Larger vessels are now being moored at terminals which are exposed to high waves and in channels which are subjected to passing-ship-induced forces. These situations increase mooring line wear and loads and sometimes cause mooring failures.

This paper will discuss some of the associated problems and some of the solutions.

Use of high-performance fiber ropes instead of wire ropes can decrease mooring loads. These mooring line ropes can be handled by fewer people. The risk of injuries is greatly reduced.

When properly cared for, these fiber ropes last longer than wires in service. But fiber ropes are vulnerable to abrasion damage, especially in vessel fairleads. Special nylon fairlead liners are now available to eliminate this wear problem.

Fiber rope tails are used on mooring lines to increase stretch and reduce peak loads. Greater vessel motions at exposed location moorings have caused cyclic loading fatigue in nylon tails. Industry recommendations have now been clarified to allow the use of longer nylon tails and of polyester tails. More durable nylon tails are now available.

Larger vessels entering into and mooring along confined channels increase the risks of passing ship problems. Passing-ship induced forces increase with vessel size and with the greater speed at which larger vessels must pass in order to maintain steerage.

Computer mooring analyses should be conducted to ensure that mooring arrangements are adequate. These analyses should account for effects of waves at exposed locations and should include appropriate passing-ship forces.

This paper will be of interest to designers and operators of large vessels and of marine terminals intended for such vessels.

Paper published with permission.

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