The port side lifting hooks of the gantry crane were not correctly engaged
On 22 July 2011, the hatch-lid gantry crane on board the dry cargo vessel Blue Note derailed while it was carrying a single hatch-lid to its stowed position in preparation for discharging cargo.
The derailment caused the chief officer, who had been riding on one of the crane's wheel units, to be thrown overboard; an able seaman, who had been riding on another wheel unit, to be left hanging by his hands over the 8.4m deep hold; and the second officer, who was operating the crane, to fall to the deck of the control platform. All three crewmen were lucky to escape with only minor injuries.
The MAIB investigation found the most likely cause of the accident was that the port side lifting hooks of the gantry crane were not correctly engaged with the hatch-lid's sockets during an operation to move the lid aft to its open stowage position.
This led to the port hooks becoming disengaged as the lid was being moved, causing it to fall and pivot about the starboard lifting hooks. The hatch-lid struck the starboard legs of the gantry crane, causing it to derail while the port side continued to fall, finally coming to rest at the bottom of the cargo hold.
For more information, read full report by clicking here.