So what is a Semi-Sub?
A semi-submersible drilling rig is normally a self-propelled working platform supported by vertical columns on submerged pontoons. By varying the amount of ballast water in the pontoons, the unit can be raised or lowered in the water. The lower the pontoons lie beneath the surface of the water, the less they are affected by wave action. This reduces vertical movement and allows drilling to continue in moderately rough seas. A semi-submersible vessel is normally held in position by up to eight very large anchors, or by dynamic positioning. Dynamic positioning systems use computer controlled directional propellers to keep the vessel stationary relative to the sea-bed, compensating for wind, wave or current. Semi-submersibles can drill in water depths to 300 meters or more all year round. There can be over one hundred people on board and although smaller than a platform, conditions are usually good. This type of rig makes its money by drilling a hole in the seabed then it moves to the next location. There is often an urgency to get things done quickly. With advancing technology some semi submersibles can drill in water depths over five thousand feet.
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Transocean Semi-Subs
Henry Goodrich Paul B. Loyd Polar Pioneer Transocean Arctic Sedco 707 Jack Bates Transocean Richardson Sedco 709 M.G. Hulme, Jr. Jim Cunningham Sedco 710 Transocean Leader Transocean Rather Sovereign Explorer Peregrine III Sedco 700 Transocean Amirante Transocean Legend C. Kirk Rhein Jr. Transocean Driller Falcon 100 Sedco 703 Sedco 711 Transocean John Shaw Sedco 714 Sedco 712 Sedneth 701 Transocean Searcher Actinia Sedco 702 Sedco 601 Transocean Prospect Transocean Winner Transocean Wildcat J. W. McLean Transocean Explorer Sedco 704 Sedco 706
GlobalSantaFe Semi-Subs
Aleutian Key Arctic I Arctic II Arctic III Arctic IV Celtic Sea Development Driller I Development Driller II Grand Banks Rig 135 Rig 140 Dada Gorgud Istiglal
Noble Corporation Semi-Subs
Noble Amos Runner Noble Bingo 9000 3 Noble Bingo 9000 4 Noble Clyde Boudreaux Noble Dave Beard Noble Homer Ferrington Noble Jim Thompson Noble Lorris Bouzigard Noble Max Smith Noble Paul Romano Noble Paul Wolff Noble Therald Martin Noble Ton van Langeveld
This page is by no means complete, but I have limited the number of links and the above companies may have other rigs that they have commissioned recently. If you want me to place a link to a rig on this page please let me know and I will do my best to do so.
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