Master links came free from lifeboat release hooks, releasing the lifeboat

A vessel was alongside waiting on weather when the decision was taken to use the opportunity to complete annual checks, including lifeboat and davit annual inspections. This included a launch and trial of the lifeboat. The launch, as per company procedure, was conducted unmanned to the water. While the boat was in the water, the fore and then the aft master links, connecting the lifeboat to its falls, became disconnected in an uncontrolled way.  There were no injuries but there was slight damage to the lifeboat.

Sequence of events:

• The lifeboat was lowered to the water, the weight taken on the water and the falls slacked as expected.
• A few seconds later the forward master link become disconnected from the lifeboat. Crew in the attending rescue boat started monitoring the lifeboat movements.
• As the rescue boat approached to assess what could be done to reconnect the forward link, the same occurred to the aft master link.
• At this point the lifeboat was only tethered by the forward and aft painters.
• The forward painter was connected to the painter release mechanism and the aft one to the bitt used for stowage position.
• A few seconds later the forward painter became disconnected. Crew saw the forward master link hit the painter release system which led to the release of the painter.
• As the lifeboat started swinging 180 degrees to starboard, the aft painter connected to the bitt became loose and released. At that point the lifeboat was free to drift away.
• The rescue boat in attendance and crew on the quayside were able to recover the lifeboat. 

The location of the master link handles was incorrectly orientated with the handles facing inboard towards the hook latch and lifeboat. The movement of the master link handles therefore impacted and released the hook safety latch, releasing the hooks.