Lifeboat falls after equipment failure

A member has reported an incident in which equipment failure allowed a lifeboat to fall free from one side of a vessel. The incident occurred during periodical function tests performed on the vessel lifeboats. When the port side lifeboat was recovered, one of the wire rerouting sheaves from the launching/recovery system buckled and broke off allowing the lifeboat to free fall from one side. The lifeboat and launching system were seriously damaged. No personnel were on board the lifeboat at the time, and there were no injuries.

A thorough investigation was conducted and the following was noted:

• When the incident occurred, one davit arm was in its rest position, while the other one was still under recovery;
• Severe deformation of the sheaves and their support plate indicated an ‘out of plane’ loading;
• The sheave had signs of groove wear and corrosion of the bottom side;
• Though the functioning of the entire lifeboat launch and recovery system was tested periodically, there was no preventive maintenance programme for separate pieces of equipment within the system.

The following remedial actions were put in place:

• Replaced lifeboat lift wire with particular attention to the length adjustment;
• Replaced damaged (bent) support plate;
• Thorough cleaning and removing old paint from boom guide and sheaves, replacing as necessary;
• Non-destructive testing on pin from sheaves.

It was also noted that owing to the work environment and equipment criticality, a preventative maintenance schedule for individual parts on the lifeboat launch and recovery system should be developed, as this would reduce the likelihood of this type of equipment failure.