The Bahamas Maritime Authority issued a safety alert to inform about the sudden disengagement of a lifeboat during a ship inspection onboard a tanker. The safety alert includes a description of the incident and lessons learnt to try and prevent similar accidents from occurring in the future.
The incident
Whilst alongside the loading port, a Aframax tanker conducted a Port State Control (PSC) inspection during which the testing of the lifeboat engine and rudder was required. While swinging out the starboard lifeboat, the lifeboat disengaged from the aft fall hook without any warning. The lifeboat hook did not open, instead the master link pulled clear through the gate on the on-load release gear resulting in the lifeboat falling heavily. The aft end of the boat hit the fish plate on the main deck and slid over the side resulting in the boat hanging from the forward hook. No personnel were in the lifeboat and no injuries were sustained.
Probable causes
Fouling of the aft gripe wire in between the base of the hook body and the base of the heel of the hook retainer gate restricted any further movement of the aft davit arm. Initially both davit arms moved outboard simultaneously however on approaching 10-15˚away from the vertical the aft arm appeared to slow down prior to stopping completely; at which point the brake lever was applied. This indicated that a restriction on the movement of the aft davit arm existed after the arm had moved from the stowed position.
With the forward davit arm still moving out, the lifeboat was no longer parallel to the deck. This developed a pull between the two davit arms, which kept on increasing as the forward arm moved further outboard. This resulted in bending of the forward davit arm beyond operational use. The aft gripe wire which was caught in between the retainer gate and hook body caused the masterlink to be drawn through the gate.
Recommendations
– It should be confirmed that each wire gripe has an unrestricted clear line of travel. Consideration of a deflection plate at the base of the hook body and base of the heel to prevent fouling of the wire gripe is advisable.
– Protrusions on the wire gripe could increase the potential for snagging. This could be mitigated by regular inspections to ensure the wire gripe is as smooth as possible.
– All retainer gates should be inspected for correct operation. All retainer gate counter weights should be examined for any damage and confirmed that they are sitting flush against the hook body.
– Fall Preventer Devices should be used to minimize the risk of failure of the release mechanism or on-load release gear.
