M1820

Placing all the stern ropes onto one bollard created a single point of failure which was aggravated when the second vessel secured to the same bollard. Either vessel could have identified this latent risk, as could the supervisor of the line-handling party. It is possible that neither the port authority nor the master understood the risk which had been created. There is no evidence of a discussion regarding the possibility of the vessel moving to an alternative berth, either before or after the strong wind warning was issued, and no additional lines were put ashore after the warning had been received. Similarly, the vessel could have brought its engine(s) to immediate notice as a prudent contingency measure.

It is good practice for port authorities who operate tugs to consider having them at immediate notice during periods of forecast bad weather. In this case, they could have been deployed to ‘push on’ or to at least minimise the swing of the vessel as it broke away. The port authority might also have considered temporarily relocating the vessel(s) to a more sheltered part of the harbour or even directing them to proceed to sea to safely ride out the poor weather.

While not an exact science, it is possible to estimate the likely forces generated by high winds on a high-sided vessel so long as the windage area is known. Many vessels keep a ‘ready reckoner’ on the bridge for quick reference, and some port authorities that regularly berth high-sided vessels have similarly developed a guide to assist them in calculating the likely ‘pull’ forces that the  bollards must accommodate. The use of auto-tensioners can cause dynamic loading of lines that potentially exceed bollard holding limits so this should be considered as well. Bollard holding strength depends on bollard rating, the surface to which it is attached and the vertical angle of pull from the mooring lines. It is possible to determine the safe holding capacity of quayside bollards using nondestructive testing.

When requesting a berth, large and high-sided vessels are strongly encouraged to include their bollard holding requirements in the pre-arrival ship/shore information exchange if they are not  already doing so. They should ask if the port has published any environmental limitations (including maximum wind speeds) for vessel movement, berthing/unberthing or cargo handling.