The Canadian Coast Guard currently operates two heavy polar icebreakers: CCGS Louis S. St-Laurent and CCGS Terry Fox. It also operates four medium icebreakers: CCGS Amundsen (nee CCGS Sir John Franklin); CCGS Henry Larsen; CCGS Des Groseilliers; and CCGS Pierre Radisson. The Louis S. St-Laurent is an Arctic Class 4 icebreaker, with a length of 119.6 meters and a gross tonnage of 11,345 tonnes. It was built by Canadian Vickers and entered service in 1969. It is due to be retired in 2017. The Terry Fox is also an Arctic Class 4 icebreaker, with a length of 88 meters and a gross tonnage of 4,234 tonnes. It was built by Burrard Yarrows and entered service in 1994. The Terry Fox is due for decommissioning in 2020. The CCGS Amundsen was built by Burrard Dry Dock Company and entered service in 1979. Originally designed and operated as an Arctic Class 3 icebreaker, it was converted into an Arctic Research Vessel in 2002. It has a length of 98.2 meters and a gross tonnage of 5,911 tonnes. It is the first research icebreaker to have undertaken two over-wintering expeditions in the Arctic. Plans for a new heavy polar icebreaker (to be named the CCGS John G. Diefenbaker) are well underway. A contract for design of the icebreaker, to be able to operate autonomously for 270 days in the Arctic and have the ability to break ice of up to 2.5 meters thickness, has been awarded to STX Canada Marine. The new icebreaker is intended to be commissioned before the CCGS Louis S. St-Laurent is taken out of service in 2017.