anchoring and mooring arrangement

7/25/2019 Anchoring and Mooring Arrangement

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ANCHORING AND MOORING ARRANGEMENT

ANCHORING ARRANGEMENT

First of all, let us see what an Anchor is.

An anchoris a device, normally made of metal, is used to connect a vessel to the bed of a

body of water to prevent the vessel from drifting due to wind or current. Anchors can either be

temporary or permanent. A permanent anchor is used in the creation of a mooring, and is rarely

moved; a specialist service is normally needed to move or maintain it. Vessels carry one or more

temporary anchors which may be of different designs and weights.

The basic anchoring consists of determining the location, dropping the anchor, laying out the

scope, setting the hook, and assessing where the vessel ends up. The ship will seek a location which is

sufficiently protected; has suitable holding ground, enough depth at low time and enough room for the

vessel to swing.

The location to drop the anchor should be approached from down wind or down current,

whichever is stronger. As the chosen spot is approached, the vessel should be stopped or even

beginning to drift back. The anchor should be lowered quickly but under control until it is on the

bottom. The vessel should continue to drift back, and the cable should be veered out under control so

it will be relatively straight.

nce the desired scope is laid out, the vessel should be gently forced astern, usually using

the au!iliary motor but possibly by backing a sail. A hand on the anchor line may telegraph a series of

"erks and "olts, indicating the anchor is dragging, or a smooth tension indicative of digging in. As the

anchor begins to dig in and resist backward force, the engine may be throttled up to get a thorough

set. #f the anchor continues to drag, or sets after having dragged too far, it should be retrieved andmoved back to the desired position $or another location chosen.%

Sea Anchor

The sea anchor is also an anchor with the only difference that it does not touch the bottom of

the ocean but haggles midway between the sea surface and the seabed. The role of the sea anchor is

the same as that of the conventional anchor, and is useful in situations where the sea bed is very deep.

#t is mostly used in smaller marine vessels such as kayaks, boats and smaller yachts.


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Anchor Images

Ship Anchor Chain arrangement

&ow we will learn about the ship anchor chain. First we need to know what an anchor chain

means in conte!t of the ship. As you know, when you park your car at night or on a hilly region, you

simply apply the hand brakes so that the car doesn't move on its own. (nfortunately there are no

brakes on the ship for the simple reason that the ship is floating on water. )o when the ship is stopped

and its engines are not running, there needs to be a mechanism to ensure that the ship does not drift

freely in the sea. *ust note that this is only necessary when the ship is stopped in open water. This is

not required when the ship is moored at the port, since in such a situation the vessel is bound by heavy

ropes. The mechanism for holding the ship in place is the anchor chain. )o we will see about the ship

anchor chain and how it helps to keep the ship stay at a particular point in water.

+asically the ship anchor chain arrangement consists of two parts the anchor and the chain.

-e already saw what an anchor is. #t is nothing but a heavy piece of metal which is normally in the

shape of a fork, as you have seen them in the diagrams. The e!act shape and sie of the anchor would

vary depending on the sie and type of ship. The anchor chain is made out of heavy metal links and it

holds the anchor at one end, while the other end is fastened to the ship.


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How is anchoring carried out?

/oming back to the ship anchor, let us see how an anchor is actually dropped into the sea.

-henever the anchor needs to be dropped in the seabed, the available marine charts of the sea area

are used to determine the nature and depth of the sea floor. After the appropriate spot has been

selected, the anchor is lowered into the water at a steady pace. A certain length of the anchor chain is

kept loose so as to allow a certain movement of the ship depending on weather conditions and

e!perience of the master. f course the actual process of anchoring is not as simple or easy as

described here, and the ship crew might have to try a few times before they find a proper spot. All

types of ocean floors are not suitable for anchoring; especially soft mudfloors are least suited for

anchoring.

The picture above shows a ship being tossed around by wind and the anchor is keeping it in

place while the picture below shows a ship dropping the anchor near port.

There is a misconception that the weight of the anchor holds the ship in place. This is notcorrect because the main role of the anchor is to grip the sea bed. The role of securing the ship is

performed mainly by the chain rather than the anchor, though the latter has a role to play in that as

well.


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nce the ship is anchored properly, it is bound to remain in a certain circular area which is

defined by the length of loose chain. f course there are several other factors which need to be

considered to ensure that the ship is safe during anchor. For e!ample if there are several other ships in

the vicinity, the navigating officers should ensure that the circular movement of one ship does not

come in the way of the circular movement of the other ships lest they collide.

Another point you might be thinking is that when the ship is in the middle of the ocean, it

may not be possible to anchor because of the depth of the seabed. Actually you are right in thinkingalong these lines but there is hardly a reason why ship should need to anchor in the deep sea. 0ven if

the engines have to be stopped for some reason in the deep sea, the ship can keep floating without

anchoring since there is hardly a ship in the vicinity.

GROND TAC!"E#

1round tackle is all equipment used in anchoring and mooring with anchors and buoy

mooring with chain and appendages. The following are defined as ground tackle2 Anchors$ Anchor

chain$ wire rope$ s%nthetic &ine, or combinations of these materials, when used with anchors

appendages consisting of connecting shac'&es or &in's$ detacha(&e &in's$ pear)shaped &in's$

end &in's$ (ending shac'&es$ mooring shac'&es$ mooring swi*e&s$ detacha(&e)&in' too& sets$

c&ear hawse pendants$ dip ropes$ chain stoppers$ wrenches +or chain stoppers$ out(oard swi*e&

shots$ chain ca(&e ,ac's$ mooring hoo's$ chain hoo's$ anchor (ars$ andanchor (uo%s.

1round tackle is one of the most vital parts of a ship's equipment. The vessel's safety

frequently depends upon the proper use of this gear; suitable ground tackle has saved many ships and

lives. The anchor wind&ass, equipped with capstan head or gypsy heads, is a vital part of the ship's

ability to handle its ground tackle and use the capstan or gypsy heads in mooring and warping

operations.


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Figure shows a typical ground tackle arrangement on a forecastle.

Figure 1round tackle and chain stowage

SHI-S. ANCHORS

All anchors are designed to take hold as quickly as possible after they hit bottom. They take

hold in one of two ways2 either by hooking into the ground with one or both of their sharp flukes or

by burying themselves completely. -hen an anchor is let go in fairly deep water, it strikes the bottom

crown first. From this position, any drag on the chain causes the flukes, if properly set, to dig into the

bottom. As the drag continues, the fluke is forced further into the bottom. #f proper scope of chain is

used, the heavier the drag, the deeper the fluke will dig in, developing the full holding power of the

anchor.

CHAIN AND /IRE RO-ECA0"ES

/hain, wire rope cables, or cable composed of both chain and wire rope for use with ships'

anchors is a part of the ship's ground tackle. Ground tackle is the collective term applied

to all equipment used in anchoring. #t includes the anchors, their chain or cables, connecting fittings,

and all associated equipment used in anchoring, mooring with anchors, buoy mooring, being towed,

or securing or letting go anchors in or from their hawsepipes.


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ANCHORS

Anchors today are grouped according to type. The most common types used are stockless

anchors, lightweight $3-T% or stockin crown anchors, and twofluke balancedfluke anchors.

STOC!"ESS ANCHORS

Though there are a number of different designs of modern stockless anchors, all share the

same distinguishing featurethey are stockless. Three designs of stoc'&ess anchorsare in use2

commercial, standard and the 4ark 5 $4k 5%. These are shown in views A, +, and / of figure shown

below. f the three, the 4k 5, with its long flukes, has the greatest holding power. The short,

commercialtype flukes have the least holding power. The stockless feature of these anchors

provides many advantages, not only in easing handling and stowing, but also in allowing the anchor

to be hoisted directly into the hawsepipe and secured, ready for letting go.

Figure Types of anchors.


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The stockless anchor consists of a heavy head in which the crown, tripping palms, and flukes

are forged in one piece. This unit is pivoted on the shank so that it can swing from 678 to either side

of the shank. The flukes are large and long, and pro"ecting shoulders or tripping palms are cast at the

base of the flukes to make them bite. As the force of the drag e!erts itself, the shoulders catch on the

bottom and force the anchor to take hold by pushing the flukes downward into the bottom. +ecause an

upward pull on the shank of a stockless anchor has a tendency to break out the flukes, a long scope of

chain must be used to make sure the shank remains on the bottom when the anchor is set. -ith too

short a scope, or even under a steady pull with a long scope, a stockless anchor may still disengage its

flukes as a result of gradually turning over and rolling out. (nder this condition, the anchor can offer

no resistance to dragging e!cept by its weight.

"IGHT/EIGHT ANCHORS

Two types of &ightweight anchorsare used2 the 4k 5 3-T and the wedge block 3-T

anchor. These are shown in views 9 and F of figure shown above. 3ightweight anchors are

constructed of comparatively light metal, but are very strong in tension. They gain their holding

power by digging deep into the bottom rather than lying as deadweight.

+oth the 4k 5 3-T anchor and the wedge block 3-T anchor have high holding power fortheir weights. The :8 fluke angle on the wedge block 3-T anchor is most effective in sand bottoms;

and the 78 fluke angle, in mud bottoms. They are used as bower and stern anchors and may also be

used as stream or kedge anchors. Anchors less then


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used to anchor buoys and torpedo testing barges. The rounded part, or crown, strikes the bottom first,

and the upper surface of the mushroom is cupped to provide a biting surface. As the anchor shifts

back and forth under strain, it digs itself deeper into the bottom, thereby increasing its holding power.

/onsequently, it takes a firm hold and remains fi!ed under the most adverse conditions. +ecause the

mushroom anchor has no pro"ecting stock or flukes to foul, the moored ob"ect can swing freely

around a mushroom anchor. =owever, since a mushroom anchor will break out if the direction of

pull is reversed, it is normally used only in groups of three or more, surrounding the central

mooring point. /ertain older class submarines use this type of anchor.

CHAIN AND A--ENDAGES

>resent day anchor chain of the flash butt welded type is the standard for new ship

constructions and replaces dielock chain as requiredfor back fit. All links are studded; that is, a

piece of steel is placed in the center of the links. )tuds prevent the chain from kinking and the links

from pounding on ad"acent links. The sie of the link is designated by its nominal diameter, which is

called wire diameter. -ire diameter is measured at the end of the link a little above the center line.

The length of a standard link is ? times its wire diameter, and its width is :.? times its wire diameter.

An anchor chain is made up of many parts besides common links and requires a variety of equipment

and fittings to use and maintain the chain.

Standard Shot

The lengths of chain that are connected to make up the ship's anchor chain are called shots

and are made up with an odd number of links. A standard shot is


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)hots of anchor chain are "oined by a detachable link, shown in figure. The detachable link

consists of a /shaped link with two coupling plates that form one side and stud of the link. A taper

pin holds the parts together and is locked in place at the large end by a lead plug. 9etachable link

parts are not interchangeable, so matching numbers are stamped on the /link and on each coupling

plate to ensure its identification and proper assembly. 9etachable link toolbo! sets contain tools,

including spare taper pins and lead plugs, for assembling and disassembling links and detachable

end links.

Chain Swi*e&s

/hain swivels are furnished as part of the outboard swivel shot. They reduce kinking or

twisting of the anchor chain.

0ending Shac'&es

+ending shackles are used to attach the anchor to the chain. ou can see that in the figure

given below.

Out(oard Swi*e& Shots

)tandard and alternate outboard swivel shots also called Bbending shots,C consist of common

links and fittings. They are fitted to attach the


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Figure utboard swivel shot arrangement

Riding$ Housing$ and Towing Chain Stoppers

Diding and housing chain stoppers consist of a turnbuckle inserted in a couple of links of

chain. A pelican hook is attached to one end of the chain; a shackle is attached at the other end. The

housing stopper is nearest the hawsepipe and must be installed outboard of the swivel; the riding

stopper is farther inboard. These stoppers are secured by the shackles to permanent pad eyes on the

ship's deck. /hain stoppers are used to hold the anchor taut in the hawsepipes, to ride to an anchor, or

to hold the anchor when the anchor chain is disconnected for any reason. -hen in use, a stopper is

attached to the anchor chain by passing the tongue over a link of the chain and securing it by

engaging the bail of the >elican hook and passing a toggle pin. -hen riding to anchor with more thanone stopper on the chain, the strain must be equalied in the stoppers by ad"usting the settings of the

turnbuckles. 3arge chain stopper wrenches are used for this purpose. )pecial housing chain stoppers,

such as devil's claw or pawltype stoppers normally are used with horiontal windlasses. Although

stoppers alone are more than adequate for holding the anchor, they should be backed up with the

wildcat brake. (pon anchoring, first the wildcat brake band should be set up tight then the stoppers

should be passed. The wildcat should be left disconnected from the windlass. A standard chain stopper

is shown in figure.

Figure )tandard chain stopper


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Mooring Shac'&es

Forged steel mooring shackles are used to attach the anchor chain to mooring buoys.

4ooring shackles are not to be used for any other purpose.

Figure 4ooring shackles

Mooring Swi*e&s

Forged steel swivels, with two links attached at each end, are used to moor with anchors.

They are inserted in the chain outboard of the hawse and serve to keep the chain from twisting as the

ship swings. 4ooring swivels are attached in the chain with the eye end outboard, or down, to prevent

them from hooking on the outer lip of the hawse when they are heaved back aboard. =owever, ships

today have large rounded lips on the hawsepipes, making it unlikely that a reversed swivel will catch.

A mooring swivel is shown in figure.

Figure 4ooring swivel

Chain ca(&e ,ac'

A cable "ack, consisting of a lever mounted on an a!le and two wheels, is used to handle

anchor chain. #t is used to pick the chain up to pass a chain stopper. A pinch point crowbar type of

anchor bar is issued for smaller sies of chain.


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C&ear Hawse -endants

A clear hawse pendant is a wire rope pendant, 7 to


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Arrangement o+ Anchoring E2uipment

The vessels should be provided with all required anchoring equipments, in accordance with

the Dules specified by a recognied classification society, for the intended operation.

The arrangement of anchoring and mooring equipment and calculations are to be prepared

and submitted for approval.

The anchors are normally to be housed in hawse pipesand anchor pockets of adequate sie,

scantlings and suitable form to prevent movement of anchor and chain due to wave action. The

arrangements are to provide an easy lead of chain cable from windlass to the anchors. (pon release of

the brake, the anchors are to immediately start falling by their own weight. )ubstantial chafing lips

are to be provided at shell and deck. These are to have sufficiently large, radiused faces to minimie

the probability of cable links being sub"ected to large bending stresses. Alternatively, ro&&er +air&eads

of suitable design may be fitted. Alternative arrangements for housing of anchors shall be specially

considered. The shell plating and framing in way of the hawse pipes are to be reinforced as necessary.

n vessels provided with a bulbous bow, and where it is not possible to obtain ampleclearance between shell plating and anchors during anchor handling, adequate local reinforcements on

bulbous bow are to be provided.

The chain locker is to have adequate capacity and depth to provide an easy direct lead for the

cable into the chain pipes, when the cable is fully stowed. The chain pipes are to be of suitable sie

and provided with chafing lips. The port and starboard cables are to have separate spaces. The chain

lockers boundaries and chain pipes are to be watertight up to the weather deck. +ulkheads, which

form common boundary of chain lockers, need not be watertight. >rovisions are to be made to

minimie the ingress of water to the chain locker in bad weather. The chain pipes are to be provided

with permanently attached closing appliances such as steel plates with cutouts for chain links or

canvas hoods with lashing arrangements.

>rovisions are to be made for securing the inboard ends of the chains to the structure. The

strength of this attachment shall be between


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Figure Anchoring of Floating production, storage and offloading $F>)% vessel

Figure Anchoring Arrangement

)ome details about the Anchors are given below.


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High Ho&ding -ower Anchor

/eight o+ Anchor$kg%

Dimensions (mm)

A 0 C D E 1 G H I


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/eight in !gs

Dimensions in mm

A 0 C D E 1 G H 3

67


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/eight o+ Anchor$kg%

Approximate Dimension in mm

A 0 C D

55


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/eight o+ Anchor Dimensions in mm

Igs "(s A 0 C D E 1 G

557 7


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C&e4ar !o&wc%$kg%

Wymlary w mm Dimensions in mm

A 0 C D E 1 G H I 3 N " " M

? 6H5 55@


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Anchor /eight Dimensions (mm)

lbs 'g A 0 C D E 1 G H I 3 !


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Anchor /eight Dimensions mm

3bs !g A 0 C D E G H I 3

7 55H


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Anchor /eight 6'g7

Dimensions in mm

A 0 C D E 1 G O H !

? 7:@


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Anchor -eight $kg%

Dimensions in mm

A 0 C D E 1 G O H !

?5 76@


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Anchor /eight$kg%

ain Dimensions in mm

A 0 C D E 1 G O H !

6 6?? :@7 :?H @7 7H


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/eight in !gs

Approximate Dimensions in mm

A 0 C D E H "

56:


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Coup&ing s%stem#

Coup&ing to the Anchor#

< Anchor shank 5 Anchor shackle 9T


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Coup&ing to the Chain "oc'er#

: 0nd link 6 0nlarged link

7 )wivel

? /ommon link

H Ienter "oining shackle


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#n the /oupling system you might have seen a few items used for connecting. 9etails of

those connecting pieces are given below.

1ittings$ Shac'&es$ Swi*e&s 8 "in's#

Anchor Shac'&e#


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DN

mm

NS

#nches

A

mm

0

mm

C

mm

D

mm

E

mm

1

mm

G

mm

H

mm

I

mm

3

mm

Ig


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The 9etachable /hain /onnecting 3ink eliminated connecting shackles. =owever, the

connection between the chain and the large anchor shackle still had to be made by use of a large,

weak, end or KbendingK shackle, which was easily caught on the lip of the hawse pipe, spread and

caused loss of a valuable anchor. 9etachable Anchor /onnecting 3ink, as pictured, consists of a K/K

link with two fi!ing caps. A stainless steel tapered pin and a plug are provided to positively lock the

caps with the K/K link. #t is possible to disassemble the link by removing the tapered pin by use of a

drift sledge.

No9 Chain Si4e A 0 C D E 1 ! "

-roo+ Test

in -ounds

0rea'

Test

in -ounds

<


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The pear shaped link is used to "oin the swivel end of the chain cable to the anchor shackle.

+ecause of its smooth profile, the pear shaped link can advantageously replace the Ienter anchor link.

#ts lightness makes it very easy to handle. The position of the closing system and its simplicity makes

it easier to use where larger chain diameters are concerned.

DN

mm

NS

inchesA

mm0

mmC

mmD

mmE

mm1

mmG

mmH

mm3

mm!

mm Ig


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This swivel shackle, fitted directly between the chain cable and the anchor, avoids the use of

an anchor shackle and a Ienter link if the chain is fitted with an end link.

9&

mm

&)

mm

A

mm

0

mm

C

mm

D

mm

E

mm

1

mm

G

mm

H

mm

I

mm

3

mm

!

mm

"

mm

M

mm Ig


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The Ienter "oining shackle is used to "oin two stud link chain elements ending in a common

link. #tEs made of =eavy 9uty forged steel $(5 (: grade%.

DN

mm

NS

#nches

A

mm

0

mm

C

mm

D

mm

E

mm

1

mm

G

mm

H

mm Ig


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The )wivel is usually fitted between the anchor and the chain cable to prevent the chain

cable from twisting and kinking. An anchor shackle with a "oining shackle or a Ienter link is needed

to complete the assembly. 4aterial of construction is heavy grade duty forged steel.

DN

mm

NS

#nches

A

mm

0

mm

C

mm

D

mm

E

mm

1

mm

G

mm

H

mm

I

mm

3

mm Ig


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The Ienter "oining shackle is used to "oin two stud link chain elements ending in a common

link or enlarged link. #tEs made of =eavy 9uty forged steel $(5 (: grade%.

9iameter)tud 3ink /hainweights

/ommon3ink

0nlarged3ink

0nd3ink

*oining)hackle Ienter

*oining )hackleType 9

Anchor )hackleType 9 )wivel

)wivel)hackle

mm kgsJm kgsJ5H.7m kgs kgs kgs kgs kgs kgs kgs kgs


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DN

&ominal )ieCommon "in' En&arged "in' End "in'

9imensions over 7

/onsecutive 3inks-eight

mm #nches

A

mm

0

mm

C

mm

E

mm

1

mm

G

mm

H

mm

I

mm

Minimum

mm

Ma5imu

m

mm kgJm


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$M5(5I51rade 5% DN6@ &Jmm5 AON

55

$M:(:I:1rade :% DP?@ &Jmm5 AONroof 3oad

k& +reaking 3oad k& Tension >roof 3oad k& +reaking 3oad k&


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ob"ect located on the sea bed with a rope or cable going to the surface where a float makes it possible

to pick it up from a vessel.

-R-OSE O1 MOORING

The purpose of a mooring is to safely hold a ship in a certain position to accomplish a

specific mission. A key need is to safely hold the vessel to protect the ship, life, the public interest,

and to preserve the capabilities of the vessel and surrounding facilities.

)hip moorings are provided for2

a. 3oadingJ(nloading 3oading and unloading items such as stores, cargo, fuel, personnel,

ammunition, etc.

b. )hip )torage )toring the ship in a mooring reduces fuel consumption and personnel costs.

)hips in an inactive or reserve status are stored at moorings.

c. 4aintenanceJDepairs 4aking a variety of repairs or conducting maintenance on the ship is

often performed with a ship moored.

d. 4ission 4oorings are used to support special mission requirements, such as surveillance,

tracking, training, etc.

Mooring &inesare used to secure a ship to a wharf, pier, dock or another ship. The sie and

strength of mooring lines is matched to the ship and generally increases as the sie of the ship

increases. 4ooring lines of nylon or polyester have most often been used. 3ines made of high

strength, low stretch, and reduced snapback aramid fibers are also approved and are becoming more

widely used because of their inherent safety characteristics. 4ooring line accessories include

tatt&eta&es$ &ine throwing de*ices$ rat guards, and fair&eaders.

4ooring fittings include choc's$ (itts$ c&eats, and hawser ree&s.

4ooring machinery facilitates the handling and securing of mooring lines. #t includes the

capstanhead and related machinery, as well as constant tension mooring winches.

A vessel is said to be mooredwhen it is fastened to a fi!ed ob"ect such as a bollard, pier,

quay or the seabed, or to a floating ob"ect such as an anchor (uo%. 4ooring is often accomplished


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using thick ropes called mooring &inesor hawsers. The lines are fi!ed to deck fittings on the vessel at

one end, and fittings on the shore, such as (o&&ards$ rings, or c&eats, on the other end.

Mooring (% permanent anchorcan be accomplished by use of a permanent anchor at the

bottom of a waterway with a rode$a line, cable, or chain% running to a float on the surface. This

allows a person on the vessel to connect to the anchor.

nce the mooring line is attached to the bollard, it is pulled tight. n large ships, this

tightening can be accomplished with the help of heavy machinery called mooring winches or

capstans.

4ooring lines are usually made out of synthetic materials such as nylon. &ylon is easy to

work with and lasts for years, but has a property of very great elasticity. This elasticity has its

advantages and disadvantages. The main advantage is that during an event, such as a high wind or the

close passing of another ship, e!cess stress can be spread among several lines. )ome ships use wire

rope for one or more of their mooring lines. -ire rope is hard to handle and maintain. There is also a

risk of using wire rope on a ship's stern in the vicinity of its propeller.

/ombination mooring lines made of both wire ropeand s%nthetic &inecan also be used.

This results in a hawser. This is more elastic and easier to handle than a wire rope, but not as elastic

as a pure synthetic line. )pecial safety precautions must be followed when constructing a combination

mooring line.

A t%pica& mooring scheme

Num(er Name -urpose

< +ow line >revent backwards movement

5 Forward +reast line Ieep close to pier

: After +ow )pring line >revent from advancing

6 Forward Muarter )pring line >revent from moving back

7 Muarter +reast line Ieep close to pier

? )tern line >revent forwards movement

MOORING "INES


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A ship is moored when itEs made fast to a buoy, when itEs between two buoys, when itEs

between two anchors, or when itEs secured by lines alongside a pier or another ship. The lines used in

mooring a ship alongside a pier are shown in figure. -ell in advance of mooring, the lines should be

faked down, fore and aft, each near the chock through which it passes in preparation for passing the

line.!at guards are hinged conical metal shields secured around mooring lines. They are used to

prevent rats from coming aboard ship. The bowline and forward spring lines prevent the ship from

drifting astern. The stern line and after spring lines prevent the ship from drifting forward. 3ook at the

figure. =ere, lines


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ease of deployment, high holding power to weight ratio, and ease of access to the required

anchor components because temporary style anchors are commonly available.

&ow you can see a mooring arrangement.

Figure 4ooring Arrangement


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&ow let us look into some of the machineries used in Anchoring and 4ooring.

Mooring /inch

A ship is a huge structure and when it comes to a port for any purpose such as cargo loading,

discharging or bunkering; it needs to be KparkedK properly so that it does not move from its position

beyond a certain degree. This could lead to disruption of operations and also could mean damage or

harm to life and nearby installations. #t is very easy to tie up a small boat to the shore, but how do you

go about securing a big sied vessel.

4ooring winch is a mechanical device used for securing a ship to the berth. An equipment

with various barrels used for pulling ropes or cables, mooring winches play an important role in

berthing the ship ashore. The barrels, also known as winch drums, are used for hauling in or letting

out the wires or ropes, which will help in fastening the ship to the berth.

4ooring winches assembly comes in various arrangements with different number of barrels,

depending on the requirement of the ship. The main parts of a mooring winch include a winch barrel

or a drum, a warp end and a driving motor. 4odern mooring winches comprises of elaborate designswith various gear assemblies, which can be electric, pneumatic or hydraulic driven.

A mooring winch assembly consists of a winch drum which has cable or rope wound around

it. The winch drum and warp end is driven with the help of a motor drive. All these parts are

supported with the help of a substantial frame, which also support a band brake, clutch and geared

drives.

The motor drive is connected to the barrel and warp end using a spur gear transmission

system. The transmission system is also provided with a clutch and a band brake. Thus, the spur gear

transmission system controls both the barrel and the warp end. The warp end acts like a locking

device, which prevents the rope from sliding off the barrel when pulled e!cessively. -arp end is

e!tremely important for moving the ship along the berth for alignment purposes. This is done by


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fastening one end of the ropes or wires to the bollards on the shore and the other end around the warp

end of the winch.

Appropriate control of the drum movement is an important aspect of the mooring operation.

For this reason, band brakes are provided to stop the drum whenever required. Also, it is important

that the drum rotates smoothly in both reverse and forward direction. A controller arrangement of the

drive motor facilitates forward and reverse direction as and when required, including selection of

speeds as per the requirement.

4ost of the modern mooring winches help in avoiding the stress related to constant

monitoring of the mooring winches when the ship is berthing at a port. #t is essential to tension or

slacken the mooring wires according to the flow of the tides and the change in the draught that takes

place due to cargo operations. The modern mooring assemblies act as an automatic self tensioning

unit, which provides for paying out or recovering wires when a preset tension is not present.

/ind&ass


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Anchoring is a process that is carried out when the ship requires a stoppage at mid sea or at

the port. For this an anchor is used for holding the ship at one place, to remain unaffected by waves

and weather. +igger the ship, larger and heavier is the anchor. The anchoring process requires

dropping and lifting of the anchor from the sea. -indlass is the device used for anchor handling on all

the ships.

(sually, a ship is provided with a pair of anchors. n almost all the ships, a single marine

windlass handles both the anchors, but if the sie of the ship is more, dedicated windlasses known as

split windlasses are used for individual anchor.

Figure -indlass Arrangement

An ideal windlass assembly consists of a cable lifter, mooring drum and a warp end. Allthese are rotating equipments that work together for the anchoring process. The cable lifter has cable

shaped snugs that are used to grip the anchor cable on the drum. The cable from the cable lifter goes

around a mooring drum, which guides the cables by paying out or letting go of the mooring wires. A

warp end is used to hold the cable at the desired position and is always driven in association with the

mooring drum for efficient carrying out of the warping duties.

Although all these units work together, they can also be individually controlled. A dog clutch

is used to separately engage or disengage each of this unit. All the rotating parts are connected to a

motor with the help of a spur gear assembly, which is used to transmit the motor drive to the shaft

where various dog clutches enable the power take off. 4oreover, separate band brakes are used to

lock the cable lifters and the mooring drums to prevent any kind of accidental movement when the

power of the motor is turned off.


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The ca(&e &i+terguides the anchor by raising and lowering the cable through the spurling

pipe. The spurling pipe is located at the top and centre of the chain or the ca(&e &oc'er. )nugs in the

cable lifter are used not only to grip the cables but also to hold the band brakes and the cables.

Anchor capstans, which are windlasses that rotate in the horiontal direction about a vertical

a!is, also have cable lifters that rotate about the same a!is. This arrangement is generally used for

heavy anchors and have the cable lifter unit located on the deck with the driving machinery on the

deck below. The same unit which drives the cable lifter is used to drive the warping end, which is

generally positioned near the cable lifter.

&owadays, different types of windlasses are used according to the weight of the anchor and

various other vessel requirements. The driving unit can be electrical, pneumatic or hydraulic, which

also depends on the ship's system requirement.


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Capstan

A shipEs capstan is a drum shaped device that is used for hoisting weights or for winding

shipEs anchor cable. A capstan is similar to a windlass, but unlike windlass, it rotates in a horiontal

plane and around a vertical a!is.

The term capstan was generally used in the days of wooden ships, when the ships were

smaller in sie. /apstans were used to weigh the shipEs anchors using anchor cables or for hoisting the

sails. =owever, as the sie of the ships went on increasing, the sie of the anchor cable also became

longer. #nstead of anchor cables, messenger cables were then used to wound it around the capstan in a

continuous loop. The messenger cables were attached to the anchor cables using small lines known as

nippers. -hen the cables were not in use, the nippers were removed to let the cables enter the holds.

All these capstans were manually operated by means of wooden bars, attached to slots made in the

upper portion of the capstan. The drum was rotated by means of pushing these wooden bars in a clock

wise direction.


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Capstan Vs Windlass

As time passed, capstans were completely made from iron and steel. 1ears were used at the

head of the capstan to provide a mechanical advantage when the bars were pushed anticlockwise.

0ven though things improved, capstans still used to be driven by human power, making their usage

stressing and difficult.

=owever, in the modern ships, the traditional capstans are replaced by hydraulically or

pneumatically operated windlass. A windlass is a comple! device meant for the same purpose as that

of capstan, but comprised of different parts, which together make the anchorage process smoother and

easier. A capstan differs from a windlass only in the matter of the a!is on which the rope or cable is

wound $for a capstan itEs vertical a!is, whereas for a windlass itEs horiontal%


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Ropes

Dopes have a variety of usages on board a ship. Dopes were the most highly seen equipment

on a shipEs deck in the olden days. Though technology has reduced their usage to a certain e!tent,

ropes still have many important applications in a shipEs operation.

9ifferent types of ropes are used for different applications on a ship. The thickness, strength

and length of the rope depend on the ropeEs usage. The material from which ropes are made can be

both, manmade and natural. #t is on the basis of the characteristics of these materials that the

selection of rope type is done for a particular use.

#n olden days these ropes were built from materials found in the natural environment. #n

those days, fishermen and boaters used ropes made from natural fibers such as helm or sisal.

=owever, presently these materials have been substituted by the modern synthetic materials, which

are stronger and durable.

Materia&s

/hoosing a material for a particular rope is a difficult task because each and every material

has its own negative and positive points. Inowing the characteristics of a material helps a sailor or

boater to choose a rope for specific uses and operations. The different characteristics of materials that

one needs to keep in mind are cost, strength, elasticity, durability and resistance to chemicals, water

and sunlight.

3etEs take a look at the most common materials of ropes.

Dope materials can be classified into two main categories2

&atural

4anmade

Natura& Materia&s

Though obsolete on commercial vessels, natural materials are still used for making ropes by

many fishermen and small vessel owners. The main disadvantage of natural fibers is that they are

shorter in length, which makes them weaker and more brittle. This also makes the rope surface harder

and difficult to handle. Also, for higher strengths the diameter of the rope needs to be larger.

4oreover, all the natural materials have a tendency to absorb more of moisture, which makes them

freee. These materials also have a tendency to decay and degrade from insects, rot and fungus

infestation.

Manmade Materia&s

)ynthetic ropes have substituted almost all the natural material ropes. These ropes are used

in a variety of applications because of the long length of their fibers, which increases the strength and

durability of the materials. The different types of synthetic materials are2


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-o&%ester

This is one of the most widely used fibers because of its strength and high resistance to load

and degradation. =aving very low elasticity, polyester does not stretch and is thus less affected by

wear and tear. #t also has a high resistance towards chemicals, acids, water and sunlight. The ropes

made of polyester do not float and are generally used for mooring applications.

-o&%prop%&ene

This is the only manmade fiber that is affected by sunlight and thus needs various additives

during making. >olypropylene can be made from a single filament fiber or a multi filamentfiber. A

polypropylene rope is not used where more of friction is there. Desistant to most of the chemicals, the

ropes made from these materials are lighter and float on water.

-o&%eth%&ene

1enerally used for making light weight ropes, this plastic easily wears and tears. The rope

made out of this material is a bit difficult to tie in knot. 9ue to the light weight of the material, the

rope made out of it floats on water.

-o&%amide

Also known as nylon, it is one of the strongest manmade materials for ropes. #t is elastic,

durable and is not affected by chemicals or water. Though the material loses strength when wet, it has

a high ability to absorb loads, tension and shocks. Dopes made from nylon float on water.

You can see how ropes are used in mooring arrangement.


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Berthing

#n reality berthing of vessel or ship on a wharf is quite a specialied "ob involving the use of

several equipment, lines etc. #t is more like parking of a car in a tight parallel parking slot. )incevessel is required to carry out cargo work at berth, positioning of vessel should be such that shore side

cargo handling equipments are aligned with vessels equipments. The access way $gangway% is placed

safely on the "etty.

)ince the "ob is quite critical and shipEs staff is not familiar with local meteorological and

topography of port, services of an e!pert, popularly called pilot, is sought. #n fact in most of the ports,

this service is mandatory. The picture below shows a ship being berthed at a port.

1actors A++ecting 0erthing

+erthing of vessel requires very specialied skills. >ilot has to take in account of various

forces, e!ternal R internal which are variable to varying degrees as well as the vesselEs controls

available to him.

Various factors are taken into account and amongst those included following (ut not &imited to;

Si4e#

A large vessel will be sluggish to turn. =er stopping distance will be considerably large as

well as time taken to pick up speed.

Disp&acement o+ *esse

9isplacement means total weight of the vessel. #t is the total volume occupied by underwater

part of vessel multiplied by the density of water. 3arger the displacement greater will be the

force required to move or stop it.

/ind speeds and direction2

0!posed part of vessel acts like a sail. ff shore wind with a speed of


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n shore wind though will assist in berthing but strong on shore wind may push the vessel

hard to berth causing damage.

Current2

/urrent affects the maneuverability of the vessel. #n tidal port with currents, berths are

designed in such a way that current will be flowing at .

1enders#

9ue to the momentum shipside or "etty may be damaged due to impact of vessel.Fenders areused to avoid the damage and designed to absorb the energy of the berthing impact at around

57 O deflection.

#n tidal port with currents, berths are designed in such a way that current will be flowing at


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anchoring and mooring arrangement

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