A rig supply vessel was in position and being discharged by the rig’s crane. The rig had a dual line crane (single whip and a double block) and was using the double block for the discharging operation. As the crane commenced lowering the double block towards the vessel’s deck, the single whip line ball and hook assembly detached from the crane and landed on top of the safe haven of the vessel.
Fortunately the deck crew were standing clear, approximately four metres from the point of impact, and suffered no physical injuries. The assembly weighed 160kg and fell approximately 50 metres giving an impact force of 784KN. This would most certainly have resulted in one or more fatalities had it struck the crew members. The cause of the failure is still under investigation.
- Be aware and warn all crew of the potential for dropped objects during cargo operations.
- Stand clear of the load route; loads should never be lifted over people.
- Maintain visual contact with the load at all times.
- Check every load to ensure nothing is loose or damaged before dispatch.
- Make sure that all loads are properly secured.
- Stand clear from moving crane boom and/or block even with no load.
- Do not approach the crane slings/hook until the crane is fully stopped and ensure all is safe and secure prior to approaching.