Nautilus Telegraph's book of the month for April 2023.

Lifting appliances on board ship, particularly ship’s cranes, are critical to a vessel earning freight. A ship is only earning money, ie, freight, when carrying cargo at sea. If the deck cranes are out of action in port the vessel will have downtime which in turn reduces the vessel’s earning capacity. For this reason, and the safety of the crew, ship’s cranes should be well maintained, usually whilst at sea, to reduce the possibility of port downtime.