The design of the swivelling column crane makes it possible to move loads in horizontal direction accurately. This is desirable on dredging vessels for the positioning of cutter units and pump parts during assembly and disassembly. TMS column cranes are robust and reliable, and they have been proving themselves for years on board of a range of dredgers. Slewing is done by a slewing gearbox which drives the slewing ring bearing. The trolley is driven by a rack on the bottom of the boom, or by a winch. The crane is executed with a lifting chain, wire rope hoist or winch.