CCGS Terry Fox is a Canadian Coast Guard heavy icebreaker. She was originally built by Burrard-Yarrows Corporation in Canada in 1983 as part of an Arctic drilling system developed by BeauDril, the drilling subsidiary of Gulf Canada Resources. After the offshore oil exploration in the Beaufort Sea ended in the early 1990s, she was first leased and then sold to the Canadian Coast Guard. Terry Foxs sister ship, Kalvik, is today owned by the Russian Murmansk Shipping Company as Vladimir Ignatyuk. Development and construction In the mid-1970s, Gulf Canada Resources began developing an Arctic drilling system consisting of two mobile drilling units: a Mobile Arctic Caisson (MAC) that could be submerged and filled with gravel to form an artificial drilling island in waters up to in depth and a floating Conical Drilling Unit (CDU) designed for drilling in water depths between while afloat. The intention of this development was to overcome the relatively short operating window of drillships during the ice-free season (100 to 110 days a year) and the water depth limitations of artificial dredged islands in the Canadian part of the Beaufort Sea. The drilling units, each capable of completing one exploration well per year, would be supported by four Arctic Class 4 vessels: two large icebreakers providing 24-hour ice management and standby services on the drilling site and two smaller icebreaking vessels responsible for anchor handling and supply runs between the drilling rigs and coastal bases. By 1982, both drilling units and all four icebreaking vessels were under construction in Canada and Japan for BeauDril, Gulf Canada's drilling subsidiary, and the company had committed itself to a billion-dollar exploration program between 1983 and 1988. The icebreaker design was provided by the Montreal-based engineering company German & Milne. During the development phase, the hull form was extensively tested at the Hamburg Ship Model Basin (HSVA) ice tank with particular emphasis of preventing broken ice floes from flowing under the hull and into the propellers. The result was a production-friendly fully-developable hull form with a semi-spoon bow and large ice plough. The construction of the two icebreakers was awarded to Burrard-Yarrows Corporation in December 1979 and the work was split between the company's Victoria and Vancouver divisions. In order to expedite the delivery of the vessels, Gulf Canada had already purchased the engines, gearboxes, shaft lines and propellers before signing the C$79 million shipbuilding contract for two hulls. The