0 a type of crane (= a machine with a part like an arm), used for moving things on and off ships -- （港口装卸货物的）长臂吊车，长臂起重机
In order to dispense with the need for high scaffolding the trestles were erected by means of derricks mounted on the original structure.
Two light jib derricks using timber poles were required to erect the fabricated vertical and side members.
However, residential construction stopped completely; wooden derricks sprung up on many of the small adjacent lots.
There, damage was limited to oil derricks and other light structures.
The aircraft were hoisted up through a hatch at the aft end of the flying-off deck by two derricks.
All her cargo space was forward and the foremast incorporated two derricks.
Larger vessels are often equipped with winches and derricks for handling the lifting lines, as well as outriggers and light booms.
Steam derricks and snagboats continued to be used until the 1960s and a few survivors soldiered on.
