Launched in Kingston on September 27, 1917, Loos was in commission between August 1, 1918 and 1920. In 1922 she entered the service of the Department of Marine and Fisheries as a lighthouse supply ship. About 1937 she was sold out of government service, but was taken up again by the RCN on December 12, 1940. By June, 1941, she had been converted to Gate Vessel 14 and served as such for a time at Shelburne. In 1945 she was returned to her previous owner, Marine Industries Ltd., and broken up in 1949.