Drilling Rigs - Semi-Submersible
A Semi-submersible platform or rig, is a mobile structure used for drilling for oil and natural gas in offshore environments. Their superstructures are supported by columns sitting on hulls or pontoons which are ballasted below the water surface. They provide excellent stability in rough, deep seas. Semi-submersible rigs can be moved from place to place; and can be ballasted up or down by altering the amount of flooding in buoyancy tanks; they are generally anchored by cable anchors during drilling operations, though they can also be kept in place by dynamic positioning. Semi-submersibles can be used in depths from 600 up to 35,000 feet (180 to more than 10,600 m).
Seadrill West Phoenix
The photo was taken while the rig was on SIT in Geoje South Korea.
Rig is on its way to Norway.
Kan Tan IV
Kan Tan IV off the coast of gulf of Mexico
Sedco 711 in Invergordon. March 2008
GSF Galaxy II
GSF Galaxy II in Invergordon. View fom Safe Bristolia helideck. March 2008
GSF ARCTIC 111
Arctic 3 in Astican shipyard Las Palmas, before going to LIBYA