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The UK Clubs inspectors frequently find that ships mooring arrangements are

both ineffective and used inefficiently, such that mooring lines are subject tounnecessary chafing.

Mooring practices

Technical Bulletin NUMBER 1 2002

UK P&I CLUB

In some cases, moorings have resembled knitting,

suggesting that ships personnel have given very little

thought to the vessels mooring arrangement and how

best to utilise it. When moorings are being deployed,

consideration should always be given to using the most

suitable leads for ropes, taking into account shoreside

facilities.

The effectiveness of any mooring line or wire is

influenced by two angles:

The vertical angle the mooring line forms with the

quay:

The horizontal angle the mooring line makes with the

parallel side of the ship.

The steeper the orientation of a mooring line, the less

effective the line will be in resisting the horizontal

loading put on it as the vessel moves in relation to the

quay. Not all berths lend themselves to ideal leads,

depending on ship type/size, and compromises have to

be made, but the officer in charge of mooring

operations should always be looking for the best leads

for his lines which arent necessarily the shortest.

A mooring arrangement should provide an efficient

mooring pattern, facilitate safe line tendering and allow

for the safe and efficient handling of tug and fire wires.

Sharp objects can chafe mooring lines

A ships mooring system is designed to prevent the ship

drifting away from the berth and hold her in place in

relation to that berth. The effectiveness of the moorings

is dependent upon the configuration of the mooring

lines. The security of a ship alongside is not something

which happens of its own accord it requires a good

understanding and use of the ships equipment.

Considerable thought should be given to the

configuration of the moorings, so that leads areeffective and do not create sharp angles. Consideration

should also be given to the order in which lines are

deployed, so as to maintain a safe working environment

at all times.

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To prevent unnecessary dangers to ships personnel,

and to prevent expensive mooring line damage,

moorings should not be crossed over each other or be

allowed to chafe against sharp objects.

Personnel on duty should ensure that moorings are

checked and tended at regular intervals and that

remedial action is taken to minimise or eliminate

damage to moorings. Actions should be taken to

prevent chafing ensuring that all rollers, deadmen,

etc. are free to turn, wrapping canvas or old fire hose

around a mooring line at potential chafing areas and, in

extreme cases, applying grease or other approved

lubricant to the line, again to reduce the effect of

chafing.

Mooring lines should be made up correctly once the

vessel is in position. When using synthetic ropes on

large sets of bitts, use two round turns(no more) on the first post, then figure-eight round both

(fig.1, below). On smaller diameter bitts, the two round

turns should be around both posts (fig. 2).

Mooring lines should not be left on drum-ends these

are designed for warping, not holding the weight of a

ship for long periods and there is a risk of lines slipping

or being thrown off drum ends when used in this

manner. Excessive turns should not be left on the

working side of a split mooring winch three turns

(1 layer) are sufficient.

The strength of a line is dependent upon its condition

the condition of mooring lines in use should be

continually monitored, as lines are subject to wear andtear. Frayed ropes are weakened by a loss in rope

diameter, damaged fibres / strands, etc. and can be

dangerous to personnel working them. They should not

be used if at all possible, but replaced / repaired.

Fig.2 Small diameter bitts

Fig.1 Large diameter bitts

When a mooring line is under tension (under load), it

stretches. Energy is stored in the line in proportion to

the load and stretch. If the line were to part, this built-

up energy would suddenly be released. The ends of the

line whip back striking anything in their path. This whip

effect is common to all lines. Even long wires underload can stretch sufficiently to part and whip back with

considerable energy. Personnel should always avoid

Split winch used correctly

An example of a mooring line in poor condition

Mooring line left on drum end

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UK P&I CLUB

IS MANAGED

BY THOMASMILLER

For further information please contact:

Loss Prevention Department, Thomas Miller P&I Ltd

Tel: +44 20 7204 2307. Fax +44 20 7283 6517

Email: lossprevention.ukclub@thomasmiller.com

standing in areas where a line is likely to whip back

through should it part.

Ridings turns rope buried under lower turns

Riding turns (where a rope is buried under lower turnson a winch) must be avoided. They make adjusting

moorings difficult as the rope under tension has to be

pulled / prised out from the slacker, lower turns.

If unnoticed, this can cause problems for mooring

gangs as the line would initially pay out when slacking

it back for letting go, but would then suddenly start

heaving back in (the winch would still be turning as if to

slack back the line). This could lead to a potentially

dangerous situation for anyone on the quay trying to

remove the line from a bollard.

Unauthorised / untrained personnel must not be

permitted to wander around mooring stations

unsupervised. Failure to do so will significantly

increase the potential for a serious - possibly fatal -

accident.

The OCIMF publication Effective Mooring(1989

Edition) is a valuable source of information with all

manner of advice on safe and efficient mooringpractices.