, slot welding may be accepted by the Society on a case by case basis.

Slot welding is, in general, permitted only where stresses act in a predominant direction. Slot welds are, as far as possi-ble, to be aligned in this direction.

2.6.2 DimensionsSlot welds are to be of appropriate shape (in general oval) and dimensions, depending on the plate thickness, and may not be completely filled by the weld.

Typical dimensions of the slot weld and the throat thickness of the fillet weld are given in Ch 12, App 1, [1.3].

The distance between two consecutive slot welds is to be not greater than a value which is defined on a case by case basis taking into account:

- the transverse spacing between adjacent slot weld lines

- the stresses acting in the connected plates

- the structural arrangement below the connected plates.

2.7 Plug welding

2.7.1 Plug welding may be adopted only when accepted by the Society on a case by case basis, according to specifi-cally defined criteria. Typical details are given in Ch 12, App 1, [1.3].

3 Specific weld connections

3.1 Corner joint welding

3.1.1 Corner joint welding, as adopted in some cases at the corners of tanks, performed with ordinary fillet welds, is permitted provided the welds are continuous and of the required size for the whole length on both sides of the joint.

3.1.2 Alternative solutions to corner joint welding may be considered by the Society on a case by case basis.

�

�

�

�

�

��

�

��

Pt B, Ch 12, Sec 1


3.2 Bilge keel connection

3.2.1 The intermediate flat, through which the bilge keel is connected to the shell according to Ch 4, Sec 4, [6], is to be welded as a shell doubler by continuous fillet welds.

The butt welds of the doubler and bilge keel are to be full penetration and shifted from the shell butts.

The butt welds of the bilge plating and those of the doublers are to be flush in way of crossing, respectively, with the doubler and with the bilge keel.

Butt welds of the intermediate flat are to be made to avoid direct connection with the shell plating, in order that they do not alter the shell plating, by using, for example, a cop-per or a ceramic backing.

3.3 Struts connecting ordinary stiffeners

3.3.1 In case of a strut connected by lap joint to the ordi-nary stiffener, the throat thickness of the weld is to be obtained, in mm, from the following formula:

where:

F : Maximum force transmitted by the strut, in kN

η : Safety factor, to be taken equal to 2

n : Number of welds in way of the strut axis

W : Length of the weld in way of the strut axis, in mm

τ : Permissible shear stress, to be taken equal to 100 N/mm2.

3.4 Connection between propeller post and propeller shaft bossing

3.4.1 Fabricated propeller posts are to be welded with full penetration welding to the propeller shaft bossing.

3.5 Bar stem connections

3.5.1 The bar stem is to be welded to the bar keel generally with butt welding.

The shell plating is also to be welded directly to the bar stem with butt welding.

3.6 Deck subjected to wheeled loads

3.6.1 Double continuous fillet welding is to be adopted for the connections of ordinary stiffeners with deck plating.

4 Workmanship

4.1 Welding procedures and consumables

4.1.1 The various welding procedures and consumables are to be used within the limits of their approval and in

accordance with the conditions of use specified in the respective approval documents.

4.2 Welding operations

4.2.1 Weather protection

Adequate protection from the weather is to be provided to parts being welded; in any event, such parts are to be dry.

In welding procedures using bare, cored or coated wires with gas shielding, the welding is to be carried out in weather protected conditions, so as to ensure that the gas outflow from the nozzle is not disturbed by winds and draughts.

4.2.2 Butt connection edge preparation

The edge preparation is to be of the required geometry and correctly performed. In particular, if edge preparation is car-ried out by flame, it is to be free from cracks or other detri-mental notches.

4.2.3 Surface condition

The surfaces to be welded are to be free from rust, moisture and other substances, such as mill scale, slag caused by oxygen cutting, grease or paint, which may produce defects in the welds.

Effective means of cleaning are to be adopted particularly in connections with special welding procedures; flame or mechanical cleaning may be required.

The presence of a shop primer may be accepted, provided it has been approved by the Society.

Shop primers are to be approved by the Society for a spe-cific type and thickness according to NR216 Materials and Welding, Ch 5, Sec 3.

4.2.4 Assembling and gap

The setting appliances and system to be used for positioning are to ensure adequate tightening adjustment and an appro-priate gap of the parts to be welded, while allowing maxi-mum freedom for shrinkage to prevent cracks or other defects due to excessive restraint.

The gap between the edges is to comply with the required tolerances or, when not specified, it is to be in accordance with normal good practice.

4.2.5 Gap in fillet weld T connections

In fillet weld T connections, a gap g, as shown in Fig 11, not greater than 2 mm may be accepted without increasing the throat thickness calculated according to [2.3.4] or [2.3.7], as applicable.

In the case of a gap greater than 2 mm, the above throat thickness is to be increased accordingly as specified in Ch 12, Sec 2 for some special connections of various ship types.

In any event, the gap g may not exceed 4 mm.

tTηF

nWτ-------------103=

Pt B, Ch 12, Sec 1


Figure 11 : Gap in fillet weld T connections

4.2.6 Plate misalignment in butt connections The misalignment m, measured as shown in Fig 12, between plates with the same gross thickness t is to be less than 0,15t, without being greater than 3 mm.

Figure 12 : Plate misalignment in butt connections

4.2.7 Misalignment in cruciform connectionsThe misalignment m in cruciform connections, measured on the median lines as shown in Fig 13, is to be less than:• t/2, in general, where t is the gross thickness of the thin-

ner abutting plate • the values specified in Ch 12, Sec 2 for some special

connections of various ship types.

The Society may require lower misalignment to be adopted for cruciform connections subjected to high stresses.

Figure 13 : Misalignment in cruciform connections

4.2.8 Assembling of aluminium alloy partsWhen welding aluminium alloy parts, particular care is to be taken so as to:

• reduce as far as possible restraint from welding shrink-age, by adopting assembling and tack welding proce-dures suitable for this purpose

• keep possible deformations within the allowable limits.

4.2.9 Preheating and interpass temperaturesSuitable preheating, to be maintained during welding, and slow cooling may be required by the Society on a case by case basis.

4.2.10 Welding sequences Welding sequences and direction of welding are to be determined so as to minimise deformations and prevent defects in the welded connection.

All main connections are generally to be completed before the ship is afloat.

Departures from the above provision may be accepted by the Society on a case by case basis, taking into account any detailed information on the size and position of welds and the stresses of the zones concerned, both during ship launching and with the ship afloat.

4.2.11 Interpass cleaningAfter each run, the slag is to be removed by means of a chipping hammer and a metal brush; the same precaution is to be taken when an interrupted weld is resumed or two welds are to be connected.

4.2.12 Stress relievingIt is recommended and in some cases it may be required that special structures subject to high stresses, having complex shapes and involving welding of elements of considerable thickness (such as rudder spades and stern frames), are pre-fabricated in parts of adequate size and stress-relieved in the furnace, before final assembly, at a temperature within the range 550°C ÷ 620°C, as appropriate for the type of steel.

t g

t

m

t

m

t1

m

t2

Pt B, Ch 12, Sec 1


4.3 Crossing of structural elements

4.3.1 In the case of T crossing of structural elements (one element continuous, the other physically interrupted at the crossing) when it is essential to achieve structural continuity through the continuous element (continuity obtained by means of the welded connections at the crossing), particular care is to be devoted to obtaining the correspondence of the interrupted elements on both sides of the continuous ele-ment. Suitable systems for checking such correspondence are to be adopted.

5 Modifications and repairs during construction

5.1 General

5.1.1 Deviations in the joint preparation and other speci-fied requirements, in excess of the permitted tolerances and found during construction, are to be repaired as agreed with the Society on a case by case basis.

5.2 Gap and weld deformations

5.2.1 Welding by building up of gaps exceeding the required values and repairs of weld deformations may be accepted by the Society upon special examination.

5.3 Defects

5.3.1 Defects and imperfections on the materials and welded connections found during construction are to be evaluated for possible acceptance on the basis of the appli-cable requirements of the Society.Where the limits of acceptance are exceeded, the defective material and welds are to be discarded or repaired, as deemed appropriate by the Surveyor on a case by case basis.

When any serious or systematic defect is detected either in the welded connections or in the base material, the manu-facturer is required to promptly inform the Surveyor and submit the repair proposal.

The Surveyor may require destructive or non-destructive examinations to be carried out for initial identification of the defects found and, in the event that repairs are under-taken, for verification of their satisfactory completion.

5.4 Repairs on structures already welded

5.4.1 In the case of repairs involving the replacement of material already welded on the hull, the procedures to be adopted are to be agreed with the Society on a case by case basis.

6 Inspections and checks

6.1 General

6.1.1 Materials, workmanship, structures and welded con-nections are to be subjected, at the beginning of the work, during construction and after completion, to inspections by

the Shipyard suitable to check compliance with the applica-ble requirements, approved plans and standards.

6.1.2 The manufacturer is to make available to the Surveyor a list of the manual welders and welding operators and their respective qualifications.

The manufacturer's internal organisation is responsible for ensuring that welders and operators are not employed under improper conditions or beyond the limits of their respective qualifications and that welding procedures are adopted within the approved limits and under the appropri-ate operating conditions.

6.1.3 The manufacturer is responsible for ensuring that the operating conditions, welding procedures and work sched-ule are in accordance with the applicable requirements, approved plans and recognised good welding practice.

6.2 Visual and non-destructive examina-tions

6.2.1 After completion of the welding operation and work-shop inspection, the structure is to be presented to the Sur-veyor for visual examination at a suitable stage of fabrication.

As far as possible, the results on non-destructive examina-tions are to be submitted.

6.2.2 Non-destructive examinations are to be carried out with appropriate methods and techniques suitable for the individual applications, to be agreed with the Surveyor on a case by case basis.

6.2.3 Radiographic examinations are to be carried out on the welded connections of the hull in accordance with[6.3]. The results are to be made available to the Society. The surveyor may require to witness some testing prepara-tions.

6.2.4 The Society may allow radiographic examinations to be replaced by ultrasonic examinations.

6.2.5 When the visual or non-destructive examinations reveal the presence of unacceptable indications, the rele-vant connection is to be repaired to sound metal for an extent and according to a procedure agreed with the Sur-veyor. The repaired zone is then to be submitted to non-destructive examination, using a method deemed suitable by the Surveyor to verify that the repair is satisfactory.

Additional examinations may be required by the Surveyor on a case by case basis.

6.2.6 Ultrasonic and magnetic particle examinations may also be required by the Surveyor in specific cases to verify the quality of the base material.

6.3 Radiographic inspection

6.3.1 A radiographic inspection is to be carried out on the welded butts of shell plating, strength deck plating as well as of members contributing to the longitudinal strength. This inspection may also be required for the joints of mem-bers subject to heavy stresses.

Pt B, Ch 12, Sec 1


The requirements [6.3.2] to [6.3.5] constitute general rules: the number of radiographs may be increased where requested by the Surveyor, mainly where visual inspection or radiographic soundings have revealed major defects, spe-cially for butts of sheerstrake, stringer plate, bilge strake or keel plate.

Provisions alteration to these rules may be accepted by the Society when justified by the organisation of the shipyard or of the inspection department; the inspection is then to be equivalent to that deduced from [6.3.2] to [6.3.5].

6.3.2 As far as automatic welding of the panels butt welds during the premanufacturing stage is concerned, the ship-yard is to carry out random non-destructive testing of the welds (radiographic or ultrasonic inspection) in order to ascertain the regularity and the constancy of the welding inspection.

6.3.3 In the midship area, radiographies are to be taken at the joinings of panels.Each radiography is situated in a butt joint at a cross-shaped welding.

In a given ship cross-section bounded by the panels, a radi-ography is to be made of each butt of sheerstrake, stringer, bilge and keel plate; in addition, the following radiogra-phies are to be taken:• bottom plating: two• deck plating: two• side shell plating: two each side.

For ships where B + C ≤ 15 m, only one radiography for each of the above items is required.

This requirement remains applicable where panel butts are shifted or where some strakes are built independently from the panels. It is recommended to take most of these radiog-raphies at the intersections of butt and panel seams.

Still in the midship area, a radiographic inspection is to be taken, at random, of the following main members of the structure:

• butts of continuous longitudinal bulkheads

• butts of longitudinal stiffeners, deck and bottom girders contributing to the overall strength

• assembly joints of insert plates at the corners of the openings.

Moreover, a radiographic inspection is to be taken, at ran-dom, of the weldings of the bilge keel and of intermediate flat.

6.3.4 Outwards the midship area, a programme of radio-graphic inspection at random is to be set up by the shipyard in agreement with the Surveyor for the major points. It is further recommended:

• to take a number of radiographies of the very thick parts and those comprising restrained joint, such as stern-frames, shaft brackets, stabiliser recesses, masts

• to take a complete set of radiographies or to increase the number of radiographies for the first joint of a series of identical joints. This recommendation is applicable not only to the assembly joints of prefabricated members completed on the slip, but also to joints completed in the workshop to prepare such prefabricated members.

6.3.5 Where a radiography is rejected and where it is decided to carry out a repair, the shipyard is to determine the length of the defective part, then a set of inspection radi-ographies of the repaired joint and of adjacent parts is to be taken. Where the repair has been decided by the inspection office of the shipyard, the film showing the initial defect is to be submitted to the Surveyor together with the film taken after repair of the joint.

Pt B, Ch 12, Sec 2


SECTION 2 SPECIAL STRUCTURAL DETAILS

Symbols

TB : Ship’s draft in light ballast condition, see Ch 5, Sec 1, [2.4.3].

1 General

1.1 Application

1.1.1 Special structural details are those characterised by complex geometry, possibly associated with high or alter-nate stresses.

1.1.2 For special structural details, specific requirements are to be fulfilled during:

• design

• construction

• selection of materials

• welding

• survey.

The purpose of these requirements is specified in [1.2] to[1.6].

1.1.3 Special structural details are those listed in [2]together with the specific requirements which are to be ful-filled.

Other structural details may be considered by the Society as special details, when deemed necessary on the basis of the criteria in [1.1.1]. The criteria to be fulfilled in such cases are defined by the Society on a case by case basis.

1.1.4 As regards matters not explicitly specified in [2], the Rule requirements are to be complied with in any event; in particular:

• Part B, Chapter 4 for design principles and structural arrangements

• Part B, Chapter 7 or Part B, Chapter 8, as applicable, for structural scantling

• Part B, Chapter 12 for construction and welding requirements

• the applicable requirements in Part D and Part E.

1.2 Design requirements

1.2.1 General requirementsDesign requirements specify:

• the local geometry, dimensions and scantlings of the structural elements which constitute the detail

• any local strengthening

• the cases where a fatigue check is to be carried out according to Ch 7, Sec 4.

1.2.2 Fatigue check requirements

Where a fatigue check is to be carried out, the design requirements specify (see Ch 7, Sec 4, [1.1]):

• the locations (hot spots) where the stresses are to be cal-culated and the fatigue check performed

• the direction in which the normal stresses are to be cal-culated

• the stress concentration factors Kh and K to be used for calculating the hot spot stress range.

1.3 Constructional requirements

1.3.1 Constructional requirements specify the allowable misalignment and tolerances, depending on the detail arrangement and any local strengthening.

1.4 Material requirements

1.4.1 Material requirements specify the material quality to be used for specific elements which constitute the detail, depending on their manufacturing procedure, the type of stresses they are subjected to, and the importance of the detail with respect to the ship operation and overall safety.

In addition, these requirements specify where material inspections are to be carried out.

1.5 Welding requirements

1.5.1 Welding requirements specify where partial or full T penetration welding (see Ch 12, Sec 1, [2.4]) or any particu-lar welding type or sequence is to be adopted. In addition, these requirements specify when welding procedures are to be approved.

Since weld shape and undercuts are influencing factors on fatigue behaviour, fillet welds are to be elongated in the direction of the highest stresses and care is to be taken to avoid undercuts, in particular at the hot spots.

1.6 Survey requirements

1.6.1 Survey requirements specify where non-destructive examinations of welds are to be carried out and, where this is the case, which type is to be adopted.

Pt B, Ch 12, Sec 2


2 List and characteristics of special structural details

2.1 General

2.1.1 This Article lists and describes, depending on the ship type, the special structural details and specifies the specific requirements which are to be fulfilled according to [1.2] to[1.6]. This is obtained through:• a description of the hull areas where the details are

located • the detail description• the requirements for the fatigue check• a reference to a table in the Appendixes where a picture

of the detail is shown together with the specific require-ments which are to be fulfilled.

2.2 All types of ships with longitudinally framed sides

2.2.1 The special structural details relevant to all types of longitudinally framed ships are listed and described in Tab 1.

2.3 Oil tankers and chemical tankers

2.3.1 The special structural details relevant to ships with the service notation oil tanker ESP and chemical tanker ESPare listed and described in Tab 2 for various hull areas.

When the structural arrangement in a certain area is such that the details considered in Tab 2 are not possible, spe-cific requirements are defined by the Society on a case by case basis, depending on the arrangement adopted.

Table 1 : Ships with longitudinally framed sides - Special structural details

Table 2 : Oil tankers and chemical tankers - Special structural details

Areareference number

Area description Detail description Fatigue checkReference tablesin Ch 12, App 2

1 Part of side extended:• longitudinally, between the after

peak bulkhead and the collision bulkhead

• vertically, between 0,7TB and 1,15T from the baseline

Connection of side longitudinal ordi-nary stiffeners with transverse prima-ry supporting members

No Ch 12, App 2, Tab 1 to Ch 12, App 2, Tab 6

Connection of side longitudinal ordi-nary stiffeners with stiffeners of trans-verse primary supporting members

For L ≥ 170 m Ch 12, App 2, Tab 7 to Ch 12, App 2, Tab 13



1 Part of side extended:• longitudinally, between

the after peak bulkhead and the collision bulk-head

• vertically, between 0,7TB and 1,15T from the base-line

Connection of side longitudinal ordinary stiffeners with transverse primary support-ing members


Connection of side longitudinal ordinary stiffeners with stiffeners of transverse pri-mary supporting members

For L ≥ 170m Ch 12, App 2, Tab 7 to Ch 12, App 2, Tab 13

2 Part of inner side and longitu-dinal bulkheads in the cargo area extended vertically above half tank height, where the tank breadth exceeds 0,55B

Connection of inner side or bulkhead lon-gitudinal ordinary stiffeners with trans-verse primary supporting members


Connection of inner side or bulkhead lon-gitudinal ordinary stiffeners with stiffeners of transverse primary supporting members


3 Double bottom in way of transverse bulkheads

Connection of bottom and inner bottom longitudinal ordinary stiffeners with floors


Connection of inner bottom with trans-verse bulkheads or lower stools

For L ≥ 170m Ch 12, App 2, Tab 30

4 Double bottom in way of hopper tanks

Connection of inner bottom with hopper tank sloping plates


5 Lower part of transverse bulk-heads with lower stools

Connection of lower stools with plane bulkheads


Connection of lower stools with corru-gated bulkheads

For L ≥ 170m (not for Ch 12, App 2, Tab 49 and Ch 12,

App 2, Tab 53)

Ch 12, App 2, Tab 46 to Ch 12, App 2, Tab 53

6 Lower part of inner side Connection of hopper tank sloping plates with inner side


Pt B, Ch 12, Sec 2


2.4 Liquefied gas carriers

2.4.1 The special structural details relevant to ships with the service notation liquefied gas carrier are listed and described in Tab 3 for various hull areas.


2.5 Bulk carriers

2.5.1 The special structural details relevant to ships with the service notation bulk carrier ESP are listed and described in Tab 4 for various hull areas.


Table 3 : Liquefied gas carriers - Special structural details

Table 4 : Bulk carriers - Special structural details



1 Part of side extended:• longitudinally, between the

after peak bulkhead and the collision bulkhead


Connection of side longitudinal ordinary stiffeners with transverse primary support-ing members


Connection of side longitudinal ordinary stiffeners with stiffeners of transverse pri-mary supporting members


3 Double bottom in way of trans-verse bulkheads



Connection of inner bottom with trans-verse cofferdam bulkheads

For L ≥ 170 m Ch 12, App 2, Tab 31





For L ≥ 170 m Ch 12, App 2, Tab 61, Ch 12, App 2, Tab 62



3 Double bottom in way of transverse bulkheads



Connection of inner bottom with transverse bulkheads or lower stools

For L ≥ 170m Ch 12, App 2, Tab 30




5 Lower part of transverse bulkheads with lower stools



Connection of lower stools with corrugated bulkheads


App 2, Tab 53)




7 Side frames Connection of side frames with hopper and topside tanks

No Ch 12, App 2, Tab 63, Ch 12, App 2, Tab 64

8 Topside tanks Connection of transverse corrugated bulk-heads with topside tanks

No Ch 12, App 2, Tab 65

10 Hatch corners Deck plating in way of hatch corners No Ch 12, App 2, Tab 68

Ends of longitudinal hatch coamings No Ch 12, App 2, Tab 69, Ch 12, App 2, Tab 70

Pt B, Ch 12, Sec 2


2.6 Ore carriers and combination carriers

2.6.1 The special structural details relevant to ships with the service notation ore carrier ESP and combination car-rier ESP are listed and described in Tab 5 for various hull areas.When the structural arrangement in a certain area is such that the details considered in Tab 5 are not possible, spe-cific requirements are defined by the Society on a case by case basis, depending on the arrangement adopted.

2.7 Container ships

2.7.1 The special structural details relevant to ships with the service notation container ship are listed and described in Tab 6 for various hull areas.


Table 5 : Ore carriers and combination carriers - Special structural details

Table 6 : Container ships - Special structural details






Connection of side longitudinal ordi-nary stiffeners with transverse primary supporting members




3 Double bottom in way of trans-verse bulkheads

Connection of bottom and inner bot-tom longitudinal ordinary stiffeners with floors


Connection of inner bottom with trans-verse bulkheads or lower stools

For L ≥ 170m Ch 12, App 2, Tab 30

4 Double bottom in way of hop-per tanks

Connection of inner bottom with hop-per tank sloping plates


5 Lower part of transverse bulk-heads with lower stools



Connection of lower stools with corru-gated bulkheads


App 2, Tab 53)




8 Topside tanks Connection of transverse corrugated bulkheads with topside tanks



Ends of longitudinal hatch coamings No Ch 12, App 2, Tab 69, Ch 12, App 2, Tab 70





• vertically, between 0,7 TB and 1,15 T from the baseline

Connection of side longitudinal ordi-nary stiffeners with transverse primary supporting members

No Ch 12, App 2, Tab 1 toCh 12, App 2, Tab 6


For L ≥ 170m Ch 12, App 2, Tab 7 toCh 12, App 2, Tab 13

9 Cross decks Connection of cross decks with side transverses


Connection between face plates of cross decks and deck girders



Ends of longitudinal hatch coamings No Ch 12, App 2, Tab 69,Ch 12, App 2, Tab 70

Pt B, Ch 12, Sec 2


3 Grinding of welds for fatigue life improvement

3.1 General

3.1.1 The purpose of grinding is to smoothly blend the tran-sition between the plate and the weld face.

3.1.2 Grinding is generally to be burr grinding. However other techniques of grinding may be considered by the Society on a case by case basis.

3.2 Grinding practice

3.2.1 The burr radius r is generally to be taken greater than 0,6 t, where t is the plate thickness at the weld toe being ground.

3.2.2 In general, grinding must extend to a depth below any visible undercut. However, the grinding depth d, in mm, is to be not greater than:

• d = 1 mm for t ≥ 14

• d = 0,07 t for 10 ≤ t < 14,

where t is the plate thickness, in mm, at the weld toe being ground.

For plate thickness less than 10 mm, grinding is generally not allowed.

3.2.3 After grinding, the weld is to be inspected by the yard quality control in order to check that the finished ground surface is as smooth as possible, with no visible evidence of the original weld toe or undercut or any grinding marks at right angles to the weld toe line. In addition, the Society may require measurements of the remaining thickness in way of the ground weld.

3.3 Grinding procedure

3.3.1 The grinding procedure required in Ch 7, Sec 4, [3.1.3] is to specify the:• weld preparation• grinding tool used• position of the tool over the weld toe• location of weld toe on which grinding is applied• extent of grinding at the ends of attachments• final weld profile (see [3.2.2])• final examination technique, including NDE.

Pt B, Ch 12, Sec 3


SECTION 3 TESTING

1 General

1.1 Application

1.1.1 The following requirements determine the testingconditions for:

• gravity tanks, including independent tanks of 5 m3 ormore in capacity

• watertight or weathertight structures.

The purpose of these tests is to check the tightness and/orthe strength of structural elements.

1.1.2 Tests are to be carried out in the presence of the Sur-veyor at a stage sufficiently close to completion so that anysubsequent work would not impair the strength and tight-ness of the structure.

In particular, tests are to be carried out after air vents andsounding pipes are fitted.

1.1.3 The Society may accept that structural testing of a sis-ter ship is limited to a single tank for each type of structuralarrangement.

However, if the Surveyor detects anomalies, he may requirethe number of tests is increased or that the same number oftests is provided as for the first ship in a series.

1.2 Definitions

1.2.1 Shop primerShop primer is a thin coating applied after surface prepara-tion and prior to fabrication as a protection against corro-sion during fabrication.

1.2.2 Protective coatingProtective coating is a final coating protecting the structurefrom corrosion.

1.2.3 Structural testingStructural testing is a hydrostatic test carried out to demon-strate the tightness of the tanks and the structural adequacyof the design. Where practical limitations prevail andhydrostatic testing is not feasible (for example when it is dif-ficult, in practice, to apply the required head at the top ofthe tank), hydropneumatic testing may be carried outinstead.

Structural testing is to be carried out according to [2.2].

1.2.4 Hydropneumatic testingHydropneumatic testing is a combination of hydrostatic andair testing, consisting in filling the tank to the top with waterand applying an additional air pressure.

Hydropneumatic testing is to be carried out according to[2.3].

1.2.5 Leak testingLeak testing is an air or other medium test carried out todemonstrate the tightness of the structure.

Leak testing is to be carried out according to [2.4].

1.2.6 Hose testingHose testing is carried out to demonstrate the tightness ofstructural items not subjected to hydrostatic or leak testingand of other components which contribute to the watertightor weathertight integrity of the hull.

Hose testing is to be carried out according to [2.5].

1.2.7 Sister shipA sister ship is a ship having the same main dimensions,general arrangement, capacity plan and structural design asthose of the first ship in a series, and built in the same ship-yard.

2 Watertight compartments

2.1 General

2.1.1 The requirements in [2.1] to [2.6] intend generally toverify the adequacy of the structural design of gravity tanks,excluding independant tanks of less than 5 m3 in capacity,based on the loading conditions which prevailed whendetermining the tank structure scantlings.

2.1.2 General requirements for testing of watertight com-partments are given in Tab 1, in which the types of testingreferred to are defined in [1.2].

2.2 Structural testing

2.2.1 Structural testing may be carried out before or afterlaunching.

2.2.2 Structural testing may be carried out after applicationof the shop primer.

2.2.3 Structural testing may be carried out after the protec-tive coating has been applied, provided that one of the fol-lowing two conditions is satisfied:• all the welds are completed and carefully inspected vis-

ually to the satisfaction of the Surveyor prior to theapplication of the protective coating

• leak testing is carried out prior to the application of theprotective coating.

In the absence of leak testing, protective coating is to beapplied after the structural testing of:• all erection welds, both manual and automatic• all manual fillet weld connections on tank boundaries

and manual penetration welds.

Pt B, Ch 12, Sec 3


Table 1 : Watertight compartments - General testing requirements


Type of testing Structural test pressure Remarks

Double bottom tanks Structural testing (1)

The greater of the following:• head of water up to the top of overflow• head of water up to the margin line

Tank boundaries tested from at least one side

Double side tanks Structural testing (1)

The greater of the following:• head of water up to the top of overflow• 2,4 m head of water above highest point of

tank (5)


Tank bulkheads, deep tanks Structural testing (1)

The greater of the following (2): • head of water up to the top of overflow• 2,4 m head of water above highest point of

tank (5) • setting pressure of the safety relief valves,

where relevant


Fuel oil bunkers Structural testing

Ballast holds of ships with service notation bulk carrier ESP

Structural testing (1)

The greater of the following:• head of water up to the top of overflow• 0,9 m head of water above top of hatch

Fore and after peaks used as tank

Structural testing The greater of the following:• head of water up to the top of overflow• 2,4 m head of water above highest point of

tank (5)

Test of the after peak carried out after the sterntube has been fitted

Fore peak not used as tank Structural testing The greater of the following:• maximum head of water to be sustained in

the event of damage• head of water up to the margin line

After peak not used as tank Leak testing

Cofferdams Structural testing (3)

The greater of the following:• head of water up to the top of overflow• 2,4 m head of water above highest point of

tank (5)

Watertight bulkheads Hose testing (4)

Watertight doors below free-board or bulkhead deck (6)

Structural testing Head of water up to the bulkhead deck Test to be carried out before the ship is put into service, either before or after the door is fitted on board

Double plate rudders Leak testing

Shaft tunnel clear of deep tanks

Hose testing

Shell doors Hose testing

Watertight hatch covers of tanks in ship with service notation bulk carrier ESP

Hose testing

Watertight hatch covers of tanks in ship with service notation combination carrier ESP

Structural testing (1)

The greater of the following:• 2,4 m head of water above the top of hatch

cover• setting pressure of the safety relief valves,

where relevant

At least every second hatch cover is to be tested

Weathertight hatchcovers and closing appliances

Hose testing

Chain locker (if aft of collision bulkhead)

Structural testing Head of water up to the top

Pt B, Ch 12, Sec 3


2.3 Hydropneumatic testing

2.3.1 When a hydropneumatic testing is performed, theconditions are to simulate, as far as practicable, the actualloading of the tank.

The value of the additional air pressure is at the discretionof the Society, but is to be at least as defined in [2.4.2] forleak testing.

The same safety precautions as for leak testing (see [2.4.2])are to be adopted.

2.4 Leak testing

2.4.1 An efficient indicating liquid, such as a soapy watersolution, is to be applied to the welds.

2.4.2 Where leak testing is carried out, in accordance withTab 1, an air pressure of 0,15.105 Pa is to be applied duringthe test.

Prior to inspection, it is recommended that the air pressurein the tank should be raised to 0,2.105 Pa and kept at thislevel for approximately 1 hour to reach a stabilised state,with a minimum number of personnel in the vicinity of thetank, and then lowered to the test pressure.

The test may be conducted after the pressure has reached astabilised state at 0,2.105 Pa, without lowering the pressure,provided the Society is satisfied of the safety of the person-nel involved in the test.

2.4.3 A U-tube filled with water up to a height correspond-ing to the test pressure is to be fitted to avoid overpressureof the compartment tested and verify the test pressure.

The U-tube is to have a cross-section larger than that of thepipe supplying air.

In addition, the test pressure is also to be verified by meansof one master pressure gauge.

Alternative means which are considered to be equivalentlyreliable may be accepted at the discretion of the Surveyor.

2.4.4 Leak testing is to be carried out, prior to the applica-tion of a protective coating, on all fillet weld connectionson tank boundaries, and penetration and erection welds ontank boundaries excepting welds made by automatic proc-esses.Selected locations of automatic erection welds and pre-erection manual or automatic welds may be required to besimilarly tested to the satisfaction of the Surveyor, takingaccount of the quality control procedures operating in theshipyard.

For other welds, leak testing may be carried out after theprotective coating has been applied, provided that suchwelds have been carefully inspected visually to the satisfac-tion of the Surveyor.

2.4.5 Any other recognised method may be accepted to thesatisfaction of the Surveyor.

2.5 Hose testing

2.5.1 When hose testing is required to verify the tightnessof the structures, as defined in Tab 1, the minimum pressurein the hose, at least equal to 2,0.105 Pa, is to be applied at amaximum distance of 1,5 m.

The nozzle diameter is to be not less than 12 mm.

2.6 Other testing methods

2.6.1 Other testing methods may be accepted, at the dis-cretion of the Society, based upon equivalency considera-tions.

Independent tanks Structural testing Head of water up to the top of overflow, but not less than 0,90 m

Ballast ducts Structural testing Ballast pump maximum pressure

(1) Hydropneumatic or leak testing may be accepted under the conditions specified in [2.3] and [2.4], respectively, provided that at least one tank of each type is structurally tested, to be selected in connection with the approval of the design. in general, structural testing need not be repeated for subsequent ships of a series of identical new buildings. This relaxation does not apply to cargo space boundaries in ships with the service notation oil tanker ESP or combination carrier ESP and to tanks for segre-gated cargoes or pollutants. If the structural test reveals weakness or severe faults not detected by the leak test, all tanks are to be structurally tested.

(2) Where applicable, the highest point of the tank is to be measured to deck and excluding hatches. In holds for liquid cargo or ballast with large hatch covers, the highest point of tanks is to be taken at the top of the hatch.

(3) Hydropneumatic or leak testing may be accepted under the conditions specified in [2.3] and [2.4], respectively, when, at the Society’s discretion, it is considered significant also in relation to the construction techniques and the welding procedures adopted.

(4) When a hose test cannot be performed without damaging possible outfitting (machinery, cables, switchboards, insulation, etc...) already installed, it may be replaced, at the Society’s discretion, by a careful visual inspection of all the crossings and welded joints. Where necessary, a dye penetrant test or ultrasonic leak test may be required.

(5) For ships of less than 40 m in length, 2,4 m may be replaced by 0,3H with 0,9 0,3 H 2,4, where H is the height of compart-ment, in m.

(6) The means of closure are to be subjected to a hose test after fitting on board.


Type of testing Structural test pressure Remarks

Pt B, Ch 12, Sec 3


3 Miscellaneous

3.1 Watertight decks, trunks, etc.

3.1.1 After completion, a hose or flooding test is to beapplied to watertight decks and a hose test to watertighttrunks, tunnels and ventilators.

3.2 Doors in bulkheads above the bulkhead deck

3.2.1 Doors are to be designed and constructed as weath-ertight doors and, after installation, subjected to a hose testfrom each side for weathertightness.

3.3 Semi-watertight doors

3.3.1 Semi-watertight doors are those defined in Ch 3, Sec3, [3.3.2].These means of closure are to be subjected to a structuraltest at the manufacturer’s works. The head of water is to beup to the highest waterline after damage at the equilibriumof the intermediate stages of flooding. The duration of thetest is to be at least 30 min.

A leakage quantity of approximately 100 l/hour is consid-ered as being acceptable for a 1,35 m2 opening.

The means of closure are to be subjected to a hose test afterfitting on board.

3.4 Steering nozzles

3.4.1 Upon completion of manufacture, the nozzle is to besubjected to a leak test.

3.5 Working test of windlass

3.5.1 The working test of the windlass is to be carried outon board in the presence of a Surveyor.

3.5.2 The test is to demonstrate that the windlass complieswith the requirements of Ch 10, Sec 4, [3.5] and, in particu-lar, that it works adequately and has sufficient power tosimultaneously weigh the two bower anchors (excludingthe housing of the anchors in the hawse pipe) when bothare suspended to 55 m of chain cable, in not more than 6min.

3.5.3 Where two windlasses operating separately on eachchain cable are adopted, the weighing test is to be carriedout for both, weighing an anchor suspended to 82,5 m ofchain cable and verifying that the time required for theweighing (excluding the housing in the hawse pipe) doesnot exceed 9 min.

Pt B, Ch 12, App 1


APPENDIX 1 WELDING DETAILS

1 Contents

1.1 General

1.1.1 Types and edge plate preparation of the manualwelds carried out on the various parts of the hull are dealtwith in this Appendix.Other types and tolerances may be used after special exam-ination of the Society.

1.1.2 The method used to prepare the parts to be welded isleft to the discretion of each shipyard, according to its owntechnology and experience. It is approved at the same time

as the approval of the welding procedures referred to in Ch12, Sec 1, [1.3.1].

1.2 Butt welding edge preparation

1.2.1 Typical butt weld plate edge preparation for manualwelding is specified in Tab 1 and Tab 2.

1.3 Lap-joint, slot and plug welding

1.3.1 Welding details of lap-joint, slot and plug welds arespecified in Tab 3.

Pt B, Ch 12, App 1


Table 1 : Typical butt weld plate edge preparation(manual welding) - See Note 1

Table 2 : Typical butt weld plate edge preparation(manual welding) - See Note 1

Detail DimensionsSquare butt

t 5 mmG = 3 mm

Single bevel butt

t > 5 mmG 3 mmR 3 mm50° 70°

Double bevel butt

t > 19 mmG 3 mmR 3 mm50° 70°

Double vee butt, uniform bevels

G 3 mmR 3 mm50° 70°

Double vee butt, non-uniform bevels

G 3 mmR 3 mm6 h t/3 mm = 50° = 90°

Note 1: Different plate edge preparation may be accepted by the Society on the basis of an appropriate welding proce-dure specification.

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Detail DimensionsSingle vee butt, one side welding withbacking strip (temporary or permanent)

3 G 9 mm30° 45°

Single vee butt

G 3 mm50° 70°R 3 mm

Note 1: Different plate edge preparation may be accepted by the Society on the basis of an appropriate welding procedure specification.

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Pt B, Ch 12, App 1


Table 3 : Typical lap joint, plug and slot welding (manual welding)

Detail Standard Remark

Fillet weld in lap joint

b = 2 t2 + 25 mm

location of lap joint to be

approved by the Society

Fillet weld in joggled lap joint

b 2 t2 + 25 mm

Plug welding

• t 12 mm = 60 mmR = 6 mm40° 50°G = 12 mmL > 2

• 12 mm < t 25 mm = 80 mmR = 0,5 t mm = 30°G = t mmL > 2

Slot welding

• t 12 mmG = 20 mm = 80 mm

2 L 3 , max 250 mm

• t > 12 mmG = 2 t = 100 mm

2 L 3 , max 250 mm

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Pt B, Ch 12, App 2


APPENDIX 2 REFERENCE SHEETS FOR SPECIAL STRUCTURAL DETAILS

1 Contents

1.1 General

1.1.1 This Appendix includes the reference sheets for spe-cial structural details, as referred to in Ch 12, Sec 2.

Table 1 : ALL LONGITUDINALLY FRAMED SIDE SHIPS

AREA 1: Side between 0,7TB and1,15T from the baseline

Connection of side longitudinal ordinary stiffeners with transverseprimary supporting members - No collar plate

Sheet 1.1

tW = web thickness of transverse primary supporting member

SCANTLINGS: FATIGUE:

Net sectional area of the web stiffener according to Ch 4, Sec 3, [4.7]. Fatigue check not required.

CONSTRUCTION: NDE:

• Web stiffener not compulsory. When fitted, its misalignment m with the web of the side longitudinal a / 50.

• Cut-outs in the web free of sharps notches.• Gap between web and side longitudinal to be not greater than 4 mm.

Visual examination 100%.

WELDING AND MATERIALS:

Welding requirements:- continuous fillet welding along the connection of web with side longitudinal,- throat thickness according to Ch 12, Sec 1, [2.3.6]; in case of gap g greater than 2 mm, increase the throat thickness by

0,7 (g 2) mm,- weld around the cuts in the web at the connection with the longitudinal and the side shell,- avoid burned notches on web.

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Pt B, Ch 12, App 2




Connection of side longitudinal ordinary stiffeners with transverseprimary supporting members - One collar plate

Sheet 1.2

tW = web thickness of transverse primary supporting membertCP = collar plate thickness



CONSTRUCTION: NDE:


• Misalignment between web and collar plate tCP.• Cut-outs in the web free of sharps notches.• Gap between web and side longitudinal and between collar plate and side

longitudinal to be not greater than 4 mm.



• Welding requirements:- continuous fillet welding along the connection of web and collar plate with side longitudinal and at the lap joint between

web and collar plate,- throat thickness according to Ch 12, Sec 1, [2.3.6]; in case of gap g greater than 2 mm, increase the throat thickness by

0,7 (g 2) mm,- weld around the cuts in the web at the connection with the longitudinal and the side shell,- avoid burned notches on web.

• Fillet welding of overlapped joint to be done all around.

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Pt B, Ch 12, App 2




Connection of side longitudinal ordinary stiffeners with transverseprimary supporting members - One large collar plate

Sheet 1.3




CONSTRUCTION: NDE:


• Misalignment between web and collar plate tCP.• Cut-outs in the web free of sharps notches.• Gap between web and side longitudinal and between collar plate and side

longitudinal to be not greater than 4 mm.



• Welding requirements:- continuous fillet welding along the connection of web and collar plate with side longitudinal and at the lap joint between

web and collar plate,- throat thickness according to Ch 12, Sec 1, [2.3.6]; in case of gap g greater than 2 mm, increase the throat thickness by

0,7 (g 2) mm,- T joint connection of collar plate with side shell: see section A-A,- weld around the cuts in the web at the connection with the longitudinal and the side shell,- avoid burned notches on web.


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Pt B, Ch 12, App 2




Connection of side longitudinal ordinary stiffeners with transverseprimary supporting members - Two collar plates

Sheet 1.4




CONSTRUCTION: NDE:


• Misalignment between collar plates across the side longitudinal tCP / 2.• Cut-outs in the web free of sharps notches.• Gap between collar plates and side longitudinal to be not greater than 4 mm.



• Welding requirements:- continuous fillet welding along the connection of collar plates with side longitudinal and at the lap joint between web and

collar plates,- throat thickness according to Ch 12, Sec 1, [2.3.6]; in case of gap g greater than 2 mm, increase the throat thickness by

0,7 (g 2) mm,- avoid burned notches on web.


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Pt B, Ch 12, App 2




Connection of side longitudinal ordinary stiffeners with transverseprimary supporting members - Two large collar plates

Sheet 1.5




CONSTRUCTION: NDE:


• Misalignment between collar plates across the side longitudinal tCP / 2.• Cut-outs in the web free of sharps notches.• Gap between collar plates and side longitudinal to be not greater than 4 mm.



• Welding requirements:- continuous fillet welding along the connection of collar plates with side longitudinal and at the lap joint between web and

collar plates,- throat thickness according to Ch 12, Sec 1, [2.3.6]; in case of gap g greater than 2 mm, increase the throat thickness by

0,7 (g 2) mm,- T joint connection of collar plates with side shell: see section A-A,- avoid burned notches on web.


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Pt B, Ch 12, App 2




Watertight connection of side longitudinal ordinary stiffeners withwatertight side diaphragms or transverse bulkheads – Example of con-nection with lugs

Sheet 1.6

tW = transverse bulkhead web thicknesstL = lug thickness


• d = 30 ÷ 60 mm.• tL tW.

Fatigue check not required.

CONSTRUCTION: NDE:


• Misalignment between lugs across the side longitudinal tL / 2.• Misalignment at the butts within lug parts tL / 5.• Gap between bulkhead plating and lugs to be not greater than

4 mm.

• Visual examination 100%.• Magnetic particle or dye penetrant examination: when

deemed necessary depending on the quality of the lap joint weld.


Welding requirements:- continuous fillet welding along the connection of lugs with the side longitudinal and at the lap joints between web and lugs,- throat thickness according to Ch 12, Sec 1, [2.3.6]; in case of gap g greater than 2 mm, increase the throat thickness by

0,7 (g 2) mm,- T joint connection of collar plates with side shell: see section A-A,- welding sequence: 1 to 5 (see sketch).

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Connection of side longitudinal ordinary stiffeners with stiffeners oftransverse primary supporting members - No bracket

Sheet 1.7

t = minimum thickness between those of:- web of side longitudinal,- stiffener of transverse primary supporting

member.


d to be as small as possible, maximum 35 mm recommended. Fatigue check to be carried out for L 170 m:• with non-watertight collar plate:

Kh = 1,30

K = 1,65• with full collar plate (watertight):

Kh = 1,25

K = 1,50

CONSTRUCTION: NDE:

• Misalignment between side longitudinal and web stiffener t / 3.• In case of fillet welding, misalignment may be as necessary to allow the

required fillet throat size, but t / 2. For bulbs, a misalignment of 6 mm may be accepted.



Welding requirements:- continuous fillet welding,- weld around the stiffener’s toes,- fair shape of fillet at toes in longitudinal direction.

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Pt B, Ch 12, App 2




Connection of side longitudinal ordinary stiffeners with stiffeners oftransverse primary supporting members - One bracket

Sheet 1.8

t = minimum thickness among those of the connected elements


• 2.• Bracket to be symmetric.• h as necessary to allow the required fillet throat size, but 15 mm.• d to be as small as possible, maximum 35 mm recommended.• Thickness of the bracket to be not less than that of web stiffener.

Fatigue check to be carried out for L 170 m:• with non-watertight collar plate:

- for 2 < 2,5Kh = 1,20

K = 1,40- for 2,5

Kh = 1,15


- for 2 < 2,5Kh = 1,15

K = 1,32- for 2,5

Kh = 1,10

K = 1,32

CONSTRUCTION: NDE:

• Misalignment between side longitudinal, web stiffener and bracket t / 3.• In case of fillet welding, misalignment may be as necessary to allow the





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Pt B, Ch 12, App 2




Connection of side longitudinal ordinary stiffeners with stiffeners oftransverse primary supporting members - One radiused bracket

Sheet 1.9



• 2.• Bracket to be symmetric.• R 1,5 ( 1) hW

• h as necessary to allow the required fillet throat size, but 15 mm.• d to be as small as possible, maximum 35 mm recommended.• Thickness of the bracket to be not less than that of web stiffener.


- for 2 < 2,5Kh = 1,15

K = 1,35- for 2,5

Kh = 1,10


- for 2 < 2,5Kh = 1,13

K = 1,30- for 2,5

Kh = 1,08

K = 1,30

CONSTRUCTION: NDE:






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Pt B, Ch 12, App 2




Connection of side longitudinal ordinary stiffeners with stiffeners oftransverse primary supporting members - One bracket

Sheet 1.10





- for 2 < 2,5Kh = 1,30

K = 1,55- for 2,5

Kh = 1,25


- for 2 < 2,5Kh = 1,25

K = 1,46- for 2,5

Kh = 1,20

K = 1,41

CONSTRUCTION: NDE:






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Pt B, Ch 12, App 2




Connection of side longitudinal ordinary stiffeners with stiffeners oftransverse primary supporting members - One radiused bracket

Sheet 1.11






- for 2 < 2,5Kh = 1,25

K = 1,50- for 2,5

Kh = 1,20


- for 2 < 2,5Kh = 1,22

K = 1,44- for 2,5

Kh = 1,18

K = 1,39

CONSTRUCTION: NDE:






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Pt B, Ch 12, App 2




Connection of side longitudinal ordinary stiffeners with stiffeners oftransverse primary supporting members - Two brackets

Sheet 1.12



• 2.• 1.• Brackets to be symmetric.• h as necessary to allow the required fillet throat size, but 15 mm.• d to be as small as possible, maximum 35 mm recommended.• Thickness of the brackets to be not less than that of web stiffener.


- for 2 < 2,5 and 1 < 1,5Kh = K = 1,15

- for 2,5 and 1,5Kh = K = 1,10

• with full collar plate (watertight):- for 2 < 2,5 and 1 < 1,5

Kh = K = 1,10- for 2,5 and 1,5

Kh = K = 1,05

CONSTRUCTION: NDE:

• Misalignment between side longitudinal, web stiffener and brackets t / 3.• In case of fillet welding, misalignment may be as necessary to allow the




• Welding requirements:- continuous fillet welding,- weld around the stiffener’s toes,- fair shape of fillet at toes in longitudinal direction.

• Material requirements:- material of brackets to be the same of longitudinals.

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Connection of side longitudinal ordinary stiffeners with stiffeners oftransverse primary supporting members - Two radiused brackets

Sheet 1.13



• 2.• 1.• Brackets to be symmetric.• R1 1,5 ( 1) hW

• R2 1,5 hW

• h as necessary to allow the required fillet throat size, but 15 mm.• d to be as small as possible, maximum 35 mm recommended.• Thickness of the brackets to be not less than that of web stiffener.


- for 2 < 2,5 and 1 < 1,5Kh = K = 1,10

- for 2,5 and 1,5Kh = K = 1,05


Kh = K = 1,10- for 2,5 and 1,5

Kh = K = 1,05

CONSTRUCTION: NDE:

• Misalignment between side longitudinal, web stiffener and brackets t /3.• In case of fillet welding, misalignment may be as necessary to allow the






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Table 14 : OIL TANKERS, CHEMICAL TANKERS

AREA 2: Inner side and longitudinalbulkheads above 0,5H

Connection of inner side or bulkhead longitudinal ordinary stiffenerswith transverse primary supporting members - No collar plate

Sheet 2.1

tW = web thickness of transverse primary supporting member



CONSTRUCTION: NDE:

• Web stiffener not compulsory. When fitted, its misalignment m with the web of the longitudinal a / 50.

• Cut-outs in the web free of sharps notches.• Gap between web and longitudinal to be not greater than 4 mm.



Welding requirements:- continuous fillet welding along the connection of web with longitudinal,- throat thickness according to Ch 12, Sec 1, [2.3.6]; in case of gap g greater than 2 mm, increase the throat thickness by

0,7 (g 2) mm,- weld around the cuts in the web at the connection with the longitudinal and the plating,- avoid burned notches on web.

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Pt B, Ch 12, App 2




Connection of inner side or bulkhead longitudinal ordinary stiffenerswith transverse primary supporting members - One collar plate

Sheet 2.2




CONSTRUCTION: NDE:


• Misalignment between web and collar plate tCP.• Cut-outs in the web free of sharps notches.• Gap between web and longitudinal and between collar plate and longitudinal

to be not greater than 4 mm.



• Welding requirements:- continuous fillet welding along the connection of web and collar plate with longitudinal and at the lap joint between web

and collar plate,- throat thickness according to Ch 12, Sec 1, [2.3.6]; in case of gap g greater than 2 mm, increase the throat thickness by

0,7 (g 2) mm,- weld around the cuts in the web at the connection with the longitudinal and the plating,- avoid burned notches on web.


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Pt B, Ch 12, App 2




Connection of inner side or bulkhead longitudinal ordinary stiffenerswith transverse primary supporting members - One large collar plate

Sheet 2.3




CONSTRUCTION: NDE:


• Misalignment between web and collar plate tCP.• Cut-outs in the web free of sharps notches.• Gap between web and longitudinal and between collar plate and longitudinal

to be not greater than 4 mm.



• Welding requirements:- continuous fillet welding along the connection of web and collar plate with longitudinal and at the lap joint between web

and collar plate,- throat thickness according to Ch 12, Sec 1, [2.3.6]; in case of gap g greater than 2 mm, increase the throat thickness by

0,7 (g 2) mm,- T joint connection of collar plate with the plating: see section A-A,- weld around the cuts in the web at the connection with the longitudinal and the plating,- avoid burned notches on web.


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Pt B, Ch 12, App 2




Connection of inner side or bulkhead longitudinal ordinary stiffenerswith transverse primary supporting members - Two collar plates

Sheet 2.4




CONSTRUCTION: NDE:


• Misalignment between collar plates across the longitudinal tCP / 2.• Cut-outs in the web free of sharps notches.• Gap between collar plates and longitudinal to be not greater than 4 mm.



• Welding requirements:- continuous fillet welding along the connection of collar plates with longitudinal and at the lap joint between web and collar

plates,- throat thickness according to Ch 12, Sec 1, [2.3.6]; in case of gap g greater than 2 mm, increase the throat thickness by

0,7 (g 2) mm,- avoid burned notches on web.


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Pt B, Ch 12, App 2




Connection of inner side or bulkhead longitudinal ordinary stiffenerswith transverse primary supporting members - Two large collar plates

Sheet 2.5




CONSTRUCTION: NDE:


• Misalignment between collar plates across the longitudinal tCP / 2.• Cut-outs in the web free of sharps notches.• Gap between collar plates and longitudinal to be not greater than 4 mm.



• Welding requirements:- continuous fillet welding along the connection of collar plates with longitudinal and at the lap joint between web and collar

plates,- throat thickness according to Ch 12, Sec 1, [2.3.6]; in case of gap g greater than 2 mm, increase the throat thickness by

0,7 (g 2) mm,- T joint connection of collar plates with the plating: see section A-A,- avoid burned notches on web.


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Pt B, Ch 12, App 2




Watertight connection of inner side or bulkhead longitudinal ordinarystiffeners with watertight side diaphragms or transverse bulkheads –Example of connection with lugs

Sheet 2.6

tW = transverse bulkhead web thicknesstL = lug thickness


• d = 30 ÷ 60 mm.• tL tW.


CONSTRUCTION: NDE:


• Misalignment between lugs across the longitudinal tL / 2.• Misalignment at the butts within lug parts tL / 5.• Gap between bulkhead plating and lugs to be not greater than 4 mm.

• Visual examination 100%.• Magnetic particle or dye penetrant examination:

when deemed necessary depending on the qual-ity of the lap joint weld.


Welding requirements:- continuous fillet welding along the connection of lugs with the longitudinal and at the lap joints between web and lugs,- throat thickness according to Ch 12, Sec 1, [2.3.6]; in case of gap g greater than 2 mm, increase the throat thickness by

0,7 (g 2) mm,- T joint connection of collar plates with the plating: see section A-A,- welding sequence: 1 to 5 (see sketch).

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Connection of inner side or bulkhead longitudinal ordinary stiffenerswith stiffeners of transverse primary supporting members - No bracket

Sheet 2.7

t = minimum thickness between those of:- web of longitudinal,- stiffener of transverse primary supporting mem-

ber.


d to be as small as possible, maximum 35 mm recommended. Fatigue check to be carried out for L 170 m:• with non-watertight collar plate:

Kh = 1,30


Kh = 1,25

K = 1,50

CONSTRUCTION: NDE:

• Misalignment between longitudinal and web stiffener t / 3.• In case of fillet welding, misalignment may be as necessary to allow the





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Pt B, Ch 12, App 2




Connection of inner side or bulkhead longitudinal ordinary stiffenerswith stiffeners of transverse primary supporting members - Onebracket

Sheet 2.8





- for 2 < 2,5Kh = 1,20

K = 1,40- for 2,5

Kh = 1,15


- for 2 < 2,5Kh = 1,15

K = 1,32- for 2,5

Kh = 1,10

K = 1,32

CONSTRUCTION: NDE:

• Misalignment between longitudinal, web stiffener and bracket t / 3.• In case of fillet welding, misalignment may be as necessary to allow the





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Pt B, Ch 12, App 2




Connection of inner side or bulkhead longitudinal ordinary stiffenerswith stiffeners of transverse primary supporting members - Oneradiused bracket

Sheet 2.9






- for 2 < 2,5Kh = 1,15

K = 1,35- for 2,5

Kh = 1,10


- for 2 < 2,5Kh = 1,13

K = 1,30- for 2,5

Kh = 1,08

K = 1,30

CONSTRUCTION: NDE:






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Pt B, Ch 12, App 2




Connection of inner side or bulkhead longitudinal ordinary stiffenerswith stiffeners of transverse primary supporting members - One bracket

Sheet 2.10





- for 2 < 2,5Kh = 1,30

K = 1,55- for 2,5

Kh = 1,25


- for 2 < 2,5Kh = 1,25

K = 1,46- for 2,5

Kh = 1,20

K = 1,41

CONSTRUCTION: NDE:






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Pt B, Ch 12, App 2




Connection of inner side or bulkhead longitudinal ordinary stiffenerswith stiffeners of transverse primary supporting members - Oneradiused bracket

Sheet 2.11






- for 2 < 2,5Kh = 1,25

K = 1,50- for 2,5

Kh = 1,20


- for 2 < 2,5Kh = 1,22

K = 1,44- for 2,5

Kh = 1,18

K = 1,39

CONSTRUCTION: NDE:






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Pt B, Ch 12, App 2




Connection of inner side or bulkhead longitudinal ordinary stiffenerswith stiffeners of transverse primary supporting members - Two brackets

Sheet 2.12



• 2.• 1.• Brackets to be symmetric.• h as necessary to allow the required fillet throat size, but 15 mm.• d to be as small as possible, maximum 35 mm recommended.• Thickness of the brackets to be not less than that of web stiffener.


- for 2 < 2,5 and 1 < 1,5Kh = K = 1,15

- for 2,5 and 1,5Kh = K = 1,10


Kh = K = 1,10- for 2,5 and 1,5

Kh = K = 1,05

CONSTRUCTION: NDE:

• Misalignment between longitudinal, web stiffener and brackets t / 3.• In case of fillet welding, misalignment may be as necessary to allow the






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Pt B, Ch 12, App 2




Connection of inner side or bulkhead longitudinal ordinary stiffenerswith stiffeners of transverse primary supporting members - Tworadiused brackets

Sheet 2.13



• 2.• 1.• Brackets to be symmetric.• R1 1,5 ( 1) hW

• R2 1,5 hW

• h as necessary to allow the required fillet throat size, but 15 mm.• d to be as small as possible, maximum 35 mm recommended.• Thickness of the brackets to be not less than that of web stiffener.


- for 2 < 2,5 and 1 < 1,5Kh = K = 1,10

- for 2,5 and 1,5Kh = K = 1,05


Kh = K = 1,10- for 2,5 and 1,5

Kh = K = 1,05

CONSTRUCTION: NDE:

• Misalignment between longitudinal, web stiffener and brackets t / 3.• In case of fillet welding, misalignment may be as necessary to allow the






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Pt B, Ch 12, App 2


Table 27 : OIL TANKERS, CHEMICAL TANKERS, LIQUEFIED GAS CARRIERS,BULK CARRIERS, ORE CARRIERS, COMBINATION CARRIERS

AREA 3: Double bottom in way oftransverse bulkheads

Connection of bottom and inner bottom longitudinal ordinary stiffen-ers with floors - No bracket

Sheet 3.1

t = minimum thickness between those of:- web of bottom or inner bottom longitudinal,- floor stiffener.


Fatigue check to be carried out for L 170 m:Kh = 1,30

K = 1,65

CONSTRUCTION: NDE:

• Misalignment between webs of bottom and inner bottom longitudinal with floor stiffener t / 3.

• In case of fillet weld, misalignment may be as necessary to allow the required fillet leg size, but t / 2. For bulbs, a misalignment of 6 mm may be accepted.



Welding requirements:- floor stiffeners to be connected with continuous fillet welding to bottom and inner bottom longitudinals,- weld all around the stiffeners,- fair shape of fillet at toes in longitudinal direction.

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Pt B, Ch 12, App 2




Connection of bottom and inner bottom longitudinal ordinarystiffeners with floors - Brackets

Sheet 3.2



h as necessary to allow the required fillet throat size, but 15 mm. Fatigue check to be carried out for L 170 m:Kh = 1,30

K = 1,55

CONSTRUCTION: NDE:





Welding requirements:- floor stiffeners and brackets to be connected with continuous fillet welding to bottom and inner bottom longitudinals,- partial penetration welding between stiffeners and brackets,- weld all around the stiffeners and brackets,- fair shape of fillet at toes in longitudinal direction.

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Pt B, Ch 12, App 2




Connection of bottom and inner bottom longitudinal ordinarystiffeners with floors - Radiused brackets

Sheet 3.3



• Brackets to be symmetric.• R 1,5 b• h as necessary to allow the required fillet throat size, but 15 mm.

Fatigue check to be carried out for L 170 m:Kh = 1,25

K = 1,50

CONSTRUCTION: NDE:





Welding requirements:- floor stiffeners and brackets to be connected with continuous fillet welding to bottom and inner bottom longitudinals,- partial penetration welding between stiffeners and brackets,- weld all around the stiffeners and brackets,- fair shape of fillet at toes in longitudinal direction.

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Pt B, Ch 12, App 2


Table 30 : OIL TANKERS, CHEMICAL TANKERS, BULK CARRIERS, ORE CARRIERS, COMBINATION CARRIERS


Connection of inner bottom with transverse bulkheads or lower stools Sheet 3.4

Hot spot stresses:SX = KSX sX

t = min ( t1 , t2 , t3 )


Fatigue check to be carried out for L 170 m:KSX = 3,85

CONSTRUCTION: NDE:

• Misalignment (median lines) between floor and bulkhead (or stool) plating t / 3.

• Cut-outs for connections of the inner bottom longitudinals to double bottom floors to be closed by collar plates welded to the inner bottom.

The following NDE are required:• VE 100%,• UE 35% of full penetration weld for absence of

cracks, lack of penetration and lamellar tears.


• Welding requirements:- bulkhead (or stool) plating and supporting floors generally to be connected with full penetration welding to inner bottom

plating (if not full penetration welding, the weld preparation is to be indicated on the approved drawings),- special approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing,- weld finishing well faired to the inner bottom plating.

• Material requirements:- the strake of inner bottom plating in way of the connection is recommended to be of Z25/ZH25 quality. If a steel of such a

quality is not adopted, 100% UE of the plate in way of the weld is required prior to and after welding.

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Pt B, Ch 12, App 2


Table 31 : LIQUEFIED GAS CARRIERS


Connection of inner bottom with transverse cofferdam bulkheads Sheet 3.5

Hot spot stresses:

SX = KSX nX

t = min ( t1 , t2 , t3 )



CONSTRUCTION: NDE:

• Misalignment (median lines) between floor and bulkhead plating t / 3, max 6 mm.

• Cut-outs for connections of the inner bottom longitudinals to double bottom floors to be closed by collar plates, welded to the inner bottom.




• Welding requirements:- bulkhead plating and supporting floors to be connected with full penetration welding to inner bottom plating,- bulkhead vertical girders and bottom girders are to be connected with partial penetration to inner bottom plating for the

extension shown in the sketch,- special approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing,- weld finishing well faired to the inner bottom plating.

• Material requirements:- the strake of inner bottom plating in way of the connection is to be of Z25/ZH25 or of a steel of the same mechanical per-

formances. In particular cases, grade E/EH steel may be accepted by the Society provided that the results of 100% UE of the plate in way of the weld, carried out prior to and after welding, are submitted for review.

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AREA 4: Double bottom in way of hoppertanks

Connection of inner bottom with hopper tank sloping plates Sheet 4.1

Hot spot stresses:• At hot spot A:

SY = KSY nY

• At hot spot B:SX = KSX nX + KSYX nY

tA = min (t1 , t2 , t3 ),tB = minimum among:- floor thickness,- hopper transverse web thickness,- t3.


d 50 mm. Fatigue check to be carried out for L 170 m:KSY = 3,85 where closed scallops

5,40 where open scallopsKSX = 1,30KSYX = 2,00

CONSTRUCTION: NDE:

• Misalignment (median lines) between girder and sloping plate tA / 3.

• Misalignment (median lines) between floor and hopper trans-verse web tB / 3.

The following NDE are required:• VE 100%,• UE 25% of full penetration weld for absence of cracks, lack

of penetration and lamellar tears.


• Welding requirements:- sloping plate to be connected with partial penetration welding to inner bottom plating,- approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing,- weld finishing well faired to the inner bottom plating on tank side.

• Material requirements:- the strake of inner bottom plating in way of the connection is recommended to be of Z25/ZH25 quality. If a steel of such a

quality is not adopted, 100% UE of the plate in way of the weld is required prior to and after welding.

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Connection of inner bottom with hopper tank sloping plates -Prolonging brackets

Sheet 4.2


SY = KSY nY


tA = min (t1 , t2 , t3 ),tB = minimum among:- floor thickness,- hopper transverse web thickness,- t3.


• Inner bottom plating to be prolonged within the hopper tank structure by brackets as shown in the sketch.

• d 50 mm.• Guidance values, to be confirmed by calculations carried out

according to Ch 7, Sec 3:- thickness of the above brackets t2,- b 0,4 times the floor spacing,- 1,5 b.

Fatigue check to be carried out for L 170 m:KSY = 2,4 where closed scallops


CONSTRUCTION: NDE:

• Misalignment (median lines) between girder and sloping plate tA / 3.

• Misalignment (median lines) between floor and hopper trans-verse web tB / 3.

The following NDE are required:• VE 100%,• UE 25% of full penetration weld for absence of cracks, lack

of penetration and lamellar tears.


• Welding requirement:- sloping plate to be connected with partial penetration welding to inner bottom plating,- brackets to be connected with full penetration welding to inner bottom plating,- approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing,- weld finishing well faired to the inner bottom plating on tank side.

• Material requirement:- the strake of inner bottom plating in way of the connection is recommended to be of Z25/ZH25 quality. If a steel of such a

quality is not adopted, 100% UE of the plate in way of the weld is required prior to and after welding,- material properties of prolonging brackets to be not less than those of the inner bottom plating.

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Connection of inner bottom with hopper tank sloping plates -Radiused construction

Sheet 4.3


SY = KSY nY


tA = minimum thickness between those of the girder and sloping plate,tB = minimum among:• floor thickness,• hopper transverse web thickness,• girder thickness.


• Inner radius of the bent plate to be between 3,5 and 5 times the thick-ness of the bent plate and to be indicated in the approved plan.

• Transverse brackets extended to the closest longitudinals to be fitted on each side of the girder, at mid-span between floors.

• Thickness of these brackets, in mm 9 + 0,03 L1 k1/2.

Fatigue check to be carried out for L 170 m:KSY = 3,15KSX = 1,30KSYX = 2,05

CONSTRUCTION: NDE:

• Misalignment (median lines) between girder and sloping plate tA / 3.• Misalignment (median lines) between floor and hopper transverse web

tB / 3.• In floor or transverse webs, in way of the bent area, scallops to be

avoided or closed by collar plates.




• Welding requirements:- floors to be connected (see sketches):

with full penetration welding to the inner bottom for a length 400 mm, with partial penetration welding to the girder for a length 400 mm, with continuous fillet welding in the remaining areas,

- approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing,- welding procedures of longitudinal girder to the bent plate to be submitted to the Society for review, with evidence given that

there is no risk of ageing after welding,- weld finishing of butt welds well faired to the inner bottom plating on ballast tank,- fair shape of fillet at hot spots.

• Material requirements:- the radiused construction may be accepted provided that the folding procedure is submitted to the Society for review, with

evidence given that the mechanical properties and, in particular, the impact properties are not deteriorated by the folding operation.

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Sheet 4.4


SY = KSY nY


t = minimum among:• floor thickness,• hopper transverse web thickness,• girder thickness,

tIB = inner bottom plating.


• Inner radius of the bent plate to be between 3,5 and 5 times the thickness of the bent plate and to be indicated in the approved plan.

• d 40 mm.• Transverse brackets extended to the closest longitudinals to be fitted on

each side of the girder, at mid-span between floors.• Thickness of these brackets, in mm 9 + 0,03 L1 k1/2.


CONSTRUCTION: NDE:

• Misalignment (median lines) between floor and hopper transverse web t / 3.

• In floor or transverse webs, in way of the bent area, scallops to be avoided or closed by collar plates.



• Welding requirements:- floors to be connected with full penetration welding to the inner bottom plating for a length 5 tIB ,- where girder is welded within the bent area, welding procedures to be submitted to the Society for review.

• Material requirements:- where girder is welded within the bent area, folding procedure to be submitted to the Society for review, with evidence given

that the mechanical properties and, in particular, the impact properties are not deteriorated by the folding operation.

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Connection of inner bottom with hopper tank sloping plates Sheet 4.5


SY = KSY nY


tA = min (t1 , t2 , t3 ),tB = minimum among:• floor thickness,• hopper transverse web thickness,• t3.


d 50 mm. Fatigue check to be carried out for L 170 m:KSY = 3,85 where closed scallops


CONSTRUCTION: NDE:

• Misalignment (median lines) between girder and sloping plate tA / 3, max 6 mm.

• Misalignment (median lines) between floor and hopper transverse web tB / 3, max 6 mm.




• Welding requirements:- sloping plate to be connected with full penetration welding to inner bottom plating, except in way of void spaces where par-

tial penetration may be accepted,- approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing,- weld finishing well faired to the inner bottom plating on tank side.


formances. In particular cases, grade E/EH low temperature steel may be accepted by the Society provided that the results of 100% UE of the plate in way of the weld, carried out prior to and after welding, are submitted for review.

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Connection of inner bottom with hopper tank sloping plates -Prolonging brackets

Sheet 4.6


SY = KSY nY


tA = min (t1 , t2 , t3 ),tB = minimum among:• floor thickness,• hopper transverse web thickness,• t3.


• Inner bottom plating to be prolonged within the hopper tank structure by brackets as shown in the sketch.

• d 50 mm.• Guidance values, to be confirmed by calculations carried out accord-

ing to Ch 7, Sec 3:- thickness of the above brackets t2 ,- b 0,4 times the floor spacing,- 1,5 b.

Fatigue check to be carried out for L 170 m:KSY = 2,4 where closed scallops


CONSTRUCTION: NDE:

• Misalignment (median lines) between girder and sloping plate tA / 3, max 6 mm.

• Misalignment (median lines) between floor and hopper transverse web tB / 3, max 6 mm.




• Welding requirements:- sloping plate to be connected with full penetration welding to inner bottom plating, except in way of void spaces where par-

tial penetration may be accepted,- prolonging brackets to be connected with full penetration welding to inner bottom plating,- approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing,- weld finishing well faired to the inner bottom plating on tank side.


formances. In particular cases, grade E/EH low temperature steel may be accepted by the Society provided that the results of 100% UE of the plate in way of the weld, carried out prior to and after welding, are submitted for review,

- material properties of prolonging brackets to be not less than those of the inner bottom plating.

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Sheet 4.7


SY = KSY nY


tA = minimum thickness between those of the girder and sloping plate,tB = minimum among:• floor thickness,• hopper transverse web thickness,• girder thickness.



• Transverse brackets extended to the closest longitudinals to be fitted on each side of the girder, at mid-span between floors.

• Thickness of these brackets, in mm 9 + 0,03 L1 k1/2.


CONSTRUCTION: NDE:

• Misalignment (median lines) between girder and sloping plate tA / 3.• Misalignment (median lines) between floor and hopper transverse web

tB / 3.• In floor or transverse webs, in way of the bent area, scallops to be

avoided or closed by collar plates.




• Welding requirements:- floors to be connected (see sketches):

with full penetration welding to the inner bottom for a length 400 mm, with partial penetration welding to the girder for a length 400 mm, with continuous fillet welding in the remaining areas,

- approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing,- welding procedures of longitudinal girder to the bent plate to be submitted to the Society for review, with evidence given that

there is no risk of ageing after welding,- weld finishing of butt welds well faired to the inner bottom plating on ballast tank,- fair shape of fillet at hot spots.

• Material requirements:- the radiused construction may be accepted provided that the bent plate is of grade E or EH and the folding procedure is sub-

mitted to the Society for review, with evidence given that the mechanical properties and, in particular, the impact properties are not deteriorated by the folding operation.

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AREA 5: Lower part of transverse bulkheads withlower stools

Connection of lower stools with plane bulkheads Sheet 5.1

A = distance to be taken not less than the spacing of bulkhead vertical webs


SX = KSX nX

• At hot spot B:SY = KSY nY + KSXY nX

tA = min (t1 , t2 , t3 )tB = minimum among:• thickness of member above stool top plate,• thickness of member below stool top plate,• t2 .


• d 1,5 t1.• t2 t1.• t3 t1 in portion A.• Thickness of members above and below stool top plate to be not

less than that of bulkhead vertical webs.

Fatigue check to be carried out for L 170 m:KSX = 3,85KSY = 1,30KSXY = 2,00

CONSTRUCTION: NDE:

• Misalignment (median lines) between bulkhead plating and stool side plating tA / 3.

• Misalignment (median lines) between members above and below stool top plate tB / 3.

The following NDE are required:• VE 100%,• UE 35% of full penetration welds for absence of



• Welding requirements:- bulkhead and stool side plating generally to be connected with full penetration welding to stool top plate (if not full penetra-

tion welding, the weld preparation is to be indicated on the approved drawings),- approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing is recommended in case Z material is not adopted for the stool top

plate,- weld finishing well faired to the stool top plate.

• Material requirements:- the stool top plate is recommended to be Z25/ZH25 quality. If a steel of such a quality is not adopted, 100% UE of the plate

in way of the weld is required prior to and after welding,- material properties of:

the stool top plate, the portion A of the stool side plating,to be not less than those of the transverse bulkhead plating.

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AREA 5: Lower part of transverse bulkheadswith lower stools

Connection of lower stools with plane bulkheads in way ofintermediate brackets

Sheet 5.2

A = distance to be taken not less than the spacing of bulkhead vertical websHot spot stresses:• At hot spot A:

SX = KSX nX


tA = min (t1 , t2 , t3 )tB = minimum among:• thickness of member above stool top plate,• thickness of intermediate bracket,• t2 .


• d 1,5 t1.• t2 t1.• t3 t1 in portion A.• Thickness of intermediate brackets and members above stool top

plate to be not less than that of bulkhead vertical webs.


CONSTRUCTION: NDE:

• Misalignment (median lines) between bulkhead plating and stool side plating tA / 3.

• Misalignment (median lines) between intermediate bracket and mem-ber above stool top plate tB / 3.

• Intermediate brackets to be fitted in place and welded after the weld-ing of the joint between the stool side plating and the stool top plate.




• Welding requirements:- bulkhead and stool side plating generally to be connected with full penetration welding to stool top plate (if not full penetra-

tion welding, the weld preparation is to be indicated on the approved drawings),- brackets to be connected with continuous fillet welding to plating and stiffeners,- approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing is recommended in case Z material is not adopted for the stool top

plate,- weld finishing well faired to the stool top plate.

• Material requirements:- the stool top plate is recommended to be Z25/ZH25 quality. If a steel of such a quality is not adopted, 100% UE of the plate

in way of the weld is required prior to and after welding,- material properties of:


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Connection of lower stools with plane bulkheads - Prolongingbrackets

Sheet 5.3


SX = KSX nX




• d 50 mm.• t2 t1.• t3 t1 in portion A.• Thickness of prolonging brackets t1.• Thickness of members above and below stool top plate to be not less

than that of bulkhead vertical webs.


CONSTRUCTION: NDE:

• Misalignment (median lines) between stool top plate and stool side plating tA / 3.





• Welding requirements:- stool side plating to be connected with full penetration welding to the bulkhead plating. Root gap to be checked along the

production steps as appropriate,- brackets to be connected with full penetration welding to transverse bulkhead plating,- full penetration weld of stool side plating to bulkhead plating to be welded first,- welding sequence against the risk of lamellar tearing in the bulkhead plating is recommended.

• Material requirements:- the lower strake of transverse bulkhead plating is recommended to be Z25/ZH25 quality. If a steel of such a quality is not

adopted, 100% UE of the strake in way of the weld is required prior to and after welding,- material properties of:

the stool top plate, the portion A of the stool side plating,to be not less than those of the transverse bulkhead plating,

- material properties of prolonging brackets to be not less than those of the bulkhead plating.

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Connection of lower stools with plane bulkheads - Radiusedconstruction

Sheet 5.4


SX = KSX nX





• t2 t1.• t3 t1 in portion A.• Thickness of members above and below stool top plate to be not less



CONSTRUCTION: NDE:

• Misalignment (median lines) between stool top plate and stool side plating tA / 3.


• If not full penetration welding of stool top plate to bulkhead, the weld preparation is to be indicated on the approved drawings.

• Butt welds between transverse bulkhead and stool side plating at a distance greater than 500 mm from the stool top plate.

The following NDE are required:• VE 100%,• UE 35% of full penetration welds, if any, for absence

of cracks, lack of penetration and lamellar tears.


• Welding requirements:- welding sequence against the risk of lamellar tearing in the bulkhead plate is recommended,- weld finishing well faired to the bulkhead plating and stool side plating.



- material properties of: the stool top plate, the portion A of the stool side plating,to be not less than those of the transverse bulkhead plating.

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Connection of lower stools with plane bulkheads in way ofintermediate brackets - Radiused construction

Sheet 5.5


SX = KSX nX


tA = min (t1 , t2 , t3 )tB = minimum among:• thickness of member above stool top plate,• thickness of intermediate bracket,• t2 .



• t2 t1.• t3 t1 in portion A.• Thickness of intermediate brackets and members above stool top plate to be not

less than that of bulkhead vertical webs.

Fatigue check to be carried out for L170m:KSX = 3,15KSY = 1,30KSXY = 2,05

CONSTRUCTION: NDE:

• Misalignment (median lines) between stool top plate and stool side plating tA / 3.• Misalignment (median lines) between intermediate bracket and member below

stool top plate tB / 3.• If not full penetration welding of stool top plate to bulkhead, the weld preparation

is to be indicated on the approved drawings.• Intermediate brackets to be fitted in place and welded after the welding of the

joint between the stool top plate and the bulkhead plating.• Butt welds between transverse bulkhead and stool side plating at a distance

greater than 500 mm from the stool top plate.

The following NDE are required:• VE 100%,• UE 35% of full penetration welds, if any,

for absence of cracks, lack of penetra-tion and lamellar tears.


• Welding requirements:- brackets to be connected with continuous fillet welding to plating and stiffeners,- welding sequence against the risk of lamellar tearing in the bulkhead plate is recommended,- weld finishing well faired to the bulkhead plating and stool side plating.



- material properties of: the stool top plate, the portion A of the stool side plating,to be not less than those of the transverse bulkhead plating.

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Connection of lower stools with plane bulkheads - Radiusedconstruction

Sheet 5.6

A = distance to be taken not less than the spacing of bulkhead vertical webs


SX = KSX nX


t = minimum among:• thickness of member above stool top plate,• thickness of member below stool top plate,• t2 .



• d 40 mm.• t2 t1.• t3 t1 in portion A.• Thickness of members above and below stool top plate to be not less



CONSTRUCTION: NDE:

• Misalignment (median lines) between members above and below stool top plate t / 3.






Material requirements:- where stool top plate is welded within the bent area, folding procedure to be submitted to the Society for review, with evidence

given that the mechanical properties and, in particular, the impact properties are not deteriorated by the folding operation,- material properties of:


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Connection of lower stools with plane bulkheads in way ofintermediate brackets - Radiused construction

Sheet 5.7

A = distance to be taken not less than the spacing of bulkhead vertical webs


SX = KSX nX


t = minimum among:• thickness of member above stool top plate,• thickness of intermediate bracket,• t2 .



• d 40 mm.• t2 t1.• t3 t1 in portion A.• Thickness of intermediate brackets and members above stool top

plate to be not less than that of bulkhead vertical webs.


CONSTRUCTION: NDE:

• Misalignment (median lines) between intermediate bracket and mem-ber above stool top plate t / 3.


• Intermediate brackets to be fitted in place and welded after the weld-ing of the joint between the stool top plate and the bulkhead plating.





Material requirements:- where stool top plate is welded within the bent area, folding procedure to be submitted to the Society for review, with evidence

given that the mechanical properties and, in particular, the impact properties are not deteriorated by the folding operation,- material properties of:


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Connection of lower stools with corrugated bulkheads Sheet 5.8

A a

Hot spot stress:SX = KSX nX

tF = corrugation flange thickness,tT = stool top plate thickness,tS = stool side plating thickness,

t = min (tF , tT , tS ).


• tT tF .• tS tF in portion A.


CONSTRUCTION: NDE:

• Misalignment (median lines) between corrugation flanges and stool side plating t / 3.

• Distance from the edge of the stool top plate to the surface of the cor-rugation flanges 1,5 tF.

• Corrugation radius according to Ch 4, Sec 7, [3.1.3].




• Welding requirements:- corrugations and stool side plating generally to be connected with full penetration welding to stool top plate (if not full pene-

tration welding, the weld preparation is to be indicated on the approved drawings); root gap to be checked along the produc-tion,

- welding sequence against the risk of lamellar tearing,- start and stop welding away from the locations of corrugation bents,- weld finishing well faired to the stool top plate, corrugation flanges and stool side plating.

• Material requirements:- the stool top plate is recommended to be of Z25/ZH25 quality. If a steel of such a quality is not adopted, 100% UE of the

plate in way of the weld is required prior to and after welding,- material properties of:

the stool top plate, the portion A of the stool side plating,to be not less than those of the corrugation flanges.

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Connection of lower stools with corrugated bulkheads -Shedder plates 45°

Sheet 5.9

A a


tF = corrugation flange thickness,tT = stool top plate thickness,tS = stool side plating thickness,tSH = shedder plate thickness,

tA = min (tF , tT , tS )

tB = min (tSH , tT , tS ).


• tT tF .• tS tF in portion A.• tSH 0,75 tF .


CONSTRUCTION: NDE:

• Misalignment (median lines) between corrugation flanges and stool side plating tA / 3.

• Misalignment (median lines) between lower edge of shedder plates and stool side plating tB / 3.

• Knuckled shedder plates are to be avoided.• Distance from the edge of the stool top plate to the surface of the corrugation

flanges 1,5 tF .• Corrugation radius according to Ch 4, Sec 7, [3.1.3].• In ships with service notations combination carrier, oil tanker or chemical

tanker, closed spaces to be filled with suitable compound compatible with the products carried.

The following NDE are required:• VE 100%,• UE 35% of full penetration welds for absence





- shedder plates to be connected with one side penetration, or equivalent, to corrugations and stool top plate,- welding sequence against the risk of lamellar tearing,- start and stop welding away from the locations of corrugation bents,- weld finishing well faired to the stool top plate, corrugation flanges and stool side plating.



the shedder plates, the stool top plate, the portion A of the stool side plating,to be not less than those of the corrugation flanges.

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Connection of lower stools with corrugated bulkheads -Shedder plates 55°

Sheet 5.10

A a



tA = min (tF , tT , tS ),





CONSTRUCTION: NDE:











- shedder plates to be connected with one side penetration, or equivalent, to corrugations and stool top plate,- welding sequence against the risk of lamellar tearing,- start and stop welding away from the locations of corrugation bents,- weld finishing well faired to the stool top plate, corrugation flanges and stool side plating.




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Connection of lower stools with corrugated bulkheads -Gusset and shedder plates

Sheet 5.11

A a


tF = corrugation flange thickness,tT = stool top plate thickness,tS = stool side plating thickness,tG = gusset plate thickness,tSH = shedder plate thickness,

tA = min (tF , tT , tS ),

tB = min (tG , tT , tS ).


• tT tF .• tG tF .

• tS tF in portion A.• tSH 0,75 tF . • hG a / 2.


CONSTRUCTION: NDE:


• Misalignment (median lines) between lower edge of gusset plates and stool side plating tB / 3.

• Distance from the edge of the stool top plate to the surface of the corrugation flanges 1,5 tF .

• Corrugation radius according to Ch 4, Sec 7, [3.1.3].• In ships with service notations combination carrier, oil tanker or chemical







- gusset plates generally to be connected with full penetration welding to stool top plate (if not full penetration welding, the weld preparation is to be indicated on the approved drawings) and with one side penetration, or equivalent, to corrugations and shedder plates,

- shedder plates to be connected with one side penetration, or equivalent, to corrugations and gusset plates,- welding sequence against the risk of lamellar tearing,- start and stop welding away from the locations of corrugation bents,- weld finishing well faired to the stool top plate, corrugation flanges and stool side plating.



the gusset plates, the shedder plates, the stool top plate, the portion A of the stool side plating,to be not less than those of the corrugation flanges.

Stool top plate

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Pt B, Ch 12, App 2




Connection of lower stools with corrugated bulkheads -Sloping stool top plate

Sheet 5.12

A a



tA = min (tF , tT , tS ).





CONSTRUCTION: NDE:











- shedder plates to be connected with one side penetration, or equivalent, to corrugations and stool top plate,- welding sequence against the risk of lamellar tearing- start and stop welding away from the locations of corrugation bents,- weld finishing well faired to the stool top plate, corrugation flanges and stool side plating.




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Connection of lower stools with corrugated bulkheads -Brackets below stool top plate

Sheet 5.13

A a,B = bracket dimension.


tF = corrugation flange thickness,tW = corrugation web thickness,tT = stool top plate thickness,tS = stool side plating thickness,tB = bracket thickness,

tA = min (tF , tT , tS ).

tB = min (tW , tT , tS ).


• tT tF

• tS tF in portion A• tB tW

• B d


CONSTRUCTION: NDE:


• Misalignment (median lines) between corrugation webs and brackets below stool top plate tB / 3.

• Distance from the edge of the stool top plate to the surface of the corrugation flanges 1,5 tF .

• Corrugation radius according to Ch 4, Sec 7, [3.1.3].






- welding sequence against the risk of lamellar tearing,- start and stop welding away from the locations of corrugation bents,- weld finishing well faired to the stool top plate, corrugation flanges and stool side plating.



the stool top plate, the portion A of the stool side plating,to be not less than those of the corrugation flanges.

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Pt B, Ch 12, App 2




Connection of lower stools with corrugated bulkheads -Shedder plates 45° and brackets below stool top plate

Sheet 5.14



tF = corrugation flange thickness,tW = corrugation web thickness,tT = stool top plate thickness,tS = stool side plating thickness,tSH = shedder plate thickness,tB = bracket thickness,

tA = min (tF , tT , tS )tB = min (tSH , tT , tS )tC = min (tW , tT , tB ).


• tT tF

• tSH 0,75 tF

• tS tF in portion A• tB tW

• B d Fatigue check to be carried out for L 170 m:KSX = 1,25

CONSTRUCTION: NDE:



• Misalignment (median lines) between corrugation webs and brackets below stool top plate tC / 3.









- shedder plates to be connected with one side penetration, or equivalent, to corrugations and stool top plate,- welding sequence against the risk of lamellar tearing- start and stop welding away from the locations of corrugation bents,- weld finishing well faired to the stool top plate, corrugation flanges and stool side plating.




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Connection of lower stools with corrugated bulkheads -Gusset and shedder plates and brackets below stool top plate

Sheet 5.15



tF = corrugation flange thickness,tW = corrugation web thickness,tT = stool top plate thickness,tS = stool side plating thickness,tG = gusset plate thickness,tSH = shedder plate thickness,tB = bracket thickness,

tA = min (tF , tT , tS )tB = min (tG , tT , tS )tC = min (tW , tT , tB ).

SCANTLINGS: FATIGUE:• tT tF• tB tW

• tS tF in portion A• hG a / 2

• tG tF• B d

• tSH 0,75 tF Fatigue check not required.

CONSTRUCTION: NDE:• Misalignment (median lines) between corrugation flanges and stool side plating tA /

3.• Misalignment (median lines) between lower edge of gusset plates and stool side plat-

ing tB / 3.• Misalignment (median lines) between corrugation webs and brackets below stool top

plate tC / 3.• Distance from the edge of the stool top plate to the surface of the corrugation flanges

1,5 tF .• Corrugation radius according to Ch 4, Sec 7, [3.1.3].• In ships with service notations combination carrier, oil tanker or chemical tanker,

closed spaces to be filled with suitable compound compatible with the products car-ried.

The following NDE are required:• VE 100%,• UE 35% of full penetration welds for

absence of cracks, lack of penetra-tion and lamellar tears.

WELDING AND MATERIALS:• Welding requirements:

- corrugations and stool side plating generally to be connected with full penetration welding to stool top plate (if not full pene-tration welding, the weld preparation is to be indicated on the approved drawings); root gap to be checked along the produc-tion,

- gusset plates generally to be connected with full penetration to stool top plate (if not full penetration welding, the weld prep-aration is to be indicated on the approved drawings) and with one side penetration, or equivalent, to corrugations and shed-der plates,

- shedder plates to be connected with one side penetration, or equivalent, to corrugations and gusset plates,- welding sequence against the risk of lamellar tearing- start and stop welding away from the locations of corrugation bents,- weld finishing well faired to the stool top plate, corrugation flanges and stool side plating.



the gusset plates, the shedder plates, the stool top plate, the portion A of the stool side plating,to be not less than those of the corrugation flanges.

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AREA 6: Lower part of inner side Connection of hopper tank sloping plates with inner side Sheet 6.1

A = distance to be taken not less than the spacing of side transverses


SX = KSX nX


tA = min (t1 , t2 , t3 )

tB = minimum among:• thickness of member above hopper tank top plate,• thickness of member below hopper tank top plate,• t2 .


• d 1,5 t1 .• t2 t1 .• t3 t1 in portion A.• Thickness of members above and below hopper tank top plate to be

not less than that of side transverses.


CONSTRUCTION: NDE:

• Misalignment (median lines) between inner side plating and hopper tank sloping plate tA / 3.

• Misalignment (median lines) between members above and below hopper tank top plate tB / 3.




• Welding requirements:- inner side and hopper tank sloping plate generally to be connected with full penetration welding to hopper tank top plate (if

not full penetration welding, the weld preparation is to be indicated on the approved drawings),- approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing is recommended in case Z material is not adopted for the hopper tank

top plate,- weld finishing well faired to the hopper tank top plate.

• Material requirements:- the hopper tank top plate is recommended to be Z25/ZH25 quality. If a steel of such a quality is not adopted, 100% UE of the

plate in way of the weld is required prior to and after welding,- material properties of the portion A of the hopper tank sloping plate to be not less than those of the inner side plating.

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AREA 6: Lower part of inner sideConnection of hopper tank sloping plates with inner side in wayof intermediate brackets

Sheet 6.2

A = distance to be taken not less than the spacing of side transversesHot spot stresses:• At hot spot A:

SX = KSX nX


tA = min (t1 , t2 , t3 )tB = minimum among:• thickness of member above hopper tank top plate,• thickness of intermediate bracket,• t2 .


• d 1,5 t1 .• t2 t1 .• t3 t1 in portion A.• Thickness of intermediate brackets and members above hopper tank top

plate to be not less than that of side transverses.


CONSTRUCTION: NDE:

• Misalignment (median lines) between inner side plating and hopper tank sloping plate tA / 3.

• Misalignment (median lines) between intermediate bracket and member above hopper tank top plate tB / 3.

• Intermediate brackets to be fitted in place and welded after the welding of the joint between the hopper tank sloping plate and the hopper tank top plate.




• Welding requirements:- inner side and hopper tank sloping plate generally to be connected with full penetration welding to hopper tank top plate (if

not full penetration welding, the weld preparation is to be indicated on the approved drawings),- brackets to be connected with continuous fillet welding to plating and stiffeners,- approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing is recommended in case Z material is not adopted for the hopper tank


• Material requirements:- the hopper tank top plate is recommended to be Z25/ZH25 quality. If a steel of such a quality is not adopted, 100% UE of the

plate in way of the weld is required prior to and after welding,- material properties of the portion A of the hopper tank sloping plate to be not less than those of the inner side plating.

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AREA 6: Lower part of inner sideConnection of hopper tank sloping plates with inner side -Prolonging brackets

Sheet 6.3


SX = KSX nX


tA = min (t1 , t2 , t3 )tB = minimum among:• thickness of member above hopper tank top plate,• thickness of member below hopper tank top plate,• t2 .


• d 50 mm.• t2 t1 .• t3 t1 in portion A.• Thickness of prolonging brackets t1 .• Thickness of members above and below hopper tank top plate to be not

less than that of side transverses.


CONSTRUCTION: NDE:

• Misalignment (median lines) between hopper tank top plate and hopper tank sloping plate tA / 3.

• Misalignment (median lines) between members above and below hop-per tank top plate tB / 3.




• Welding requirements:- hopper tank sloping plate to be connected with full penetration welding to the inner side plating. Root gap to be checked

along the production steps as appropriate,- prolonging brackets to be connected with full penetration welding to inner side plating,- full penetration weld of hopper tank sloping plate to inner side plating to be welded first,- welding sequence against lamellar tearing in the inner side plating is recommended.

• Material requirements:- the lower strake of inner side plating is recommended to be Z25/ZH25 quality. If a steel of such a quality is not adopted,

100% UE of the strake in way of the weld is required prior to and after welding,- material properties of the portion A of the hopper tank sloping plate to be not less than those of the inner side plating,- material properties of prolonging brackets to be not less than those of the inner side plating.

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AREA 6: Lower part of inner sideConnection of hopper tank sloping plates with inner side -Radiused construction

Sheet 6.4



SX = KSX nX


tA = min (t1 , t2 , t3 )tB = minimum among:• thickness of member above hopper tank top plate,• thickness of member below hopper tank top plate,• t2 .



• t2 t1 .• t3 t1 in portion A.• Thickness of members above and below hopper tank top plate to be not



CONSTRUCTION: NDE:


• Misalignment (median lines) between members above and below hopper tank top plate tB / 3.

• If not full penetration welding of hopper tank top plate to inner side, the weld preparation is to be indicated on the approved drawings.

• Butt welds between inner side and hopper tank sloping plate at a distance greater than 500 mm from the hopper tank top plate.

The following NDE are required:• VE 100%,• UE 25% of full penetration welds, if any, for

absence of cracks, lack of penetration and lamellar tears.


• Welding requirements:- welding sequence against the risk of lamellar tearing in the inner side plate is recommended,- weld finishing well faired to the inner side plating and hopper tank sloping plate.


evidence given that the mechanical properties and, in particular, the impact properties are not deteriorated by the folding operation,

- material properties of the portion A of the hopper tank sloping plate to be not less than those of the inner side plating.

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AREA 6: Lower part of inner sideConnection of hopper tank sloping plates with inner side in wayof intermediate brackets - Radiused construction

Sheet 6.5


SX = KSX nX





• t2 t1 .• t3 t1 in portion A.• Thickness of intermediate brackets and members above hopper tank top



CONSTRUCTION: NDE:


• Misalignment (median lines) between intermediate bracket and member above hopper tank top plate tB / 3.


• Intermediate brackets to be fitted in place and welded after the welding of the joint between the hopper tank top plate and the inner side plating.





• Welding requirements:- brackets to be connected with continuous fillet welding to plating and stiffeners,- welding sequence against the risk of lamellar tearing in the inner side plate is recommended,- weld finishing well faired to the inner side plating and hopper tank sloping plate.


evidence given that the mechanical properties and, in particular, the impact properties are not deteriorated by the folding operation,


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AREA 6: Lower part of inner sideConnection of hopper tank sloping plates with inner side -Radiused construction

Sheet 6.6



SX = KSX nX


t = minimum among:• thickness of member above hopper tank top plate,• thickness of member below hopper tank top plate,• t2 .



• d 40 mm.• t2 t1 .• t3 t1 in portion A.• Thickness of members above and below hopper tank top plate to be not



CONSTRUCTION: NDE:

• Misalignment (median lines) between members above and below hopper tank top plate t / 3.






Material requirements:- where hopper tank top plate is welded within the bent area, folding procedure to be submitted to the Society for review, with evi-

dence given that the mechanical properties and, in particular, the impact properties are not deteriorated by the folding operation,- material properties of the portion A of the hopper tank sloping plate to be not less than those of the inner side plating.

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AREA 6: Lower part of inner sideConnection of hopper tank sloping plates with inner side in wayof intermediate brackets - Radiused construction

Sheet 6.7



SX = KSX nX


t = minimum among:• thickness of member above hopper tank top plate,• thickness of intermediate bracket,• t2 .



• d 40 mm.• t2 t1 .• t3 t1 in portion A.• Thickness of intermediate brackets and members above hopper tank top



CONSTRUCTION: NDE:

• Misalignment (median lines) between intermediate bracket and member above hopper tank top plate t / 3.


• Intermediate brackets to be fitted in place and welded after the welding of the joint between the hopper tank top plate and the inner side plating.





Material requirements:- where hopper tank top plate is welded within the bent area, folding procedure to be submitted to the Society for review, with evi-

dence given that the mechanical properties and, in particular, the impact properties are not deteriorated by the folding operation,- material properties of the portion A of the hopper tank sloping plate to be not less than those of the inner side plating.

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AREA 6: Lower part of inner side Connection of hopper tank sloping plates with inner side Sheet 6.8



SX = KSX nX


tA = min (t1 , t2 , t3 )

tB = minimum among:• thickness of member above hopper tank top plate,• thickness of member below hopper tank top plate,• t2 .


• d 1,5 t1 .• t2 t1 .• t3 t1 in portion A.• Thickness of members above and below hopper tank top plate to be

not less than that of side transverses.


CONSTRUCTION: NDE:

• Misalignment (median lines) between inner side plating and hopper tank sloping plate tA / 3, max 6 mm.

• Misalignment (median lines) between members above and below hopper tank top plate tB / 3, max 6 mm.




• Welding requirements:- inner side and hopper tank sloping plate to be connected with full penetration welding to hopper tank top plate, except in

way of void spaces where partial penetration may be accepted,- approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing is recommended in case Z material is not adopted for the hopper tank


• Material requirements:- the hopper tank top plate is to be of Z25/ZH25 or of a steel of the same mechanical performances. In particular cases, grade

E/EH low temperature steel may be accepted by the Society provided that the results of 100% UE of the plate in way of the weld, carried out prior to and after welding, are submitted for review,


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AREA 6: Lower part of inner sideConnection of hopper tank sloping plates with inner side in wayof intermediate brackets

Sheet 6.9


SX = KSX nX




• d 1,5 t1 .• t2 t1 .• t3 t1 in portion A.• Thickness of intermediate brackets and members above hopper tank top



CONSTRUCTION: NDE:

• Misalignment (median lines) between inner side plating and hopper tank sloping plate tA / 3, max 6 mm.

• Misalignment (median lines) between intermediate bracket and member above hopper tank top plate tB / 3, max 6 mm.

• Intermediate brackets to be fitted in place and welded after the welding of the joint between the hopper tank sloping plate and the hopper tank top plate.




• Welding requirements:- inner side and hopper tank sloping plate to be connected with full penetration welding to hopper tank top plate, except in

way of void spaces where partial penetration may be accepted,- brackets to be connected with continuous fillet welding to plating and stiffeners,- approval of the procedure on a sample representative of the actual conditions foreseen in production,- welding sequence against the risk of lamellar tearing is recommended in case Z material is not adopted for the hopper tank


• Material requirements:- the hopper tank top plate is to be of Z25/ZH25 or of a steel of the same mechanical performances. In particular cases, grade

E/EH low temperature steel may be accepted by the Society provided that the results of 100% UE of the plate in way of the weld, carried out prior to and after welding, are submitted for review,


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Table 63 : BULK CARRIERS

AREA 7: Side framesConnection of side frames with hopper and topside tanks - Symmetric faceplate frame with integral brackets

Sheet 7.1

tw = fitted thickness, in mm, of side frame webbF = bracket flange width, in mm

tw,min = (7,0 + 0,03 L1) mm tF = bracket flange thickness, in mm.


• Thickness of lower bracket, in mm, max (tw , tw, min + 2).• Thickness of upper bracket, in mm, max (tw , tw, min ).• Section modulus of the frame with the upper or lower bracket, at the locations shown in the

sketch, to be not less than twice the section modulus required for the frame mid-span area.• Dimensions of lower and upper brackets to be not less than those shown in the sketch.• Structural continuity with the upper and lower end connections of side frames is to be ensured

within hopper tanks and upper wing tanks by connecting brackets.• Frame flange to be curved (not knuckled ) at the connection with the end brackets, r 0,4 bF

2 / tF .• Ends of flange to be sniped.


CONSTRUCTION: NDE:

• Misalignment between frame web and the connecting brackets inside hopper tank and upper wing tank t / 3, where t is the mini-mum thickness among those of the connected elements.

• Soft toe: tapering of frame flange at ends: thickness 1:3, width 1:5.

The following NDE are required:• VE 100%, with particular care for fillet shape and

undercuts on the plating at the soft toes,• ME or dye penetrant depending on the results of VE.


Welding requirements:- frames and brackets to be connected with continuous fillet welding to side plating, hopper tank and upper wing tank plating,

with throat thickness to be not less than : 0,45 t in “zone a”, 0,40 t in “zone b”,where t is the minimum thickness between those of the two connected elements,

- welding sequence to minimise restraints at the frame butt joints, i.e.: leaving about 200 mm unwelded, each side of butt joint, of the connections between frame web and side plating and

between frame web and flange, performing the frame butt joints, completing the fillet welding,

- turn the fillet weld all around the end of integral brackets and scallops giving an elongated shape, well faired to the plating,- avoid burned notches at the scallops, if existing, in way of frame flange butt joints; if scallops not adopted, care to be taken to

avoid end defects at web butt joints.

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Table 64 : BULK CARRIERS

AREA 7: Side framesConnection of side frames with hopper and topside tanks - Non symmetric faceplate frame with separate brackets

Sheet 7.2

This solution is permitted only for ships less than 190 m in length with side frames built in normal strength steel.

tw = fitted thickness, in mm, of side frame webbF = bracket flange width, in mm

tw,min = (7,0 + 0,03 L1) mm tF = bracket flange thickness, in mm.

SCANTLINGS: FATIGUE:• Thickness of lower bracket, in mm, max (tw , tw, min + 2).• Thickness of upper bracket, in mm, max (tw , tw, min ).• Section modulus of the frame with the upper or lower bracket, at the locations shown in the sketch,

to be not less than twice the section modulus required for the frame mid-span area.• Dimensions of lower and upper brackets to be not less than those shown in the sketch.• Structural continuity with the upper and lower end connections of side frames is to be ensured

within hopper tanks and upper wing tanks by connecting brackets.• Ends of flange to be sniped.• z 50 mm.


CONSTRUCTION: NDE:• Misalignment between frame brackets and the connecting brackets

inside hopper tank and upper wing tank t / 3, where t is the mini-mum thickness among those of the connected elements.

• Bracket overlap: 1,5 d, in mm.• Soft toe: tapering of frame flange at ends: thickness 1:3, width 1:5.


undercuts on the plating at the soft toes ,• ME or dye penetrant depending on the results of VE.

WELDING AND MATERIALS:Welding requirements:- frames and brackets to be connected with continuous fillet welding to side plating, hopper tank and upper wing tank plating,

with throat thickness to be not less than : 0,45 t in “zone a”, 0,40 t in “zone b”,where t is the minimum thickness between those of the two connected elements,

- brackets to be connected with continuous fillet welding to frames, with throat thickness to be not less than half thickness of brackets,

- welding procedure of frame butt joint, if any, to be approved with particular care for the welding of the bulbs and of the corner in case of L sections,

- welding sequence to minimise restraints at the frame butt joints, i.e.: leaving about 200 mm unwelded, each side of butt joint, of the connections between frame web and side plating and

between frame web and flange, performing the frame butt joints, completing the fillet welding,

- turn the fillet weld all around the end of integral brackets and scallops giving an elongated shape, well faired to the plating,- avoid burned notches at fillet welds of overlapped joints and at scallops.

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Table 65 : BULK CARRIERS, ORE CARRIERS, COMBINATION CARRIERS

AREA 8: Topside tanks Connection of transverse corrugated bulkheads with topside tanks Sheet 8.1

t = minimum thickness among those of the connected elements.


A transverse web or an intercostal reinforcement is to be fitted inside the top-side tank in line with the flanges of corrugation and the upper stool side plat-ing. Its arrangement is to be indicated in the approved plan.


CONSTRUCTION: NDE:

Misalignments between:- transverse web or intercostal reinforcement fitted inside the upper wing

tank and corrugation flanges,- transverse web or intercostal reinforcement fitted inside the upper wing

tank and upper stool side plating,- upper stool side plating and corrugation flanges,are to be t / 3.


undercuts on the plating,• UE 100% of full penetration weld for absence of



Welding requirements:- bulkhead plating to be connected with continuous fillet welding to topside plating and upper stool plating, full penetration weld

is recommended in way of corner of vertical and inclined plating of upper wing tank,- throat thickness = 0,45 t, where t is the minimum thickness between those of the two connected elements,- gap at T joint reduced to the minimum,- welding sequence to minimise restraints.

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Pt B, Ch 12, App 2


Table 66 : CONTAINER SHIPS

AREA 9: Cross decks Connection of cross decks with side transverses Sheet 9.1



• Cross deck strips between hatches to be suitably overlapped at ends.• Stresses due to forces transmitted by cross deck strips to web frames

calculated taking into account frame openings.

Fatigue check not required

CONSTRUCTION: NDE:

Misalignment between brackets and webs of cross decks and web frames t / 3.

The following NDE are required:• Visual examination 100%, with particular care for:

- fillet shape and undercuts at ends of brackets, if grinding on plating is not adopted,

- quality of cuts at bracket free edge,• UE 100% of full penetration welds, if any, for absence



Welding requirements:- cross deck structures to be connected with continuous fillet welding to web frame structures, full penetration weld recommended

in areas indicated in the sketch,- throat thickness = 0,45 t, where t is the minimum thickness between those of the two connected elements,- turn the fillet weld all around the bracket ends giving an elongated shape, well faired to the frame and cross deck, avoiding

notches; grinding recommended.

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Pt B, Ch 12, App 2


Table 67 : CONTAINER SHIPS

AREA 9: Cross decks Connection between face plates of cross decks and deck girders Sheet 9.2

B = min (B1 , B2 )


• R B.• t3 max (t1 , t2 ).


CONSTRUCTION: NDE:

Cut edges to be carefully executed. The following NDE are required:• Visual examination 100%,• UE 100% of full penetration welds for absence of cracks,

lack of penetration and lamellar tears.


Welding requirements:- brackets to be connected with full penetration welding to deck girder and cross deck face plates,- welds recommended to be continued on auxiliary pieces temporarily fitted at both end of each joint, to be cut away; joint ends

to be carefully ground.

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Pt B, Ch 12, App 2


Table 68 : BULK CARRIERS, ORE CARRIERS, COMBINATION CARRIERS, CONTAINER SHIPS

AREA 10: Hatch corners Deck plating in way of hatch corners Sheet 10.1


• Insert plates with circular profiles in general to be fitted in way of corners of hatchways located within the cargo area. The radius of circular corners to be in accordance with Ch 4, Sec 6, [6.2.1].

• Insert plates not required in way of corners of hatchways located in the above positions, where corners have an elliptical or parabolic profile according to Ch 4, Sec 6, [6.2.2].

• Where insert plates are required, their thickness to be defined according to Ch 4, Sec 6, [6.2.3] and their extension to be such that d1 , d2 , d3 and d4 s, s being the ordinary frame spacing.


CONSTRUCTION: NDE:

• Corners of insert plates to be rounded, unless corresponding to joints of deck strakes.

• Insert cut edges to be carefully executed.

The following NDE are required:• VE 100%,• RE / UE in areas indicated in the sketch.


• Welding requirements:- welds recommended to be continued on auxiliary pieces temporarily fitted at the free end of each joint, to be cut away; the

joint ends are to be carefully ground.• Materials requirements:

- insert plate material of same or higher quality than the adjacent deck plating, depending on the insert thickness according to Ch 4, Sec 1, [2].

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AREA 10: Hatch corners Ends of longitudinal hatch coamings - Bracket welded to deck plating Sheet 10.2

tA = minimum among:- thickness of bracket flange at

lower end,- deck plating thickness,- under deck transverse stiffener

web thickness,

tB = minimum among:- bracket web thickness,- deck plating thickness,- thickness of the under deck longi-

tudinal member.


An additional under deck transverse stiffener is to be fitted in way of termination bracket toe, where the toe is clear of normal stiffener.


CONSTRUCTION: NDE:

• Misalignment between bracket flange and under deck transverse stiffener tA / 3.

• Misalignment between bracket and under deck longitudinal tB / 3.

The following NDE are required:• VE 100%, with particular care for the weld shape and

undercuts on deck plating at the bracket flange connec-tion,

• UE 100% of full penetration welds for absence of cracks, lack of penetration and lamellar tears.


Welding requirements:- bracket flange to be connected with full penetration welding to deck plating, with half V bevel and weld shape elongated on

deck plating (see sketch),- ends of bracket webs to be connected with full penetration welding to deck plating for the extension shown in the sketch, with

half X bevel,- under deck transverse stiffener to be connected with full penetration welding to deck plating in way of the bracket flange,- care is to be taken to ensure soundness of the crossing welds at the bracket toe, if the case, adopting small scallop to be closed by

welding.

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AREA 10: Hatch corners Ends of longitudinal hatch coamings - Bracket sniped at deck plating Sheet 10.3

t = minimum among:- bracket web thickness,- deck plating thickness,- thickness of the under deck

longitudinal member.


R 500 mm. 30°.


CONSTRUCTION: NDE:

• Misalignment between bracket and under deck longitu-dinal tB / 3.

• Soft toe: tapering of bracket flange at ends: thickness 1:3, width 1:5.

The following NDE are required:• VE 100%, with particular care for the weld shape and undercuts

on deck plating,• UE 100% of full penetration welds for absence of cracks, lack of

penetration and lamellar tears.


Welding requirements:- ends of bracket webs to be connected with full penetration welding to deck plating for the extension shown in the sketch, with

half X bevel.

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SECTION 1 GENERAL

1 General

1.1 Application

1.1.1 Service notation “Oil tanker”

a) The requirements of this Chapter apply to ships havingthe service notation oil tanker, as defined in Pt A, Ch 1,Sec 2, [4.4.2]. They also apply to ships having the addi-tional service feature flash point > 60°C and asphaltcarrier, taking into account the specific provisions givenin the different Sections.

Note 1: The specific provisions referred to in a) above do not applyto ships intended for the carriage of bulk cargoes at a tempera-ture above the flash point of the product carried.

b) Departures from these requirements are given for shipsthat have the service notation oil tanker, flash point> 60°C and are intended only for the carriage of bulkcargoes:

• at a temperature below and not within 15°C of theirflash point, or

• having a flash point above 100°C.

c) Ch 7, Sec 4, [8] provides additional requirements forships having the service notation oil tanker, asphalt car-rier.

d) The list of substances the carriage in bulk of which iscovered by the service notations oil tanker, oil tanker,flash point > 60°C and oil tanker, asphalt carrier isgiven in Ch 7, App 3, Tab 1.

1.1.2 Service notation FLS tanker

a) The requirements of this Chapter apply to ships havingthe service notation FLS tanker, as defined in Pt A, Ch 1,Sec 2, [4.4.5]. They also apply to ships having the addi-tional service feature FLS tanker, flash point > 60°C,taking into account the specific provisions given in Ch7, Sec 4.

Note 1: The specific provisions referred to in a) above do not applyto ships intended for the carriage of bulk cargoes at a tempera-ture above the flash point of the product carried.

b) Ch 7, Sec 4, [9] provides additional requirements forships having the service notations FLS tanker and FLStanker, flash point > 60°C in the case of carriage of pol-lution category Z products.

c) The list of substances the carriage in bulk of which iscovered by the service notations FLS tanker and FLStanker, flash point > 60°C is given in Ch 7, App 4.

Note 2: The service notation FLS tanker does not cover cargoescontaining 10% of benzene or more. Ships carrying such car-goes are to comply with the relevant requirements of Part D,Chapter 8.

Note 3: Where the provisions of this Chapter applicable to theservice notation oil tanker and those applicable to the servicenotation FLS tanker are simultaneously complied with, a shipmay be granted both service notations oil tanker - FLS tankeror oil tanker - FLS tanker, flash point > 60°C, as applicable.

1.2 Summary table

1.2.1 Tab 1 indicates the Sections of this Chapter contain-ing additional requirements applicable to ships having thefollowing service notations:• oil tanker• oil tanker, flash point > 60°C• oil tanker, asphalt carrier• FLS tanker• FLS tanker, flash point > 60°C.

1.3 Definitions

1.3.1 Cargo areaThe cargo area is that part of the ship that contains cargotanks as well as slop tanks, cargo pump rooms includingpump rooms, cofferdams, ballast or void spaces adjacent tocargo tanks or slop tanks as well as deck areas throughoutthe entire length and breadth of the part of the ship abovethese spaces.When independent tanks are installed in hold spaces, thecofferdams, ballast or void spaces at the after end of theaftermost hold space or at the forward end of the forward-most hold space are excluded from the cargo area.

Table 1 : Content of Chapter 7

Main subject Reference

Ship arrangement Ch 7, Sec 2

Hull and stability Ch 7, Sec 3

Machinery and cargo system Ch 7, Sec 4 (1)

Electrical installations Ch 7, Sec 5

Automation (2)

Fire protection, detection and extinction Ch 7, Sec 6

Devices to prevent the passage of flames into cargo tanks

Ch 7, App 1

Crude oil washing system Ch 7, App 2

List of oils Ch 7, App 3

List of easy chemicals Ch 7, App 4

Damage assumptions and outflow of oil Ch 7, App 5

(1) This Section contains a table summarising the depar-tures applicable to the different service notations.

(2) This chapter do not contain specific requirements foroil tanker and FLS tanker on this subject.

Pt D, Ch 7, Sec 1


1.3.2 Cargo pump room

Cargo pump room is a space containing pumps and theiraccessories for the handling of products covered by theservice notation granted to the ship.

1.3.3 Cargo service spaces

Cargo service spaces are spaces within the cargo area usedfor workshops, lockers and storerooms of more than 2 m2 inarea, intended for cargo handling equipment.

1.3.4 Clean ballast

Clean ballast means the ballast in a tank which since oil waslast carried therein, has been so cleaned that the effluenttherefrom if it were discharged from a ship which is station-ary into clean calm water on a clear day would not producevisible traces of oil on the surface of the water or on adjoin-ing shorelines or cause a sludge or emulsion to be depositedbeneath the surface of the water or upon adjoining shore-lines. If the ballast is discharged through an oil dischargemonitoring and control system approved by the Society, evi-dence based on such a system to the effect that the oil con-tent of the effluent did not exceed 15 parts per million is tobe determinative that the ballast was clean, notwithstandingthe presence of visible traces.

1.3.5 Cofferdam

For the purpose of Ch 7, Sec 2, [2], a cofferdam is an isolat-ing space between two adjacent steel bulkheads or decks. Itis to meet the following criteria:

a) the minimum distance between the two bulkheads ordecks is to be sufficient for safe access and inspection.

b) in order to meet the single failure principle, in the par-ticular case when a corner-to-corner situation occurs,this principle may be met by welding a diagonal plateacross the corner.

1.3.6 Crude oil

Crude oil is any oil occurring naturally in the earth whetheror not treated to render it suitable for transportation andincludes:

a) crude oil from which certain distillate fractions havebeen removed, and

b) crude oil to which certain distillate fractions may havebeen added.

1.3.7 Crude oil tanker

Crude oil tanker means an oil tanker engaged in the trade ofcarrying crude oil.

1.3.8 Hold space

Hold space is the space enclosed by the ship’s structure inwhich an independent cargo tank is fitted

1.3.9 Fuel oil

Fuel oil means any oil used as fuel in connection with thepropulsion and auxiliary machinery of the ship on whichsuch oil is carried.

1.3.10 Non-sparking fanA fan is considered as non-sparking if in either normal orabnormal conditions it is unlikely to produce sparks. Forthis purpose, the following criteria are to be met:

a) Design criteria

1) The air gap between the impeller and the casing is tobe not less than 1/10 of the shaft diameter in way ofthe impeller bearing and in any case not less than 2mm, but need not exceed 13 mm

2) Protective screens with square mesh of not morethan 13 mm are to be fitted to the inlet and outlet ofventilation ducts to prevent objects entering the fanhousing.

b) Materials

1) The impeller and the housing in way of the impellerare to be made of spark-proof materials which arerecognised as such by means of an appropriate testto the satisfaction of the Society

2) Electrostatic charges, both in the rotating body andthe casing, are to be prevented by the use of anti-static materials. Furthermore, the installation onboard of ventilation units is to be such as to ensuretheir safe bonding to the hull

3) Tests may not be required for fans having the follow-ing material combinations:• impellers and/or housings of non-metallic mate-

rial, due regard being paid to the elimination ofstatic electricity

• impellers and housings of non-ferrous materials• impellers of aluminium alloys or magnesium

alloys and a ferrous (including austenitic stain-less steel) housing on which a ring of suitablethickness of non-ferrous material is fitted in wayof the impeller

• any combination of ferrous (including austeniticstainless steel) impellers and housings with notless than 13 mm design tip clearance.

4) The following impeller and housing combinationsare considered as sparking and therefore are not per-mitted:• impellers of an aluminium alloy or a magnesium

alloy and a ferrous housing, regardless of tipclearance

• housings made of an aluminium alloy or a mag-nesium alloy and a ferrous impeller, regardless oftip clearance

• any combination of ferrous impeller and housingwith less than 13 mm design tip clearance.

5) Complete fans are to be type-tested in accordancewith either the Society’s requirements or national orinternational standards accepted by the Society.

1.3.11 Oil-like substancesOil-like substances are those substances listed in Ch 7, App3, Tab 2.

1.3.12 Oil mixtureOil mixture means a mixture with any oil content.

Pt D, Ch 7, Sec 1


1.3.13 Product carrierProduct carrier means an oil tanker engaged in the trade ofcarrying oil other than crude oil.

1.3.14 Pump roomPump room is a space, located in the cargo area, containingpumps and their accessories for the handling of ballast andfuel oil, or cargoes other than those covered by the servicenotation granted to the ship.

1.3.15 Segregated ballastSegregated ballast means the ballast water introduced into atank which is completely separated from the cargo oil andfuel oil system and which is permanently allocated to the

carriage of ballast or to the carriage of ballast or cargoesother than oil or noxious substances as variously defined inPart D, Chapter 7 and Part D, Chapter 8.

1.3.16 Slop tank

Slop tank means a tank specifically designated for the col-lection of tank draining, tank washings and other oily mix-tures.

1.3.17 Void space

Void space is an enclosed space in the cargo area externalto a cargo tank, except for a hold space, ballast space, fueloil tank, cargo pump room, pump room, or any space nor-mally used by personnel.

Pt D, Ch 7, Sec 2


SECTION 2 SHIP ARRANGEMENT

Symbols

LLL : Load line length, in m, defined in Pt B, Ch 1,Sec 2, [3.2].

1 General

1.1 Application

1.1.1 Except otherwise specified, the requirements of thisSection apply to the ships having one of the following serv-ice notations:• oil tanker• oil tanker, flash point > 60°C• oil tanker, asphalt carrier• FLS tanker• FLS tanker, flash point > 60°C.

1.1.2 The requirements of this Section apply to ships hav-ing a propelling machinery located at the aft part of theship. Ships with other arrangements are to be specially con-sidered by the Society.

1.2 Documents to be submitted

1.2.1 Tab 1 are to be submitted for approval.

Table 1 : Documents to be submitted

2 General arrangement of the ship with regard to fire prevention and crew safety

2.1 Location and separation of spaces

2.1.1 Applicationa) The provisions of [2.1.2] to [2.1.5] apply only to ships

having the service notations oil tanker or FLS tanker.

b) Ships having one of the following service notations:• oil tanker, flash point > 60°C• oil tanker, asphalt carrier• FLS tanker, flash point > 60°Care to comply with the provisions of [2.1.6].

2.1.2 Cargo tank area

a) Unless expressly provided otherwise, tanks containingcargo or cargo residues are to be segregated fromaccommodation, service and machinery spaces, drink-ing water and stores for human consumption by meansof a cofferdam, or any other similar compartment.

b) Fore and aft peaks are not to be used as cargo tanks.

c) Double bottom tanks adjacent to cargo tanks are not tobe used as oil fuel tanks.

2.1.3 Cargo pump rooms

a) The cargo pump rooms are to be separated from theother spaces of the ship by oiltight bulkheads and arenot to have, in particular, any direct communicationswith the machinery spaces.

b) Where glazed ports are provided on the bulkhead sepa-rating the cargo pump room from the machinery com-partment, they are to satisfy the following conditions:

• they are to be efficiently protected from mechanicaldamage

• strong covers are to be permanently secured on themachinery compartment side

• glazed ports are to be so constructed that glass andsealing are not impaired by the working of the ship

• the glazed ports are to be so constructed as to main-tain the structural integrity and the bulkheads resist-ance to fire and smoke.

2.1.4 Machinery spaces

Machinery spaces are to be positioned aft of cargo tanksand slop tanks; they are also to be situated aft of cargopump rooms and cofferdams, but not necessarily aft of thefuel oil bunker tanks. Any machinery space is to be isolatedfrom cargo tanks and slop tanks by cofferdams, cargo pumprooms, fuel oil bunker tanks or ballast tanks. Pump roomscontaining pumps and their accessories for ballasting thosespaces situated adjacent to cargo tanks and slop tanks andpumps for fuel oil transfer are to be considered as equiva-lent to a cargo pump room within the context of Article [2],provided that such pump rooms have the same safetystandard as that required for cargo pump rooms. However,the lower portion of the pump room may be recessed intomachinery spaces of category A to accommodate pumps,provided that the deck head of the recess is in general notmore than one third of the moulded depth above the keel,except that in the case of ships of not more than 25000tonnes deadweight, where it can be demonstrated that for

Item N° Description of the document

1 General arrangement drawing with indication of:• access and openings• capacity and size of the cargo tanks, slop tanks

and ballast tanks

2 Diagram of the mechanical and natural ventilation with indication of the ventilation inlets and outlets

Pt D, Ch 7, Sec 2


reasons of access and satisfactory piping arrangements thisis impracticable, the Society may permit a recess in excessof such height, but not exceeding one half of the mouldeddepth above the keel.

2.1.5 Accommodation spaces, service spaces and control stations

a) Accommodation spaces, main cargo control stations,control stations and service spaces (excluding isolatedcargo handling gear lockers) are to be positioned aft ofcargo tanks, slop tanks, and spaces which isolate cargoor slop tanks from machinery spaces but not necessarilyaft of the fuel oil bunker tanks and ballast tanks, but bearranged in such a way that a single failure of a deck orbulkhead not permit the entry of gas or fumes from thecargo tanks into an accommodation space, main cargocontrol stations, control station, or service spaces. Arecess provided in accordance with [2.1.4] need not betaken into account when the position of these spaces isbeing determined.

b) However, where deemed necessary, the Society maypermit accommodation spaces, main cargo control sta-tions, control stations, and service spaces forward of thecargo tanks, slop tanks and spaces which isolate cargoand slop tanks from machinery spaces, but not neces-sarily forward of fuel oil bunker tanks or ballast tanks.Machinery spaces, other than those of category A, maybe permitted forward of the cargo tanks and slop tanksprovided they are isolated from the cargo tanks and sloptanks by cofferdams, cargo pump rooms, fuel oil bunkertanks or ballast tanks. All of the above spaces are to besubject to an equivalent standard of safety and appropri-ate availability of fire-extinguishing arrangements beingprovided to the satisfaction of the Society. Accommoda-tion spaces, main cargo control spaces, control stationsand service spaces are to be arranged in such a way thata single failure of a deck or bulkhead not permit theentry of gas or fumes from the cargo tanks into suchspaces. In addition, where deemed necessary for thesafety or navigation of the ship, the Society may permitmachinery spaces containing internal combustionmachinery not being main propulsion machinery havingan output greater than 375 kW to be located forward ofthe cargo area provided the arrangements are in accord-ance with the provisions of this paragraph.

c) Where the fitting of a navigation position above thecargo area is shown to be necessary, it is to be for navi-gation purposes only and it is to be separated from thecargo tank deck by means of an open space with aheight of at least 2 m. The fire protection of such naviga-tion position is to be in addition as required for controlspaces in Ch 7, Sec 6 and other provisions, as applica-ble, of this Chapter.

d) Means be provided to keep deck spills away from theaccommodation and service areas. This may be accom-plished by provision of a permanent continuous coam-

ing of a height of at least 300 mm, extending from sideto side. Special consideration be given to the arrange-ments associated with stern loading.

Note 1: The provisions of paragraph d) above also apply to bowand stern cargo loading stations.

e) Exterior boundaries of superstructures and deckhousesenclosing accommodation and including any overhang-ing decks which support such accommodation, is to beconstructed of steel and insulated to A-60 standard forthe whole of the portions which face the cargo area andon the outward sides for a distance of 3 m from the endboundary facing the cargo area. The distance of 3 m isto be measured horizontally and parallel to the middleline of the ship from the boundary which faces thecargo area at each deck level. In the case of the sides ofthose superstructures and deckhouses, such insulation isto be carried up to the underside of the deck of the nav-igation bridge.

Note 2: Service spaces and control stations (except the wheel-house) located in superstructures and deckhouses enclosingaccommodation are to comply with the provisions of item e).

f) The location and arrangement of the room where foodsare cooked are to be selected such as to minimize therisk of fire.

2.1.6 Case of ships having the service notations oil tanker, flash point > 60°C, oil tanker, asphalt carrier or FLS tanker, flash point > 60°C

On ships having one of the following service notations:

• oil tanker, flash point > 60°C

• oil tanker, asphalt carrier

• FLS tanker, flash point > 60°C,

the location and separation of spaces is not required tocomply with requirements [2.1.2] to [2.1.5].

However, the following provisions are to be complied with:

a) Tanks containing cargo or cargo residues are to be seg-regated from accommodation, service and machineryspaces, tanks containing drinking water and stores forhuman consumption by means of a cofferdam or similarspace.

b) Double bottom tanks adjacent to cargo tanks are not tobe used as fuel oil tanks.

c) Means are to be provided to keep deck spills awayfrom accommodation and service areas.

2.2 Access and openings

2.2.1 Application

a) Ships with the service notation oil tanker ESP of lessthan 500 gross tonnage, and ships with the service nota-tion oil tanker or FLS tanker are to comply with the pro-visions of [2.2.2] to [2.2.6].

b) Ships having one of the following service notations:



• FLS tanker, flash point > 60°C

are to comply with the provisions of [2.2.7].

Pt D, Ch 7, Sec 2


c) Ships with the service notation oil tanker ESP of 500gross tonnage and over, are to comply with the provi-sions of [2.2.2], [2.2.4], [2.2.5] and [2.2.6] and with theInternational Convention for the Safety of Life at Sea,1974, as amended, Chapter II-1, Part A-1, Regulation 3-6, for details and arrangements of openings and attach-ments to the hull structure.

2.2.2 Access and openings to accommodation spaces, service spaces, control stations and machinery spaces

a) Except as permitted in paragraph b), access doors, airinlets and openings to accommodation spaces, servicespaces, control stations and machinery spaces are not toface the cargo area. They are to be located on the trans-verse bulkhead not facing the cargo area or on the out-board side of the superstructure or deckhouse at adistance of at least 4% of the length of the ship but notless than 3 m from the end of the superstructure ordeckhouse facing the cargo area. This distance need notexceed 5 m.

b) The Society may permit access doors in boundary bulk-heads facing the cargo area or within the 5 m limitsspecified in paragraph a), to main cargo control stationsand to such service spaces used as provision rooms,store-rooms and lockers, provided they do not giveaccess directly or indirectly to any other space contain-ing or providing for accommodation, control stations orservice spaces such as galleys, pantries or workshops, orsimilar spaces containing sources of vapour ignition. Theboundary of such a space is to be insulated to “A-60”class standard, with the exception of the boundary fac-ing the cargo area. Bolted plates for the removal ofmachinery may be fitted within the limits specified inparagraph a). Wheelhouse doors and windows may belocated within the limits specified in paragraph a) solong as they are designed to ensure that the wheelhousecan be made rapidly and efficiently gas tight and vapourtight.

Note 1: An access to a deck foam system room (including the foamtank and the control station) can be permitted within the limitsmentioned in paragraph a), provided that the conditions listedin paragraph b) are satisfied and that the door is located flushwith the bulkhead.

Note 2: The navigating bridge door and windows are to be testedfor gas tightness. If a water hose test is applied, the followingtest conditions are deemed acceptable by the Society:

• nozzle diameter: minimum 12 mm

• water pressure just before the nozzle: not less than 2 bar,

• distance between the nozzle and the doors or windows:maximum 1,5 m.

c) Windows and sidescuttles facing the cargo area and onthe side of the superstructures and deckhouses withinthe limits specified in paragraph a) are to be of the fixed(non-opening) type. Such windows and sidescuttles,except whellhouse windows, are to be constructed to“A-60” class standard.

d) Air intakes and air outlets of machinery spaces are to belocated as far aft as practicable and, in any case, outsidethe limits stated in a) above.

e) Where the ship is designed for bow or stern loading andunloading, entrance, air inlets and openings to accom-modation, service and machinery spaces and controlstations are not to face the cargo shore connection loca-tion of bow or stern loading or unloading arrangements.They are to be located on the outboard side of thesuperstructure or deckhouse at a distance of at least 4%of the length of the ship but not less than 3 m from theend of the deckhouse facing the cargo shore connectionlocation of the bow or stern loading and unloadingarrangements. This distance, however, need not exceed5 m. Sidescuttles facing the shore connection locationand on the sides of the superstructure or deckhousewithin the distance mentioned above are to be of thefixed (non-opening) type. In addition, during the use ofthe bow or stern loading and unloading arrangements,all doors, ports and other openings on the correspond-ing superstructure or deckhouse side are to be keptclosed.

Note 3: Where, in the case of small ships, compliance with theprovisions of paragraph e) is not possible, the Society may per-mit departures.

2.2.3 Access to spaces in the cargo area

a) Access to cofferdams, ballast tanks, cargo tanks andother compartments in the cargo area is to be directfrom the open deck and such as to ensure their com-plete inspection. Access to double bottom compart-ments may be through a cargo pump room, pumproom, deep cofferdam, pipe tunnel or similar compart-ments, subject to consideration of ventilation aspects.

Safe access to cofferdams, ballast tanks, cargo tanks andother compartments in the cargo area is to be directfrom the open deck and such as to ensure their com-plete inspection. Safe access to double bottom compart-ments or to forward ballast tanks may be from a pump-room, deep cofferdam, pipe tunnel, double hull com-partment or similar compartment not intended for thecarriage of oil or hazardous cargoes.

Note 1: Access manholes to forward gas dangerous spaces are per-mitted from an enclosed gas-safe space provided that:

• their closing means are gastight and

• a warning plate is provided in their vicinity to indicate thatthe opening of the manholes is only permitted after check-ing that there is no flammable gas inside the compartmentin question.

Note 2: Unless other additional arrangements provided to facilitatetheir access are considered satisfactory by the Society, the dou-ble bottom tanks are to be provided with at least two separatemeans of access complying with a) above.

b) For access through horizontal openings, hatches ormanholes, the dimensions are to be sufficient to allow aperson wearing a self-contained air-breathing apparatusand protective equipment to ascend or descend any lad-der without obstruction and also provide a clear open-ing to facilitate the hoisting of an injured person fromthe bottom of the compartment. The minimum clearopening is to be not less than 600 mm x 600 mm.

Pt D, Ch 7, Sec 2


c) For access through vertical openings, or manholes, inswash bulkheads, floors, girders and web frames provid-ing passage through the length and breadth of the com-partment, the minimum opening is to be not less than600 mm x 800 mm at a height of not more than 600 mmfrom the bottom shell plating unless gratings or otherfoot holds are provided.

d) For oil tankers of less than 5000 t deadweight smallerdimensions may be approved by the Society in specialcircumstances, if the ability to traverse such openings orto remove an injured person can be proved to the satis-faction of the Society.

For oil tankers of less than 5,000 tonnes deadweight, theSociety may approve, in special circumstances, smallerdimensions for the openings referred to in paragraphs a)and b), if the ability to traverse such openings or toremove an injured person can be proved to the satisfac-tion of the Society.

e) Access ladders of cargo tanks are to be fitted with hand-rails and to be securely attached to the tank structure.They are not to be fitted vertically, unless justified by thesize of the tanks. Rest platforms are to be provided atsuitable intervals of not more than 10 m.

2.2.4 Access to the pipe tunnels

a) The pipe tunnels in the double bottom are to complywith the following requirements:

1) they are not to communicate with the engine room,

2) provision is to be made for at least two exits to theopen deck arranged at a maximum distance fromeach other. One of these exits fitted with a watertightclosure may lead to the cargo pump room.

b) Where there is permanent access from a pipe tunnel tothe main pump room, a watertight door is to be fittedcomplying with the requirements of Pt B, Ch 2, Sec 1,[5] and in addition with the following:

1) in addition to the bridge operation, the watertightdoor is to be capable of being manually closed fromoutside the main pump room entrance,

2) the watertight door is to be kept closed during nor-mal operations of the ship except when access to thepipe tunnel is required.

Note 1: A notice is to be affixed to the door to the effect that it maynot be left open.

2.2.5 Access to the forecastle spaces

Access to the forecastle spaces containing sources of igni-tion may be permitted through doors facing cargo area pro-vided the doors are located outside hazardous areas asdefined in Ch 7, Sec 5.

2.2.6 Access to the bow

Every tanker is to be provided with the means to enable thecrew to gain safe access to the bow even in severe weatherconditions. Such means of access are to be approved by theSociety.

Note 1: The Society accepts means of access complying with theGuidelines for safe access to tanker bows adopted by the MarineSafety Committee of IMO by Resolution MSC.62(67).






the access and openings are not required to comply withthe provisions of [2.2.2]. However, the access doors, airinlets and openings to accommodation spaces, servicespaces and control stations are not to face the cargo area.

2.3 Ventilation

2.3.1 Application

a) The requirements of [2.3.2] to [2.3.5] apply only to shipshaving the service notations oil tanker or FLS tanker.

b) Ships having one of the following service notations:



• FLS tanker, flash point > 60°C

are to comply with the provisions of [2.3.6].

2.3.2 General

a) Enclosed spaces within the cargo area are to be pro-vided with efficient means of ventilation. Unless other-wise specified, portable means are permitted for thatpurpose. Ventilation fans are to be of non sparking con-struction according to Ch 7, Sec 1, [1.3.10].

b) Ventilation inlets and outlets, especially for machineryspaces, are to be situated as far aft as practicable. Dueconsideration in this regard is to be given when the shipis equipped to load or discharge at the stern. Sources ofignition such as electrical equipment are to be soarranged as to avoid an explosion hazard.

2.3.3 Ventilation of cargo pump rooms

a) Ventilation exhaust ducts are to discharge upwards inlocations at least 3 m from any ventilation intake andopening to gas safe spaces.

b) Ventilation intakes are to be so arranged as to minimizethe possibility of recycling hazardous vapours from ven-tilation discharge openings.

c) The ventilation ducts are not to be led through gas safespaces, cargo tanks or slop tanks.

d) See also Ch 7, Sec 4, [3.5.1].

Pt D, Ch 7, Sec 2


2.3.4 Ventilation of other pump rooms

a) Ventilation of pump rooms containing:

• ballast pumps serving spaces adjacent to cargo orslop tanks

• oil fuel pumps

is to comply with paragraphs a) to c) of [2.3.3] and a) ofCh 7, Sec 4, [3.5.1].

b) The ventilation intakes of the pump rooms referred to ina) are to be located at a distance of not less than 3 mfrom the ventilation outlets of cargo pump rooms.

2.3.5 Ventilation of double hull and double bottom spaces

Double hull and double bottom spaces are to be fitted withsuitable connections for the supply of air.






the ventilation is not required to comply with requirements[2.3.2] to [2.3.5]. However, the following provisions apply:

a) Where the ship is intended only for the carriage of cargowith flashpoint above 100°C:

• spaces located within the cargo area are to be effi-ciently ventilated

• portable means of ventilation are permitted exceptfor the cargo pump room, which is to be mechani-cally ventilated.

b) Where the ship is intended for the carriage of cargo withflashpoint of 100°C or below:

• spaces located within the cargo area are to be effi-ciently ventilated. Portable means of ventilation arepermitted

• ventilation of the cargo pump room is to complywith [2.3.3].

3 General arrangement of the ship with regard to pollution prevention

3.1 Application

3.1.1 Service notations

The requirements of the present Article apply only to shipshaving one of the following notations:

• oil tanker


• oil tanker, asphalt carrier.

3.1.2 Tonnage

Unless otherwise specified, the requirements of the presentArticle apply only to ships of 150 tons gross tonnage andabove.

3.2 Protection of the cargo tank length in the event of grounding or collision

3.2.1 Application

The requirements of the present sub-article apply to ships of600 tons deadweight and above.

3.2.2 General

a) The design and construction of oil tankers is to pay dueregard to the general safety aspects including the needfor maintenance and inspections of wing and doublebottom tanks or spaces.

b) Oil is not to be carried in any space extending forwardof a collision bulkhead located in accordance with Pt B,Ch 2, Sec 1, [2]. An oil tanker that is not required tohave a collision bulkhead in accordance with that regu-lation is not to carry oil in any space extending forwardof the transverse plane perpendicular to the centrelinethat is located as if it were a collision bulkhead locatedin accordance with that regulation.

3.2.3 Case of ships of 5000 tons deadweight and above

On oil tankers of 5000 tons deadweight and above, theentire cargo tank length is to be protected by ballast tanksor spaces other than cargo and fuel oil tanks as follows:

a) Wing tanks or spaces

Wing tanks or spaces are to extend either for the fulldepth of the ship’s side or from the top of the doublebottom to the uppermost deck, disregarding a roundedgunwale where fitted. They are to be arranged such thatthe cargo tanks are located inboard of the moulded lineof the side shell plating, nowhere less than the distancew which, as shown in Fig 1 is measured at any cross-sec-tion at right angles to the side shell, as specified below:

or w = 2,0 m, whichever is the lesser.

The minimum value of w = 1,0 m.

b) Double bottom tanks or spaces

At any cross-section, the depth of each double bottomtank or compartment is to be such that the distance hbetween the bottom of the cargo tanks and themoulded line of the bottom shell plating measured atright angles to the bottom shell plating, as shown in Fig1 is not less than specified below:

• B/15 (m), or

• 2,0 m, whichever is the lesser.

The minimum value of h = 1,0 m.

w 0 5 DW20000---------------- m +=

Pt D, Ch 7, Sec 2


Figure 1 : Cargo tank boundary lines

Note 1: Double bottom tanks or spaces as required by the aboveparagraph may be dispensed with, provided that the design ofthe tanker is such that the cargo and vapour pressure exertedon the bottom shell plating forming a single boundary betweenthe cargo and the sea does not exceed the external hydrostaticwater pressure, as expressed by the following formula:

where:

hc : Height of cargo in contact with the bottom shellplating, in metres

c : Maximum cargo density, in t/m3

dn : Minimum operating draught under any expectedloading conditions, in metres

s : Density of seawater, in t/m3

p : Maximum set pressure of pressure/vacuum valveprovided for the cargo tanks, in bars

f : Safety factor = 1,1

g : Standard acceleration of gravity (9,81 m/s2).

Any horizontal partition necessary to fulfil the above require-ments are to be located at a height of not less than B/6 or 6 m,whichever is the lesser, but not more than 0,6D, above thebaseline where D is the moulded depth amidships.

The location of wing tanks or spaces is to be as defined in para-graph a) above except that, below a level 1,5h above the base-line where h is as defined above, the cargo tank boundary linemay be vertical down to the bottom plating, as shown in Fig 2.

c) Turn of the bilge area or at locations without a clearlydefined turn of the bilge

Where the distance h and w are different, the distancew is to have preference at levels exceeding 1,5h abovebaseline as shown in Fig 1.

d) Aggregate capacity of the ballast tanks

On crude oil tankers of 20000 t deadweight and aboveand product carriers of 30000 t deadweight and above,the aggregate capacity of wing tanks, double bottomtanks, forepeak tanks and afterpeak tanks is to be notless than the capacity of segregated ballast tanks neces-sary to meet the requirements of [3.3.2]. Wing tanks orcompartments and double bottom tanks used to meetthe requirements of [3.3.2] are to be located as uni-formly as practicable along the cargo tank length. Addi-tional segregated ballast capacity provided for reducing

longitudinal hull girder bending stress, trim, etc., may belocated anywhere within the ship.


Note 2: In calculating the aggregate capacity under paragraph d)above, the following is to be taken into account:

• the capacity of engine-room ballast tanks is to be excludedfrom the aggregate capacity of ballast tanks,

• the capacity of ballast tanks located inboard of double hull isto be excluded from the aggregate capacity of ballast tanks,

• spaces such as void spaces located in the double hullwithin the cargo tank length is to be included in the aggre-gate capacity of ballast tanks.

e) Suction wells in cargo tanks may protube into the dou-ble bottom below the boundary line defined by the dis-tance h provided that such wells are as small aspracticable and the distance between the well bottomand bottom shell plating is not less than 0,5h.

f) Ballast and cargo piping is to comply with the provi-sions of Ch 7, Sec 4, [2.3.7] and Ch 7, Sec 4, [3.4.1].

Note 3: Other methods of design and construction of oil tankersmay also be accepted as alternatives to the requirements pre-scribed in items a) to f), provided that such methods ensure at leastthe same level of protection against oil pollution in the event of col-lision or stranding and are approved in principle by the Society.

The Society will accept the methods of design and constructiondescribed in IMO Resolution MEPC.66(37).

w

w

hh h

h < w

base line

1.5

h

w

w

h > w

�

�

�

h

�

�

�

��

f hc c g 100p+ dn s gW

W

1.5

h

base line

�

�

Pt D, Ch 7, Sec 2


3.2.4 Case of ships of less than 5000 tons deadweight

Oil tankers of less than 5000 tons deadweight are to:

a) at least be fitted with double bottom tanks or spaceshaving such a depth that the distance h specified in[3.2.3] b) complies with the following:

h = B/15 (m)

with a minimum value of h = 0,76 m;

in the turn of the bilge area and at locations without aclearly defined turn of bilge, the cargo tank boundaryline is to run parallel to the line of the midship flat bot-tom as shown in Fig 3; and

b) be provided with cargo tanks so arranged that thecapacity of each cargo tank does not exceed 700 m3

unless wing tanks or spaces are arranged in accordancewith [3.2.3] a) complying with the following:

with a minimum value of w = 0,76 m.


3.3 Segregation of oil and water ballast

3.3.1 General

a) In oil tankers of 150 tons gross tonnage and above, noballast water is to be carried in any oil fuel tank.

b) Every crude oil tanker of 20000 tons deadweight andabove and every product carrier of 30000 tons dead-weight and above are to be provided with segregatedballast tanks and are to comply with requirements[3.3.2] and [3.3.3].

3.3.2 Capacity of the segregated ballast tanks

The capacity of the segregated ballast tanks is to be sodetermined that the ship may operate safely on ballast voy-ages without recourse to the use of cargo tanks for waterballast. In all cases, however, the capacity of segregated bal-last tanks is to be at least such that, in any ballast conditionat any part of the voyage, including the conditions consist-ing of lightweight plus segregated ballast only, the ship'sdraughts and trim can meet each of the following require-ments:

a) the moulded draught amidships, dm in metres (withouttaking into account any ship's deformation) is to be notless than:dm = 2,0 + 0,02 LLL

b) the draughts at the forward and after perpendicular areto correspond to those determined by the draught amid-ships dm as specified above, in association with the trimby the stern of not greater than 0,015LLL , and

c) in any case the draught at the after perpendicular is tobe not less than that which is necessary to obtain fullimmersion of the propeller(s).

Refer also to paragraph d) of [3.2.3].Note 1: In case of oil tankers less than 150 metres in length, theabove formulae may be replaced by those set out in Appendix I tothe Unified Interpretations of Annex I of MARPOL 73/78.

3.3.3 Carriage of ballast water in cargo tanksa) In no case is ballast water to be carried in cargo tanks,

except:

1) on those rare voyages when weather conditions areso severe that, in the opinion of the Master, it is nec-essary to carry additional ballast water in cargotanks for the safety of the ship, and

2) in exceptional cases where the particular characterof the operation of an oil tanker renders it necessaryto carry ballast water in excess of the quantityrequired under [3.3.3], provided that such operationof the oil tanker falls under the category of excep-tional cases.

Note 1: Exceptional cases are defined in the Unified Interpretationsof Annex I of MARPOL 73/78

Such additional ballast water is to be processed and dis-charged in compliance with regulation 34 of Annex I ofMARPOL 73/78 and an entry is to be made in the OilRecord Book Part II referred to in regulation 36 of thatAnnex.

b) In the case of crude oil tankers, the additional ballastpermitted in paragraph a) above is to be carried in cargotanks only if such tanks have been crude oil washed inaccordance with [3.5] before departure from an oilunloading port or terminal.

3.4 Accidental oil outflow performance

3.4.1 Oil tankers are to comply with the requirements ofthe Regulation 25 of Annex I to Marpol Convention, asamended.

3.5 Cleaning of cargo tanks

3.5.1 Generala) Adequate means are to be provided for cleaning the

cargo tanks.Note 1: This provision does not apply to ships of less than 150 tons

gross tonnage provided the conditions stated in [3.6.1] are ful-filled.

b) Every crude oil tanker of 20000 tons deadweight andabove is to be fitted with a cargo tank cleaning systemusing crude oil washing complying with the followingrequirements. Unless such oil tanker carries crude oil

w 0 4 2 4DW20000

--------------------- m +=

h

base line

h

Pt D, Ch 7, Sec 2


which is not suitable for crude oil washing, the oil tankeris to operate the system in accordance with thoserequirements.

The crude oil washing installation and associated equip-ment and arrangements are to comply with the require-ments of Ch 7, App 2.

3.5.2 Ballasting of cargo tanksWith respect to the ballasting of cargo tanks, sufficientcargo tanks are to be crude oil washed prior to each ballastvoyage in order that, taking into account the tanker’s trad-ing pattern and expected weather conditions, ballast wateris put only into cargo tanks which have been crude oilwashed.

3.5.3 Operations and Equipment ManualEvery oil tanker operating with crude oil washing systems isto be provided with an Operations and Equipment Manualdetailing the system and equipment and specifying opera-tional procedures. Such a Manual is to be to the satisfactionof the Society and is to contain all the information set out inCh 7, App 2. If an alteration affecting the crude oil washingsystem is made, the Operating and Equipment Manual is tobe revised accordingly.

3.6 Retention of oil on board - Slop tanks

3.6.1 Application

a) The provisions of requirements [3.6.2] to [3.6.4] do notapply to ships of less than 150 tons gross tonnage forwhich the control of discharge of oil under Ch 7, Sec 4,[5.2.1] is to be effected by the retention of oil on boardwith subsequent discharge of all contaminated washingsto reception facilities, unless adequate arrangements aremade to ensure that any effluent which is allowed to bedischarged into the sea is effectively monitored toensure that the provisions of Ch 7, Sec 4, [5.2.1].

Note 1: The provisions of requirements [3.6.2] to [3.6.4] may bewaived for any oil tanker which engages exclusively on bothvoyages of 72 hours or less in duration and within 50 milesfrom the nearest land, provided that the oil tanker is engagedexclusively in trades between ports or terminals within a StateParty to MARPOL 73/78 Convention. Any such waiver is to besubject to the requirements that the oil tanker is to retain onboard all oily mixtures for subsequent discharge to receptionfacilities and to the determination by the Administration thatfacilities available to receive such oily mixtures are adequate.

b) The provisions of Ch 7, Sec 4, [5] are also to be com-plied with.

3.6.2 General

a) Adequate means are to be provided for transferring thedirty ballast residue and tank washings from the cargotanks into a slop tank approved by the Society.

b) Arrangements are to be provided to transfer the oilywaste into a slop tank or combination of slop tanks insuch a way that any effluent discharged into the seacomply with the provisions of Ch 7, Sec 4, [5.2].

3.6.3 Capacity of slop tanksThe arrangement of the slop tank or combination of sloptanks is to have a capacity necessary to retain the slop gen-

erated by tank washings, oil residues and dirty ballast resi-dues. The total capacity of the slop tank or tanks is not to beless than 3% of the oil carrying capacity of the ship, exceptthat the Society may accept:

a) 2% for oil tankers where the tank washing arrangementsare such that once the slop tank or tanks are chargedwith washing water, this water is sufficient for tankwashing and, where applicable, for providing the driv-ing fluid for eductors, without the introduction of addi-tional water into the system

b) 2% where segregated ballast tanks are provided inaccordance with [3.3], or where a cargo tank cleaningsystem using crude oil washing is fitted in accordancewith [3.5]. This capacity may be further reduced to1,5% for oil tankers where the tank washing arrange-ments are such that once the slop tank or tanks arecharged with washing water, this water is sufficient fortank washing and, where applicable, for providing thedriving fluid for eductors, without introduction of addi-tional water into the system.

Oil tankers of 70 000 tons deadweight and above are to befitted with at least two slop tanks.

3.6.4 Design of slop tanks

Slop tanks are to be so designed particularly in respect ofthe position of inlets, outlets, baffles or weirs where fitted,so as to avoid excessive turbulence and entrainment of oil oremulsion with the water.

3.7 Deck spills

3.7.1 Means are to be provided to keep deck spills awayfrom the accommodation and service areas. This may beaccomplished by providing a permanent continuous coam-ing of a suitable height extending from side to side.

Where gutter bars are installed on the weather decks of oiltankers in way of cargo manifolds and are extended aft asfar as the aft bulkhead of superstructures for the purpose ofcontaining cargo spills on deck during loading and dis-charge operations, the free surface effects caused by con-tainment of a cargo spill during liquid transfer operations orof boarding seas while underway are to be considered withrespect to the vessel’s available margin of positive initial sta-bility (GMo).

Where the gutter bars installed are higher than 300 mm,they are to be treated as bulwarks with freeing portsarranged in accordance with Pt B, Ch 9, Sec 9, [5] and pro-vided with effective closures for use during loading and dis-charge operations. Attached closures are to be arranged insuch a way that jamming is prevented while at sea, enablingthe freeing ports to remain effective.

On ships without deck camber, or where the height of theinstalled gutter bars exceeds the camber, and for oil tankershaving cargo tanks exceeding 60% of the vessel’s maximumbeam amidships regardless of gutter bar height, gutter barsmay not be accepted without an assessment of the initialstability (GMo) for compliance with the relevant intact sta-bility requirements taking into account the free surfaceeffect caused by liquids contained by the gutter bars.

Pt D, Ch 7, Sec 2


3.8 Pump-room bottom protection

3.8.1 This Article is applicable to oil tankers of 5000 tonsdeadweight and above.

3.8.2 The pump-room is to be provided with a double bot-tom such that at any cross-section the depth of each doublebottom tank or space is to be such that the distance hbetween the bottom of the pump-room and the ship’s baseline measured at right angles to the ship’s base line is to benot less than the lesser of:• h= B/15 m• h = 2 mwithout being taken less than 1 m.

3.8.3 In case of pump rooms whose bottom plate is locatedabove the base line by at least the minimum height requiredin [3.8.2] (e.g. gondola stern designs), there is no need fora double bottom construction in way of the pump-room.

3.8.4 Ballast pumps are to be provided with suitablearrangements to ensure efficient suction from double bot-tom tanks.

3.8.5 Notwithstanding the provisions of [3.8.2] and [3.8.3],where the flooding of the pump-room would not render theballast or cargo pumping system inoperative, a double bot-tom need not be fitted.

Pt D, Ch 7, Sec 3


SECTION 3 HULL AND STABILITY

Symbols

LLL : Load line length, in m, defined in Pt B, Ch 1, Sec 2, [3.2]

Ry : Minimum yield stress, in N/mm2, of the mate-rial, to be taken equal to 235/k N/mm2, unless otherwise specified

k : Material factor for steel, defined in Pt B, Ch 4, Sec 1, [2.3]

E : Young’s modulus, in N/mm2, to be taken equal to:

• E = 2,06.105 N/mm2 for steels in general

• E = 1,95.105 N/mm2 for stainless steels.

1 Stability

1.1 Application

1.1.1 The requirements in [1.2.2] and [1.3] apply only to ships with the service notation oil tanker ESP.

1.2 Intact stability

1.2.1 GeneralThe stability of the ship for the loading conditions in Pt B, Ch 3, App 2, [1.2.6] is to be in compliance with the require-ments in Pt B, Ch 3, Sec 2. In addition, the requirements in[1.2.2] are to be complied with.

1.2.2 Liquid transfer operationsShips with certain internal subdivision may be subjected to lolling during liquid transfer operations such as loading, unloading or ballasting. In order to prevent the effect of loll-ing, the design of oil tankers of 5000 t deadweight and above is to be such that the following criteria are complied with:

a) The intact stability criteria reported in b) is to be com-plied with for the worst possible condition of loading and ballasting as defined in c), consistent with good operational practice, including the intermediate stages of liquid transfer operations. Under all conditions the ballast tanks are to be assumed slack.

b) The initial metacentric height GMo, in m, corrected for free surface measured at 0° heel, is to be not less than 0,15. For the purpose of calculating GMo, liquid surface corrections are to be based on the appropriate upright free surface inertia moment.

c) The vessel is to be loaded with:

• all cargo tanks filled to a level corresponding to the maximum combined total of vertical moment of vol-ume plus free surface inertia moment at 0° heel, for each individual tank

• cargo density corresponding to the available cargo deadweight at the displacement at which transverse KM reaches a minimum value

• full departure consumable

• 1% of the total water ballast capacity.The maximum free surface moment is to be assumed in all ballast tanks.

1.3 Damage stability for ships where the additional class notation SDS is required

1.3.1 General

Every oil tanker is to comply with the subdivision and dam-age stability criteria as specified in [1.3.8], after the assumed side or bottom damage as specified in [1.3.2], for the stand-ard of damage described in [1.3.3], and for any operating draught reflecting actual partial or full load conditions con-sistent with trim and strength of the ship as well as specific gravities of the cargo.

The actual partial or full load conditions to be considered are those specified in Pt B, Ch 3, App 2, [1.2.6], but ballast conditions where the oil tanker is not carrying oil in cargo tanks, excluding any oil residues, are not to be considered.

1.3.2 Damage dimensions

The assumed extent of damage is to be as defined in Tab 1.

The transverse extent of damage is measured inboard the ship side at right angles to the centreline at the level of the summer load line.

Table 1 : Extent of damage

Damage Longitudinal extent Transverse extent Vertical extent

Side lC = 1/3 LLL2/3 or 14,5 m (1) tC = B/5 or 11,5 m (1) vC = without limit

Bottom For 0,3 LLL from the forward perpendicular lS = 1/3 LLL2/3 or 14,5 m (1) tS = B/6 or 10 m (1) vS = B/15 or 6 m (1)

any other part lS = 1/3 LLL2/3 or 5 m (1) tS = B/6 or 5 m (1) vS = B/15 or 6 m (1)

(1) Whichever is the lesser

Pt D, Ch 7, Sec 3


For the purpose of determining the extent of assumed dam-age, suction wells may be neglected, provided such wells are not excessive in areas and extend below the tank for a minimum distance and in no case more than half the height of the double bottom.

The vertical extent of damage is measured from the moulded line of the bottom shell plating at centreline.

If any damage of a lesser extent than the maximum extent of damage specified in Tab 1 would result in a more severe condition, such damage is to be considered.

Table 2 : Standard of damage

1.3.3 Standard of damage

The damage in [1.3.2] is to be applied to all conceivable locations along the length of the ship, according to Tab 2.

1.3.4 Calculation method

The metacentric heights (GM), the stability levers (GZ) and the centre of gravity positions (KG) for judging the final sur-vival conditions are to be calculated by the constant dis-placement method (lost buoyancy).

1.3.5 Flooding assumptions

The requirements of [1.3.8] are to be confirmed by calcula-tions which take into consideration the design characteris-tics of the ship, the arrangements, configuration and contents of the damaged compartments and the distribu-tion, specific gravities and free surface effect of liquids.

Where the damage involving transverse bulkheads is envis-aged as specified in [1.3.3], transverse watertight bulkheads are to be spaced at least at a distance equal to the longitudi-nal extent of assumed damage specified in [1.3.2] in order to be considered effective. Where transverse bulkheads are spaced at a lesser distance, one or more of these bulkheads within such extent of damage is to be assumed as non-exist-ent for the purpose of determining flooded compartments.

Where the damage between adjacent transverse watertight bulkheads is envisaged as specified in [1.3.3], no main transverse bulkhead bounding side tanks or double bottom tanks is to be assumed damaged, unless:

• the spacing of the adjacent bulkheads is less than the longitudinal extent of assumed damage specified in[1.3.2] or,

• there is a step or a recess in a transverse bulkhead of more than 3,05 metres in length, located within the

extent of penetration of assumed damage. The step formed by the after peak bulkhead and after peak tank top is not to be regarded as a step.

1.3.6 Progressive flooding

If pipes, ducts or tunnels are situated within the assumed extent of damage penetration as defined in [1.3.2], arrange-ments are to be made so that progressive flooding cannot thereby extend to compartments other than those assumed to be floodable in the calculation for each case of damage.

1.3.7 Permeabilities

The specific gravity of cargoes carried, as well as any out-flow of liquid from damaged compartments, are to be taken into account for any empty or partially filled tank.

The permeability of compartments assumed to be damaged are to be as indicated in Tab 3.

Table 3 : Permeability

1.3.8 Survival requirements

Oil tankers are to be regarded as complying with the dam-age stability criteria if the requirements of [1.3.9] and[1.3.10] are met.

1.3.9 Final stage of flooding

a) The final waterline, taking into account sinkage, heel and trim, is to be below the lower edge of any opening through which progressive flooding may take place. The progressive flooding is to be considered in accordance with Pt B, Ch 3, Sec 3, [3.3].

b) The angle of heel due to unsymmetrical flooding may not exceed 25°, except that this angle may be increased up to 30° if no deck edge immersion occurs.

c) The stability is to be investigated and may be regarded as sufficient if the righting lever curve has at least a range of 20° beyond the position of equilibrium in association with a maximum residual righting lever, in m, of at least 0,1 within the 20° range; the area, in m.rad, under the curve within this range is to be not less than 0,0175.

1.3.10 Intermediate stage of flooding

The Society is to be satisfied that the stability is sufficient during the intermediate stages of flooding. To this end the Society applies the same criteria relevant to the final stage of flooding also during the intermediate stages of flooding.

Ship’s length,in m

Damage anywhere in ship’s length

Damage between

transverse bulkheads

Machinery space

flooded

LLL ≤ 100 No Yes (1) (2) No

100 < LLL ≤ 150 No Yes (1) No

150 < LLL ≤ 225 Yes No Yes, alone

LLL > 225 Yes No Yes

(1) Machinery space not flooded.(2) Exemptions from the requirements of [1.3.8] may be

accepted by the Society on a case-by-case basis.

Compartments Permeability

Appropriate for stores 0,60

Occupied by accommodation 0,95

Occupied by machinery 0,85

Void compartments 0,95

Intended for consumable liquids 0 to 0,95 (1)

Intended for other liquids 0 to 0,95 (1)

(1) The permeability of partially filled compartments is to be consistent with the amount of liquid carried in the compartment.

Pt D, Ch 7, Sec 3


1.3.11 Bottom raking damage

This requirement applies to oil tankers of 20000 t dead-weight and above.

The damage assumptions relative to the bottom damage prescribed in [1.3.2] are to be supplemented by the assumed bottom raking damage of Tab 4.

The requirements of [1.3.8] are to be complied with for the assumed bottom raking damage.

Table 4 : Bottom damage extent

1.3.12 Equalisation arrangements

Equalisation arrangements requiring mechanical aids such as valves or cross levelling pipes, if fitted, may not be con-sidered for the purpose of reducing an angle of heel or attaining the minimum range of residual stability to meet the requirements of [1.3.9] and sufficient residual stability is to be maintained during all stages where equalisation is used. Compartments which are linked by ducts of a large cross-sectional area may be considered to be common.

1.3.13 Information to the Master

The Master of every oil tanker is to be supplied in an approved form with:

• information relative to loading and distribution of cargo necessary to ensure compliance with the requirements relative to stability, and

• data on the ability of the ship to comply with damage stability criteria as determined in [1.3.8] including the effect of relaxation that may have been allowed as spec-ified in Tab 2.

2 Structure design principles

2.1 Framing arrangement

2.1.1 In general, within the cargo tank region of ships of more than 90 m in length, the bottom, the inner bottom and the deck are to be longitudinally framed.

Different framing arrangements are to be considered by the Society on a case-by-case basis, provided that they are sup-ported by direct calculations.

2.2 Bulkhead structural arrangement

2.2.1 General

Transverse bulkheads may be either plane or corrugated.

2.2.2 Corrugated bulkheads

For ships of less than 120 m in length, vertically corrugated transverse or longitudinal bulkheads may be connected to the double bottom and deck plating.

For ships equal to or greater than 120 m in length, lower and upper stools are to be fitted.

3 Design loads


3.1.1 Still water loads

In addition to the requirements in Pt B, Ch 5, Sec 2, [2.1.2], still water loads are to be calculated for the following load-ing conditions, subdivided into departure and arrival condi-tions as appropriate:

• homogeneous loading conditions (excluding tanks intended exclusively for segregated ballast tanks) at maximum draft

• partial loading conditions

• any specified non-homogeneous loading condition

• light and heavy ballast conditions

• mid-voyage conditions relating to tank cleaning or other operations where, at the Society’s discretion, these differ significantly from the ballast conditions.

3.2 Local loads

3.2.1 Bottom impact pressure

For oil tankers of 20000 t deadweight and above and prod-uct carriers of 30000 t deadweight and above, the draught TF, to be considered in the calculation of the bottom impact pressure according to Pt B, Ch 9, Sec 1, [3.2], is that calcu-lated by using the segregated ballast tanks only.

3.2.2 Cargo mass density

In the absence of more precise values, a cargo mass density of 0,9 t/m3 is to be considered for calculating the internal pressures and forces in cargo tanks according to Pt B, Ch 5, Sec 6.

3.2.3 Partial filling

The carriage of cargoes with a mass density above the one considered for the design of the cargo tanks may be allowed with partly filled tanks under the conditions stated in Pt B, Ch 5, Sec 6, [2]The classification certificate or the annex to this certificate provided for in Pt A, Ch 1, Sec 2, [4.4] is to mention these conditions of carriage.

3.2.4 Overpressure due to cargo filling operations

For ships having the additional service feature asphalt car-rier, the overproduce which may occurred under load-ing/unloading operations are to be considered, if any. In such a case, the diagram of the pressures in loading/unload-ing conditions is to be given by the Designer.

DeadweightLongitudinal

extent Transverse

extentVertical extent

< 75000 t 0,4 LLL (1) B/3 (2)

≥ 75000 t 0,6 LLL (1) B/3 (2)

(1) Measured from the forward perpendicular.(2) Breach of the outer hull.

Pt D, Ch 7, Sec 3


4 Hull scantlings

4.1 Plating


The net thickness of the strength deck and bulkhead plating is to be not less than the values given in Tab 5.

Table 5 : Minimum net thickness ofthe strength deck and bulkhead plating

4.2 Ordinary stiffeners


The net thickness of the web of ordinary stiffeners is to be not less than the value obtained, in mm, from the following formulae:

tMIN = 0,75 L1/3 k1/6 + 4,5 s for L < 275 m

tMIN = 1,5 k1/2 + 7,0 + s for L ≥ 275 m

where s is the spacing, in m, of ordinary stiffeners.


4.3.1 Minimum net thicknessesThe net thickness of plating which forms the webs of pri-mary supporting members is to be not less than the value obtained, in mm, from the following formula:

tMIN = 1,45 L1/3 k1/6

4.3.2 Loading conditions for the analyses of primary supporting members

The still water and wave loads are to be calculated for the most severe loading conditions as given in the loading man-ual, with a view to maximising the stresses in the longitudi-nal structure and primary supporting members.

Where the loading manual is not available, the loading con-ditions to be considered in the analysis of primary support-ing members in cargo and ballast tanks are those shown in:• Fig 1 for ships less than 200 m in length• Fig 2 and Fig 3 for ships equal to or greater than 200 m

in length.

4.3.3 Strength check of floors of cargo tank structure with hopper tank analysed through a three dimensional beam model

Where the cargo tank structure with hopper tank is ana-lysed through a three dimensional beam model, to be car-ried out according to Pt B, Ch 7, App 1, the net shear sectional area of floors within 0,1 from the floor ends (seeFig 4 for the definition of ) is to be not less than the value obtained, in cm2, from the following formula:

where:Q : Shear force, in kN, in the floors at the ends of ,

obtained from the structural analysisγR : Resistance partial safety factor:

γR = 1,2

γm : Material partial safety factor:γm = 1,02

Figure 1 : Loading conditions for ships less than 200 m in length

Plating Minimum net thickness, in mm

Strength deck (5,5 + 0,02 L) k1/2

(8 + 0,0085 L) k1/2

for L < 200for L ≥ 200

Tank bulkhead L1/3 k1/6 + 4,5 s1,5 k1/2 + 8,2 + s

for L < 275for L ≥ 275

Watertight bulkhead 0,85 L1/3 k1/6 + 4,5 s1,5 k1/2 + 7,5 + s

for L < 275for L ≥ 275

Wash bulkhead 0,8 + 0,013 L k1/2 + 4,5 s3,0 k1/2 + 4,5 + s

for L < 275for L ≥ 275

Note 1:s : Length, in m, of the shorter side of the plate

panel.

ASh 20γRγmQ

Ry

----------------=

Homogeneous loadingcondition at draught T

Non homogeneous loadingcondition at draught T

Partial loading conditionat draught equal to 0,5D

Light ballast conditionat the relevant draught

Pt D, Ch 7, Sec 3


Figure 2 : Loading conditions for ships equal to or greater than 200 m in length

Figure 3 : Loading conditions for ships equal to or greater than 200 m in length

Figure 4 : End area of floors 4.3.4 Strength checks of cross-ties analysed through a three dimensional beam model

a) Cross-ties analysed through three dimensional beam model analyses according to Pt B, Ch 7, Sec 3 are to be considered, in the most general case, as being subjected to axial forces and bending moments around the neutral axis perpendicular to the cross-tie web. This axis is iden-tified as the y axis, while the x axis is that in the web plane (see Figures in Tab 6).

Light ballast conditions at the relevant draught

Non homogeneous loading conditions at draught T

Homogeneous loading conditions at draught T

��

��

��

� 0,1��

Pt D, Ch 7, Sec 3


The axial force may be either tensile or compression. Depending on this, two types of checks are to be carried out, according to b) or c), respectively.

b) Strength check of cross-ties subjected to axial tensile forces and bending moments.

The net scantlings of cross-ties are to comply with the following formula:

where:

FT : Axial tensile force, in kN, in the cross-ties, obtained from the structural analysis

Act : Net sectional area, in cm2, of the cross-tie

M : Max (|M1|, |M2|)

M1, M2 : Algebraic bending moments, in kN.m, around the y axis at the ends of the cross-tie, obtained from the structural analysis

wyy : Net section modulus, in cm3, of the cross-tie about the y axis

γR : Resistance partial safety factor:

γR = 1,02

γm : Material partial safety factor:

γm = 1,02

c) Strength check of cross-ties subjected to axial compres-sive forces and bending moments.

The net scantlings of cross-ties are to comply with the following formulae:

where:

FC : Axial compressive force, in kN, in the cross-ties, obtained from the structural analysis

Act : Net cross-sectional area, in cm2, of the cross-tie

FEX : Euler load, in kN, for buckling around the x axis:

Ixx : Net moment of inertia, in cm4, of the cross-tie about the x axis

: Span, in m, of the cross-tie

e : Distance, in cm, from the centre of gravity to the web of the cross-tie, specified in Tab 6for various types of profiles

www : Net section modulus, in cm3, of the cross-tie about the x axis

Mmax : Max (|M0|, |M1|, |M2|)

FEY : Euler load, in kN, for buckling around the y axis:

Iyy : Net moment of inertia, in cm4, of the cross-tie about the y axis

M1,M2 : Algebraic bending moments, in kN.m, around the y axis at the ends of the cross-tie, obtained from the structural analysis

wyy : Net section modulus, in cm3, of the cross-tie about the y axis


γR = 1,02


γm = 1,02

4.3.5 Strength checks of cross-ties analysed through a three dimensional finite element model

a) In addition to the requirements in Pt B, Ch 7, Sec 3, [4]and Pt B, Ch 7, Sec 3, [6], the net scantlings of cross-ties subjected to compression axial stresses are to comply with the following formula:

where:

σ : Compressive stress, in N/mm2, obtained from a three dimensional finite element analysis, based on fine mesh modelling, according to Pt B, Ch 7, Sec 3 and Pt B, Ch 7, App 1

σc : Critical stress, in N/mm2, defined in b)


γR = 1,02


γm = 1,02

b) The critical buckling stress of cross-ties is to be obtained, in N/mm2, from the following formulae:

where:

σE = min (σE1, σE2)

10FT

Act

------- 103 Mwyy

-------- Ry

γRγm

----------≤+

10FC1

Act

------- Φewxx

--------+ Ry

γRγm

----------≤

10FC

Act

------- 103Mmax

wyy

------------ Ry

γRγm

----------≤+

Φ 1

1 FC

FEX

-------–-----------------=

FEXπ2EIxx

105

2---------------=

M01 t2+ M1 M2+( )

2 u( )cos--------------------------------------------=

t 1u( )tan

----------------- M2 M1–M2 M1+--------------------- =

u π2--- FC

FEY

-------=

FEYπ2EIyy

105

2---------------=

σ σC

γRγm

----------≤

σc σE for σERy

2-----≤=

σc Ry 1 Ry

4σE

---------– for σE

Ry

2----->=

Pt D, Ch 7, Sec 3


σE1 : Euler flexural buckling stress, to be obtained, in N/mm2, from the following for-mula:

I : Min (Ixx, Iyy)

Ixx : Net moment of inertia, in cm4, of the cross-tie about the x axis defined in [4.3.4] a)

Iyy : Net moment of inertia, in cm4, of the cross-tie about the y axis defined in [4.3.4] a)

Act : Net cross-sectional area, in cm2, of the cross-tie

: Span, in m, of the cross-tieσE2 : Euler torsional buckling stress, to be

obtained, in N/mm2, from the following for-mula:

Iw : Net sectorial moment of inertia, in cm6, of the cross-tie, specified in Tab 6 for various types of profiles

Io : Net polar moment of inertia, in cm4, of the cross-tie:

Io = Ixx + Iyy + Act (yo + e)2

yo : Distance, in cm, from the centre of torsion to the web of the cross-tie, specified in Tab 6for various types of profiles

e : Distance, in cm, from the centre of gravity to the web of the cross-tie, specified in Tab 6for various types of profiles,

J : St. Venant’s net moment of inertia, in cm4, of the cross-tie, specified in Tab 6 for various types of profiles.

4.4 Strength check with respect to stresses due to the temperature gradient

4.4.1 Direct calculations of stresses induced in the hull structures by the temperature gradient are to be performed for ships intended to carry cargoes at temperatures exceed-ing 90°C. In these calculations, the water temperature is to be assumed equal to 0°C.The calculations are to be submitted to the Society for review.

4.4.2 The stresses induced in the hull structures by the tem-perature gradient are to comply with the checking criteria inPt B, Ch 7, Sec 3, [4.3].

5 Other structures

5.1 Machinery space

5.1.1 Extension of the hull structures within the machinery space

Longitudinal bulkheads carried through cofferdams are to continue within the machinery space and are to be used preferably as longitudinal bulkheads for liquid cargo tanks.

In any case, such extension is to be compatible with the shape of the structures of the double bottom, deck and plat-forms of the machinery space.

5.2 Opening arrangement

5.2.1 Tanks coversCovers fitted on all cargo tank openings are to be of sturdy construction, and to ensure tightness for hydrocarbon and water. Aluminium is not permitted for the construction of tank covers. The use of reinforced fibreglass covers is to be spe-cially examined by the Society.For the protection of cargo tanks carrying crude oil and petroleum products having a flash point not exceeding 60°C, materials readily rendered ineffective by heat are not to be used for tank opening covers so as to prevent the spread of fire to the cargo.

6 Hull outfitting

6.1 Equipment

6.1.1 Emergency towing arrangementsThe specific requirements in Pt B, Ch 10, Sec 4, [4] for ships with the service notation oil tanker ESP or FLS tanker and of 20000 t deadweight and above are to be complied with.

7 Protection of hull metallic structures

7.1 Protection by aluminium coatings

7.1.1 The use of aluminium coatings is prohibited in cargo tanks, the cargo tank deck area, pump rooms, cofferdams or any other area where cargo vapour may accumulate.

7.2 Material and coatings of tanks

7.2.1 The resistance of materials and coatings and their compatibility with intended cargoes are the responsibility of the builder or owner. All supporting documents are, how-ever, to be given to the Society to allow the issue of the list of cargoes annexed to the classification certificate.Copy of the charts of coating and/or material resistance issued by the manufacturers is to be kept on board. These documents are to indicate the possible restrictions relative to their use.

8 Cathodic protection of tanks

8.1 General

8.1.1 Internal structures in spaces intended to carry liquids may be provided with cathodic protection.Cathodic protection may be fitted in addition to the required corrosion protective coating, if any.

8.1.2 Details concerning the type of anodes used and their location and attachment to the structure are to be submitted to the Society for approval.

σE1π2EI

104Act2

---------------------=

σE2π2EIw

104Io2

------------------ 0 41, E JIo

---+=

Pt D, Ch 7, Sec 3


Table 6 : Calculation of cross-tie geometric properties

8.2 Anodes

8.2.1 Magnesium or magnesium alloy anodes are not per-mitted in oil cargo tanks and tanks adjacent to cargo tanks.

8.2.2 Aluminium anodes are only permitted in cargo tanks and tanks adjacent to cargo tanks in locations where the potential energy does not exceed 28 kg m. The height of the anode is to be measured from the bottom of the tank to the centre of the anode, and its weight is to be taken as the weight of the anode as fitted, including the fitting devices and inserts.However, where aluminium anodes are located on horizon-tal surfaces such as bulkhead girders and stringers not less

than 1 m wide and fitted with an upstanding flange or face flat projecting not less than 75 mm above the horizontal surface, the height of the anode may be measured from this surface.

Aluminium anodes are not to be located under tank hatches or washing holes, unless protected by the adjacent structure.

8.2.3 There is no restriction on the positioning of zinc anodes.

8.2.4 Anodes are to have steel cores and are to be declared by the Manufacturer as being sufficiently rigid to avoid reso-nance in the anode support and designed so that they retain the anode even when it is wasted.

Cross-tie profile e y0 J IW

T symmetrical

0 0

T non-symmetrical

0 0

Non-symmetrical

bf

hw Y

t f

t f

O

tw

X

13--- 2bftf

3 hwtw3+( ) tfhw

2 bf3

24----------------

��

��

� �

�

�

��

tw

t f

13--- b1 b2+( )tf

3 hwtw3+

tfhw2 b1f

3b2f3

12 b1f3 b2f

3+( )-------------------------------------

bf

hw

tf

yoO e G

Y

X

b2tf

htw 2btf+------------------------- 3bf

2tf

6bftf hwtw+----------------------------- 1

3--- 2bftf

3 hwtw3+( )

tfbf3h2

12---------------3bftf 2hwtw+

6bftf hwtw+---------------------------------

Pt D, Ch 7, Sec 3


8.2.5 The steel inserts are to be attached to the structure by means of a continuous weld. Alternatively, they may be attached to separate supports by bolting, provided a mini-mum of two bolts with lock nuts are used. However, other mechanical means of clamping may be accepted.

8.2.6 The supports at each end of an anode may not be attached to separate items which are likely to move inde-pendently.

8.2.7 Where anode inserts or supports are welded to the structure, they are to be arranged by the Shipyard so that the welds are clear of stress peaks.

8.2.8 As a general rule, the requirements [8.2.1] to [8.2.7]apply also to spaces or compartments adjacent to cargo or slop tanks.

8.3 Impressed current systems

8.3.1 Impressed current cathodic protections are not accepted in cargo or slop tanks, unless specially authorized by the Society.

9 Construction and testing

9.1 Welding and weld connections

9.1.1 For all the members, the web is to be connected to the face plate by means of continuous fillet welding.

It is recommended to use continuous fillet welding to con-nect the web to its associated shell plating. The throat thick-ness of such a welding is not to be less than the value specified in Pt B, Ch 12, Sec 1, Tab 2.

Discontinuous welds are not allowed for primary members perpendicular to ordinary stiffeners.

For longitudinals, scallop welding can be accepted as for primary members parallel to longitudinals, especially in small ships.

Scallop welding can be accepted for some members.

Where scallop fillet is used, the scallops are to be avoided:

• in way of the connecting brackets and at least more than 200 mm beyond the beginning of the bracket

• more than 200 mm about on either side of the connec-tion of the ordinary stiffeners to the primary stiffeners

• on bottom transverses, shell stringers and longitudinal bulkhead stringers

• on the lower half of side shell and longitudinal bulk-head transverses, and on the web frames of transverse bulkheads.

9.1.2 The welding factors for some hull structural connec-tions are specified in Tab 7. These welding factors are to be used, in lieu of the corresponding factors specified in Pt B, Ch 12, Sec 1, Tab 2, to calculate the throat thickness of fillet weld T connections according to Pt B, Ch 12, Sec 1, [2.3]. For the connections of Tab 7, continuous fillet welding is to be adopted.

9.1.3 For ships of more than 250 m in length, throat thick-nesses of fillet welds for transverse web frames and horizon-tal stringers on transverse bulkheads are to be reinforced as shown in Fig 5 and Fig 6.

The length, in m, of reinforcement is not to be less than the greater of the following values:

• = 2s

• = 1,2

where s is the spacing, in m, of the ordinary stiffeners.

9.1.4 The minimum throat thickness of continuous fillet welding or of scallop welding is not to be less than 4 mm for assemblies of high tensile steel.

9.2 Special structural details

9.2.1 The specific requirements in Pt B, Ch 12, Sec 2, [2.3]for ships with the service notation oil tanker ESP are to be complied with.

Table 7 : Welding factor wF

Hull areaConnection Welding factor

wFof to

Double bottom in way of cargo tanks

girders bottom and inner bottom plating 0,35

floors (interrupted girders) 0,35

floors bottom and inner bottom plating 0,35

inner bottom in way of bulkheads or their lower stools 0,45

girders (interrupted floors) 0,35

Bulkheads (1) ordinary stiffeners bulkhead plating 0,35

(1) Not required to be applied to ships with the additional service feature flash point > 60oC.

Pt D, Ch 7, Sec 3


Figure 5 : Reinforcement of throat thicknessfor ships greater than 250 m

Figure 6 : Reinforcement of throat thicknessfor ships greater than 250 m

Partial penetration

Partial penetration

Partial penetration

CL

0,40e 0,40e0,45e

0,40e

0,40e

0,45e

Partial penetration

CL

0,45e

0,40e

DOUBLEHULL

CENTRECARGO

TANK

0,35e

0,45e

0,45e

0,45e

0,35e

LATERALCARGO TANK

TRANSVERSEBULKHEAD

Partial penetration

0,40e

0,45e

Pt D, Ch 7, App 3


APPENDIX 3 LISTS OF OILS

1 Application

1.1 Scope of the lists of oils

1.1.1 The lists set out in this Appendix include the oils thecarriage in bulk of which is covered by the service notationsoil tanker or oil tanker, flash point > 60°C or oil tanker,asphalt carrier, under the provisions of Ch 7, Sec 1, [1.1.1].

2 Lists of products

2.1 List of oils

2.1.1 The list given in Tab 1 is reproduced from Appendix 1of the MARPOL 73/78 Convention, except that naphtha sol-vent is, in the opinion of the Society, to be considered as achemical to which Part D, Chapter 8 applies. This list is notnecessarily comprehensive.

Table 1 : List of oils

Asphalt solutions• Blending stocks• Roofers flux• Straight run residue

Oils• Clarified• Crude oil• Mixtures containing crude oil• Diesel oil• Fuel oil n° 4• Fuel oil n° 5• Fuel oil n° 6• Residual fuel oil• Road oil• Transformer oil• Aromatic oil (excluding vegetable oil)• Lubricating oils and blending stocks • Mineral oil• Spindle oil• Turbine oil

Distillates• Straight run• Flashed feed stocks

Gas oil• Cracked

Gasoline blending stock• Alkylates - fuel• Reformates• Polymer - fuel

Gasolines• Casinghead (natural)• Automotive• Aviation• Straight run• Fuel oil n° 1 (kerosene)• Fuel oil n° 1-D• Fuel oil n° 2• Fuel oil n° 2-D

Jet fuels• JP-1 (kerosene)• JP-3• JP-4• JP-5 (kerosene, heavy)• Turbo fuel• Kerosene• Mineral spirit

Naphtha• Petroleum• Heartcut distillate oil

Pt D, Ch 7, App 4


APPENDIX 4 LIST OF CHEMICALS FOR WHICH PART D, CHAPTER 8 AND IBC CODE DO NOT APPLY

1 Application

1.1 Scope of the list

1.1.1 The list set out in this Appendix includes all chemicalproducts to which Part D, Chapter 8 and IBC Code do notapply. Such products are allowed to be carried by ships hav-ing the service notation FLS tanker or, where their flashpoint is above 60 °C, also by ships having the service nota-tion FLS tanker flash point > 60 °C.

Where indicated in the list, some products are also allowedto be carried by ships having the service notation tanker.

1.2 Safety and pollution hazards

1.2.1

a) The following are chemicals which have been reviewedfor their safety and pollution hazards and determinednot to present hazards to such an extent as to warrantapplication of the IBC Code and Part D, Chapter 8. Thismay be used as a guide in considering bulk carriage ofchemicals whose hazards have not yet been evaluated.

b) Although the chemicals listed in this Chapter fall outsidethe scope of the IBC Code and Part D, Chapter 8, theattention is drawn to the fact that some safety precau-tions are needed for their safe transportation. Relevantrequirements are summarized in Tab 1.

c) Some chemicals are identified as falling into pollutioncategory Z and, therefore, subject to certain operationalrequirements of Annex II of MARPOL 73/78.

d) Liquid mixtures which are provisionally assessed underRegulation 6(4) of Annex II of MARPOL 73/78 as fallinginto pollution category Z, and which do not presentsafety hazards, may be carried under the entry for "nox-ious liquid, not otherwise specified" in this Chapter.Similarly, those mixtures provisionally assessed as fallingoutside pollution category X, Y or Z, and which do notpresent safety hazards, may be carried under the entryfor "non-noxious liquid not otherwise specified" in thisAppendix.

e) The substances identified as falling into pollution cate-gory OS are not subject to any requirements of Annex IIof MARPOL 73/78 in particular in respect of:• the discharge of bilge or ballast water or other resi-

dues or mixtures containing only such substances• the discharge into the sea of clean ballast or segre-

gated ballast.

2 List of chemicals for which Part D, Chapter 8 and IBC code do not apply

2.1

2.1.1 The list of chemicals for which Part D, Chapter 8 andIBC code do not apply is given in Tab 1. The relevant sym-bols and notations used in Tab 1 are given in Tab 2.

Pt D, Ch 7, App 4


Tab

le 1

: L

ist

of

easy

ch

emic

als

Prod

uct n

ame

Pollu

tion

cate

gory

Tank

ve

nts

Elec

. eqp

t te

mp.

cl

ass

Elec

. eqp

t ap

para

tus

grou

p

Flas

h-po

int

(°C

)G

au-

ging

Vap

our

dete

c-tio

n

Fire

prot

ec-

tion

Hig

h le

vel

alar

m

Che

m.

fam

ilyD

ensi

ty(t/

m3 )

Mel

ting

poin

t (°

C)

Serv

ice

nota

tion

(a)

(b)

(c)

(d)

(e)

(f)(g

)(h

)(i)

(j)(k

)(l)

(m)

(n)

Ace

tone

ZC

ont

T1IIA

-18

RF

AY

180,

79-

FLS

Alc

ohol

ic b

ever

ages

, not

oth

erw

ise

spec

ified

.Z

Con

t-

-20

to 6

0 (1

)R

FA

Y-

1,00

-FL

S

App

le ju

ice

OS

Ope

n-

-N

FO

--

N-

1,00

-T

n-B

utyl

alc

ohol

ZC

ont

T2IIA

29R

FA

Y20

0,81

-FL

S

sec-

But

yl a

lcoh

olZ

Con

tT2

IIA24

RF

AY

200,

81-

FLS

Cal

cium

nitr

ate

solu

tions

50%

or

less

)Z

Ope

n-

-N

FO

--

N-

1,50

-T

Cla

y sl

urry

O

SO

pen

--

NF

O-

-N

-1,

50-

T

Coa

l slu

rry

OS

Ope

n-

-N

FO

-A

, BN

-1,

50-

T

Die

thyl

ene

glyc

olZ

Ope

nT3

IIB>

60O

-A

N40

1,12

-FL

S>60

Ethy

l alc

ohol

Z

Con

tT2

IIA13

RF

AY

200,

79-

FLS

Ethy

lene

car

bona

teZ

Ope

nT2

->

60O

-A

N-

1,32

36FL

S>60

Glu

cose

sol

utio

nO

SO

pen

--

NF

O-

-N

-1,

50-

T

Gly

ceri

neZ

Ope

nT2

IIA>

60O

-A

N20

1,26

18FL

S>60

Hex

amet

hyle

nete

tram

ine

solu

tions

ZO

pen

--

NF

O-

-N

71,

50-

T

Hex

ylen

e gl

ycol

ZO

pen

T2IIA

>60

O-

B, C

N20

0,92

-FL

S>60

Hyd

roge

nate

d st

arch

hyd

roly

sate

OS

Ope

n-

-N

FO

--

--

1,02

5-

T

Isop

ropy

l alc

ohol

ZC

ont

22R

FA

Y20

0,78

-FL

S

Kao

lin s

lurr

yO

SO

pen

NF

O-

-N

431,

50-

T

Leci

thin

OS

Ope

nN

FO

--

N-

1,75

-T

Mag

nesi

um h

ydro

xide

slu

rry

ZO

pen

--

NF

O-

-N

-1,

23-

T

Mal

titol

sol

utio

nO

SO

pen

--

NF

O-

-N

-1,

025

-T

Met

hyl p

ropy

l ket

one

ZC

ont

--

<60

RF

AY

180,

82-

FLS

Mol

asse

sO

SO

pen

--

>60

O-

AN

201,

45-

FLS>

60

Nox

ious

liqu

id (1

1), n

ot o

ther

wis

esp

ecifi

ed, C

at. Z

ZC

ont

--

<60

RF

AY

-1,

00-

FLS

Non

-nox

ious

liqu

id (1

2), n

ot o

ther

wis

e sp

ecifi

ed, C

at. O

SO

SC

ont

--

<60

RF

AY

-1,

00-

FLS

Pt D, Ch 7, App 4


Poly

alum

iniu

m c

hlor

ide

solu

tion

ZO

pen

--

NF

O-

-N

-1,

25-

T

Poly

glyc

erin

, sod

ium

sal

t sol

utio

n (c

on-

tain

ing

less

than

3%

sod

ium

hyd

roxi

de)

ZO

pen

--

>60

O-

-N

-1,

27-

FLS>

60

Pota

ssiu

m fo

rmat

e so

lutio

nZ

Ope

n-

-N

FO

--

N-

1,02

5-

FLS>

60

Prop

ylen

e gl

ycol

Z

Ope

nT2

IIA>

60O

-A

N20

1,03

-FL

S>60

Prop

ylen

e ca

rbon

ate

ZO

pen

--

NF

O-

-N

-1,

025

-FL

S>60

Sodi

um a

ceta

te s

olut

ions

ZO

pen

--

NF

O-

-N

-1,

45-

T

Sodi

um s

ulph

ate

solu

tions

Z

Ope

n-

-N

FO

--

N-

1,45

-T

Sorb

itol s

olut

ion

OS

Ope

n-

->

60O

-A

N20

1,50

-FL

S>60

Sulp

hona

ted

poly

acry

late

sol

utio

nZ

Ope

n-

-N

FO

--

N-

1,02

5-

FLS>

60

Tetr

aeth

ys s

ilica

te m

onom

a/ol

igom

a(2

0% in

eth

anol

ZO

pen

--

NF

O-

-N

-1,

025

-FL

S>60

Trie

thyl

ene

glyc

olZ

Ope

nT2

IIA>

60O

-A

N40

1,12

-FL

S>60

Veg

etab

le p

rote

in s

olut

ion

(hyd

roly

sed)

OS

Ope

n-

-N

FO

--

N-

1,20

-T

Wat

erO

SO

pen

--

NF

O-

-N

-1,

00-

T

(1)

Com

posi

tion

depe

nden

t

Prod

uct n

ame

Pollu

tion

cate

gory

Tank

ve

nts

Elec

. eqp

t te

mp.

cl

ass

Elec

. eqp

t ap

para

tus

grou

p

Flas

h-po

int

(°C

)G

au-

ging

Vap

our

dete

c-tio

n

Fire

prot

ec-

tion

Hig

h le

vel

alar

m

Che

m.

fam

ilyD

ensi

ty(t/

m3 )

Mel

ting

poin

t (°

C)

Serv

ice

nota

tion

(a)

(b)

(c)

(d)

(e)

(f)(g

)(h

)(i)

(j)(k

)(l)

(m)

(n)

Pt D, Ch 7, App 4


Table 2 : Symbols and notations used in the list of easy chemicals

Items Col. Comments

Product name (a) Gives the alphabetical name of the products.

Pollution category (b) The letter Z refers to the pollution category Z as defined in Annex II of MARPOL 73/78.The symbol OS means that the product was evaluated and found to fall outside the pollution cat-egories X, Y and Z defined in Annex II of MARPOL 73/78.

Tank vents (c)

Electrical equipment temperature class

(d) The symbols T1 to T6 refer to the electrical equipment temperature classes defined in IEC Publi-cation 79-0.

Electrical equipment apparatus group

(e) The symbols IIA and IIB refer to the electrical equipment apparatus groups defined in IEC Publi-cation 79-0.

Flash point (f)

Gauging (g)

Vapour detection (h)

Fire protection (i) The letters A, B, C and D refer to the following fire-extinguishing media determined to be effec-tive for certain products:A : Alcohol-resistant foam (or multi-purpose foam)B : Regular foam, encompasses all foams that are not of an alcohol-resistant type,

including fluoro-protein and aqueous-film-forming foam (AFFF)C : Water sprayD : Dry chemical (powder).

High level alarm (j)

Chemical family (k)

Density (l)

Melting point (m)

Service notation (n) The symbols FLS, FLS>60 and T are defined as follows:FLS : Means that the product is allowed to be carried by a ship having the service notation

FLS tankerFLS>60 : Means that the product is allowed to be carried by a ship having the service notation

FLS tanker, flash point > 60°CT : Means that the product is allowed to be carried by a ship having the service notation

tanker.

Pt D, Ch 7, App 5


APPENDIX 5 DAMAGE ASSUMPTIONS AND OUTFLOW OF OIL

Symbols

LLL : Load line length, in m, defined in Pt B, Ch 1,Sec 2, [3.2].

1 General

1.1 Purpose

1.1.1 The purpose of the present Appendix is to provide amethod for the calculation of the hypothetical oil outflowreferred to in Ch 7, Sec 2, [3.4.1].

1.2 Application

1.2.1 The requirements of the present Appendix apply onlyto ships having one of the following notations:

• oil tanker


• oil tanker, asphalt carrier.

2 Damage assumptions and calculation of hypothetical oil outflows

2.1 Damage assumptions

2.1.1 GeneralFor the purpose of calculating hypothetical oil outflow fromoil tankers, damages having the extent defined in [2.1.2] areassumed.

2.1.2 Damage extentThe assumed extents of damage are specified in Tab 1.Three dimensions of the extent of damage of a parallelepi-ped on the side and bottom of the ship are assumed. In thecase of bottom damages, two conditions are set forth to beapplied individually to the stated portions of the oil tanker.

2.2 Hypothetical outflow of oil

2.2.1 GeneralThe hypothetic outflow of oil in case of side damage andbottom damage is to be calculated by the formulae given in[2.2.2] with respect to compartments breached by damageto all conceivable locations along the length of the ship tothe extent as defined in [2.1].

2.2.2 Calculation of oil outflow The oil outflow is to be calculated as follows:

a) for side damages:

Note 1: If a void space or segregated ballast tank of a length li lessthan lc as defined in Ch 7, Sec 3, [1.3.2] is located betweenwing oil tanks, Oc may be calculated on the basis of volume Wi

being the actual volume of one such tank (where they are ofequal capacity) adjacent to such space, multiplied by Si asdefined below and taking for all other wing tanks involved insuch a collision the value of the actual full volume.

where li = length in metres of the void space or segregated bal-last tank under consideration

b) for bottom damages:

Note 2: In the case where bottom damage simultaneously involvesfour centre tanks, the value of Os may be calculated using theformula:

where:Wi : Volume of a wing tank in cubic metres assumed

to be breached by the damage as specified in[2.1]; Wi for a segregated ballast tank may betaken equal to zero

Table 1 : Extent of damage

OC Wi KiCi+=

Si 1li

lc

---–=

OS13--- ZiWi ZiCi+ =

OS14--- ZiWi ZiCi+ =

Type of damage Longitudinal extent Transverse extent Vertical extent

Side damage lC = 1/3 LLL2/3 or 14,5 m

whichever is the lesstC = B/5 or 11,5 m whichever is the less (1)

vC = from the base line upwards without limit

Bottomdamage

For 0,3 LLL from the forwardperpendicular of the ship

lS = LLL/10 tS = B/6 or 10 m whichever is the less, but not less than 5 m

vS = B/15 or 6 m, whichever is the less

Any other part of the ship lS = LLL/10 or 5 mwhichever is the less

tS = 5 m vS = B/15 or 6 m, whichever is the less

(1) tc is to be measured inboard the ship side at right angles to the centreline at the level corresponding to the assigned summer freeboard.

Pt D, Ch 7, App 5


Ci : Volume of a centre tank in cubic metresassumed to be breached by the damage asspecified in [2.1]; Ci for a segregated ballast tankmay be taken equal to zero

Ki : Coefficient defined as:• 1 bi / tC for bi < tC

• 0 for bi tC

Zi : Coefficient defined as:• 1 hi / vS for hi < vS

• 0 for hi vS

bi : Width, in m, of wing tank under considerationmeasured inboard from the ship side at rightangles to the centreline at the level correspond-ing to the assigned summer freeboard.

Note 3: In a case where the width bi is not constant along thelength of a particular wing tank, the smallest bi valuein the tank is to be used for the purposes of assessingthe hypothetical outflows of oil OC and OS.

hi : Minimum depth, in m, of the double bottomunder consideration; where no double bottomis fitted hi is to be taken equal to zero

tC : Transverse extent of side damage as defined inTab 1

vS : Vertical extent of bottom damage as defined inTab 1.

2.2.3 Assumptionsa) For the purpose of calculating OS, credit is only to be

given in respect of double bottom tanks which are eitherempty or carrying clean water when cargo is carried inthe tanks above.

b) Where the double bottom does not extend for the fulllength and width of the tank involved, the double bot-tom is considered non-existent and the volume of thetanks above the area of the bottom damage is to beincluded in the formula of Os in [2.2.2] even if the tank

is not considered breached because of the installation ofsuch a partial double bottom.

c) Suction wells may be neglected in the determination ofthe value hi provided such wells are not excessive inarea and extend below the tank for a minimum distanceand in no case more than half the height of the doublebottom. If the depth of such a well exceeds half theheight of the double bottom hi is to be taken equal tothe double bottom height minus the well height.

Piping serving such wells if installed within the doublebottom is to be fitted with valves or other closingarrangements located at the point of connection to thetank served to prevent oil outflow in the event of dam-age to the piping.

2.2.4 Reduction of oil outflow

The Society may credit as reducing oil outflow in the eventof bottom damage, an installed cargo transfer system havingan emergency high suction in each cargo oil tank, capableof transferring from a breached tank or tanks to segregatedballast tanks or to available cargo tankage if it can beensured that such tanks will have sufficient ullage. Credit forsuch a system would be governed by ability to transfer intwo hours of operation oil equal to one half of the largest ofthe breached tanks involved and by availability of equiva-lent receiving capacity in ballast or cargo tanks. The creditis to be confined to permitting calculation of Os accordingto the formula in [2.2.2], Note 2. The pipes for such suctionsare to be installed at least at a height not less than the verti-cal extent of the bottom damage vS.

vS is the vertical extent of bottom damage as defined in[2.1.2].

2.2.5 Alternative methods for calculating oil outflowAs an alternative to the formulae indicated in [2.2.2], theprobabilistic methodology for calculating oil outflow asdescribed in IMO Resolution MEPC.66(37) may be applied.

Pt E, Ch 1, Sec 1


SECTION 1 STAR-HULL

1 General

1.1 Principles

1.1.1 Application

The additional class notation STAR-HULL is assigned, inaccordance with Pt A, Ch 1, Sec 2, [6.2.5], to ships comply-ing with the requirements of this Section.

1.1.2 Scope

The additional class notation STAR-HULL is assigned to aship in order to reflect the fact that a procedure includingperiodical and corrective maintenance, as well as periodi-cal and occasional inspections of hull structures and equip-ment, (hereafter referred to as the Inspection andMaintenance Plan) are dealt with on board by the crew andat the Owner’s offices according to approved procedures.

The assignment of the notation implies that a structural tridi-mensional analysis has been performed for the hull struc-tures, as defined in Pt B, Ch 7, App 1 or Pt B, Ch 7, App 2 orPt B, Ch 7, App 3, as applicable.

The implementation of the Inspection and MaintenancePlan is surveyed by the Society through:

• periodical audits carried out at the Owner’s offices andon board

• examination of the data recorded by the Owner andmade available to the Society through an electronic shipdatabase suitable for consultation and analysis

• periodical check of the hull structure, normally at theclass renewal survey, against defined acceptance crite-ria and based on:

- the collected data from actual implementation of theInspection and Maintenance Plan

- the results of the inspections, thickness measure-ments and other checks carried out during the classrenewal survey (see Pt A, Ch 5, Sec 2, [2]).

1.1.3 Safety management system

The Inspection and Maintenance Plan required under thescope of the STAR-HULL notation may form part of theSafety Management System to be certified in compliancewith the ISM Code.

1.2 Conditions for the assignment of the notation

1.2.1 Assignment of the notation

The procedure for the assignment of the STAR-HULL nota-tion is the following:

• a request for the notation is to be sent to the Society:

- signed by the party applying for the classification, inthe case of new ships

- signed by the Owner, in the case of existing ships

• the following documents are to be submitted to theSociety by the Interested Party:

- plans and documents necessary to carry out thestructural analysis, and information on coatings andon cathodic protection (see [2.1])

- the hot spot map of the structure (see [2.2])

- the Inspection and Maintenance Plan to be imple-mented by the Owner (see [2.3])

- information concerning the ship database and rele-vant electronic support to be implemented by theOwner (see [1.3.1])

• the Society reviews and approves the Inspection andMaintenance Plan, taking into account the results of thestructural analysis, as well as the information concern-ing the ship database

• the Society carries out an initial shipboard audit to ver-ify the compliance of the procedures on board withrespect to the submitted documentation.

1.3 Ship database

1.3.1 The ship database, to be available on board and atthe Owner’s offices, using an electronic support suitable forconsultation and analysis, is to provide at least the follow-ing information:

• the hot spot map, as indicated in [2.2]

• the documents required for the Inspection and Mainte-nance Plan, as indicated in [2.3], and the correspondingreports during the ship operation, as indicated in [3.5].

The ship database is to include a backup system in order forthe data to be readily restored, if needed.

1.3.2 The ship database is to be:

• updated by the Owner each time new inspection andmaintenance data from the ship are available

• kept by the Owner.

Access to the databases is to be logged, controlled andsecured.

1.3.3 The ship database is to be made available to the Soci-ety.

This ship database is to be transmitted to the Society at leastevery six months. It may be agreed between the Owner andthe Society that the required data are automatically down-loaded into the Society’s ship database after they are col-lected.

Pt E, Ch 1, Sec 1


2 Documentation to be submitted

2.1 Plans and documents to be submitted

2.1.1 Structural analysisThe plans and documents necessary to support and/or per-form the structural analysis covering hull structures are:

• those submitted for class as listed in Pt B, Ch 1, Sec 3,for new ships

• those listed in Tab 1, for existing ships. However,depending on the service and specific features of theship, the Society reserves the right to request additionalor different plans and documents from those in Tab 1.

Table 1 : Existing ships - Plans and documentsto be submitted to perform the structural analysis

2.1.2 CoatingsThe following information on coatings is to be submitted:

• list of all structural items which are effectively coated

• characteristics of the coating system.

2.1.3 Cathodic protectionThe following information on sacrificial anodes is to be sub-mitted:

• localisation of anodes in spaces, on bottom plating andsea chests

• dimensions and weight of anodes in new condition.

2.2 Hot spot map

2.2.1 The items to be included in the hot spot map are, ingeneral, the following:

• items (such as a plating panels, ordinary stiffeners or pri-mary supporting members) for which the structural anal-ysis carried out at the design stage showed that the ratiobetween the applied loads and the allowable limitsexceeded 0,975

• items identified as “hot spot item” during the structuralreassessment, according to Ch 1, App 2

• structural details subjected to fatigue, based on the listdefined in Pt B, Ch 12, App 2

• other items, depending on the results of the structuralanalyses and/or on experience.

2.2.2 The hot spot map may indicate which items are to beinspected periodically under the Owner’s responsibility.

2.3 Inspection and Maintenance Plan (IMP)

2.3.1 The Inspection and Maintenance Plan is to be basedon the Owner’s experience and on the results of the struc-tural analyses including the hot spot map.

The Inspection and Maintenance Plan is to include:

• the list of areas, spaces and hull equipment to be sub-jected to inspection

• the periodicity of inspections

• the elements to be assessed during the inspection foreach area or space, as applicable:

- coating

- anodes

- thicknesses

- pitting

- fractures

- deformations

• the elements to be assessed during the inspection of hullequipment.

2.3.2 As regards the maintenance plan, the following infor-mation is to be given:

• maintenance scope

• maintenance type (inspection, reconditioning)

• maintenance frequency (periodicity value unit is to beclearly specified, i.e. hours, week, month, year)

• place of maintenance (port, sea, etc.)

• manufacturer’s maintenance and repair specifications,as applicable

• procedures contemplated for repairs or renewal of struc-ture or equipment.

3 Inspection and Maintenance Plan (IMP)

3.1 Minimum requirements

3.1.1 The minimum requirements on the scope of theInspection and Maintenance Plan (IMP), the periodicity ofinspections, the extent of inspection and maintenance to bescheduled for each area, space or equipment concerned,and the minimum content of the report to be submitted tothe Society after the inspection are given hereafter.

3.1.2 At the Owner’s request, the scope and periodicitymay be other than those specified below, provided that thisis agreed with the Society.

Plans and documents

Midship section

Transverse sections

Shell expansion

Longitudinal sections and decks

Double bottom

Pillar arrangements

Framing plan

Deep tank and ballast tank bulkheads

Watertight subdivision bulkheads

Watertight tunnels

Wash bulkheads

Fore part structure

Aft part structure

Last thickness measurement report

Loading manual

Pt E, Ch 1, Sec 1


3.1.3 The IMP performed at periodical intervals does notprevent the Owner from carrying out occasional inspec-tions and maintenance as a result of an unexpected failureor event (such as damage resulting from heavy weather orcargo loading/unloading operation) which may affect thehull or hull equipment condition.

Interested parties are also reminded that any damage to theship which may affect the class is to be reported to the Society.

3.2 General scope of IMP

3.2.1 The IMP is to cover at least the following areas/items:

• deck area structure

• hatch covers and access hatches

• deck fittings

• steering gear

• superstructures

• shell plating

• ballast tanks, including peaks,

• cargo holds, cargo tanks and spaces

• other accessible spaces

• rudders

• sea connections and overboard discharges

• sea chests

• propellers.

3.3 Periodicity of inspections

3.3.1 Inspections are to be carried out at least with the fol-lowing periodicity:

• Type 1: two inspections every year, with the followingprinciples:

- one inspection is to be carried out outside the win-dow provided for the execution of the annual classsurvey, in the vicinity of the halfway date of theanniversary date interval

- the other inspection is to be carried out preferablynot more than two months before the annual classsurvey is conducted

- the minimum interval between any two consecutiveinspections of the same item is to be not less thanfour months.

• Type 2: inspection at annual intervals, preferably notmore than four months before the annual class survey iscarried out.

• Type 3: inspection at bottom surveys.

3.3.2 The following areas/items are to be inspected with aperiodicity of Type 1:

• deck area structure

• shell plating above waterline

• hatch covers and access hatches

• deck equipment

• superstructures

• ballast tanks, including peaks

• cargo holds and spaces

• other accessible spaces• sea connections and overboard discharges.

For ships less than 5 years old, 25% in number of ballasttanks (with a minimum of 1) are to be inspected annually, inrotation, so that all ballast tanks are inspected at least onceduring the 5-year class period.

For ships 5 years old or more, all ballast tanks are to beinspected annually.

3.3.3 The following areas are to be inspected with a perio-dicity of Type 2:• bunker and double bottom fuel oil tanks• fresh water tanks• cargo tanks.

3.3.4 Whenever the outside of the ship’s bottom is exam-ined in drydock or on a slipway, inspections are to be car-ried out on the following items:• rudders• propellers• bottom plating• sea chests and anodes.

In addition, the requirement under Pt A, Ch 2, Sec 2, [5.4.2]is to be complied with.

3.4 Extent of inspections

3.4.1 Deck area structureThe deck plating, structure over deck and hatch coamings,as applicable are to be visually examined for assessment ofthe coating, and detection of fractures, deformations andcorrosion.

When structural defects affecting the class (such as fracturesor deformations) are found, the Society is to be called foroccasional survey attendance. If such structural defects arerepetitive in similar areas of the deck, a program of addi-tional close-up surveys may be planned at the Society’s dis-cretion for the next inspections.

In other cases, such as coating found in poor condition,repairs or renewal are to be dealt with, or a program ofmaintenance is to be set in agreement with the Society, at asuitable time, but at the latest at the next intermediate orclass renewal survey, whichever comes first.

3.4.2 Hatch covers and small hatchesCargo hold hatch covers and related accessories are to bevisually examined and checked for operation under thesame scope as that required for annual class survey in Pt A,Ch 3, Sec 1, [2.2]. The condition of coating is to beassessed.

Access hatches are to be visually examined, in particulartightness devices, locking arrangements and coating condi-tion, as well as signs of corrosion.

Any defective tightness device or securing/locking arrange-ment is to be dealt with. Operating devices of hatch coversare to be maintained according to the manufacturer’srequirements and/or when found defective.

For structural defects or coating found in poor condition,refer to [3.4.1].

Pt E, Ch 1, Sec 1


3.4.3 Deck fittingsThe inspection of deck fittings is to cover at least the follow-ing items:

• Piping on deck

A visual examination of piping is to be carried out, withparticular attention to coating, external corrosion, tight-ness of pipes and joints (examination under pressure),valves and piping supports. Operation of valves is to bechecked.

Any defective tightness, supporting device or valve is tobe dealt with.

• Vent system

A visual examination of the vent system is to be carriedout. Dismantling is to be carried out as necessary forchecking the condition of closure (flaps, balls) andclamping devices and of screens.

Any defective item is to be dealt with.

• Ladders, guard rails, bulwarks, walkways

A visual examination is to be carried out with attentionto the coating condition (as applicable), corrosion,deformation or missing elements.


• Anchoring and mooring equipment

A visual examination of the windlass, winches, cap-stans, anchor and visible part of the anchor chain is tobe carried out. A working test is to be effected by lower-ing a sufficient length of chain on each side and thechain lengths thus ranged out are to be examined(shackles, studs, wastage).

Any defective item is to be dealt with. For replacementof chains or anchors, the Society is to be requested forattendance.

The manufacturer’s maintenance requirements, if any,are to be complied with.

• Other deck fittings

Other deck fittings are to be visually examined anddealt with under the same principles as those detailed inthe items above according to the type of fitting.

3.4.4 Steering gearThe inspection of the installation is to cover:

• examination of the installation

• test with main and emergency systems

• changeover test of working rams.

3.4.5 SuperstructuresThe structural part of superstructures is to be visually exam-ined and checked under the same scope as that required fordeck structure.

The closing devices (doors, windows, ventilation system,skylights) are to be visually examined with attention totightness devices and checked for their proper operation.


3.4.6 Shell platingThe shell plating, sides and bottom, are to be visually exam-ined for assessment of the coating, and detection of frac-tures, deformations and corrosion.

When structural defects affecting the class (such as fracturesor deformations) are found, the Society is to be called foroccasional survey attendance. If such structural defects arerepetitive in similar areas of the shell plating, a program ofadditional close-up surveys may be planned at the Society’sdiscretion for the next inspections.

In other cases, such as coating found in poor condition,repairs or renewal are to be dealt with, or a program ofmaintenance is to be set in agreement with the Society, at asuitable time, but at the latest at the next intermediate orclass renewal survey, whichever comes first.

3.4.7 Ballast tanks

Ballast tanks, including peaks, are to be overall surveyedwith regards to:

• structural condition (fractures, deformations, corrosion)

• condition of coating and anodes, if any

• fittings such as piping, valves.

A program of close-up survey may also be required,depending on the results of the structural analyses and thehot spot map.

When structural defects affecting the class are found, theSociety is to be called for occasional survey attendance. Ifsuch structural defects (such as fractures or deformations)are repetitive in similar structures in the same ballast tanksor in other ballast tanks, a program of additional close-upsurvey may be planned at the Society’s discretion for thenext inspections.

In other cases, such as coating found in poor condition oranodes depleted, repairs or renewal are to be dealt with, ora program of maintenance is to be set in agreement with theSociety, at a suitable time, but at the latest at the next inter-mediate or class renewal survey, whichever comes first.

3.4.8 Cargo holds and spaces

Dry cargo holds and other spaces such as container holds,vehicle decks are to be subjected to overall examinationand dealt with in the case of defects, under the same scopeas that required for ballast tanks. Attention is also to begiven to other fittings, such as bilge wells (cleanliness andworking test) and ladders.

Cargo tanks are to be overall surveyed with regards to:

• structural condition (fractures, deformations, corrosion)

• condition of coating and anodes, if any

• fittings such as piping, valves.


When structural defects affecting the class are found, theSociety is to be called for occasional survey attendance. Ifsuch structural defects (such as fractures or deformations)are repetitive in similar structures in the same cargo tanks orin other cargo tanks, a program of additional close-up sur-vey may be planned at the Society’s discretion for the nextinspections.

Pt E, Ch 1, Sec 1



3.4.9 Other accessible spacesOther spaces accessible during normal operation of the shipor port operations, such as cofferdams, void spaces, pipetunnels and machinery spaces are to be examined and dealtwith under the same scope as that required for dry cargoholds and spaces.

Consideration is also to be given to the cleanliness ofspaces where machinery and/or other equivalent equipmentexist which may give rise to leakage of oil, fuel water orother leakage (such as main and auxiliary machineryspaces, cargo pump rooms, cargo compressor rooms,dredging machinery spaces, steering gear space).

3.4.10 Rudder(s)A visual examination of rudder blade(s) is to be carried outto detect fractures, deformations and corrosion. Plugs, ifany, have to be removed for verification of tightness of therudder blade(s). Thickness measurements of plating are tobe carried out in case of doubt. Access doors to pintles (ifany) have to be removed. Condition of pintle(s) has to beverified. Clearances have to be taken.

Condition of connection with rudder stock is to be verified.

Tightening of both pintles and connecting bolts is to bechecked.

3.4.11 Sea connections and overboard dischargesA visual external examination of sea inlets, outlet corre-sponding valves and piping is to be carried out in order tocheck tightness. An operation test of the valves andmanoeuvring devices is to be performed.

Any defective tightness and/or operability is to be dealtwith.

3.4.12 Sea chestsSea chests have to be examined with regards to:• structural condition (fractures, deformations, corrosion)• condition of cleanliness, coating and anodes• visual examination of accessible part of piping or valve.

3.4.13 PropellersA visual examination of propeller blades, propeller bossand propeller cap is to be carried out as regards fractures,deformations and corrosion. For variable pitch propellers,absence of leakage at the connection between the bladesand the hub is to be also ascertained.

Absence of leakage of the aft tailshaft sealing arrangementis to be ascertained.

3.4.14 Cargo tanks, bunker and double bottom fuel oil tanks, fresh water tanks

Bunker and double bottom fuel oil tanks are to be overallsurveyed with regards to:• structural condition (fractures, deformations, corrosion)• condition of coating and anodes, if any• fittings such as piping, valves.


When structural defects affecting the class are found, theSociety is to be called for occasional survey attendance. Ifsuch structural defects (such as fractures or deformations)are repetitive in similar structures in the same bunker/doublebottom fuel oil tanks or in other bunker/double bottom fueloil tanks, a program of additional close-up survey may beplanned at the Society’s discretion for the next inspections.


3.5 Inspection reports

3.5.1 Inspection reports are to be prepared by the personresponsible after each survey. They are to be kept on boardand made available to the Surveyor at his request. An elec-tronic form is to be used for this purpose (see [1.3]).

A copy of these reports is to be transmitted to the Owner’soffices, for the records and updating of the ship database.

3.5.2 The inspection reports are to include the following.

• General information such as date of inspection/mainte-nance, identification of the person performing theinspection with his signature, identification of thearea/space/equipment inspected.

• For inspection of structural elements (deck area, hatchcovers and small hatches, superstructures, ballast tanks,dry cargo holds and spaces, other spaces), the report isto indicate:

- coating condition of the different boundaries andinternal structures and, if any, coating repairs

- structural defects, such as fractures, corrosion(including pitting), deformations, with the identifica-tion of their location, recurrent defects

- condition of fittings related to the space inspected,with description as necessary of checks, workingtests, dismantling, overhaul

• For inspection of equipment (deck equipment, sea con-nections and overboard discharges), the report is to indi-cate the results of visual examination, working tests,dismantling, repairs, renewal or overhaul performed.

3.5.3 When deemed necessary or appropriate, the report isto be supplemented by documents, sketches or photo-graphs, showing for example:

• location and dimension of fractures, pitting, deforma-tions

• condition of equipment before repairs

• measurements taken.

3.5.4 Models of inspection reports for structural elementsand equipment are given in Ch 1, App 4.

These models are to be used as a guide for entering the col-lected data into the ship database, in an electronic form.

Pt E, Ch 1, Sec 1


3.6 Changes to Inspection and Maintenance Plan

3.6.1 Changes to ship operation, review of the inspectionand maintenance reports, possible subsequent changes tothe hot spot map and corrosion rates different than thoseexpected may show that the extent of the maintenance per-formed needs to be adjusted to improve its efficiency.

Where more defects are found than would be expected, itmay be necessary to increase the extent and/or the fre-quency of the maintenance program. Alternatively, theextent and/or the frequency of the maintenance may bereduced subject to documented justification.

4 Acceptance criteria

4.1 Coating assessment

4.1.1 CriteriaThe acceptance criteria for the coating condition of eachcoated space is indicated in Tab 2.

Where acceptance criteria are not fulfilled, coating is to berepaired.

Table 2 : Acceptance criteria for coatings

4.1.2 RepairsThe procedures for repairs of coatings are to follow thecoating manufacturer’s specification for repairs, under theOwner’s responsibility.

4.2 Sacrificial anode condition

4.2.1 CriteriaThe acceptance criteria for sacrificial anodes in each coatedspace fitted with anodes is indicated in Tab 3 in terms ofpercentage of losses in weight.

Where acceptance criteria are not fulfilled, sacrificialanodes are to be renewed.

Table 3 : Acceptance criteria for sacrificial anodes

4.3 Thickness measurements

4.3.1 General

The acceptance criteria for measured thicknesses are indi-cated in:

• Ch 1, App 1 for isolated areas of items (for example alocalised area of a plate)

• Ch 1, App 2 for items (for example a plating panel or anordinary stiffener)

• Ch 1, App 3 for zones (for example the bottom zone).

When the acceptance criteria are not fulfilled, actionsaccording to [4.3.2] to [4.3.4] are to be taken.

4.3.2 Isolated area

The thickness diminution of an isolated area of an item isthe localised diminution of the thickness of that item suchas, for example, the grooving of a plate or a web or a localsevere corrosion. It is expressed as a percentage of the rele-vant as built thickness.

It is not to be confused with pitting (see [4.4]).

If the criteria of acceptable diminution are not fulfilled for anisolated area, then this isolated area is to be repaired orreplaced. In any case, the criteria of thickness diminutionare to be considered for the corresponding item (see[4.3.3]).

4.3.3 Item

For each item, thicknesses are measured at several pointsand the average value of these thicknesses is to satisfy theacceptance criteria for the relevant item.

If the criteria of measured thicknesses are not fulfilled for anitem, then this item is to be repaired or replaced.

Where the criteria are fulfilled but substantial corrosion asdefined in Pt A, Ch 2, Sec 2, [2.2.7] is observed, the IMP isto be modified by making adequate provision.

In any case, for the items which contribute to the hull girderlongitudinal strength, the criteria in [4.3.4] are to be consid-ered.

4.3.4 Zone

For consideration of the hull girder longitudinal strength,the transverse section of the ship is divided into three zones:

• deck zone

• neutral axis zone

• bottom zone.

The sectional area diminution of a zone, expressed as a per-centage of the relevant as built sectional area, is to fulfil thecriteria of acceptable diminution for that zone.

If the criteria of acceptable diminution are not fulfilled for azone, then some items belonging to that zone are to bereplaced (in principle, those which are most worn) in orderto obtain after their replacement an increased sectional areaof the zone fulfilling the relevant criteria.

Condition Acceptance criteria

Ships less than 10 years old Coatings in GOOD condition

Ships 10 years old or more Coatings in GOOD or FAIR condition

Note 1:GOOD : only minor spot rustingFAIR : local breakdown at edges of stiffeners and

weld connections and/or light rusting over 20% or more of areas under consideration, but less than as defined for POOR condition

POOR : general breakdown of coating over 20% or more of areas or hard scale at 10% or more of areas under consideration.

Condition Percentage of loss in weight

Ships less than 10 years old Less than 25

Ships 10 years old or more Less than 50

Pt E, Ch 1, Sec 1


4.4 Pitting

4.4.1 Pitting intensity

The pitting intensity is defined by the percentage of areaaffected by pitting.

The diagrams in Pt A, Ch 2, App 3 are to be used to identifythe percentage of area affected by pitting and thus the pit-ting intensity.

4.4.2 Acceptable wastage

The acceptable wastage for a localised pit (intensity 3%) is23% of the average residual thickness.

For areas having a pitting density of 50% or more, theacceptable wastage in pits is 13% of the average residualthickness.

For intermediate values (between localised pit and 50% ofaffected area), the acceptable wastage in pits is to beobtained by interpolation between 23% and 13% of theaverage residual thicknesses (see Tab 4).

Table 4 : Pitting intensity and correspondingacceptable wastage in pits

4.4.3 Repairs

Application of filler material (plastic or epoxy compounds)is recommended as a mean for stopping/reducing the corro-sion process but this is not an acceptable repair for pittingexceeding the maximum permissible wastage limits.

Welding repairs may be accepted when performed inaccordance with agreed procedures.

4.5 Fractures

4.5.1 General

Fractures are found, in general, at locations where stressconcentrations occur.

In particular, fractures occur at the following locations:

• beginning or end of a run of welding

• rounded corners at the end of a stiffener

• traces of lifting fittings used during the construction ofthe ship

• weld anomalies

• welding at toes of brackets

• welding at cut-outs

• intersections of welds

• intermittent welding at the ends of each length of weld.

The structure under examination is to be cleaned and pro-vided with adequate lighting and means of access to facili-tate the detection of fractures.

If the initiation points of the fractures are not apparent, thestructure on the other side of the plating is to be examined.

4.5.2 Criteria

Where fractures are detected, the Society’s Surveyor isalways to be called for attendance.

Pitting intensity, in %(see Pt A, Ch 2, App 3)

Acceptable wastage in pits, in percentage of the average

residual thickness

3 23

5 22

10 21

15 20

20 19

25 18

30 17

40 15

50 13

Pt E, Ch 1, Sec 2


SECTION 2 VERISTAR-HULL, VERISTAR-HULL SIS

1 General

1.1 Application

1.1.1 The additional class notation VeriSTAR-HULL andVeriSTAR-HULL SIS are assigned at the design stage or afterconstruction. The notation VeriSTAR-HULL SIS is to bemaintained during the service life. These notations aregranted to ships complying with the requirements of thisSection, in accordance with Pt A, Ch 1, Sec 2, [6.2].

These additional class notations may be completed by DFLxx years, with xx being equal to the increased designfatigue life, TFL, in years, having a value between 25 and 40,when a fatigue assessment is carried out according to Pt B,Ch 7, Sec 4 or for ships of less than 170 m in length subjectto special consideration by the Society.

1.2 Scope

1.2.1 The additional class notation VeriSTAR-HULL isassigned to a ship in order to reflect the following:

• a structural tridimensional analysis has been performedfor the hull structures, as defined in Pt B, Ch 7, App 1 orPt B, Ch 7, App 2 or Pt B, Ch 7, App 3 or in the CommonStructural Rules (NR522 and NR523), as applicable.

1.2.2 The additional class notation VeriSTAR-HULL SIS isassigned to a ship in order to reflect the following:

• a structural tridimensional analysis has been performedfor the hull structures, as defined in Pt B, Ch 7, App 1 orPt B, Ch 7, App 2 or Pt B, Ch 7, App 3, as applicable.

• the hull structure condition is periodically assessed,usually at the class renewal survey, using the results ofthe inspections and thickness measurements performedduring the survey. The results of this assessment is madeavailable to the Owner.

2 Assignment of the notation

2.1 New buildings

2.1.1 The procedure for the assignment of a VeriSTAR-HULL notation to a new ship is as follows :

a) The Interested Party submits to the Society the followingdocuments:

• Plans and documents necessary to carry out thestructural analysis, listed in Pt B, Ch 1, Sec 3 or inthe Common Structural Rules (NR522 and NR523)

• Results of the analysis of the longitudinal strengthand local scantlings of the plating and secondarystiffeners located in the cargo area in compliancewith the requirements of Part B, Chapter 6 and Pt B,Ch 7, Sec 1 and Pt B, Ch 7, Sec 2, respectively, or ofthe Common Structural Rules (NR522 and NR523)

• Results of the tridimensional analysis of the hullstructure described in Pt B, Ch 7, Sec 3, [1.3] or inthe Common Structural Rules (NR522 and NR523)

• The hot spot map of the structure

b) the Interested Party reports to the Society the changes instructural scantlings or design made during the designand building phase. In particular, an as-built version ofthe structural models is to be submitted to the Societyfor further reference

c) the Society reviews the structural analyses and contentsof the ship structural database and , if satisfied with theresults, grants the VeriSTAR-HULL notation.

2.2 Ships in service

2.2.1 The procedure for the assignment of a VeriSTAR-HULL SIS notation to an existing ship is as follows:

a) the Interested Party supplies the documents listed in Tab1. In addition, depending of the service and specific fea-tures of the ship, the Society may request plans and doc-uments in addition to those listed in Tab 1

b) the Society may request additional measurements orinspections in order to update the latest available thick-ness gaugings and condition reports in order to obtain areliable picture of the ship structure in its actual condi-tion

c) the Interested Party supplies the results of the structuralanalyses described in [2.1.1] for the ship in the as-builtcondition and with the actual conditions revealed bythe updated thickness gaugings and inspections

d) the Society reviews the results of these analyses and thecontent of the structural model of the ship and, if satis-fied, grants the VeriSTAR-HULL SIS notation.

Pt E, Ch 1, Sec 2


Table 1 : Existing ships - Plans and documentsto be submitted to perform the structural analysis

Plans and documents

Midship section

Transverse sections

Shell expansion

Longitudinal sections and decks

Double bottom

Pillar arrangements

Framing plan

Deep tank and ballast tank bulkheads

Watertight subdivision bulkheads

Watertight tunnels

Wash bulkheads

Fore part structure

Aft part structure

Last thickness measurement report

Loading manual

Pt E, Ch 1, App 1


APPENDIX 1 ACCEPTANCE CRITERIA FOR ISOLATED AREAS OF ITEMS

1 General

1.1 Application

1.1.1 The acceptance criteria consist in checking that thethickness diminution of an isolated area of an item (meas-ured according to Ch 1, Sec 1, [4.3.2]) is less than theacceptable limits specified in [1.1.2]. Otherwise, actionsaccording to Ch 1, Sec 1, [4.3.2] are to be taken.

1.1.2 The acceptable limits for the thickness diminution ofisolated areas of items contributing to the hull girder longi-tudinal strength are specified in:

• Tab 1 for the bottom zone items

• Tab 2 for the neutral axis zone items

• Tab 3 for the deck zone items.

The acceptable limits for the thickness diminution of iso-lated areas of items not contributing to the hull girder longi-tudinal strength are specified in Tab 4.

Table 1 : Acceptable limits for the thickness diminution of isolated areas of itemsItems contributing to the hull girder longitudinal strength and located in the bottom zone

Table 2 : Acceptable limits for the thickness diminution of isolated areas of itemsItems contributing to the hull girder longitudinal strength and located in the neutral axis zone

ItemAcceptable limit

L < 90 m L 90 m

Plating of:• keel, bottom and bilge• inner bottom• lower strake of inner side and longitudinal bulkheads• hopper tanks

22% 18%

Longitudinal ordinary stiffeners of:• keel, bottom and bilge• inner bottom• lower strake of inner side and longitudinal bulkheads• hopper tanks

Web 22% 18%

Flange 18% 15%

Longitudinal primary supporting members

Web 22% 18%

Flange 18% 15%


L < 90 m L 90 m

Plating of:• side• inner side and longitudinal bulkheads• ‘tweendecks

22% 18%

Longitudinals ordinary stiffeners of:• side• inner side and longitudinal bulkheads• ‘tweendecks

Web 22% 18%

Flange 18% 15%

Longitudinal primary supporting members Web 22% 18%

Flange 18% 15%

Pt E, Ch 1, App 1


Table 3 : Acceptable limits for the thickness diminution of isolated areas of itemsItems contributing to the hull girder longitudinal strength and located in the deck zone

Table 4 : Acceptable limits for the thickness diminution of isolated areas of itemsItems not contributing to the hull girder longitudinal strength

ItemAcceptable limits

L < 90 m L 90 m

Plating of:• upper deck, stinger plate and sheerstrake• upper strake of inner side and longitudinal bulkheads• side in way of topside tank• topside tanks (lower horizontal part, sloping plate and upper vertical part)

22% 18%

Longitudinal ordinary stiffeners of:• upper deck, stringer plate and sheerstrake• upper strake of inner side and longitudinal bulkheads• side in way of topside tank• topside tanks (lower horizontal part, sloping plate and upper vertical part)

Web 22% 18%

Flange 18% 15%

Longitudinal primary supporting members Web 22% 18%

Flange 18% 15%


L < 90 m L 90 m

Non-continuous hatch coamings Plating 22% 18%

Brackets 26% 22%

Hatch covers Top plating 22% 18%

Side and end plating 22% 18%

Ordinary stiffeners 22% 18%

Plating of transverse bulkheads 22% 18%

Ordinary stiffeners of transverse bulkheads Web 26% 22%

Flange 22% 18%

Brackets 26% 22%

Vertical primary supporting members and horizontal girders of bulkheads

Web 22% 18%

Flange 18% 15%

Brackets / stiffeners 22% 18%

Side frames Web 22% 18%

Flange 18% 15%


Deck and bottom transverse primary supporting members Web 22% 18%

Flange 18% 15%

Brackets 22% 18%

Topside tank and hopper tank primary supporting members Web 22% 18%

Flange 18% 15%

Plating of the forward and aft peak bulkheads 22% 18%

Ordinary stiffeners of the forward and aft peak bulkheads Web 26% 22%

Flange 22% 18%

Cross ties Web 22% 18%

Flange 18% 15%


Pt E, Ch 1, App 2


APPENDIX 2 ACCEPTANCE CRITERIA FOR ISOLATED ITEMS

Symbols

tA : As-built thickness of plating, in mm

tM : Measured thickness of plating, in mm

tC : Corrosion additions, in mm, defined in Pt B, Ch 4, Sec 2, [3]

tC1, tC2 : Corrosion additions, in mm, defined in Pt B, Ch 4, Sec 2, [3] for the two compartments sepa-rated by the plating under consideration. For plating internal to a compartment, tC1 = tC2 = tC

tR : Overall renewal thickness, in mm, of plating, in mm, defined in:

• [2.2.1] in general

• [4.3.1] for the plating which constitutes pri-mary supporting members

tR1 : Minimum renewal thickness, in mm, of plating defined in [2.2.2]

tR2 : Renewal thickness, in mm, of plating subjected to lateral pressure or wheeled loads, i.e. the thickness that the plating of a ship in service is to have in order to fulfil the strength check, according to the strength principles in Pt B, Ch 4, Sec 3, [1.1]. This thickness is to be calculated as specified in [2.2.3]

tR3 : Compression buckling renewal thickness, in mm, i.e. the thickness that the plating of a ship in service is to have in order to fulfil the com-pression buckling check, according to the strength principles in Pt B, Ch 4, Sec 3, [1.3.1]. This thickness is to be calculated as specified in[2.2.4]

tR4 : Shear buckling renewal thickness, in mm, i.e. the thickness that the plating of a ship in service is to have in order to fulfil the shear buckling check, according to the strength principles in Pt B, Ch 4, Sec 3, [1.3.1]. This thickness is to be considered only for ships equal to or greater than 90 m in length and is to be calculated as specified in [2.2.5]

tG : Rule gross thickness, in mm, of plating, defined in [2.2.6]

tA,W : As built thickness of ordinary stiffener web, in mm

tA,F : As built thickness of ordinary stiffener face plate, in mm

tM,W : Measured thickness of ordinary stiffener web, in mm

tM,F : Measured thickness of ordinary stiffener face plate, in mm

wM : Section modulus, in cm3, of ordinary stiffeners, to be calculated as specified in Pt B, Ch 4, Sec 3, [3.4] on the basis of the measured thick-nesses of web, face plate and attached plating

wR : Renewal section modulus, in cm3, of ordinary stiffeners i.e. the section modulus that an ordi-nary stiffener of a ship in service is to have to fulfil the yielding check, according to the strength principle in Pt B, Ch 4, Sec 3, [1.2.1]

tR,W : Renewal thickness, in mm, of ordinary stiffener web, i.e. the web thickness that an ordinary stiffener of a ship in service is to have in order to fulfil the buckling check, according to the strength principle in Pt B, Ch 4, Sec 3, [1.3.2]. This thickness is to be calculated as specified in[3.2.2]

tR,F : Renewal thickness, in mm, of ordinary stiffener face plate, i.e. the face plate thickness that an ordinary stiffener of a ship in service is to have in order to fulfil the buckling check, according to the strength principle in Pt B, Ch 4, Sec 3, [1.3.2]. This thickness is to be calculated as specified in [3.2.2]

wG : Rule gross section modulus, in cm3, of ordinary stiffeners, defined in [3.2.3]

WRR : Re-assessment work ratio, defined in [4.2.1]

WRA : As-built work ratio, defined in [4.2.2]

tR5 : Yielding renewal thickness, in mm, of primary supporting members, i.e. the thickness that the plating which constitutes primary supporting members of a ship in service is to have in order to fulfil the yielding check, according to the strength principles in Pt B, Ch 4, Sec 3, [1.2.2]. This thickness is to be calculated as specified in[4.3.2]

tR6 : Buckling renewal thickness, in mm, of primary supporting members, i.e. the thickness that the plating which constitutes primary supporting members of a ship in service is to have in order to fulfil the buckling check, according to the strength principles in Pt B, Ch 4, Sec 3, [1.3.1]. This thickness is to be calculated as specified in[4.3.3]

E : Young’s modulus, in N/mm2, to be taken equal to:

• for steels in general:

E = 2,06.105 N/mm2

• for stainless steels:

E = 1,93.105 N/mm2

Pt E, Ch 1, App 2


ν : Poisson’s ratio. Unless otherwise specified, a value of 0,3 is to be taken into account

ReH : Minimum yield stress, in N/mm2, of the mate-rial, defined in Pt B, Ch 4, Sec 1, [2]

γm, γR, γK1, ... , γK9 : Partial safety factors, defined in [1].

1 Partial safety factors

1.1 General

1.1.1 The partial safety factors γm and γR are defined in:

• Pt B, Ch 7, Sec 1, [1.2] or Pt B, Ch 8, Sec 3, [1.2], as applicable, for plating

• Pt B, Ch 7, Sec 2, [1.2] or Pt B, Ch 8, Sec 4, [1.2], as applicable, for ordinary stiffeners

• Pt B, Ch 7, Sec 3, [1.4] or Pt B, Ch 8, Sec 5, [1.3], as applicable, for primary supporting members.

1.2 Partial safety factors based on the increased knowledge of the structure

1.2.1 General

The partial safety factors γK1, γK2, γK3, γK4, γK5, γK6 and γK7 take into account the increased knowledge of the structural behaviour obtained through the surveys carried out on in-service ship structures and verification of their perform-ances. Therefore, they have values equal to or less than 1,0 and apply to reduce the partial safety factor on resistance, γR, adopted in the strength checks of new ships (see Part B, Chapter 7 or Part B, Chapter 8, as applicable).

1.2.2 Partial safety factors γK1, γK2, γK3 and γK4 for plating

These partial safety factors are to be calculated as specified in:

• [2.2.2] for minimum thicknesses (γK1)

• [2.2.3] for the strength checks of plate panels subjected to lateral pressure or wheeled loads (γK2)

• [2.2.4] for the compression buckling strength checks (γΚ3)

• [2.2.5] for the shear buckling strength checks (γΚ4).

1.2.3 Partial safety factor γK5 for ordinary stiffeners

The partial safety factor for yielding checks of ordinary stiff-eners (γΚ5) is to be calculated as specified in [3.2.1].

1.2.4 Partial safety factors γK6, γK7, γK8 and γK9 for primary supporting members

These partial safety factors are to be calculated as specified in:

• [4.2.1] for reassessment structural analyses (γK6, γK7)

• [4.3.2] for yielding strength checks (γK8)

• [4.3.3] for buckling strength checks (γΚ9).

2 Acceptance criteria for plating

2.1 Application

2.1.1 General

The acceptance criteria for measured thicknesses of plating, together with the application procedure to be adopted dur-ing the reassessment of hull structures, are indicated in Fig 1.

Figure 1: Acceptance criteria for measured thicknesses of plating and application procedure

Steel renewal requiredtM < tRThickness measurements tM

tM > tR + 0,25 (tG - tR)

YES

HOT SPOT ITEM

No steel renewal requiredYES

NO

NO

Pt E, Ch 1, App 2


Table 1: Acceptance criteria to be applied in specific cases

2.1.2 Specific cases

For the specific cases indicated in Tab 1, the acceptance cri-teria to be applied, in lieu of those in [2.1.1], are those specified in the Rules to which reference is made in the same table.

2.2 Renewal thicknesses

2.2.1 Overall renewal thickness

The overall renewal thickness is to be obtained, in mm, from the following formula:

tR = max (tR1, tR2, tR3, tR4)

2.2.2 Minimum renewal thickness

The minimum renewal thickness is to be obtained, in mm, from the following formula:

tR1 = t1 γK1

where:

t1 : Minimum net thickness, in mm, to be calcu-lated as specified in Pt B, Ch 7, Sec 1, [2.2] or Pt B, Ch 8, Sec 3, [2.2], as applicable

γK1 : Partial safety factor (see [1.2.2]):

γK1 = NP Ψ1


Np : Coefficient defined in Tab 2

2.2.3 Renewal thickness of plating subjected to lateral pressure or wheeled loads

The renewal thickness of plating subjected to lateral pres-sure or wheeled loads is to be obtained, in mm, from the following formula:

tR2 = t2 γK2

where:

t2 : Net thickness, in mm, to be calculated as speci-fied in:

• Pt B, Ch 7, Sec 1, [3] or Pt B, Ch 8, Sec 3, [3], as applicable, for plating subjected to lateral pressure

• Pt B, Ch 7, Sec 1, [4] or Pt B, Ch 8, Sec 3, [4], as applicable, for plating subjected to wheeled loads

where the hull girder stresses are to be calcu-lated considering the hull girder transverse sec-tions constituted by elements (plating, ordinary stiffeners, primary supporting members) having their measured thicknesses and scantlings


γK2 = NP Ψ2



Table 2: Coefficient NP

Ship type Item Rules to be applied

Ships with the service notation bulk carrier, of single side skin con-struction, having L ≥ 150 m, intended for the carriage of bulk car-goes having dry bulk density equal to or greater than 1,0 t/m3, contracted for construction on or after 1 July 1998

Plating of vertically corrugated transverse watertight bulkheads

Pt A, Ch 2, App 3, Tab 6

Ships with the service notation bulk carrier, contracted for con-struction on or after 1 July 1998

Hatch cover plating Pt A, Ch 2, App 3, Tab 6

Ships with the service notation bulk carrier, of single side skin con-struction, having L ≥ 150 m, intended for the carriage of bulk car-goes having dry bulk density equal to or greater than 1,78 t/m3, contracted for construction prior to 1 July 1998

Plating of vertically corrugated transverse watertight bulkhead between cargo holds No. 1 and 2

Pt A, Ch 6, App 1, [2.6]

Ψ1 1 tC1 tC2+t1

-------------------+= Ψ2 1 tC1 tC2+t2

-------------------+=

PlatingCoefficient NP

L < 90 m L ≥ 90 m

In general, including that which constitutes web of primary supporting members 0,75 0,80

Plating which constitutes face plate of primary supporting members 0,80 0,85

Bottom primary supporting members of ships with one of the service notations bulk carrier, ore carrier and combination carrier

0,80 0,85

Hatch coaming brackets 0,70 0,75

Cross ties of ships with the service notation oil tanker 0,80 0,85

Pt E, Ch 1, App 2


2.2.4 Compression buckling renewal thickness

The compression buckling renewal thickness is to be obtained, in mm, from the following formula:

tR3 = t3 γK3

where:

t3 : Net thickness to be obtained, in mm, from the following formulae:

b : Length, in m, of the plate panel side, defined inPt B, Ch 7, Sec 1, [5.1.2]

σx1 : In plane hull girder normal stress, in N/mm2 to be calculated as specified in Pt B, Ch 7, Sec 1, [5.2.2], considering the hull girder transverse sections as being constituted by elements (plat-ing, ordinary stiffeners, primary supporting members) having their measured thicknesses and scantlings

ε, K1 : Coefficients defined in Pt B, Ch 7, Sec 1, [5.3.1]


γK3 = NP Ψ3



2.2.5 Shear buckling renewal thickness

The shear buckling renewal thickness is to be obtained, in mm, from the following formula:

tR4 = t4 γK4

where:

t4 : Net thickness to be obtained, in mm, from the following formulae:

b : Length, in m, of the plate panel side, defined inPt B, Ch 7, Sec 1, [5.1.3]

τ1 : In plane hull girder shear stress, in N/mm2, to be calculated as specified in Pt B, Ch 7, Sec 1, [5.2.3], considering the hull girder transverse sections as being constituted by elements (plat-ing, ordinary stiffeners, primary supporting members) having their measured thicknesses and scantlings

K2 : Coefficient defined in Pt B, Ch 7, Sec 1, [5.3.2]


γK4 = NP Ψ4



2.2.6 Rule gross thicknessThe rule gross thickness is to be obtained, in mm, from the following formula:

tG = max (t1 , t2 , t3 , t4) + tc1 + tc2

where t1, t2, t3 and t4 are the net thicknesses defined in[2.2.2], [2.2.3], [2.2.4] and [2.2.5], respectively.

3 Acceptance criteria for ordinary stiffeners

3.1 Application

3.1.1 The acceptance criteria for measured scantlings of ordinary stiffeners, together with the application procedure to be adopted during the reassessment of hull structures, are indicated in Fig 2.

3.2 Renewal scantlings

3.2.1 Renewal section modulus

The renewal section modulus is to be obtained, in cm3, from the following formula:

wR = wY γK5

where:

wY : Net section modulus, in cm3, to be calculated as specified in Pt B, Ch 7, Sec 2, [3] or Pt B, Ch 8, Sec 4, [3], as applicable, where the hull girder stresses are to be calculated considering the hull girder transverse sections constituted by elements (plating, ordinary stiffeners, primary supporting members) having their measured thicknesses and scantlings


γK5 = NS Ψ5


NS : Coefficient defined in Tab 3

α, β : Parameters, depending on the type of ordinary stiffener, defined in Pt B, Ch 4, Sec 2, Tab 1.

Table 3 : Coefficient NS

t3bπ--- σx1γRγm12 1-ν2( )

EK1ε-------------------------------------------103= for γmγRσx1

ReH

2--------≤

t3bπ--- 3 1-ν2( )ReH

2

EK1ε ReH-σx1γRγm( )------------------------------------------------103= for γmγRσx1

ReH

2-------->

Ψ3 1 tC1 tC2+t3

-------------------+=

t4bπ--- τ1γRγm12 1-ν2( )

EK2

----------------------------------------103= for γmγRτ1ReH

2 3-----------≤

t4bπ--- 3 1-ν2( )ReH

2

EK2 ReH- 3τ1γRγm( )--------------------------------------------------103= for γmγRτ1

ReH

2 3----------->

Ordinary stiffenersCoefficient NS

L < 90 m L ≥ 90 m

Flat bars and bulb profiles 0,75 0,80

Flanged profiles 0,80 0,81

Ψ4 1 tC1 tC2+t4

-------------------+=

Ψ5

1 βtC

wY

--------+

1 αtC–-----------------=

Pt E, Ch 1, App 2


Figure 2: Acceptance criteria for measured scantlings of ordinary stiffeners and application procedure

3.2.2 Renewal web and face plate thicknesses

The renewal web and face plate thicknesses are to be obtained, in mm, from the following formulae:

tR,W = hW / CW

tR,F = bF / CF

where:

hw : Web height, in mm

bf : Face plate breadth, in mm

CW, CF : Coefficients depending on the type and material of ordinary stiffeners, defined in Tab 4.

In any case, the renewal web and face plate thicknesses are to be not less than those obtained according to Pt A, Ch 2, App 3, [4].

3.2.3 Rule gross section modulus The rule gross section modulus is to be obtained, in cm3, from the following formula:

where:α, β : Parameters, depending on the type of ordinary

stiffener, defined in Pt B, Ch 4, Sec 2, Tab 1wN,R : Net section modulus, in cm3, defined in [3.2.1].

Table 4: Coefficients CW and CF

Steel renewal required

WM < WROR

tM,W < tR,WOR

tM,F < tR,F

Scantling measurementstM' tM,W' tM,F

YES

HOT SPOT ITEM

No steel renewal requiredYES

NO

NO

WM > WR + 0,25(WG - WR)

AND

tM,W > tR,W + 0,25(tA,W - tR,W)

AND

tM,F > tR,F + 0,25(tA,F - tR,F)

wGwR βtC+1 αtC–

---------------------=

Type of ordinary stiffenersCW CF

ReH = 235 ReH = 315 ReH = 355 ReH = 235 ReH = 315 ReH = 355

Flat bar 20 18 17,5 Not applicable

Bulb 56 51 49 Not applicable

With symmetrical face plate 56 51 49 34 30 29

With non-symmetrical face plate 56 51 49 17 15 14,5

Note 1: ReH is given in N/mm2

Pt E, Ch 1, App 2


4 Acceptance criteria for primary supporting members

4.1 Application

4.1.1 The acceptance criteria for measured scantlings of primary supporting members and the application procedure to be adopted during the reassessment of hull structures are indicated in Fig 3.

4.2 Work ratios

4.2.1 Reassessment work ratio

The reassessment work ratio is to be obtained from the fol-lowing formula:

WRR = max (γK6WRY, γK7WRB)

where:


γK6 = 0,9


γK7 = 1,0

WRY : Yielding work ratio, defined in [4.2.3]

WRB : Buckling work ratio, defined in [4.2.4].

4.2.2 As-built work ratioThe as-built work ratio is to be obtained from the following formula:

WRA = max (WRY, WRB)

where:


WRB : Buckling work ratio, defined in [4.2.4].

Figure 3: Application procedure for reassessment of the hull structure

Steel renewalrequired

WRR > 0,975

OR

tM < 0,7tAOR

Damage is found

HOT SPOTITEM

YES

Scantling measurementstM

STRUCTURAL ANALYSIS

Damage is found ? tM > tRYES YES

ReinforcementdefinitionNO NO

No steel renewalrequired

Repair withreinforcement

STRUCTURALANALYSISUPDATE

tM > tR

NO

WRA > 1,0

for the item affected

by the damage

YES

NO

NOYES

Pt E, Ch 1, App 2


4.2.3 Yielding work ratioThe yielding work ratio is to be obtained from the following formula:

where:

σVM : Equivalent stress, in N/mm2, to be calculated as specified in Pt B, Ch 7, App 1, [5.1.2], consider-ing the hull structure as being constituted by elements (plating, ordinary stiffeners, primary supporting members) having their measured thicknesses and scantlings for the calculation of WRR and net scantlings according to Pt B, Ch 4, Sec 2 for the calculation of WRA and renewal thickness

Ry : Minimum yield stress, in N/mm2, of the mate-rial, to be taken equal to 235/k N/mm2

k : Material factor, defined in Pt B, Ch 4, Sec 1, [2.3].

4.2.4 Buckling work ratioThe buckling element work ratio is to be obtained from the following formula:

WRB = max (WRB1, WRB2, WRB3, WRB4)

where:

WRB1 : Compression buckling work ratio:

WRB2 : Shear buckling work ratio:

WRB3 : Compression, bending and shear buckling work ratio:

WRB4 : Bi-axial compression and shear buckling work ratio:

σa, σb, τb: Normal and shear stresses, in N/mm2, defined in Pt B, Ch 7, Sec 1, [5.4]

σc,τc : Critical buckling stresses, in N/mm2, defined inPt B, Ch 7, Sec 1, [5.3]

F : Coefficient defined in Pt B, Ch 7, Sec 1, [5.4.4]

Fc : Coefficient to be obtained from the following formula:

σcomb : Combined stress in N/mm2, defined in Pt B, Ch 7, Sec 1, [5.4.4]

σc,a, σc,b : Critical buckling stresses, in N/mm2, defined inPt B, Ch 7, Sec 1, [5.4.5]

The above quantities are to be calculated considering the hull structure as being constituted by elements (plating, ordinary stiffeners, primary supporting members) having their measured thicknesses and scantlings for the calcula-tion of WRR and net scantlings according to Pt B, Ch 4, Sec 2 for the calculation of WRA and renewal thickness.

4.3 Renewal scantlings

4.3.1 Overall renewal thickness

The overall renewal thickness may be obtained without prior knowledge of the thickness measurements, from the following formula, in mm:

tR = max (tRY , tRB , 0,7 tA)

4.3.2 Yielding renewal thickness

The yielding renewal thickness is to be obtained, in mm, from the following formula:

tRY = tY γK8

where:

tY : Net thickness to be obtained, in mm, from the following formula:

tY = [tA − 0,5 (tC1 + tC2)] WRY



γK8 = NP ΨY


4.3.3 Buckling renewal thickness

The buckling renewal thickness is to be obtained, in mm, from the following formula:

tRB = tB γK9

where:

tB : Net thickness to be obtained, in mm, from the following formula:

WRB : Buckling work ratio, defined in [4.2.4]


γK9 = NP ΨB


WRYγRγmσVM

Ry

---------------------=

WRB1γRγmσb

σc

-----------------=

WRB2γRγmτb

τc

----------------=

WRB3FFc

----=

WRB4γRγmσa

σc a,-----------------

1 9, γRγmσb

σc b,-----------------

1 9, γRγmτb

τc

----------------

1 9,

+ +=

for σcomb

F------------- ReH

2γRγm

-------------- :≤

Fc 1 =

for σcomb

F------------- ReH

2γRγm

-------------- :>

Fc4σcomb

ReH γRγm⁄----------------------- 1 σcomb

ReH γRγm⁄-----------------------–

=

ΨY 1 0 5 tC1 tC2+( ),tY

---------------------------------+=

tB tA 0 5 tC1 tC2+( ),–[ ] WRB3=

ΨB 1 0 5 tC1 tC2+( ),tB

---------------------------------+=

Pt E, Ch 1, App 3


APPENDIX 3 ACCEPTANCE CRITERIA FOR ZONES

1 General

1.1 Application

1.1.1 The acceptance criteria consist in checking that thesectional area diminution of a zone (measured according toCh 1, Sec 1, [4.3.4]) is less than the acceptable limits speci-fied in [1.1.2]. Otherwise, actions according to Ch 1, Sec 1,[4.3.4] are to be taken.

1.1.2 The acceptable limits for the sectional area diminu-tion of zones are specified in Tab 1.

Table 1 : Acceptable limits for the sectional areadiminution of zones

Zone Acceptable limit

Bottom zone 7%

Neutral axis zone

Side 11%

Inner side andlongitudinal bulkheads

11%

Deck zone 7%

NR 216, Ch 2, Sec 1

October 2008 Bureau Veritas 39

SECTION 1 ROLLED STEEL PLATES, SECTIONS AND BARS

1 General

1.1 Scope

1.1.1 The requirements of this Section apply to hot rolledplates, strips, sections and bars intended for hull, structuralapplications, boilers, pressure vessels and parts of machin-ery.Article [1] specifies the requirements common to all theabove-mentioned steel products, while the appropriate spe-cific requirements are indicated in Articles [2] to [9].

1.2 Manufacture

1.2.1 Steel is to be manufactured by the electric furnace,basic oxygen or open hearth processes.The use of other processes may be specially approved bythe Society.

1.2.2 The steel is to be cast in ingot moulds or by a contin-uous casting process.Provision is to be made for sufficient discard such as toensure:• at both ends of the ingots, the soundness of the material • at the transitory zones of continuous casting material, a

homogeneous chemical composition along the longitu-dinal axis.

1.3 Approval

1.3.1 The manufacturing process is to be approved by theSociety for individual steelmakers, grade of steel and prod-ucts, as specified in the applicable Articles.Provisions for the approval are given in the documentNR480 “Approval of the manufacturing process of metallicmaterials”.

1.3.2 It is the manufacturer’s responsibility to assure thateffective process and production controls in operation areadhered to within the manufacturing specifications. Wherecontrol imperfection inducing possible inferior quality ofproduct occurs, the manufacturer is to identify the causeand establish a countermeasure to prevent its recurrence.Also, the complete investigation report is to be submitted tothe surveyor. For further use, each affected piece is to betested to the Surveyor’s satisfaction. The frequency of testingfor subsequent products offered may be increased at the dis-cretion of the Society.

1.4 Quality of materials

1.4.1 All products are to have a workmanlike finish and tobe free from surface or internal defects which may impairtheir proper workability and use.

1.5 Visual, dimensional and non-destructive examinations

1.5.1 Visual, dimensional and, as appropriate, non-destruc-tive examinations are to be performed by the Manufactureron the materials supplied prior to delivery, as required.

The general provisions indicated in Ch 1, Sec 1, [3.6] andspecific requirements for the various products as specifiedin the relevant Articles of this Section apply.

Non-destructive examinations may be required by the Sur-veyor when deemed necessary.

1.5.2 The thickness of the plates and strips is to be meas-ured at random locations, whose distance from the longitu-dinal edge is to be at least 10 mm.

The under thickness requirements are indicated in the Arti-cles relevant to the various products.

1.6 Rectification of surface defects

1.6.1 Rectification of surface defects by grindingDefects which need to be repaired may be removed bygrinding.

The general provisions of Ch 1, Sec 1 and specific require-ments for the various products as specified in the relevantArticles of this Section apply.

The repaired areas are to be ground smooth to the adjacentsurface of the plate.

The Surveyor may request that the complete removal ofdefects is verified by suitable non-destructive examination.

1.6.2 Rectification of surface defects by weldingSurface defects of products which cannot be removed asstated in [1.6.1] may be repaired by chipping or grindingfollowed by welding subject to the Surveyor’s consent andunder his supervision.

The general provisions of Ch 1, Sec 1 and specific require-ments for the various products as specified in the relevantArticles of this Section apply.

1.7 Condition of supply

1.7.1 The conditions of supply are specified in the Articlesrelevant to the various products.

Where alternative supply conditions are agreed, the choiceof the supply condition, unless otherwise required, is left tothe Manufacturer; the condition of supply is always to bementioned in the testing documentation.

1.7.2 When acceptable as an alternative to normalising,the procedures relevant to controlled or thermo-mechanicalrolling process are to be specially approved for individualsteelworks.

NR 216, Ch 2, Sec 1

40 Bureau Veritas October 2008

1.7.3 The rolling practice applied is to comply with theappropriate condition of supply. The applicable proceduresare defined as follows:

a) As Rolled, AR

This procedure involves the rolling of steel at high tem-perature followed by air cooling. The rolling and finish-ing temperatures are typically in the austeniterecrystallization region and above the normalising tem-perature. The strength and toughness properties of steelproduced by this process are generally less than those ofsteel either heat treated after rolling or produced byadvanced process.

b) Normalising, N

Normalising involves heating rolled steel above the crit-ical temperature, Ac3 , and in the lower end of theaustenite recrystallization region followed by air cool-ing. The process improves the mechanical properties ofas rolled steel by refining the grain size.

c) Controlled Rolling, CR (Normalising Rolling, NR)

This is a rolling procedure in which the final deforma-tion is carried out in the normalising temperature range,resulting in a material condition generally equivalent tothat obtained by normalising.

d) Quenching and Tempering, QT

Quenching is a procedure which involves a heat treat-ment process in which steel is heated to an appropriatetemperature above the Ac3 and then cooled with anappropriate coolant for the purpose of hardening themicrostructure. Tempering subsequent to quenching is aprocess in which the steel is reheated to an appropriatetemperature not higher than the Ac1 to restore tough-ness properties by improving the microstructure.

e) Thermo-Mechanical rolling, TM (Thermo-MechanicalControlled Processing, TMCP)

This is a procedure which involves the strict control ofboth the steel temperature and the rolling reduction.Generally a high proportion of the rolling reduction iscarried out close to the Ar3 temperature and mayinvolve the rolling in the dual phase temperature region.Unlike controlled rolling (normalising rolling), the prop-erties conferred by TM (TMCP) cannot be reproducedby subsequent normalising or other heat treatment.

The use of accelerated cooling on completion of TM-rolling may also be accepted, subject to the specialapproval of the Society. The same applies for the use oftempering after completion of the TM-rolling.

f) Accelerated Cooling, AcC

Accelerated cooling is a process which aims to improvethe mechanical properties by controlled cooling withrates higher than air cooling immediately after the finalTM-rolling operation. Direct quenching is excludedfrom accelerated cooling.

The material properties conferred by TM and AcC can-not be reproduced by subsequent normalising or otherheat treatment.

1.8 Sampling and tests

1.8.1 General All products are to be presented for testing in the final sup-ply condition in batches or rolled units as specified in theArticles relevant to the various products.

1.8.2 Sampling The samples required for the preparation of test specimensare, in general, to be cut from:

a) the end of the plate or section corresponding to the topposition of the ingot, in the case of casting in ingotmoulds

b) any end of the plate or section, where such products arerolled from blooms or billets manufactured by continu-ous casting, on the understanding that sufficient discardis taken from the transitory zones of the cast beginningand end

c) both the ends of the coil for plates fabricated in coils. Samples are to be taken from the following positions:• plates and flats having width ≥ 600 mm: at approxi-

mately one quarter of the width from an edge (see Fig 1)

Figure 1 : Plates and flats

• flats having width < 600 mm, bulb flats and sections: atapproximately 1/3 of the width from an edge (see Fig 2,Fig 3 and Fig 4); alternatively, for channels, beams orbulb angles: on the web, at approximately 1/4 of thewidth from the centreline (see Fig 4)

Figure 2 : Bulb flats

Figure 3 : Angles

1/4

W

W

1/3 W

W

W

1/3 W

NR 216, Ch 2, Sec 1


Figure 4 : Sections

• hollow sections: if rectangular, at approximately in thecentreline of one side; if circular, at any position alongthe circumference

• bars: at approximately 1/3 of the radius or half-diagonalfrom the outer surface; the axis of the sample should beat least 12 mm from the outer surface, except for barshaving diameter 25 mm or less, in which case the sam-ple is to be concentric with the bar (see Fig 5).

Figure 5 : Bars

1.8.3 Preparation of test specimens

The test specimens are to be cut from the samples with theirprincipal axis parallel (longitudinal test) or perpendicular(transverse test) to the direction of rolling, as required in theArticles relevant to the various products.

For the preparation of test specimens and for the testing pro-cedures, reference is to be made to the applicable require-ments of Ch 1, Sec 2.

1.8.4 Tensile test

The results of the test are to comply with the values speci-fied in the Tables relevant to the various products.

If during the tensile test there is no marked yield stress ReH,the 0,2% proof stress Rp0,2, may be taken as an alternative.

1.8.5 Impact test

The average value is to comply with the minimum averagevalue specified in the Tables relevant to the various prod-ucts and only one individual value may be less than theaverage required, provided that it is not less than 70% of it.

The minimum average values are relevant to the standardspecimen 10x10 mm2.

For subsize specimen dimensions and requirements, refer-ence is to be made to Ch 1, Sec 2, [4.2.2].

1.8.6 Re-test procedures

Reference is made to Ch 1, Sec 1, [3.5].

For tensile re-test procedure, reference is made to Ch 1, Sec2, [2.3].

For Charpy V-notch re-test procedure, reference is made toCh 1, Sec 2, [4.4].

1.9 Identification and marking

1.9.1 The Manufacturer is to adopt a suitable system ofidentification which enables the product to be traced to itsoriginal cast.

1.9.2 All products which have been tested with satisfactoryresults are to be identified and marked, in addition to theSociety’s brand required in Ch 1, Sec 1, [4.1.3], with the fol-lowing indications:

a) Manufacturer’s name or trade mark

b) identification mark for the grade of steel

c) cast number or other marking, which will enable thehistory of the fabrication of the product to be traced.

Different marking systems are to be agreed with the Society.

1.10 Documentation and certification

1.10.1 Information required

The testing documentation indicated in Ch 1, Sec 1, [4.2.1]is required and is to contain all the appropriate information.

The ladle analysis is to include the content of refining andalloying elements as applicable.

1.10.2 Inspection certificate

Before signing the Society’s inspection certificate or endors-ing the inspection certificate issued by the Manufacturer(mill sheets), the Surveyor is to be provided by the Manufac-turer with a written declaration, stating that the material hasbeen manufactured by a process accepted by the Society,complies with the applicable requirements and has beensatisfactorily tested in accordance with the Rules.

The following wording may be acceptable, either printed orstamped on the delivery documents, with the name of thesteel Manufacturer and signed by one of his authorised rep-resentatives: "We hereby certify that the material has beenmade by an approved process and has been satisfactorilytested in accordance with the Society’s Rules".

A

1/4

B1/3 A

B

R

1/3 R

NR 216, Ch 2, Sec 1


1.10.3 Casting and rolling in different works

When the steel is rolled, heat treated, etc., in a workshopother than that where it is originally cast, the Surveyor is tobe supplied with the steelmaker’s certificate stating themanufacturing process, the type of steel, the identificationof the cast and the ladle analysis.

The workshop where the steel was produced is to beapproved by the Society.

The Society’s Surveyors are to have free access to the work-shop of the original Manufacturer, who is fully responsiblefor complying with all applicable requirements.

2 Normal and higher strength steels for hull and other structural applications

2.1 Scope

2.1.1 The requirements of this Article apply to weldablenormal and higher strength steel hot rolled plates, wideflats, sections and bars intended for use in hull constructionand other structural applications.

2.1.2 Provision is made for:

• plates and wide flats of all grades not exceeding100 mm in thickness

• sections and bars of all grades not exceeding 50 mm inthickness.

2.1.3 For thickness greater than the above, the require-ments may be modified, as appropriate, in the individualcases.

2.2 Steel grades

2.2.1 The steels are classed, on the basis of a minimumyield strength level ReH (N/mm2), into normal strength(ReH=235) and higher strength (32: ReH=315 - 36: ReH=355 -40: ReH = 390).

Normal strength steels are divided into four grades A, B, Dand E. For normal strength steels, the letters A, B, D and Emean impact properties at +20, 0, −20 and −40°C, respec-tively.

Higher strength steels are divided into four grades identifiedby the letters AH, DH, EH and FH followed by a numberrelated to the yield strength level. For higher strength steels,the letters AH, DH, EH and FH mean impact properties at 0,−20, −40 and −60°C, respectively.

2.2.2 Steels differing in chemical composition, deoxidationpractice, conditions of supply and mechanical propertiesmay be accepted, subject to the special approval of theSociety. Such steels are to be given a special designation.

2.3 Manufacture

2.3.1 ApprovalThe Manufacturers are to be approved by the Society andthe relevant requirements of [1.2] apply.

2.3.2 Deoxidation processThe method of deoxidation is specified in Tab 1 and Tab 2.

Table 1 : Normal strength steels - Chemical composition and deoxidation practice

Steel grade A B D E

Deoxidation practice for thickness t (mm)

t ≤ 50 mm: any method except rimmed (1)t > 50 mm: killed

t ≤ 50 mm: any method except rimmed t > 50 mm: killed

t ≤ 25 mm: killedt > 25 mm: killed and fine grain treated

killed and fine grain treated

Chemical composition (%) (2) (3) (4)

C max (5)Mn min (5)Si maxP maxS maxAl (acid soluble) min

0,21 (6)2,5 x C

0,500,0350,035

0,21 0,80 (7)

0,350,0350,035

0,210,600,35

0,0350,035

0,015 (8) (9)

0,180,700,350,0350,035

0,015 (9)

(1) For sections up to a thickness of 12,5 mm, rimmed steel may be accepted subject to the special approval of the Society.(2) When any grade of steel is supplied in the thermo-mechanically rolled condition, variations in the specified chemical composi-

tion may be allowed or required by the Society and are to be stated at the approval.(3) The Society may limit the amount of residual elements which may have an adverse effect on the working and use of the steel,

e.g. copper and tin.(4) Where additions of any other element have been made as part of the steelmaking practice, the content is to be indicated in the

ladle analysis certificate.(5) C +1/6 Mn is not to exceed 0,40%.(6) Max. 0,23% for sections.(7) When Grade B steel is impact tested, the minimum manganese content may be reduced to 0,60%. (8) Al is required for thickness greater than 25 mm.(9) The total aluminum content may be determined instead of acid soluble content. In such cases the total aluminum content is to

be not less than 0,020%. Other suitable grain refining elements may be used subject to the special approval of the Society.

NR 216, Ch 2, Sec 1


Table 2 : Higher strength steels - Chemical composition and deoxidation practice

2.3.3 Rolling practice

Where CR (NR) and TM with or without AcC are applied,the programmed rolling schedules are to be submitted tothe Society at the time of the approval and are to be madeavailable when required by the attending Surveyor. On themanufacturer’s responsibility, the programmed rollingschedules are to be adhered to during the rolling operation(as per [1.3.2]). To this effect, the actual rolling records areto be reviewed by the manufacturer and, occasionally, bythe Surveyor.

When deviation from the programmed rolling schedulesoccurs, the manufacturer is to take further measures, to theSurveyor’s satisfaction, in accordance with [1.3.2].

2.3.4 Tolerances on dimensions

For plates and wide flats with thicknesses of 5mm and over,an under thickness tolerance of 0,3 mm is permitted.

For sections and bars, the under thickness tolerance is to bein accordance with the requirements of a recognised inter-national or national standard.

Measurements are to be made as indicated in [1.5.2].

2.3.5 Non-destructive examinations

Ultrasonic testing of plates intended for offshore structuralapplications of first and special category as defined in theSociety’s Offshore Rules is required and is to be performedin accordance with a recognised standard (e.g. EN 10160 orASTM A 578) and an examination level accepted by theSociety.

2.3.6 Rectification of surface defects by grinding

Surface defects may be removed by grinding as indicated in[1.6.1] provided that:

a) the nominal thickness will not be reduced by more than7% or 3 mm, whichever is the lesser

b) each single ground area does not exceed 0,25 m2

c) the total area of local grinding does not exceed 2% ofthe total surface of the plate.

Adjacent repairs located at a distance less than their meanwidth are considered as forming a single ground area.

In the case of ground areas lying opposite each other onboth surfaces of the plate, the resulting thickness is to satisfyin any place the values indicated in item a).

Steel gradeAH32, DH32, EH32AH36, DH36, EH36AH40, DH40, EH40

FH32, FH36, FH40

Deoxidation practice killed and fine grain treated killed and fine grain treated

Chemical composition (%) (1) (5)

C max. Mn Si max. P max. S max. Al (acid soluble) min (3) (4) Nb (4) V (4) Ti max. (4) Cu max. Cr max. Ni max. Mo max. N max.

0,18 0,90 - 1,60 (2)

0,500,0350,0350,015

0,02 - 0,050,05 - 0,10

0,02 0,350,200,400,08

0,160,90 - 1,60

0,500,0250,0250,015

0,02 - 0,050,05 - 0,10

0,020,350,200,800,08

0,009 (0,012 if Al is present)

(1) Alloying elements other than those listed above or exceeding the specified limits may be accepted by the Society when pro-posed by the steelmaker at the time of approval and their content is to be indicated in the ladle analysis.

(2) Up to a thickness of 12,5 mm, the minimum manganese content may be reduced to 0,70.(3) The total aluminium content may be determined instead of the acid soluble content. In such cases the total aluminium content

is to be not less than 0, 020 %.(4) The steel is to contain aluminium, niobium, vanadium or other suitable grain refining elements, either singly or in any combina-

tion. When used singly, the steel is to contain the specified minimum content of the grain refining element. When used in com-bination, the specified minimum content of at least one grain refining element is applicable; the sum of Nb+V+Ti is not to exceed 0,12%.

(5) When any grade of higher strength steel is supplied in the thermo-mechanically rolled condition, variations in the specified chemical composition may be allowed or required by the Society and are to be stated at the approval.

NR 216, Ch 2, Sec 1


2.3.7 Rectification of surface defects by weldingSurface defects of products which cannot be removed asstated in [2.3.6] may be repaired by chipping or grindingfollowed by welding subject to the Surveyor’s agreementand witnessing when requested, provided that:

a) after removal of defects and before welding, the thick-ness of the piece is in no place reduced by more than20% with respect to the nominal thickness

b) repair is carried out by an approved procedure and byqualified welders using approved low hydrogen elec-trodes and the excess weld thickness is subsequentlyground smooth to the surface level

c) no single welded area exceeds 0,125 m2 and the sum ofall welded areas does not exceed 2% of the total surfacearea of the plate

d) after the final grinding the piece is normalised or stress-relieved, where required by the Surveyor. For plates tobe supplied in normalised condition, a new normalisingheat treatment is required as a rule, except for repairs ofnegligible size, when the piece had already been nor-malised before repair; for products obtained by thermo-mechanical rolling processes, the conditions stated atthe approval of the rolling process apply

e) the repaired plates are presented to the Surveyor foracceptance; in addition to the visual inspection the Sur-veyor may require the soundness to be verified by ultra-sonic, magnetic particle or dye penetrant methods, asappropriate.


2.4.1 The products are to be supplied in the condition indi-cated in Tab 5 and Tab 6 for normal strength steels and Tab9 and Tab 10 for higher strength steels.The definition of the supply conditions is given in [1.7.3].

2.5 Chemical composition

2.5.1 General The chemical composition is determined by the Manufac-turer on ladle samples (see Ch 1, Sec 1, [2.2.1]).

2.5.2 Normal strength steels The chemical composition is to comply with the require-ments specified in Tab 1.

2.5.3 Higher strength steelsThe chemical composition is to comply with the require-ments specified in Tab 2.

At the time of the approval of higher strength steels, anupper limit for carbon equivalent CEQ on the ladle analysismay be specified.

Unless otherwise agreed, the value of CEQ is calculated bythe following formula:

For steel produced by thermo-mechanical rolling, CEQ is tocomply with the requirements of Tab 3.

As an alternative to CEQ, at the discretion of the Society, thecold cracking susceptibility Pcm may be used for evaluatingthe weldability.

Pcm is given by the following formula and an upper limitmay be agreed at the time of the approval of the steel:

When a limit of CEQ and Pcm is required, the relevant val-ues are to be stated by the Manufacturer and included inthe testing documentation for each cast.

Table 3 : Carbon equivalent for higher strength steels up to 100 mm in thickness produced by TM process

2.6 Mechanical Properties

2.6.1 Normal strength steels The mechanical properties are indicated in Tab 4.

The number of impact tests to be performed is indicated inTab 5 for plates and wide flats and Tab 6 for sections and bars.

Table 4 : Normal strength steels - Mechanical properties

Steel gradeCarbon equivalentCEQ max. (%) (1)

t ≤ 50 50 < t ≤ 100

AH32, DH32, EH32, FH32AH36, DH36, EH36, FH36AH40, DH40, EH40, FH40

0,360,380,40

0,380,400,42

t = thickness (mm)

(1) More stringent carbon equivalent limits may be agreed between the Manufacturer and the shipbuilder in indi-vidual cases.

CEQ C Mn6

--------- Cr Mo V+ +5

-------------------------------- Ni Cu+15

--------------------- %+ + +=

Pcm C Si30------ Mn

20--------- Cu

20------- Ni

60------ Cr

20------ Mo

15--------- V

10------ 5B %+ + + + + + + +=

Steel grade

Yield stress ReH

(N/mm2) min.

Tensilestrength

Rm

(N/mm2)

El. A5 (%) min

(1)

Average impact energy (J) minKVL longitudinal - KVT transverse - t = thickness (mm)

Test temp (°C)

t ≤ 50 50 < t ≤ 70 70 < t ≤ 100

KVL KVT KVL KVT KVL KVT

A 235 400/520 (2) 22 +20 34 24 41 27

B 235 400/520 22 0 27 20 34 24 41 27

D 235 400/520 22 −20 27 20 34 24 41 27

E 235 400/520 22 −40 27 20 34 24 41 27

(1) El.: elongation. For full thickness flat tensile test specimens with a width of 25 mm and a gauge length of 200mm, the elonga-tion is to comply with the minimum values given for strength level 32 in Tab 8.

(2) For sections in grade A of all thicknesses, the upper limit for the specified tensile stress range may be exceeded up to a maxi-mum of 540 N/mm2.

NR 216, Ch 2, Sec 1


Table 5 : Normal strength plates and wide flats - Condition of supply and number of impact tests

Table 6 : Normal strength sections and bars - Condition of supply and number of impact tests

2.6.2 Higher strength steels

The mechanical properties are indicated in Tab 7.

The condition of supply and the number of impact tests tobe performed are indicated in Tab 9 for plates and wide flatsand Tab 10 for sections and bars.

2.7 Mechanical Tests

2.7.1 General

Samples for mechanical tests are to be cut from the prod-ucts in the final supply condition.The tests are to be carriedout on pieces selected from batches or on individual piecesas required in [2.7.5] and [2.7.6].

2.7.2 Batch testing

All materials in the batch are to be from the same heat, ofthe same product type, in the same condition of supply andwithin the following ranges of thickness and mass:

a) difference between minimum and maximum thicknessnot exceeding 10 mm

b) mass not exceeding 50 t.

For products of steel type A intended for secondary applica-tions, the batch composition may not be required to berestricted to material from the same heat, but in such casethe mass of the batch is not to exceed 25 t.

Steel grade

Condition of supply (1)Batch for impact tests in tons ( ) for thickness t (mm) (2)

t ≤ 25 25 < t < 35 35 ≤ t ≤ 50 50 < t ≤ 100

A A(−) (3) (N,TM)(−) NR(50) AR*(50)

B (4) A (−) A(50) (N,TM)(50) NR(25) AR*(25)

D A(50) (N,NR,TM)(50) (N,TM)(50) NR(25)

E N or TM (each piece)

(1) Abbreviations:A : Any N : Normalised Condition (heat treatment) NR : Normalising Rolled Condition as an alternative to Normalising TM : Thermo-Mechanical Rolling AR* : As Rolled Condition subject to the special approval of the Society.

(2) One set of impact tests is to be taken from each batch of the weight in tons specified in brackets (), from each fraction thereof or from each piece as indicated. When impact tests are not required the indication is (−).

(3) Charpy V-notch tests are generally not required for fine grained grade A products over 50 mm thick N or TM; when required, the rate is at the Society’s discretion.

(4) Charpy V-notch tests are generally not required for Grade B steel with thickness of 25 mm or less; when required, the rate is at the Society’s discretion.

Steel grade

Condition of supply (1)Batch for impact tests in tons ( ) for thickness t (mm) (2)

t ≤ 25 25< t ≤ 35 35 < t ≤ 50

A A (−)

B (3) A (−) A (50)

D A (50) N(50) NR(50) TM(50) AR*(25)

E N(25) TM(25) AR*(15) NR*(15)

(1) Abbreviations:A : Any N : Normalised Condition (heat treatment) NR : Normalising Rolled Condition as an alternative to Normalising TM : Thermo-Mechanical Rolling AR* : As Rolled Condition subject to the special approval of the SocietyNR* : Normalising Rolled Condition subject to the special approval of the Society.

(2) One set of impact tests is to be taken from each batch of the weight in tons specified in brackets ( ) or fraction thereof. When impact tests are not required, the indication is (−).

(3) Charpy V-notch impact tests are generally not required for Grade B steel with thickness of 25 mm or less.

NR 216, Ch 2, Sec 1


Table 7 : Higher strength steels - Mechanical properties

Table 8 : Elongation (%) on a gauge length of 200 mm for thickness t (mm)

Table 9 : Higher strength plates and wide flats - Condition of supply and number of impact tests

Steel gradeYield stress

ReH

(N/mm2) min.

Tensile strength Rm

(N/mm2)

Elong. A5 (%) min.

(1)

Average impact energy (J) min. for thickness t (mm)

Test temp. (°C)

t ≤ 50 50 < t ≤ 70 70 < t ≤ 100

KVL KVT KVL KVT KVL KVT

AH32DH32EH32FH32

315 440/570 22 0− 20− 40− 60

31 31 31 31

22 22 22 22

38383838

26262626

46464646

31313131

AH36DH36EH36FH36

355 490/630 21 0− 20− 40− 60

34 34 34 34

24 24 24 24

41414141

27272727

50505050

34343434

AH40DH40EH40FH40

390 510/660 20 0− 20− 40− 60

39 39 39 39

26262626

46464646

31313131

55555555

37373737

(1) For full thickness flat tensile test specimens with a width of 25 mm and a gauge length of 200 mm, the elongation is to comply with the minimum values given in Tab 8.

Strength grade t ≤ 5 5 < t ≤ 10 10 < t ≤ 15 15 < t ≤ 20 20 < t ≤ 25 25 < t ≤ 30 30 < t ≤ 40 40 < t ≤ 50

32 14 16 17 18 19 20 21 22

36 13 15 16 17 18 19 20 21

40 12 14 15 16 17 18 19 20

Steel gradeGrain refining

elements

Condition of supply (1) Batch for impact tests in tons ( ) for thickness t (mm) up to: (2)

12,5 20 25 35 50 100

AH32 (3)AH36 (3)

Nb and/or V A(50) N(50), NR(50), TM(50) N(50), NR(25), TM(25)

Al only A(50) AR*(25) Not applicable

or with Ti N(50), NR(50), TM(50) N(50), NR(25), TM(50)

AH40 Any A(50) N(50), NR(50), TM(50) N(50), TM(50), QT (each piece as heat treated)

DH32DH36

Nb and/or V A(50) N(50), NR(50), TM(50) N(50), NR(25), TM(50)

Al only A(50) AR*(25) Not applicable

or with Ti N(50), NR(50), TM(50) N(50), NR(25), TM(50)

DH40 Any N(50), NR(50), TM(50) N(50), TM(50), QT (each piece as heat treated)

EH32 EH36

Any N (each piece), TM (each piece)

EH40 Any N (each piece), TM (each piece), QT (each piece as heat treated)

FH32FH36

Any N (each piece), TM (each piece), QT (each piece as heat treated)

FH40 Any N (each piece), TM (each piece), QT (each piece as heat treated)

(1) Abbreviations:A : Any N : Normalised Condition (heat treatment) NR : Normalising Rolled Condition as an alternative to Normalising TM : Thermo-Mechanical Rolling QT : Quenched and Tempered Condition AR* : As Rolled Condition subject to the special approval of the Society.

(2) One set of impact tests is to be taken from each batch of the weight in tons specified in brackets ( ), from each fraction thereof or from each piece as indicated. When impact tests are not required the indication is (−).

(3) For Grades AH32 and AH36 steels, a relaxation in the number of impact tests may be permitted by special agreement with the Society, provided that satisfactory results are obtained from occasional checks.

NR 216, Ch 2, Sec 1


Table 10 : Higher strength sections and bars - Condition of supply and number of impact tests

2.7.3 Individual testing

For tests on individual pieces the term piece means rolledunit as defined in Ch 1, Sec 1, [3.3.3].

2.7.4 Sampling

For plates and flats having width ≥ 600 mm, the specimensfor tensile test are to be taken in the transverse direction andthe specimens for the Charpy V impact test in the longitudi-nal direction (KVL).

In other cases the specimens are to be taken in the longitu-dinal direction, unless otherwise required by or agreed withthe Society.

The impact test requirements specified on transverse speci-mens (KVT) are to be fulfilled by the Manufacturer and ran-dom checks may be required by the Society.

Generally, impact tests are not required when the nominalproduct thickness is less than 6 mm.

For plates fabricated in coils, the tensile and impact testsrequired are to be duplicated on specimens taken fromsamples cut at both ends of the coil.

Sampling positions are indicated in [1.8.2].

Additional through thickness tests may be required for spe-cial applications and are to be carried out according to therequirements of Article [9].

2.7.5 Number of tensile tests

One tensile test is to be carried out from one piece for eachbatch presented or fraction thereof.

In general the specimen is to be taken from a piece selectedin the batch among those with the highest thickness.

2.7.6 Number of impact tests

The number of sets of impact tests required is indicated inTab 5 and Tab 6 for normal strength products and Tab 9 andTab 10 for higher strength products.

When testing is by batches, the specimens are to be takenfrom a piece selected among those of the batch having thehighest thickness.

The number of sets of specimens for the impact test, each ofthree specimens, summarised in the above-mentionedTables, is to be in accordance with the following require-ments:

a) one set is required for each batch of 50 tons, or fractionthereof for the following grades of steel, unless other-wise specified in b):

• A, for products having thickness > 50 mm

• B, for products having thickness > 25 mm

• D, AH32, DH32, AH36, DH36, AH40, DH40

Steel gradeGrain refining

elements

Condition of supply (1)Batch for impact test in tons( ) for thickness t (mm) up to: (2)

12,5 20 50

AH32 (3)AH36 (3)

Nb and/or V A(50 ) N(50), NR(50), TM(50), AR*(25)

Al only or with Ti A(50) N(50), NR(50), TM(50), AR*(25)

AH40 Any A(50) N(50), NR(50), TM(50)

DH32 DH36

Nb and/or V A (50) N(50), NR(50), TM(50), AR*(25)

Al only or with Ti A(50) N(50), NR(50), TM(50), AR*(25)

DH40 Any N(50), NR(50), TM(50)

EH32 EH36

Any N(25), TM(25), AR*(15), NR*(15)

EH40 Any N(25), TM(25), QT(25)

FH32FH36

Any N(25), TM(25), QT(25), NR*(15)

FH40 Any N(25), TM(25), QT(25)

(1) Abbreviations:A : AnyN : Normalised Condition (heat treatment) NR : Normalising Rolled Condition as an alternative to Normalising TM : Thermo-Mechanical Rolling QT : Quenched and Tempered Condition AR* : As Rolled Condition subject to the special approval of the Society NR* : Normalising Rolled Condition subject to the special approval of the Society.

(2) One set of impact tests is to be taken from each batch of the weight in tons specified in brackets ( ) or fraction thereof. (3) For Grades AH32 and AH36 steels, a relaxation in the number of impact tests for acceptance purposes may be permitted by

special agreement with the Society provided that satisfactory results are obtained from occasional checks.

NR 216, Ch 2, Sec 1


b) except for grade A, for products supplied subject to spe-cial approval in the as rolled condition (AR*), and forproducts with thickness higher than 50 mm supplied inthe controlled rolled condition (NR), the mass of thebatches for the purpose of impact tests is to be 25 t, or afraction thereof

c) one set of three impact test specimens is required for:

• each piece for grades E and F in all strengths

• each batch of 25 t or fraction thereof of sections ofgrades E and F in all strengths

d) when, subject to special approval, sections of steelgrades E and F in all strengths other than 40 are suppliedin the as rolled (AR*) or controlled rolled (NR*) condi-tion, the mass of the batches for the purpose of impacttests is to be 15 t, or a fraction thereof.

Random checks of the impact values may be required at thediscretion of the Surveyor.

3 High strength quenched and tempered steels

3.1 Scope

3.1.1 The requirements of this Article apply to weldableferritic high strength quenched and tempered steel platesand wide flats with thickness up to 70 mm.

These requirements may also be applied to products withthickness above 70 mm and to other product forms, such assections and tubulars, subject to special agreement with theSociety.

3.2 Steel grades

3.2.1 The requirements apply to carbon-manganese andlow alloyed steels.

The steels are classed into six groups indicated by minimumyield strength levels ReH (N/mm2) 420, 460, 500, 550, 620and 690.

Each group is further subdivided into four grades A, D, Eand F based on the impact test temperature.

The letters A, D, E and F mean impact test at 0, −20, −40and −60°C, respectively.

3.3 Manufacture

3.3.1 ApprovalThe Manufacturers are to be approved by the Society andthe relevant requirements of [1.2] apply.

3.3.2 Deoxidation processThe steel is to be fully killed and fine grain treated.

3.3.3 Dimensional tolerances and surface conditions

Unless otherwise agreed or specially required, for underthickness tolerances, surface condition and rectification ofsurface defects, the requirements depend on the applicationsand are indicated in [2.3.4], [2.3.6] and [2.3.7] for structuralapplications, in [4.3.4], [4.3.5] and [4.3.6] for applicationsunder pressure and in [6.3.3] for parts of machinery.

Repair by welding is to be specially approved.

3.3.4 Non-destructive examinationFor specific applications, ultrasonic examination in accord-ance with recognised standards may be required.

Ultrasonic testing of plates intended for offshore structuralapplications of first and special category as defined in theSociety’s Offshore Rules is required and is to be performedin accordance with a recognised standard (e.g. EN 10160 orASTM A 578) and an examination level accepted by theSociety.


3.4.1 The products are to be supplied in the quenched andtempered condition.However, thermo-mechanical rolling may be also permittedsubject to special approval for thicknesses up to 50 mm, forsteels up to grade 550.

For the definition of rolling procedures, see [1.7.3].


3.5.1 The chemical composition on ladle analysis is tocomply with the requirements specified in Tab 11 and inthe approved specification.The approved specification is also to include the alloyingand grain refining elements and the maximum Pcm value(cold cracking susceptibility index), agreed during the initialapproval tests of the steel.

Table 11 : Chemical composition

Yield strength level (N/mm2)

Steel grade

Chemical composition (%) (1)

C max. Mn max Si max. P max. S max. Al min. (2) N max.

420 up to690

A 0,21 1,70 0,55 0,035 0,035 0,015 0,020

D - E 0,20 1,70 0,55 0,030 0,030 0,015 0,020

F 0,18 1,60 0,55 0,025 0,020 0,015 0,020

(1) The content of other elements used for alloying and fine grain treatment is to be within the limits specified for the steel at the time of its approval and is not normally to exceed the following per cent limits:Cu max.= 1,5 ; Cr max.= 2,0 ; Ni max.= 2,0 ; Mo max.= 1,0 ; N max.= 0,020 ; B max.= 0,06 ; Nb max.= 0,06 ; V max.= 0,10 ; Ti max.= 0,20 ; Zr max.= 0,15.

(2) The acid soluble Al content may be totally replaced by Nb, V or Ti. The total aluminium content may be determined instead of the acid soluble content and in such cases the total aluminium content is to be not less than 0,020%.

NR 216, Ch 2, Sec 1


The Pcm value is to be calculated from the ladle analysis inaccordance with the following formula:

The alloying and grain refining elements and Pcm value, asapplicable, are to be stated by the steelmaker and includedin the testing documentation for each cast.

3.6 Mechanical properties

3.6.1 The mechanical properties are specified in Tab 12.

3.7 Mechanical tests

3.7.1 General

Samples for tests are to be cut from the products in the finalsupply condition. The tests are to be carried out on eachrolled unit as heat treated.

The definition of rolled unit is given in Ch 1, Sec 1, [3.3.3].

For continuously heat treated products, special samplingprocedures may be agreed at the Society’s discretion.

Table 12 : Mechanical properties

Table 13 : Minimum elongation values for flat specimens 25 mm width and 200 mm gauge length

Pcm C Si30------ Mn

20--------- Cu

20------- Ni

60------ Cr

20------ Mo

15--------- V

10------ 5B %+ + + + + + + +=

Steel gradeYield stressReH (N/mm2)

min. (1)

Tensile strength Rm (N/mm2)

ElongationA5 (%)

min. (2)

Average impact energy test (J)min.

Test temp (C°) Longitudinal KVL Transverse KVT

A420 0

D420 420 530 - 680 18 − 20 42 28

E420 − 40

F420 − 60

A460 0

D460 460 570 - 720 17 − 20 46 31

E460 − 40

F460 − 60

A500 0

D500 500 610 - 770 16 − 20 50 33

E500 − 40

F500 − 60

A550 0

D550 550 670 - 830 16 − 20 55 37

E550 − 40

F550 − 60

A620 0

D620 620 720 - 890 15 − 20 62 41

E620 − 40

F620 − 60

A690 0

D690 690 770 - 940 14 − 20 69 46

E690 − 40

F690 − 60

(1) A yield strength to ultimate tensile strength ratio may be required when specified in the steel approval conditions.(2) For full thickness flat test specimens with a width of 25 mm and a gauge length of 200 mm, the elongation is to comply with the

values given in Tab 13. The elongation values specified in Tab 12 and Tab 13 are relevant to tensile specimens taken in thetransverse direction. In the case of specimens taken in the longitudinal direction, the elongation values are to be 2 percentageunits above those listed in Tab 12 and Tab 13.

Strength levelThickness t (mm)

t ≤ 10 10 < t ≤ 15 15 < t ≤ 20 20 < t ≤ 25 25 < t ≤ 40 40 < t ≤ 50 50 < t ≤ 70

420 11 13 14 15 16 17 18

460 11 12 13 14 15 15 17

500 10 11 12 13 14 15 16

550 10 11 12 13 14 15 16

620 9 11 12 12 13 14 15

690 9 10 11 11 12 13 14

NR 216, Ch 2, Sec 1


3.7.2 Sampling

In the case of plates and flats having width ≥ 600 mm, thetensile test and impact test specimens are to be taken in thetransverse direction.


3.7.3 Number of tests

The following test specimens are to be taken from eachsample:

a) 1 tensile test specimen,

b) 1 set of 3 Charpy V-notch impact test specimens.

4 Steels for boilers and pressure vessels

4.1 Scope

4.1.1 The requirements of this Article apply to weldableferritic steel products (plates, flats, sections and bars)intended for boilers and pressure vessels.

Provision is made for products with thickness up to 60 mmand impact properties at a temperature not lower than −20°C.

These requirements may also be applied to products withthickness above 60 mm subject to agreement with the Soci-ety.

4.1.2 Special requirements may be specified in the case ofapplications intended for dangerous substances or particu-larly severe service conditions.

4.1.3 In the case of applications involving the storage andtransport of liquefied gases, the relevant requirements of theSociety’s Rules for the Classification of Steel Ships apply.

4.2 Steel grades

4.2.1 The requirements apply to carbon and carbon man-ganese steels and low alloy steels (Mo and Cr-Mo steels).

4.2.2 Carbon and carbon manganese steels are classed intofour groups indicated by the minimum ultimate tensilestrength Rm ( N/mm2): 360, 410, 460 and 510.

Each group may be further subdivided into grades HA, HBand HD, as appropriate, based on the quality level andimpact properties.

The letters HA, HB and HD mean impact properties at+20°C, 0°C and −20°C, respectively.

4.2.3 Low alloy steels are designated according to thechemical composition into the grades 0,3Mo - 1Cr0,5Mo -2,25Cr1Mo.Two types of 2,25Cr1Mo steel are specified in relation tothe heat treatment and consequent mechanical properties.

The figures mean the nominal percentage content of themain alloying elements.

4.3 Manufacture

4.3.1 ApprovalUnless otherwise agreed by the Society, the Manufacturers areto be approved and the relevant requirements of [1.2] apply.

4.3.2 Deoxidation processThe method of deoxidation is specified in Tab 14 and Tab15.

4.3.3 Rolling practiceWhere CR (NR) are applied, the programmed rolling sched-ules are to be submitted to the Society at the time of theapproval and are to be made available when required bythe attending Surveyor. On the manufacturer’s responsibil-ity, the programmed rolling schedules are to be adhered toduring the rolling operation (as per [1.3.2]). To this effect,the actual rolling records are to be reviewed by the manu-facturer and, occasionally, by the Surveyor.

Table 14 : Carbon and carbon manganese steels - Chemical composition

Steel grade DeoxidationChemical composition (%) (1)

C max Mn Si P max S max Al tot. min. (1) Ni max

360HA not rimmed 0,16 ≥ 0,40 ≤ 0,35 0,030 0,030

360HB killed 0,16 0,40 - 1,20 0,10 - 0,35 0,030 0,030

360HD killed and fine grained 0,16 0,40 - 1,20 0,10 - 0,35 0,030 0,030 0,020

410HA not rimmed 0,20 ≥ 0,50 ≤ 0,35 0,030 0,030 0,30

410HB killed 0,20 0,50 - 1,40 0,10 - 0,35 0,030 0,030 0,30

410HD killed and fine grained 0,20 0,50 - 1,40 0,10 - 0,35 0,030 0,030 0,020 0,30

460HB killed 0,20 0,80 - 1,50 0,10 - 0,40 0,030 0,030 0,30


(1) Nb, V or Ti may be used for grain refining as a complete or partial substitute for Al. The grain refining elements are to be speci-fied at the time of approval; in general Nb and V are not to exceed 0,05 and 0,10%, respectively.Additional alloying elements are to be submitted for consideration and approval. Residual elements not intentionally added are not to exceed the following limits:Cu ≤ 0,30% ; Cr ≤ 0,25% ; Mo ≤ 0,10% . Total: Ni + Cu + Cr + Mo ≤ 0,70%

NR 216, Ch 2, Sec 1


Table 15 : Low alloy steels - Chemical composition

When deviation from the programmed rolling schedulesoccurs, the manufacturer is to take further measures, to theSurveyor’s satisfaction, in accordance with [1.3.2].

4.3.4 Dimensional tolerances Minus tolerances on the thickness are not normally permit-ted.

4.3.5 Rectification of surface defects by grindingSurface defects may generally be removed by grinding asindicated in [1.6.1], provided that the thickness, after grind-ing, is not less than the nominal thickness.

However the extent of repairs is to be agreed with the Sur-veyor. Where the thickness is reduced below the nominalthickness given in the approved plans, the possible accept-ance and the relevant conditions are subject to special con-sideration by the Society.

4.3.6 Rectification of surface defects by weldingDefects which cannot be removed by grinding may gener-ally be repaired by welding under the conditions given in[1.6.2], except that suitable heat treatment and non-destructive examination are always required after repair.

The purchaser is to be informed as to the extent and posi-tion of the repairs carried out on the individual plates.


4.4.1 The products are to be supplied in the conditionsindicated in Tab 16 for carbon and carbon manganesesteels and Tab 17 for low alloy steels.

4.4.2 The products to be processed after supply by hotforming may also be supplied, where agreed, in the asrolled condition.In such cases heat treatment is to be carried out after hotforming and provision for the mechanical tests indicated in[4.8.4] is to be made.


4.5.1 The chemical composition on ladle analysis is tocomply with the requirements specified in Tab 14 for car-bon and carbon manganese steels and Tab 15 for low alloysteels and/or in the approved specification.The approved specification is also to include the alloyingand grain refining elements (not specified in the above-mentioned Tables).

The relevant elements as applicable are to be stated by thesteelmaker and included in the testing documentation foreach cast.

For C and C-Mn steels, an upper limit for carbon equivalentCEQ on the ladle analysis may be specified at the time ofapproval of the individual steels.


Unless otherwise agreed, when a limit for CEQ is required,the relevant values are to be stated by the steelmaker andincluded in the testing documentation for each cast.

510HB killed 0,22 0,90 - 1,60 0,10 - 0,50 0,030 0,025 0,30


Steel gradeDeoxidation

(2)Chemical composition (%) (1)

C Mn Si P max S max Cr Mo

0,3Mo Si killed 0,12 - 0,20 0,40 - 0,90 0,10 - 0,35 0,030 0,030 ≤ 0,30 0,25-0,35

1Cr 0,5Mo Si killed 0,08 - 0,18 0,40 - 1,00 0,15 - 0,35 0,030 0,030 0,70-1,20 0,40-0,60

2,25Cr 1Mo Si killed 0,07 - 0,15 0,40 - 0,80 0,15 - 0,50 0,030 0,030 2,00-2,50 0,90-1,10

(1) Residual elements are not to exceed the following limits: Cu ≤ 0,30%, Ni ≤ 0,30%.(2) Aluminium total max 0,020% for all grades of steel. The aluminium content is to be mentioned in the ladle analysis certificate.

Steel grade DeoxidationChemical composition (%) (1)

C max Mn Si P max S max Al tot. min. (1) Ni max

(1) Nb, V or Ti may be used for grain refining as a complete or partial substitute for Al. The grain refining elements are to be speci-fied at the time of approval; in general Nb and V are not to exceed 0,05 and 0,10%, respectively.Additional alloying elements are to be submitted for consideration and approval. Residual elements not intentionally added are not to exceed the following limits:Cu ≤ 0,30% ; Cr ≤ 0,25% ; Mo ≤ 0,10% . Total: Ni + Cu + Cr + Mo ≤ 0,70%

CEQ C= Mn6

--------- Cr Mo V+ +5

-------------------------------- Ni Cu+15

--------------------- %+ + +

NR 216, Ch 2, Sec 1


Table 16 : Carbon and carbon manganese steels - Mechanical properties

Table 17 : Low alloy steels - Mechanical properties


4.6.1 The mechanical properties are specified in Tab 16 forcarbon and carbon manganese steels and Tab 17 for lowalloy steels.

4.7 Mechanical properties at elevated tem-peratures

4.7.1 The values for the yield stress or 0,2% proof stress(Rp0,2) at temperatures of 100°C and higher are given in Tab18.The above values are for design purposes only. Their verifi-cation is in general not required during the testing, unless

figures higher than those shown in the above Tables but inaccordance with recognised standards are proposed by thesteel Manufacturer.

In such cases, the verification is required and the proce-dures detailed in [4.7.2] and [4.7.3] are to be followed.

4.7.2 When Rp0,2 is required to be verified, at least one ten-sile test for each cast is to be carried out at the agreed tem-perature.

The sample is to be cut from the thickest plate of the castand, if applicable, at the end of the plate that has shown thelowest figures in the tensile test at ambient temperature.

Steelgrade

Heattreatment

(1)

Yield stress ReH (N/mm2) min.for thickness (mm)

Tensilestrength

Rm

(N/mm2)

Elong. A5

(%) min.

Average impact energy (J)min.

t ≤ 16 16 < t ≤ 40 40 < t ≤ 60 Test temp (°C) KVT KVL

360HA

N or NR

215 205 195 360 - 480 25 + 20 27 41

360HB360HD

235 225 215 0

− 20

410HA

N or NR

245 235 225 410 - 530 23 + 20

410HB410HD

265 255 245 0

− 20

460HBN or NR

285 270 260 460 - 580 22 0

460HD 295 285 280 − 20

510HBN or NR

345 335 325 510 - 630 21 0

510HD 355 345 335 − 20

(1) N : Normalising - NR : Normalising Rolling. As an alternative to normalising, the as rolled condition may be accepted for sec-tions, subject to approval of individual steelmakers.

Steel gradeHeat

treatment (1)

Yield stress ReH (N/mm2)min. for thickness (mm)

Tensile strength Rm

(N/mm2)

Elongation A5 (%) min. for thickness (mm)

Average impact energy (J) min.

at + 20°C

t ≤ 16 16 < t ≤ 40 40 < t ≤ 60 t ≤ 40 40 < t ≤ 60 KVT

0,3Mo N 275 270 260 430 - 600 24 23 31

1Cr 0,5Mo N + T 300 295 295 450 - 610 20 19

2,25Cr 0,5Mo N + T 295 285 275 520 - 670 18 18

N+T or Q+T 310 310 310 470 - 620

(1) N = Normalising; T = Tempering; Q = Quenching

NR 216, Ch 2, Sec 1


Table 18 : Minimum proof stress (Rp0,2) values at elevated temperatures

The sample is to be taken halfway between the edge and theaxis of the piece, and the axis of the test specimen is to belocated at one quarter of the thickness from one of therolled surfaces.

The dimensions of the specimens and the testing procedureare to be in accordance with the requirements of Ch 1, Sec2, [2.1] and Ch 1, Sec 2, [2.2.5], respectively.

The results of tests are to comply with the specified values.

4.7.3 As an alternative to the systematic verification of therequired Rp0,2 as in [4.7.2], it may be agreed with the indi-vidual steelmakers to carry out an adequate program of testson the normal production for each type of steel to beapproved.For Manufacturers and steel types approved on this basis,tensile tests at elevated temperatures are not generallyrequired during the routine testing of the material supplied;they may be required by the Society as a random check forthe confirmation of the approval.

4.7.4 For design purposes only, the estimated values of thestress to rupture in 100000 hours are given in Tab 19 forgroups of steels.


4.8.1 General

Unlesss otherwise agreed (see [4.8.6]), samples for tests areto be cut from the products in the final supply conditions.

4.8.2 Samples from plates and wide flats

One sample is to be taken from one end of each rolled unitwhen the mass and the length do not exceed 5t and 15m,respectively.

When either of these limits is exceeded, samples are to becut at both ends of each rolled unit.


4.8.3 Samples from sections and bars

One sample is to be taken from each batch homogeneousfor cast, section size and condition of supply. Each batch isto contain not more than 50 pieces and its total mass is notto exceed 10 t.

Steelgrade

Thickness (mm)

Rp0,2 (N/mm2) at a temperature (°C) of

100 150 200 250 300 350 400 450 500 550 600

360HA (1) ≤ 16> 16 ≤ 40> 40 ≤ 60

175171162

172169158

168162152

150144141

124124124

117117117

115115115

360HB (1)360HD (1)

≤ 16> 16 ≤ 40> 40 ≤ 60

204196179

185183172

165164159

145145145

127127127

116116116

110110110

410HA (1) ≤ 16> 16 ≤ 40> 40 ≤ 60

211201192

208198188

201191181

180171168

150150150

142142142

138138138

410HB (1)410HD (1)

≤ 16> 16 ≤ 40> 40 ≤ 60

235228215

216213204

194192188

171171171

152152152

141141141

134134134

460HB (1)460HD (1)

≤ 16> 16 ≤ 40> 40 ≤ 60

262260251

247242235

223220217

198198198

177177177

167167167

158158158

510HB (1)510HD (1)

≤ 60 290 270 255 235 215 200 180

0,3Mo ≤ 60 215 200 170 160 150 145 140

1Cr 0,5Mo ≤ 60 230 220 205 190 180 170 165

2,25Cr 1Mo ≤ 60 (2) ≤ 60 (3)

235265

230255

220235

210225

200215

190205

180195

(1) The values at Rp0,2 for temperatures ≤ 250°C are for guidance only.(2) Normalised and tempered (3) Normalised and tempered or quenched and tempered

NR 216, Ch 2, Sec 1


Table 19 : Average values for stress to rupture in 100000 hours (N/mm2)

4.8.4 Sampling of test specimens In the case of plates and wide flats having width ≥ 600mm,the tensile test and impact test specimens are to be taken inthe transverse direction.


4.8.5 Number of test specimensThe following test specimens are to be taken from eachsample:

a) 1 tensile test specimen (2 tests in the case of barsintended for tie rods)

b) 1 set of 3 Charpy V-notch impact test specimens (onlyfor grades HB and HD unless otherwise specified)

c) 1 tensile test specimen at elevated temperature, for eachcast, when required.

4.8.6 Material to be hot workedWhen for material to be hot worked after delivery, it isagreed that the heat treatment required will be carried outby the purchaser, the samples are to be submitted by the

steelmaker to such treatment before the cutting of test spec-imens.

In particular cases (when the material is submitted to coldor hot working during fabrication), tests additional to theroutine testing may be required on samples in the final con-dition of the material after fabrication.

These may also include tests on material submitted to artifi-cial aging treatment as indicated in Ch 1, Sec 2, [8.1.1].

5 Ferritic steels for low temperature service

5.1 Scope

5.1.1 The requirement of this Article apply to ferritic steelproducts (plates, flats, sections and bars) intended for cargotanks, storage tanks, process pressure vessels and systemsfor liquefied gases and other pressure vessels in general,when impact properties at temperature lower than −20°Care required.

Temperature (°C)Steel grade

360 - 410 460 - 510 0,3Mo 1Cr 0,5Mo 2,25Cr 1Mo

380 170 225

390 155 200

400 140 175

410 125 155

420 110 135

430 100 115

440 90 100

450 75 85 235 285 220

460 (60) (70) 205 250 205

470 (50) (60) 175 220 185

480 (40) (55) 145 190 170

490 (45) 120 160 150

500 (40) 100 135 135

510 80 120 120

520 65 95 105

530 50 80 90

540 60 75

550 50 65

560 40 55

570 30 50

580 45

590 (40)

600 (35)

Note 1: The values shown are estimated average values; the lower limit of the range is approximately 20% less than the average value. The values in brackets for some higher temperatures indicate that the steel is not suitable for continuous use at such tempera-tures.

NR 216, Ch 2, Sec 1


Provision is made for products with thickness up to 60mm.

The extension to higher thicknesses and relevant conditionsare subject to agreement with the Society.

5.1.2 Special requirements may be specified in the case ofapplications intended for dangerous substances or particu-larly severe service conditions.

5.1.3 In case of applications involving the storage andtransport of liquefied gases, the appropriate requirements ofthe Society’s Rules for the Classification of Steel Ships alsoapply.

5.2 Steel grades

5.2.1 The requirements apply to carbon, carbon manga-nese and Ni alloy steels.

5.2.2 The carbon and carbon manganese steels are classedinto four groups indicated by the minimum ultimate tensilestrength Rm (N/mm2): 410, 460, 510 and 550.

Each group is further subdivided into two grades, LE and LF,based on the quality level and impact properties.

The letters LE and LF mean impact properties at −40 and −60°C, respectively.

5.2.3 Ni alloy steels are designated according to the chem-ical composition into the grades: 1,5Ni - 3,5Ni - 5Ni - 9Ni.The figures mean the Ni nominal percentage content.

5.3 Manufacture

5.3.1 Approval

The Manufacturers are to be approved by the Society (see[1.2]).

5.3.2 Deoxidation process

The steel is to be killed and fine grained.

5.3.3 Dimensional tolerances

For pressure vessels, minus tolerances on thickness are notnormally permitted.

5.3.4 Surface conditions

For repairs, the provisions of [4.3.5] and [4.3.6] apply.

Repairs by welding are not normally allowed on 5% or 9%nickel steels.


5.4.1 Unless otherwise accepted by the Society, carbonand carbon manganese products are to be supplied in nor-malised (N) condition.

Nickel steel products are to be supplied in the conditionsindicated in Tab 23.

5.4.2 The products to be processed after supply by hotworking may also be supplied, where agreed, in the asrolled condition.

In such cases heat treatment is to be carried out after form-ing and provision for the mechanical tests indicated in[4.8.6] is to be made.


5.5.1 The chemical composition on ladle analysis is tocomply with the requirements specified in Tab 20 and Tab21 and/or in the approved specification.

The approved specification is also to include the alloyingand grain refining elements (not specified in Tab 20).

The content of the above elements, as applicable, is to bestated by the steelmaker for each heat and included in thetesting documentation.

For C and C-Mn steels, an upper limit for carbon equivalentCEQ on the ladle analysis may be specified at the time ofapproval of the individual steels.

Table 20 : Carbon and carbon manganese steels - Chemical composition

Steel grade


C max Mn Si P max S max Al tot min Ni max

410 LE 0,18 0,50 - 1,40 0,10 - 0,35 0,030 0,030 0,020 0,30

410 LF 0,16 0,50 - 1,40 0,10 - 0,35 0,030 0,030 0,020 0,80

460 LE 0,18 0,80 - 1,50 0,10 - 0,40 0,030 0,030 0,020 0,30

460 LF 0,16 0,80 - 1,50 0,10 - 0,40 0,030 0,030 0,020 0,80

510 LE 0,18 1,00 - 1,70 0,10 - 0,50 0,030 0,025 0,020 0,30

510 LF 0,16 1,00 - 1,70 0,10 - 0,50 0,030 0,025 0,020 0,80

550 LE 0,18 1,00 - 1,70 0,10 - 0,50 0,030 0,025 0,020 0,30

550 LF 0,16 1,00 - 1,70 0,10 - 0,50 0,030 0,025 0,020 0,80

(1) Nb, V or Ti may be used for grain refining as a complete or partial substitute for Al. The grain refining elements are to be speci-fied at the time of approval; in general Nb and V are not to exceed 0,05 and 0,10 %, respectively. Additional alloying elements are to be submitted for consideration and approval. Residual elements not intentionally added are not to exceed the following limits (%): Cu ≤ 0,30, Cr ≤ 0,15, Mo ≤ 0,10.

NR 216, Ch 2, Sec 1


Table 21 : Nickel alloy steels - Chemical composition


Unless otherwise agreed, when a limit for CEQ is requiredthe relevant values are to be stated by the steelmaker andincluded in the testing documentation for each cast.


5.6.1 The products are to comply with the mechanicalproperties specified in Tab 22 and Tab 23.


5.7.1 General

Unless otherwise agreed in the case of materials to be hotworked after delivery [5.4.2], samples for tests are to be cutfrom the products in the final supply conditions.

5.7.2 Plates and wide flats

One sample is to be taken from one end of each rolled unitwhen the mass and the length do not exceed 5t and 15m,respectively.

When either of these limits is exceeded, samples are to becut at both ends of each rolled unit.


5.7.3 Sections and bars

One sample is to be taken from each batch homogeneousfor heat, section size and condition of supply.

Each batch is to contain not more than 50 pieces and itstotal mass is not to exceed 10 t.

5.7.4 Sampling

In the case of plates and wide flats having width ≥ 600mm,the tensile test and impact test specimens are to be taken inthe transverse direction.


5.7.5 Number of tests

The following test specimens are to be taken from eachsample:

a) 1 tensile test specimen

b) 1 set of 3 Charpy V-notch impact test specimens

c) 2 or more drop weight test specimens, when required.

Table 22 : Carbon and carbon manganese steels - Mechanical properties

Steel gradeChemical composition (1) (2)

C max Mn Si max P max S max Ni Cr max Mo max

1,5 Ni 0,18 0,30 - 1,50 0,35 0,035 0,020 1,30 - 1,70 0,25 0,10

3,5 Ni 0,15 0,30 - 0,90 0,35 0,035 0,020 3,20 - 3,80 0,25 0,10

5,0 Ni 0,12 0,30 - 0,90 0,35 0,035 0,020 4,70 - 5,30 0,25 0,10

9,0 Ni 0,10 0,30 - 0,90 0,35 0,035 0,020 8,50 - 10,0 0,25 0,10

(1) Residual elements are not to exceed the following limits (%): Cu ≤ 0,35 ; V ≤ 0,05 . Total Cr + Cu + Mo ≤ 0,50(2) Aluminium total not less than 0,020 for all grades of steels. The aluminium content is to be mentioned in the ladle analysis cer-

tificate.

CEQ C= Mn6

--------- Cr Mo V+ +5

-------------------------------- Ni Cu+15

--------------------- %+ + +

Steelgrade

Yield stress ReH (N/mm2) min.for thickness t (mm) Tensile strength

Rm (N/mm2)Elong.

A5 (%) min

Average impact energy (J ) min.

t ≤ 16 16 < t ≤ 40 40 < t ≤ 60 Temp (°C) KVT KVL

410 LE 265 255 245 410 - 530 23 − 40 27 41

410 LF 290 280 270 410 - 530 23 − 60 27 41

460 LE 295 285 270 460 - 580 22 − 40 27 41

460 LF 320 310 300 460 - 580 22 − 60 27 41

510 LE 355 345 335 510 - 630 21 − 40 27 41

510 LF 355 345 335 510 - 630 21 − 60 27 41

550 LE 390 380 375 550 - 670 20 − 40 27 41

550 LF 390 380 375 550 - 670 20 − 60 27 41

NR 216, Ch 2, Sec 1


Table 23 : Nickel steels - Mechanical properties

6 Steels for machinery

6.1 Scope

6.1.1 The requirements of this Article apply to carbon, car-bon manganese, low alloy and alloy rolled steel productsintended for use in the construction of structures and partsof machinery and equipment operating at ambient tempera-ture.

In the case of applications in low or high temperature pres-sure systems, reference is to be made to the applicablerequirements of Articles [5] and [4] respectively.

6.1.2 The products are grouped as follows, depending onthe application:

a) structural parts of deck equipment

b) welded machinery structures such as bedplates, crank-cases, frame entablatures or similar items

c) rolled products, such as bars for small shafts, pins, boltsor similar items, when, in the limit of diameters of250mm, they are accepted in lieu of forgings.

6.2 Steel grades and relevant properties

6.2.1 The type of steels covered by Articles [2], [4], [5] and[7] may be used as appropriate.

Chemical and mechanical properties are to comply with therequirements given therein.

For products having thickness exceeding the maximumthickness considered in the above-mentioned Articles, thefollowing deviations in mechanical properties are permit-ted:

• the minimum yield stress ReH required is reduced by 1%for every 5 mm thickness over the a.m. maximum

• the minimum elongation A5 min. required is reduced by1 unit for thickness over than the a.m. max up to 100mm and by 2 units for thickness greater than 100 mm.

6.3 Manufacture and condition of supply

6.3.1 Products intended for applications under [6.1.2] a)and [6.1.2] b) are to be manufactured and supplied as indi-cated in [2.3] and [2.4], [4.3] and [4.4], [5.3] and [5.4], asappropriate.

For products intended for applications under [6.1.2] c), theapplicable requirements of Sec 3 apply; unless otherwise

agreed, a reduction ration of 6:1 in respect of the originalingot is generally required.

Table 24 : Under thickness tolerance

6.3.2 For specific applications, ultrasonic examinations inaccordance with approved standards or procedures may berequired.Rolled bars for shaft lines, used in lieu of forgings and hav-ing a diameter higher than 150 mm, are to be submitted tonon-destructive (ultrasonic and magnetoscopic) examina-tions.

6.3.3 Unless otherwise agreed or specially required, theunder thickness tolerances indicated in Tab 24 apply toplates and wide flats.


6.4.1 For applications under [6.1.2] a) and [6.1.2] b), irre-spective of the grade of steel, the testing may be in batchesin accordance with the relevant requirements of Article [2].One tensile test is to be carried out from one piece for eachbatch presented or fraction thereof.

Unless otherwise required, the impact tests may be omitted.

6.4.2 For applications under [6.1.2] c), the testing proce-dure is to be in accordance with the requirements of Sec 3,[1.8.4] relevant to forgings.

6.4.3 The results of tensile and impact tests are to complywith requirements of Articles [2], [4] and [5], [7], as appli-cable.

7 Stainless steel products

7.1 Scope

7.1.1 The requirements of this Article apply to austeniticand austenitic-ferritic (duplex) rolled stainless productsintended for use in construction of cargo tanks, storage

Steelgrade

Heat treatment (1)

Yield stress ReH (N/mm2)min.

Tensile strength Rm (N/mm2)

Elongation A5 (%) min.


Temp (°C) KVT KVL

1,5 Ni N+T or Q+T 275 490 - 640 22 − 80 27 41

3,5 Ni N+T or Q+T 285 450 - 610 21 − 95 27 41

5,0 Ni N+T or Q+T 390 540 - 740 21 − 110 27 41

9,0 Ni N+N+T or Q+T 490 640 - 790 18 − 196 27 41

(1) N=normalising T= tempering Q = quenching

Nominal thickness t (mm) Under thickness tolerance (mm)

5 ≤ t ≤ 8 0,4

8 < t ≤ 15 0,5

15 < t ≤ 25 0,6

25 < t ≤ 40 0,8

t > 40 1,0

NR 216, Ch 2, Sec 1


tanks and pressure vessels for chemicals and limitedly to theaustenitic grades for liquefied gases.

7.1.2 Austenitic stainless steels are suitable for use both atelevated and low temperatures.

When austenitic stainless steels are proposed for use at ele-vated temperatures, details of chemical composition, heattreatment and mechanical properties are to be submitted forconsideration and approval.

Unless otherwise specified, austenitic-ferritic stainless steelsare in general suitable for service temperature between −20°C and +275°C.

7.1.3 Stainless steel bars may be used for propeller shafts orsimilar applications under the conditions given in [6.1.2] c).

7.1.4 In cases of applications involving the storage andtransport of liquefied gases in bulk, the appropriate require-ments of the Society’s Rules for the Classification of SteelShips apply.

7.2 Steel grades

7.2.1 The requirements apply to Cr-Ni austenitic and auste-nitic-ferritic stainless steels.

Note 1: Reference is made for designation to the correspondingAISI grade.

Other stainless steel of martensitic types, in accordancewith international or national standards, may be acceptedfor specific applications such as in [7.1.3].

7.3 Manufacture

7.3.1 Approval

Unless otherwise agreed, the Manufacturers of steelintended for the construction of chemical carriers are to beapproved by the Society and the relevant requirements of[1.2] apply.

7.3.2 Corrosion resistance The resistance of tank material to cargoes is under theresponsibility of the yard.

Justification of such resistance is to be submitted to theSociety.

7.3.3 Dimensional tolerances With the exception of pressure vessels (see [4.3.4]), theminimum tolerance on thickness is to be 0,3 mm.

7.3.4 Surface conditionsSurface defects may be removed by grinding, provided thatthe plate thickness at the location of the ground zone is notless than the minimum thickness specified in [7.3.3].

Surface defects which cannot be removed by grinding maybe generally repaired under the conditions given in [2.3.7],as applicable.


7.4.1 All materials are to be supplied in the solution treatedcondition.


7.5.1 The chemical composition on ladle analysis is tocomply with the requirements specified in Tab 25.


7.6.1 The mechanical properties are specified in Tab 26.


7.7.1 Batch compositionThe products are grouped in batches of 20 tons or fractionthereof, consisting of parts coming from the same cast, thethickness of which differs by no more than 5mm in the caseof flat products.

When the batch is made up of plates, the plate selected totake the test specimens is to be one of those of highestthickness.

Table 25 : Chemical composition

AISI gradedesignation


C max Mn max Si max P max S max Cr Ni Mo Others

Austenitic

304 L 0,030 2,0 1,0 0,040 0,030 17,0 - 19,0 9,0 - 12,0 −

304 LN 0,030 2,0 1,0 0,040 0,030 17,0 - 19,0 8,5 - 11,0 − 0,14 ≤ N ≤ 0,22

316 L 0,030 2,0 1,0 0,040 0,030 16,0 - 18,5 10,0 - 14,0 2,0 - 3,0

316 LN 0,030 2,0 1,0 0,040 0,030 16,0 - 18,5 10,0 - 14,0 2,0 - 3,0 0,14 ≤ N ≤ 0,22

317 L 0,030 2,0 1,0 0,040 0,030 18,0 - 20,0 14,0 - 16,0 3,0 - 4,0

317 LN 0,030 2,0 1,0 0,040 0,030 18,0 - 20,0 12,5 - 14,0 3,0 - 4,0 0,14 ≤ N ≤ 0,22

321 0,080 2,0 1,0 0,040 0,030 17,0 - 19,0 9,0 - 13,0 − 5xC ≤ Ti ≤ 0,80

(1) With the exception of refining elements, additional alloying elements are to be submitted for consideration and approval. Residual elements are permitted provided they do not impair the properties, subsequent processing or behaviour in service of the material.

NR 216, Ch 2, Sec 1


Table 26 : Mechanical properties

7.7.2 Sampling

In the case of plates and wide flats having width ≥ 600mm,the tensile test and impact test specimens are to be taken inthe transverse direction.


7.7.3 Number of testsThe following tests are to be carried out:

a) one tensile test at ambient temperature

b) unless otherwise required, 3 Charpy V-notch impacttests at:• −196°C for austenitic steels intended for use in con-

structions with design temperature lower than −105°C • −20°C for austenitic-ferritic steels.

347 0,080 2,0 1,0 0,040 0,030 17,0 - 19,0 9,0 - 13,0 − 10xC ≤ Nb ≤ 0,80

Duplex austenitic-ferritic

UNS S 31803 0,030 2,0 0,75 0,035 0,010 21,0 - 23,0 4,5 - 6,5 2,5 - 3,0 0,10 ≤ N ≤ 0,22

UNS S 32550 0,030 2,0 0,75 0,035 0,010 24,0 - 26,0 5,5 - 7,5 2,7 - 3,9 1,0 ≤ Cu ≤ 2,0

UNS S 32750 0,030 2,0 0,80 0,035 0,020 24,0 - 26,0 6,0 - 8,0 3,0 - 5,0 Cu ≤ 0,50


Yield strength (N/mm2) min. (1) Tensile strength Rm (N/mm2)

A5 (%) min.


Rp0,2 Rp1,0 KVL KVT

Austenitic at −196°C at −196°C

304 L 175 215 470 - 670 45 41 27

304LN 270 310 570 - 790 40

316L 195 235 490 - 690 45

316LN 300 340 ≥ 590 45

317L 195 235 490 - 690 40

317LN 300 340 ≥ 590 45

321 205 245 500 - 750 40

347 205 245 500 - 750 40

Duplex austenitic-ferritic at −20°C at −20°C

UNS S31803 ≥ 470 660 - 800 25 41 27

UNS S32550 ≥ 490 690 - 890 25

UNS S32750 ≥ 530 730 - 930 25

(1) The yield strength Rp0,2 is in general to be determined



C max Mn max Si max P max S max Cr Ni Mo Others

(1) With the exception of refining elements, additional alloying elements are to be submitted for consideration and approval. Residual elements are permitted provided they do not impair the properties, subsequent processing or behaviour in service of the material.

NR 216, Ch 2, Sec 1


7.8 Metallographic structure inspection

7.8.1 When required, a metallographic structure inspectionis to be carried out on sections parallel to the rolling direc-tion of the product, and taken over the whole thickness ofthe product.

The inspection is to be performed with magnification 200x.

No detrimental intermetallic phase (sigma phase) is toappear in appreciable quantity.

7.9 Intergranular corrosion test

7.9.1 When required, an intergranular corrosion test is tobe carried out in compliance with standard ASTM A262Practice E, or other recognised standards.

The test is to reveal no sensitivity to intergranular corrosion.

7.10 Through thickness tests

7.10.1 Where improved through thickness ductility isrequired, through thickness tests are to be performed butare generally not required for grades 304L, 304LN, 321 and347.

7.10.2 Tests and results are to be in accordance with therequirements of Article [9] and [7.10.3].

7.10.3 When the reduction in area is between 25 and 35per cent, additional metallographic examination or otherevidence is required to show that no significant amount ofany detrimental phase, such as sigma, is present.

8 Clad steel plates

8.1 Scope

8.1.1 The requirements of this Article apply to clad steelplates consisting of a base material ”backing steel” and athinner stainless steel layer ”cladding steel” on one or bothsides, continuously and integrally bonded, by hot rolling orby explosion bonding.

Provision is made for plates having total thickness higherthan 5mm; unless otherwise accepted by the Society, thethickness of the cladding metal is to be ≥ 2mm.

8.2 Steel grades

8.2.1 The grade of the backing steel is to be chosen fromthe steel grades for boilers and pressure vessels defined inArticle [4].

Other backing steel grades may be accepted subject to theSociety’s approval.

8.2.2 The cladding metal in austenitic or austenitic-ferriticstainless steel is to correspond to the grades defined in Arti-cle [7].

The use of other grades for stainless steel cladding is to beproposed to the Society for prior approval.

8.3 Manufacture

8.3.1 Approval Clad steel plate manufacturing process is to be approved bythe Society and the conditions for approval are indicated inthe document NR480 “Approval of the manufacturing proc-ess of metallic materials”.

8.3.2 Surface condition and dimensional tolerances The Manufacturer is responsible for examination of the sur-face condition, as well as the compliance with the dimen-sions and the tolerances. However the Surveyor mayrequire to have the cladding surface presented for visualexamination.


8.4.1 The plates are to be supplied in the same heat treat-ment condition as stated during the approval.


8.5.1 Works’ certificates for backing and cladding steelsstating the chemical composition are to be supplied by theManufacturer.


8.6.1 The mechanical properties of the backing materialare to comply with the requirements given in Article [4].The check of the mechanical properties of the claddingmaterial is not required.


8.7.1 Batch compositionThe batch is to be composed of plates having the sameoverall thickness, cladding thickness and cast of backingsteel, and mass not exceeding 20 t.

8.7.2 Number of testsThe following tests are to be performed:• 1 tensile test on the full clad plate• 2 bend tests on the the full clad plate• 1 series of impact tests on the backing steel• 1 shear test on the cladding.

8.7.3 Tensile testDuring the tensile test of the full clad plate, the strength is tobe not less than the value given by the following formula:

where:Rb : Nominal minimum ReH or Rm of backing mate-

rialRc : Nominal minimum ReH or Rm of cladding mate-

rialtb : Nominal thickness of backing materialtc : Nominal thickness of cladding materialt : Nominal thickness of the full clad plate.

R Rb tb Rc tc⋅+⋅t

----------------------------------=

NR 216, Ch 2, Sec 1


If the values resulting from the tensile test yield stress, ulti-mate tensile strength) are lower than those given by theabove formula, one additional test is to be performed afterremoval of the cladding material.

During the tests the requirements for the backing materialare to be satisfied.

The value of elongation specified for the backing materialapplies also to the full clad plate.

8.7.4 Bend testsThe bending conditions (mandrel diameter in general 3times the plate thickness) are those required for the backingsteel grade. One bend test is carried out with the claddingmetal on the tensioned side (outer side of bend) and anotherwith the cladding metal on the compressed side (inner sideof bend). In the latter test, separations of the cladding notexceeding 25% of the bent portion are admitted.

8.7.5 Shear testThe shear test is carried out in accordance with ASTM A264. The shear strength is to be at least 140 N/mm2.

8.8 Corrosion testing

8.8.1 When required, an accelerated corrosion test is to becarried out to check the resistance of the cladding metalagainst intergranular corrosion. This corrosion test may becarried out according to a national or an internationalstandard, or to a particular specification, in agreement withthe Society. ASTM A 262 practice E may be used.

8.9 Ultrasonic testing

8.9.1 Ultrasonic inspection of the adhesion of the claddingis generally to be performed on plates with an overall thick-ness (backing + cladding) equal to or greater than 10mm.For overall thickness less than 10mm, the ultrasonic inspec-tion procedure is to be defined in agreement with the Soci-ety.

8.9.2 The ultrasonic inspection is to be performed with thefollowing procedures:• peripheral inspection of a strip of 50mm in width on all

the plate edges• continuous inspection according to a grid with square

meshes, 200 mm long and parallel to the plate edges.

Random checks may be required by the Surveyor.

8.9.3 The reflection technique is used, with a normal probehaving a diameter ranging from 20 to 35 mm and a fre-quency from 3 to 5 Mhz.

8.9.4 Unless otherwise agreed with the Society, non-adhe-sion areas which do not exceed (50 mm x 50 mm) are toler-ated without repair, provided that they are at least 500 mmapart.

8.10 Surface defects and repairs

8.10.1 Surface defects may be accepted by the Surveyorwhen they are not detrimental to the proper use of the prod-uct and its corrosion resistance.

8.10.2 All the surface defects are to be ground so as torestore the surface continuity. Nevertheless, such repair bygrinding is admitted only if the remaining thickness of thecladding is at least equal to its guaranteed nominal thick-ness.

8.10.3 In cases where, after grinding, the cladding thick-ness is less than the guaranteed nominal thickness, therepair is carried out by welding. The filler metal is to be ofthe same grade as the cladding and the repair procedure isto be defined in agreement with the Surveyor and prelimi-narily approved.

8.10.4 If, after grinding of the defect, the remaining thick-ness of the cladding is less than half of the guaranteed nom-inal thickness, it is necessary to replace the cladding bytapering and to rebuild the whole of the cladding by weld-ing. Such repair is to be carried out in agreement with theSurveyor and preliminarily approved.

8.11 Adhesion defects in the cladding and repairs

8.11.1 In the case of adhesion defects detected by an ultra-sonic inspection as defined in [8.9], the areas of non-adhe-sion of the cladding which exceed the limits specified in[8.9.4] are to be removed by cutting off or to be repaired.

9 Steels with specified through thickness properties

9.1 Scope

9.1.1 The requirements of this Article apply to steel platesand wide flats having thickness not less than 15mm, whereimproved through thickness ductility in the direction ofthickness is required.

The extension to lower thicknesses and relevant conditionsare at the discretion of the Society.

9.2 Steel grades

9.2.1 The requirements of Article [9] are intended as a sup-plement to the requirements of Articles [2], [3], [4], [5], [6]and [7] which specify the quality of steels for hull struc-tures, boilers, pressure vessels, low temperature applica-tions and machinery.

9.2.2 The Z designation is to be given to any steel gradewhich has been tested according to the above mentionedspecifications, and has been successfully subjected to thetests defined in [9.6] and [9.7].

9.3 Manufacture

9.3.1 ApprovalAny Z grade steel must be submitted to the approval of theSociety.

The conditions for approval are indicated in the documentNR480 “Approval of the manufacturing process of metallicmaterials”.

NR 216, Ch 2, Sec 1



9.4.1 In addition to the requirements of the appropriatesteelgrade, the maximum sulphur content is to be 0,008%determined by the laddle analysis.


9.5.1 The ductility in the direction of thickness is evalu-ated, for the purpose of these requirements with the value ofthe reduction area measured on tensile test specimens takenin the through thickness direction of the product and pre-pared as specified in [9.7.3].


9.6.1 Plates and wide flats

Plates and wide flats are to be tested by rolled unit or bybatch in accordance with the conditions mentioned in Tab27.

Table 27 : Batch size dependent on productand sulphur content

9.7 Test preparation

9.7.1 The sample is to be taken close to the longitudinalcentreline of one end of the rolled piece to be tested asshown in Fig 6.

The sample must be large enough for the preparation of sixspecimens. Three specimens are to be prepared while therest of the sample remains for possible retest.

Figure 6 : Plate and wide flat sampling position

9.7.2 Cylindrical tensile test specimens are to be used hav-ing the following dimensions:

a) diameter:

• d = 6 mm for product thickness between 15 mmand 25 mm

• d = 10 mm for product thickness exceeding 25 mm

b) parallel length: not less than 2 d.

Other dimensions are to be according to ISO 6892-84 orother recognised standards.

Where the product thickness does not allow the preparationof specimens of sufficient length for the gripping jaws of thetesting machine, the ends of the specimens may be built upby suitable welding methods in such a way as to not impairthe portion of the specimen within the parallel length.

9.7.3 The preparation of samples is indicated in Fig 7 andFig 8.

Figure 7 : Normal test specimen

Figure 8 : Welded test specimen

9.8 Test results

9.8.1 The three tensile test specimens taken in the throughthickness direction are to be tested at ambient temperature.The minimum average value for the reduction of area mustbe that shown for the appropriate grade given in Tab 28.Only one individual value may be below the minimumaverage but not less than minimum individual value shownfor the appropriate grade. A value less than the minimumindividual is a cause for rejection.

Table 28 : Reduction of area acceptance values

Product S > 0,005% S ≤ 0,005%

Plates Each piece(parent plate)

Maximum 50 t ofproducts of the samecast, thickness andheat treatment

Wide flats ofnominal thick-ness ≤ 25 mm



Wide flats ofnominal thick-ness > 25 mm



Principal rolling direction

Central line of product

Testsample

Testspecimens

Grade Z25 Z35

Minimum average 25% 35%

Minimum individual 15% 25%

Plate thickness

Parallel length > 2d

d

d

Plate thickness

Parallel length > t + 4mm

Weldedextension

Weldedextension

NR 216, Ch 2, Sec 1


9.9 Re-test

9.9.1 Three additional test specimens taken from theremaining test sample can be prepared and tested in threecases shown in Fig 9. The average of all six tensile tests is tobe greater than the required minimum average with nomore than two results below the minimum average.In the case of failure after retest, either the batch repre-sented by the piece is rejected or each piece within thebatch is required to be tested.

9.10 Ultrasonic testing

9.10.1 Ultrasonic testing is required and is to be performedin accordance with either EN10160 Level S1/E1 or ASTMA578 Level C. Ultrasonic testing is to be carried out on eachpiece in the final supply condition and unless otherwiseagreed with a probe frequency of 4MHz.

9.11 Marking

9.11.1 in addition to the material grade designation, prod-ucts complying with these requirements are to be markedwith the letter Z followed by the indication of the reductionof area required, e.g.: EH 36-Z 25.

Figure 9 : Diagram showing acceptance / rejection and retest criteria

Individual result Average result

Acceptableresult

Minimum

Average

Minimum

Individual

Result where retest is permitted Acceptableretest