IMCA: Dropped object due to over-ridden limit switch

The event occurred whilst lifting an item (weighing approx. 300kg) from the deck of a vessel deck, for overboarding in subsea operations. The crane operator’s instructions were to heave the crane wire rope to lift the crane hook; whilst doing this, the crane operator disengaged the safety limit switch in order to be able to lift the hook around 2m higher.

As the wire came in, the mini beacon (positioned just above the hook weight – weighing approx. 6kg) contacted the safety limit switch clump weight, resulting in the beacon coming loose and falling to the main deck (approx. 4m). One of the two wire restraints for the clump weight parted, and a cable from one proximity sensor parted. There were no injuries.

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