A large single spar fixed on board ship, for hoisting boats, cargo, and other heavy weights, though it is now a relic of the past. It pivoted at the lower or inboard end and was fitted with stays and guy pendants, and had a topping lift and a purchase attached to it. It was controlled laterally by the guy pendants, which allowed it to swing through a wide arc, and vertically by the topping lift, which positioned the hook of the purchase directly over the object to be lifted. The name comes from a 17th-century hangman named Derrick who was employed in his grisly trade at Tyburn, London, presumably because in both cases weights dangle from the ends of ropes.
Subjects: Maritime History.