Main Hoisting System
All major lifting equipment directly involved in lifting pipe, riser etc. into and out of the well, such as drawworks, hydraulic cylinders, top drive, links, elevators etc.
Pipe handling equipment used for making up and breaking out pipe/stands are not considered main hoisting systems.
Source: Rules for Classification – Offshore units, DNVGL-OU-0101, Offshore drilling and support units, DNV GL, July 2015. Global Standards