The International Marine Contractors Association (IMCA) has issued a safety flash about an incident that saw an object fall to the deck of a vessel, which could have caused a fatality.
During lifting operations with the crane on a vessel, a buffer plate fell from the crane boom. It fell approximately 10 m. The object weighed 70 kg and was 90 cm x 40 cm. The purpose of the buffer plate is to be a buffer between the jib and the boom so the steel is not damaged.
It landed inside a barriered-off area on the back deck of the vessel.
Fortunately, there were no personnel nearby.
Clearly this could have been a potential fatality had someone been struck by the plate.
The immediate cause of the incident was found to be that the bolts holding the buffer broke due to metal fatigue.
The root cause was found to be inadequate or insufficient planned maintenance and inspection.
Fatigue in the bolts had been allowed to develop over several years and there had been no proper inspection of the bolts. It was not possible to see damage to the bolts during the visual inspections of the crane which were regularly carried out.
What lessons were learnt? What actions were taken?
- The bolts used subsequently to re-attach the buffer plate were increased in size from M12 to M14.
- Secondary securing of the buffer plate was installed to prevent it from falling.
- On all of the company’s vessels with similar cranes, the planned maintenance system was modified to include maintenance and inspection of the buffer plate including bolts.
A DROPS check of all cranes was made to assess for potential dropped objects during operation.