Recently, an incident occurred where a 1740-ton shipboard mounted crane (CR)
boom collapsed. There was a failure of the coupling between the boom winch motor and the wire winch drum. Improperly set brakes on the crane’s winch drums and an inoperable overspeed trip on the winch drum compounded a relatively minor mechanical failure into a catastrophic casualty. This incident resulted in millions of dollars of damage to the crane, crane equipment and the vessel. The vessel was in the process of making a light lift using the shipboard crane when the crane boom started to lower uncontrollably. The crane operator attempted to stop the downward motion of the crane boom by applying the crane’s braking system, but was unsuccessful. Unable to stop the descent of the boom and in an effort to prevent the crane boom and load from falling and injuring crewmembers working on deck, the crane operator swung the boom over its cradle where it collapsed causing extensive damage. An ensuing investigation revealed that the mechanical braking system on the crane boom was improperly installed, which prevented the brakes from engaging. Quick action on the part of the crane operator to swing the boom away from the personnel on the dock prevented a possibly deadly situation. Proper maintenance and testing of this equipment could have prevented this incident from occurring.
When developing a maintenance plan for shipboard cranes, it is important to check the manufacturer’s specifications and maintenance requirements for the crane and its machinery
. Schedule routine tests of the crane and its equipment, which must include the testing of the crane winch motors, braking systems, and emergency stopping systems. Vessel owners and operators should routinely inspect and test equipment, even if it was installed, set and tested by the manufacturer. This will help to ensure the safety of your vessel and everyone onboard.