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A submersible drilling rig is a marine vessel design that can be floated to location and lowered onto the sea floor for offshore drilling activities.〔(【引用サイトリンク】 url=http://www.glossary.oilfield.slb.com/Display.cfm?Term=submersible%20drilling%20rig )〕 ==Design and operation== The submersible drilling platform is supported on large pontoon-like structures. These pontoons provide buoyancy allowing the unit to be towed from location to location. Once on the location, the pontoon structure is slowly flooded until it rests securely on its anchors, of which there are usually two per corner. The operating deck is elevated 100 feet above the pontoons on large steel columns to provide clearance above the waves. After the well is drilled, the water is pumped out of the buoyancy tanks and the vessel is re-floated and towed to the next location. ''Submersibles'', as they are known informally, operate in relatively shallow water, since they must rest on the sea floor. Other floating vessel types are used in deeper water depths. The term Mobile Offshore Drilling Unit (MODU) is generally used for all offshore drilling rigs that can be moved from location to location. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Submersible drilling rig」の詳細全文を読む スポンサード リンク
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