twin hull semisubmersible drilling vessel
1Semi-submersible — For semi submersible boats used for drug smuggling, see Narco submarine. Deepsea Delta semi submersible drilling rig in North Sea …
2Oil platform — A typical offshore oil/gas platform. An oil platform, also referred to as an offshore platform or, somewhat incorrectly, oil rig, is a lаrge structure with facilities to drill wells, to extract and process oil and natural gas, and to temporarily… …
