Derrick: the main hoist winch and a system of elevators lifts 1,250 tons of pipes and machinery through the 72.
钻塔：主起吊绞车和升降机系统可通过船底72英尺宽的开口，提升1,250吨重的管道和机械。
2
The frame of mast derrick that is designed for hydraulic wheel tractor hoist adopt welding of armor plate, its section is oblong armor plate, and its material is HG60.
The air hoist may be used to hoist a workman (other than derrick-man) when a bosom chair with safety belt or derrick climbing belt is used to hoist the workman.