UK CLUB
Technical Bulletin 01/2002
MOORING PRACTICES The UK Club’s inspectors frequently find that ships’ mooring arrangements are both ineffective and used inefficiently, inefficiently, such that mooring lines are subject to unnecessary chafing. In some cases, moorings have resembled “knitting”, suggesting that ships’ personnel have given very little thought to the vessel’s 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, t aking into account shoreside facilities.
A ship’s 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 ship’s equipment. Considerable thought should be given to the configuration of the moorings, so that leads are effective 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. The effectiveness of any mooring line or wire is influenced by two angles:
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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 operations should always be looking for the best leads for his lines - which aren’t necessarily the shortest.
UK P&I CLUB
Loss Prevention Department, International House 26 Creechurch Lane, London EC3A 5BA Email:
[email protected]
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. To prevent unnecessary dangers danger s to ships’ personnel, and to prevent preve nt 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 interval s 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 fir e 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). On smaller diameter bitts, the two round turns should be around both posts (fig. 2).
Fig.1 Large Diameter Bitts
Fig.2 Small Diameter Bitts
UK P&I CLUB
Loss Prevention Department, International House 26 Creechurch Lane, London EC3A 5BA Email:
[email protected]
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 manner should not be left on the working working side of a split mooring mooring winch - three turns (1 layer) are sufficient.
Mooring line left on drum end
Split winch used correctly
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 and tear. 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.
An example of a mooring line in poor condition
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 under load can stretch sufficiently to part and whip back with considerable energy. Personnel should always avoid standing in areas where a line is likely to whip back through should it part.
UK P&I CLUB
Loss Prevention Department, International House 26 Creechurch Lane, London EC3A 5BA Email:
[email protected]
Riding turns (where a rope is buried under lower turns on 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 unsuper vised. Failure to do so will significantly increase the potential for a serious - possibly fatal - accident. The OCIMF publication “Effective “Effectiv e Mooring” (1989 Edition) is a valuable source of information with all manner of advice on safe and efficient mooring practices.
Sourc So urce e of inform informati ation: on:
UK P&I P&I Ship Ship Inspe Inspecti ction on / Loss Loss Preven Preventio tion n Dept. Dept.
UK P&I CLUB
Loss Prevention Department, International House 26 Creechurch Lane, London EC3A 5BA Email:
[email protected]
