Deepwater Drillship

A self-propelled, ship-shaped mobile offshore drilling unit that holds station by dynamic positioning while drilling wells in deep water, typically rated for water depths of roughly 4,000 to 7,500 ft (about 1,200 to 2,300 m). It carries a derrick over a moonpool, a marine riser, and a subsea blowout preventer. Unlike a moored semi-submersible it relies on thrusters and DP rather than anchors, so it suits fields beyond practical mooring depth. Such units are MODUs under the IMO MODU Code.