Semi-Submersible Drilling Rig (anchored)

A semi-submersible rig is a mobile offshore drilling unit. The purpose of the rig is to drill new wells, alter existing wells, or suspend or abandon older wells. A semi-submersible rig has no propulsion system and must be towed to location. When on location, anchors are deployed, often extending outside of the 500 metre safety zone. Semi-submersibles can be used in greater water depths – not requiring foundations to the seabed.