Sedco 135 F

This vessel was the first Canadian-built offshore drilling vessel. The Sedco 135 was the first caisson-stabilized unit to be designed for drilling in semi-submerged position in water depths to 800 feet. It was chartered by Shell Oil exploration for its drilling program off the BC Coast, drilling 14 holes between 1969 and 1976. It was then towed to New Zealand for another drilling program. Ixtoc I was an exploratory oil well being drilled by the semi-submersible drilling rig Sedco 135-F in the Bay of Campeche of the Gulf of Mexico, about 100 km (62 mi) northwest of Ciudad del Carmen, Campeche in waters 50 m (160 ft) deep. On June 3, 1979, the well suffered a blowout resulting in one of the largest and worst oil spills in history. This vessel was the first semi-submersible to complete a world tour by traveling from Victoria, where this vessel was constructed, to New Zealand, the North Sea, Brazil, Mexico and eventually India where this vessel was broken up.