1Global Maritime

DP SEMINARDP SEMINAR

The Principles, Practices and The Principles, Practices and Problems of Safe DP OperationsProblems of Safe DP Operations

2Global Maritime

INTRODUCTION TO GMINTRODUCTION TO GM• Jose Vera Vega

• Chris Jenman

• Walter Rodriguez

• Doug Phillips

• Jack Mercier

• Kees van Beveren

3Global Maritime

MORNING SESSIONMORNING SESSIONINTRODUCTION TO GMDP HISTORYBASIC PHILOSOPHYSCOPE OF DPDP EQUIPMENT CHARACTERISTICS ADVANTAGES AND DISADVANTAGES OF DPDP CAPABILITYFMEAOPERATIONS, TRAINING AND DOCUMENTATIONWEATHER PRECAUTIONSINTERNATIONAL, GOVERNMENT AND REGULATIONASSESSMENT TOOLS

4Global Maritime

AFTERNOON SESSIONSAFTERNOON SESSIONS• FOUR GROUPS --- DP PROBLEMSFOUR GROUPS --- DP PROBLEMS

(KNOWLEDGE TRANSFER)(KNOWLEDGE TRANSFER)• PIPE LAY• ACCOMMODATION• HEAVY LIFT• DIVING

• Closing combined session on the way forward• DP incidents

5Global Maritime

Global Maritimethe leading marine, offshore & engineering consultant

Global Maritimethe leading marine, offshore & engineering consultant

Established 1979

6Global Maritime

Global Maritime GroupGlobal Maritime Group

Eagle Lyon PopeLimited(7 Staff)

HalifaxCanada

(Branch office)

S ingaporeFar East

(Branch office)

BakuAzerbaijan

(Branch office)

G lobal MaritimeConsultancy Limited

(34 Staff)

G lobal MaritimeScotland Limited

(20 Staff)

Ciudad del CarmenMexico

(Branch office)

AmericanG lobal Maritime Inc

(18 Staff)

G lobal Maritime A/SStavanger(32 Staff)

G LO BAL MARITIMEHOLDINGS LIMITED

7Global Maritime

Mariners18%

Naval Architects

26%Administration

8%

Marine Engineers

11%Civil/Strucural

Engineers21%

Others16%

8Global Maritime

Global Maritime and DPGlobal Maritime and DP• 1980 Investigating DP incidents• 1981 design review and FMEA of 3 new DP vessels• 1994 UK Government contract• 1985-1990 DP Incident publication for UK DoE• 1990 Formation of DPVOA (GM Secretariat) • 1990-91 “Guidelines for the design and operation of DP

vessels”• 1992-3 IMO working group for MSC 645• 1994 IMO MSC 645 in force• 1995 Petrobras DPPS Group• 1995-6 IMO MCS 738 “Training and Experience of key DP

Personnel”• 1996 DPVOA + AODC = IMCA• 1996-present Technical Advisors and Committee Members

to IMCA

9Global Maritime

the leading marine, offshore & engineering consultant

Current DP Work

• Original Design: New semi, new heavy lift vessel

• Design Advice: Three new DP drilling semi-subs, One new Accommodation semi, One new special semi

• Upgrades: One DP DSV, One DP drilling Semi,

• FMEA and Trials, Three DP tankers, One Drillship, two DP DSVs

• Analysis: 2003 DP Incidents, 10 years of DP incident data, Update of safety of tanker offtake, Data base for DP drilling units running WSOG

• Surveys: various

10Global Maritime

ELECTRICALFAULT

POWERGENERATION

FAULT

THRUSTERFAULT

ENVIRONMENTALFORCE

SOFTWAREFAULT

or

POWER ORTHRUSTFAULT

INSUFFICIENTPOWER OR

THRUST

or

OPERATORERROR

and

LOSS OFPOSITION

HARDWAREFAULT

REFERENCEFAULT

or

DPEQUIPMENT

FAULT

OPERATORERROR

and

LOSS OFPOSITION

or

EMERGENCYDISCONNECT

OPERATORERROR

NEWFAILURE

MODE

NORECOVERY

LIKELY

0.0870.087

0.1740.174

0.0650.065

0.1520.152

0.0220.022

0.2610.261

0.1090.109

0.1300.130

ELECTRICALFAULT

POWERGENERATION

FAULT

THRUSTERFAULT

ENVIRONMENTALFORCE

SOFTWAREFAULT

or

POWER ORTHRUSTFAULT

INSUFFICIENTPOWER OR

THRUST

or

OPERATORERROR

and

LOSS OFPOSITION

HARDWAREFAULT

REFERENCEFAULT

or

DPEQUIPMENT

FAULT

OPERATORERROR

and

LOSS OFPOSITION

or

EMERGENCYDISCONNECT

OPERATORERROR

NEWFAILURE

MODE

NORECOVERY

LIKELY

0.0870.087

0.1740.174

0.0650.065

0.1520.152

0.0220.022

0.2610.261

0.1090.109

0.1300.130

11Global Maritime

Courtesy of Fugro GEOS

DP HISTORYDP HISTORYDP HISTORYDP HISTORY

12Global Maritime

DP HISTORYDP HISTORY• 1961 Mohole Project• Mohorovici discontinuity• Cuss 1 La Jolla California (manual)• Eureka for drilled in 500 ft for Shell

(automatic)• 1968 Glomar Challenger – drill in 5000 m

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Courtesy of Fugro GEOS

What is the Mohorovicic Discontinuity?

The surface of the earth is called the crust, which is the uppermost part of the Lithosphere (which includes the upper portions of the mantle). The "Moho" is the boundary between the crust and upper mantle.

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DP DEVELOPMENTDP DEVELOPMENT• 1970s – Drilling then Diving• 1980s – More Diving then ROV Vessels• 1990 – More Construction, Accommodation, 5th Gen

Drilling Vessels and many other applications - • Pipe lay, heavy lift, mine hunt, buoy tender, rock

dump, dredge, well stim, offtake tankers, FPSO, cruise liners, cable layers, offshore supply, seismic, diamond mining, treasure hunting, etc.

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SUPPLIERSSUPPLIERS• Early 1970s – Honeywell then1990s Nautronix• Mid to Late 1970s – GEC and Kongsberg –

Cegelec and Simrad, Alstom and Kongsberg, • Acoustics – Honeywell and Simrad, Later

Sonardyne and then Nautronix• DGPS – Racal, John E Chance, Fugro now

Thales

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Basic PhilosophyBasic Philosophy

DynamicDynamicPositioning??Positioning??

DynamicDynamicPositioning??Positioning??

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DP DefinitionDP Definition

May be defined as a system which automatically maintains the position and heading exclusively by means of active thrust

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DP DefinitionDP Definition

A dynamically positioned vessel (DP-vessel) means a unit or a vessel which automatically maintains its position (fixed location or predetermined track) exclusively by means of thruster force.

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Wind

Waves

Current Forces

Courtesy of Fugro GEOS

UNLIKELY IDEA?UNLIKELY IDEA?

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Rotational about the Vertical Axis

Linear along the Vertical Axis

Linear along theAthwartship Axis

Rotational aboutthe LongitudinalAxis

Rotational about theAthwartship Axis

Linear alongthe Longitudinal Axis

Courtesy of Petroleum Extension Service, U at Austin

24Global Maritime

What DP DoesWhat DP Does• External forces (wind,waves,current move

the vessel away from desired position.• DP system controls vessel motion in the

Surge, Sway and Yaw axis.• Commands are sent to the thrusters such

that the vessel returns to the desired set point.

• It all revolves around knowing where you were, where you want to be, (how fast you are getting there) and where you are now.

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Basic PhilosophyBasic Philosophy• A fully operational DP system shall

Reliably keep a vessel in position.Have a max. excursion = or < than 1/2 the

critical excursion for work carried out.All necessary equipment is working.Provide adequate information to operators.Have a permanently manned DP & ECR.

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Basic PhilosophyBasic Philosophy• Safe working limits be determined forSafe working limits be determined forLocationType of task to be performedKnown failure modesTime to restore the DP system and/or

move to a safe situation.

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Basic PhilosophyBasic Philosophy• 'safe situation''safe situation' where the work could immediately cease

and there are no serious consequences from position loss. • 'safe working limits''safe working limits' are the environmental limits that

would make a critical excursion from a single fault very unlikely, because – adequate control and power remaining,– environmental loads are small– the time to reach a safe situation is short in comparison to the

speed of position loss– because in the existing circumstances and conditions position loss

does not have any serious consequences.

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DP EQUIPMENT CLASSESDP EQUIPMENT CLASSES

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DP ClassDP Class• 4 Classes (levels) of redundancy

• Class 0 – No redundancy• Class 1 – Limited redundancy (a back up joystick

control)• Class 2 – Redundant – No single failure, hidden

failure, or act of mal-operation• Class 3 – As with class 2, plus redundancy in event

of loss of compartment due to fire or flooding.

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DP Class 2DP Class 2• Additional requirements

• DP system must have full Failure Modes and Effects Analysis (FMEA)

• Automatic bump less changeover

• Consequence analysis.

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DP Class 3 DP Class 3 • All of Class 2 plus:• Able to maintain position in the event of the

loss of ANY one compartment. • Separate engine rooms (fuel supplies, air,

cooling)• Separate switchboard rooms• Separate cable runs for all DP systems• Back up DP control system and necessary

equipment in separate room with A60 bulkhead

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DP Class DP Class

• . BodyBody Class 2Class 2 Class 3Class 3

IMO Class 2 Class 3

ABS DPS-2 DPS-3

LRS AA AAA

DNV AUTR AUTRO

BV MAR MARS

IMCA Class 2 Class 3

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Some DifferencesSome Differences

• IMO and Lloyds require 3 gyrocompasses for class 2 certification

• ABS require 2 gyrocompasses• DNV now include hidden failures• GL and BV do not have many DP vessels• Class relies on local surveyors• Notation is not weather related

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IMO DP Class IMO DP Class • IMO in MSC Circular 645 (Ref. 1),

recommends that DP vessels built after 1st July 1994 be assigned an Equipment Class.

Class 1.Class 2.Class 3.

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IMO DP Class 1 IMO DP Class 1

• Loss of position may occur in the event of a single fault.

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IMO DP Class 2 IMO DP Class 2 • Loss of position should not occur from a single

fault of an active component or system such as generators, thruster, switchboards remote controlled valves etc. A loss of position is possible from a fire of water ingress or after failure of a static component such as cables, pipes, manual valves etc.

• .

& & & &

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IMO DP Class IMO DP Class • Class 3 - Loss of position should not occur

from any single failure including a completely burnt fire sub division or flooded watertight compartment.

• NOTE - A single fault includes a single inadvertent act by any person on board the DP Vessel.

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The boundaries are uncertainThe boundaries are uncertain

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SCOPESCOPEOF AOF A

DYNAMIC POSITIONING DYNAMIC POSITIONING SYSTEMSYSTEM

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Scope of Dynamic Positioning Scope of Dynamic Positioning • A Dynamic Positioning system comprises• All equipment that directly or indirectly effects the

position keeping ability• The DP comprise three main areasthree main areas:-

– Power generationPower generation, distribution & consumptiondistribution & consumption (by thrusters)-

– ControlControl - power management and position control

– ReferencesReferences - sensors for position, environmental and vessel attitude

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““DP SYSTEM”DP SYSTEM”

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DPController

DPController

ThrusterAllocate

ThrusterAllocate

Wind Comp

Wind Comp

ThrusterCurves

ThrusterCurves

ThrustersThrusters VesselVessel

Position Measure Position Measure

WindWavesCurrent

WindWavesCurrent

Wind SensorWind Sensor

CurrentEstimator

CurrentEstimator

Per Axis:– Surge – Sway - YawPer Axis:– Surge – Sway - Yaw

BarredZones

BarredZones

Power System

Power System

VRSGyro

VRSGyro

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Scope of Dynamic Positioning Scope of Dynamic Positioning • Equipment that provides redundancy has

to be on line or immediately availableSuch thatSuch that • sudden failure of one item will not cause

an unexpected position excursion• transfer of control between redundant

equipment should be smooth.• So no unwanted thruster activity occurs.

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Deepwater HorizonDeepwater Horizon

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DP EquipmentDP Equipment

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FUEL

PRIME MOVER

GENERATOR

DISTRIBUTION

DRIVE

PROPELLER

OPPOSE WEATHER

ENERGY ENERGY TRANSLATIONTRANSLATION

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COFFEE BREAK!!!!COFFEE BREAK!!!!

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DP Equipment DP Equipment

• Power GenerationPower Generation – prime movers, generators, fuel, sea water cooling, fresh water cooling, lube oil, compressed air, ventilation.

• Power DistributionPower Distribution – high voltage, medium voltage, low voltage, control voltage, DC voltage, UPS

• ThrustersThrusters – drives, azimuth control, thrust control, cooling, ventilation, feedbacks, emergency stops, direct manual controls.

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DP Equipment DP Equipment • Power ManagementPower Management – Redundancy, Auto Start and

Stop, Start Blocking, Load Sharing – kW, Load Sharing kVAR, Black Out Recovery, Load Shed, Phase Back, DP Power Limiting

• Position ControlPosition Control – Arrangement, Networks (number, topography), Operator Stations, Outstations, Power Supplies (diodes), Control Modes, Thruster Modes, features (consequence analysis, fast current update), DP Interruptible Power Supplies, distribution (batteries, duration, distribution)

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DP Equipment DP Equipment

• Position Reference SystemsPosition Reference Systems – DGPS, Acoustics, Taut Wire, Artemis, Fan Beam, Gangway, - Pos Ref Processing (weighting, voting, median test)

• SensorsSensors Gyro compasses, Vertical Reference Sensors, Wind Sensors, - Voting

•  

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DP Equipment DP Equipment

• For Class 3For Class 3

• Cabling and Physical Separation

 

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DP Equipment Human FactorsDP Equipment Human FactorsControl Position - view of work area, radar, Manual

Control nearby, e stops, CCTV monitors, cameras, layouts, night, sun

Communications DP alerts, VHF, SPT, telephone, talk back

Operations Manual, Standing Orders, Emergency Procedures, Check Lists DP, ECR,

Qualifications, Shift Pattern and DP watch, ECR manning when on DP.

•  

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Consequence AnalysisConsequence Analysis• Real-time station keeping monitoring

program• Predicts if vessel would be able to

maintain current position if single worst failure occurs– Thruster failure– Generator failure– Switchboard failure– Compartment failure (class 3 only)

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Position Reference SystemPosition Reference System• Class 2 and 3 Operations require 3 or

more position references, preferably different types.

• Older system used only 1 at a time and switched to the standby system upon failure

• Currently systems are weighted together to form a blended position with a Median Test (voter).

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SubsurfaceReference

Beacon No. 3

SubsurfaceReference

Beacon No. 2

TranspondedAcoustic

Signal fromBeacon

Acoustic SignalTransmission

from Hydrophone

Ships Course

HydrophoneShipFix

SubsurfaceReferenceBeacon No. 1

Long Base Line System

SingleHydrophone

Threecloselyspacedsensors

Individualcycle of toneburst

Free runningBeacon

Single Hydrophone phase comparison system

ToneBurst

Phasemeasuringreceiver

Phasemeasuringreceiver

Phasemeasuringreceiver

PositionComputer

Phase delay used tocompute position

Types of Acoustic Systems

Short Base Line System

UltrashortBase Line System

Courtesy of Nautronix

Courtesy of Nautronix

Courtesy of Nautronix

Pages

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SECTION SLIDESECTION SLIDE

                                                                                                                                                       

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Laser BasedLaser Based

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Pos

ition

Ref

eren

ce S

enso

r P

roce

ssin

gS

enso

r V

alid

atio

n

Sen

sor

Cal

ibra

tion

Laser Radar

Beacon 1

DGPS (REF)

T.W. Beacon 2

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Processing of Position SignalsProcessing of Position Signals • Redundant Operations require 3 or more

position references, preferably different types.

• Older system used only 1 at a time and switched to the standby system upon failure

• Currently systems are automatically weighted together to form a blended position

• Then used by to update the Kalman Model and come up with a ‘best’ position error and velocity estimate.

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Median Check (‘voting’)Median Check (‘voting’)

• Problem with seemingly ‘perfect’ measurements

• Requires a minimum of 3 position feedbacks• Compares all feedbacks to the middle

(median) value• Any that exceed an operator determined set

point are rejected from the weighted average• So rejects “perfect”measurement

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InteractionsInteractions

• VRS – Acoustic, Taut Wire, DGPS, Fan Beam, Artemis

• Gyro – position calculation, HPR, DGPS, survey

• Thruster Feedbacks into Kalman

• UPS – through these

• Power info to DP

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Other Control SystemsOther Control Systems• Pitch, Speed and Rudder Servos

• AVR

• Governors

• Power Management System

(phase back, thrust reduction, DP limit

- predictive or reactive)

• SW, LTFW, HTFW Cooling

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Weak PointsWeak Points• Auto Manual Changeover

• Power Interface

• Networks

• Diodes

• Consistent worse case failure

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DP ADVANTAGESDP ADVANTAGES&&

DISADVANTAGESDISADVANTAGES

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WHY DP?WHY DP?

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Benefits of DPBenefits of DP• Reduced deployment time & no anchors

• Increased mobility of the unit (survey work, dive work) and DP drill ships are self propelled (No tugs) Escape from hurricanes

• Accurate station keeping, independent of water depth, in nearly all weather (2-3 meters accuracy)

• Greater freedom in design phase of the vessel. Greater deck loads, Able to carry all the required equipment all the time

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Drawbacks of DPDrawbacks of DP• Increased CAPEX• Higher OPEX (balanced by quicker

deployment time)• Increased maintenance and equipment

requirements• Not a passive system, DP control room

requires 24 hours a day manning. • Requires additional skilled labor (ETs and

DPOs)• Can go wrong dramaticallyCan go wrong dramatically

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APPLICATIONSAPPLICATIONS• Once used only when mooring was not an option

– Used worldwide for numerous applications• CraneCrane ,DiveDive, ROV, Buoy Handling,• Pipe layPipe lay, rock dumping, dredging• Cable Lay, AccommodationAccommodation• Offshore Offloading Tankers, FPSO• Platform Support, Drilling • Seismic, Cruise

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DP CAPABILITYDP CAPABILITY

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DP CAPABILITYDP CAPABILITY• The purpose of is to have a plots for

the operators that shows the limitthe limit that cannot be exceeded if position is to be kept when the

• most effective thrustermost effective thruster suddenly stops

• or the worse case failureworse case failure occurs.

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The max. operational station keeping capability for The max. operational station keeping capability for the DP system be calculated for:the DP system be calculated for:

All thrusters operational with maximum thrust

All thrusters, except the most effective operational with max. effective thrust

The maximum number of thrusters and/or power units that could be operational after the worst single failure.

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DP Capability PlotDP Capability Plot

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CAPABILITY CASESCAPABILITY CASES• Polar plot form for various current speeds,

e.g.1.0, 1.51.5 and 2 knots• Co-incident with wind and associated wave

loads fully developed sea• Realistic allowance for losses - thruster

interaction, tunnel length, high current, control system response, etc.

• Footprints and full scale confirmation

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FMEAFMEAFMEA?FMEA?

!!!!!!!!FMEA?FMEA?

!!!!!!!!

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FMEAFMEA

• FFAILURE

• MMODES

• &

• EEFFECTS

• AANALYSIS

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FMEA and TrialsFMEA and Trials

• FFailure MModes and EEffects AAnalysis • Required by IMO, IMCA and Classification

Societies for class 2 and class 3 vessels• Seeks to ensure no single faultno single fault that could

result in loss of position• Needs to be proven in practice during

FMEA proving trialsFMEA proving trials– Failures are simulated and results

documented

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OBJECTIVES OF DP FMEAOBJECTIVES OF DP FMEA

DRIFT OFFDRIFT OFF DRIVE OFFDRIVE OFF LARGE EXCURSIONLARGE EXCURSION HIDDEN FAILUREHIDDEN FAILURE SINGLE ACT OF MAL OPERATIONSINGLE ACT OF MAL OPERATION

In principle can any of the known DP In principle can any of the known DP incidents happen on this vessel?incidents happen on this vessel?

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FMEAFMEA• A formal FMEA study.• The modes that should be considered are; • Sudden loss of major items of equipment• Sudden or sequential loss of several items of

equipment with a common link• Control instability failures and their method of

detection and isolation• Faults that can be hidden until another fault

occurs should also be considered• The likely operator responses

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FMEAFMEA• Operator responses to the failures should be in the

operations manual for operational scenarios for which the vessel is intended.

• The FMEA should also consider likely operational scenarios – shallow water– high tidal streams– working close to installations

• FMEA updated if modifications are made that are likely to effect the FMEA

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FMEA Proving TrialsFMEA Proving Trials• DP vessels have to undergo FMEA proving trials, in addition

to and after, dockside testing, commissioning and customer acceptance trials.

• Failure modes should be simulated to prove the FMEA• Results of such tests independently documented by a 3rd

party• Performance should be demonstrated in both the intact and

various failed conditions• Proving trials be properly documented and the results

available • Value lost if findings not transferred to operators

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ANNUAL TRIALSANNUAL TRIALS• Re checks redundancy of the system• Demonstrate DP to potential clients • Prevent repetition of tests when taken

on hire• Introduce problems newly found by

the industry

BUT the system is not perfect!!!!!!!!

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OPERATION, TRAINING OPERATION, TRAINING AND DOCUMENTATIONAND DOCUMENTATION

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OPERATIONOPERATION• Every DP vessel should have an

operations manual that is particular to that DP system and the operating practice of the owners or operators of the vessel.

• Cover all the work for which the vessel is designed or likely to be used. It should not be what the DP vendor supplies but reference this document (not repeat it)

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OPERATIONS MANUAL OPERATIONS MANUAL include but not be limited toinclude but not be limited to

• Capability plots and verification trials data• Proving trials data• Working profiles and capabilities of equipment• DP alerts, emergency responses and procedures• Responsibilities and communications• Approach, setting up, checking and testing of the DP system• Reporting and recording• DP footprints• Manning

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DOCUMENTATIONDOCUMENTATIONJob Specific Documentation• In addition to the operations manual -

each work location, task or operation of the DP vessel may require a document particular project if the general document will not suffice e.g. project safety plan HAZOP/HAZID exercises and close out documentation.

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DOCUMENTATIONDOCUMENTATION• Check Lists, Tests and Trials• Vessel acceptance trials results • Annual trials for quality assurance of the DP

system• Mobilisation checks for new charter• DP bridge check list for new location• ECR check list for new location• Watch status check lists• Acoustic and Taut Wire Logs• Schematics of DGPS options .

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DOCUMENTATIONDOCUMENTATION

• Reporting and recording • DP log books • Data logging• Print outs• Incidents

• Maintenance, modifications & service

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TRAININGTRAINING• IMO MSC 738 - Training and Experience of Key DP

Personnel• Nautical Institute accredited DP log books and

certificates• A shore based induction course – 4 to 5 days• At least one month as an under study trainee DPO• Shore based simulator training – 4 to 5 days• Six months supervised training as Junior DPO• Apply to Nautical Institute assessed and signed of by

Captain• Requirements for familiarization when on a new vessel

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WEATHER PRECAUTIONSWEATHER PRECAUTIONS

??????????????

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WEATHER PRECAUTIONSWEATHER PRECAUTIONSDPO’s should pay attention to any

indications of impending weather changes - sudden shifts in wind force and direction, and tidal changes

to ensure that timely action is taken to reduce the possibility of a critical excursion that exceeds the safe working limits.

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WEATHER PRECAUTIONSWEATHER PRECAUTIONSObtain regular & frequent weather forecasts

for the area, use of fax facilities and charts.Info.from other units in the vicinity about

prevailing weather conditions in their areas.Use of experience to assess the prevailing

conditions and likely trends.The environmental information measured by

the DP system and any trendsUse of onboard meteorological instruments

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WEATHER PRECAUTIONSWEATHER PRECAUTIONSNotes:-Notes:-

Vessel is to work to upwindupwind (or up current) of a platform or obstruction the additional additional powerpower that might be required to reach a safe situation

DP capability based on fully developed sea so wrong impression at beginning of a storm

Any doubt the vessel should move clear deselect thrusters according to the worst deselect thrusters according to the worst case failurecase failure and see if position is maintained.

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INTERNATIONAL, GOV. & REGINTERNATIONAL, GOV. & REG

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INTERNATIONAL, GOV. & REGINTERNATIONAL, GOV. & REGClass Societies – ABS, BV, DNV

and LloydsIMO – DP guidelinesFlag StatePort AuthorityIMCA – Design and Operation of

Dynamically Positioned Vessels

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ASSESSMENT TOOLSASSESSMENT TOOLS

??????????????

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BASIC ASSESSMENT TOOLSBASIC ASSESSMENT TOOLS IMCA/UKOAA Marine and DP AuditBlack BookFMEA and Trials IMCA MembershipCapability Plots Proven Incident Reporting Independent Third Party for Annual TrialsNo warning AuditsPersonnel,Qualifications,assessment and

ownership

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AFTERNOON SESSIONAFTERNOON SESSION

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AFTERNOON SESSIONAFTERNOON SESSION• FOUR GROUPS --- DP PROBLEMS – FOUR GROUPS --- DP PROBLEMS –

(KNOWLEDGE TRANSFER)(KNOWLEDGE TRANSFER)

• PIPE LAY• ACCOMMODATION• HEAVY LIFT• DIVING

Closing combined session on the way forwardDP Incidents – Chris Jenman

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AFTERNOON SESSIONAFTERNOON SESSION Equipment Failure, Drift Off, Drive Off, or Excursion Operator Error Three reference systems Proximity of platform - clearances Anchor Wires Clearances Use of tugs and of safety anchors DP Simultaneous operations Acoustic Frequencies Communications

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ACCOMMODATIONACCOMMODATION

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ACCOMMODATIONACCOMMODATION• Gangway instrumentation• Gangway possible damage to

platform• Alarms and Auto lift

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HEAVY LIFT

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HEAVY LIFTHEAVY LIFT• Lifting wire tension• Simultaneous operations with Ballasting• Heavy Lift Mode

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PIPELAY

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PIPE LAYPIPE LAY• Time to abandon pipe• Pipe tension interface• Pipe tension effect on DP• Backing over the pipe

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DIVING

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DIVINGDIVING

• Umbilical

• Down Lines (inc acoustics and taut wires)

• Shallow Water

• Taut Wires

• Movements

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LUNCH BREAK!!!!LUNCH BREAK!!!!