Lifeboat incident as a result of a suspension chain failure

A serious incident occurred during a routine lifeboat operational test, involving the lowering of a vessel lifeboat into the water. A three-man crew boarded the lifeboat, strapped themselves in, and prepared to lower the boat to the embarkation deck using the remote break release wire from within the boat. Just after the davits reached the end of their travel and the boat started to descend, a loud noise was heard and the aft end of the lifeboat broke away from the hook. Shortly afterwards the forward hook broke away from the boat and the lifeboat fell into the water.

The cause of the lifeboat falling was the breaking of the aft hook suspension chain. The action transferred the whole weight of the lifeboat onto the forward hook, which pulled out of the GRP deck under the excess load. The exact cause of the suspension chain failure could not be established but the most probable mode of failure was brittle failure exacerbated by corrosion pitting.

The recommendations arising from the incident included ensuring that suspension links and chain are suitably heat-treated for use in a marine environment.