HMCS Canada was originally a Canadian Government Ship that served as a patrol ship in the Fisheries Protection Service of Canada, an enforcement agency that was part of the Department of Marine and Fisheries. She is considered to the nucleus of the Royal Canadian Navy for her role in training Canadian naval officers and asserting Canadian sovereignty. Canada saw service in the First World War and was commissioned into the Royal Canadian Navy as HMCS Canada during that conflict.
After the First World War broke out in August 1914, the CGS Canada was officially transferred to the Royal Canadian Navy (RCN). She underwent a refit to become a naval patrol ship which saw her forecastle raised and the Maxim guns for fisheries patrol use were replaced with two 12-pounder and two 3-pounder naval guns. She was commissioned as HMCS Canada in 1915 and served on the Atlantic coast.
On 6 December 1917 she was one of the ships anchored at HMC Dockyard in Halifax Harbour during the Halifax Explosion. She suffered minor damage and one crew member was seriously injured. The crew was sent ashore to lend assistance to the shattered city.
HMCS Canada was decommissioned from the RCN in November 1919 and she resumed her former civilian fisheries patrol duties as CGS Canada before being retired from government service in 1920.
After being laid up in Halifax for four years she was sold and renamed "MV Queen of Nassau", and pressed into service shuttling passengers between Miami, Florida and Nassau, Bahamas. Later, she was resold to Mexican interests, however when she was being delivered, on 2 July 1926, she sank in 35 fathoms (64 m) of water off Islamorada. The wreck was located in 2001. Archeologists are working toward designating the wreck a U.S. National Historic Site because of the significance it holds in the evolution of Canada's military.