Failure of lifeboat winch on ro-ro passenger ferry P&OSL Calais and behaviour of self-lifting sprag clutch

Location: Exercise at the Port of Dover, England.

Accident Investigation Report 13/2001

Investigation report into two marine accidents including what happened, safety lessons and recommendations made:

p&o calais.pdf (1,117.57 kb)

Summary

On 25 June 1999 in the port of Dover the ro-ro passenger ferry P&OSL Calais was conducting a routine crew training exercise. An empty lifeboat was raised and when in position the winch operator stopped the motor. The winch then went into reverse involuntarily, allowing the boat to lower until the bowsing gear took its weight.

The manufacturers of the winch identified the loss of control as being caused by the failure of the one-way clutch on the winch’s drive motor. Although unable to offer supporting data, they also offered the opinion that this failure was because the clutch had been filled with oil of too great a viscosity. MAIB’s records showed that similar failures had occurred on other vessels having winches fitted with clutches of similar design, fortunately without serious consequences. In light of these failures, the MAIB decided that its investigation should cover the likely effects of incorrect lubricant on the performance of this type of clutch.

Published: April 2001

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