HMCS Stettler (K681)

HMCS Stettler was a River-class frigate that served with the Royal Canadian Navy during the Second World War. She served primarily as a convoy escort in the Battle of the Atlantic. She was named for Stettler, Alberta. After the war she was converted to a Prestonian-class frigate and served until 1966.

Stettler was ordered in October 1941 as part of the 1942–1943 River-class building program. She was laid down on 31 May 1943 by Canadian Vickers Ltd. at Montreal, Quebec and launched 9 October later that year. She was commissioned into the Royal Canadian Navy on 7 May 1944 at Montreal.

Background
The River-class frigate was designed by William Reed of Smith's Dock Company of South Bank-on-Tees. Originally called a "twin-screw corvette", its purpose was to improve on the convoy escort classes in service with the Royal Navy at the time, including the Flower-class corvette. The first orders were placed by the Royal Navy in 1940 and the vessels were named for rivers in the United Kingdom, giving name to the class. In Canada they were named for towns and cities though they kept the same designation. The name "frigate" was suggested by Vice-Admiral Percy Nelles of the Royal Canadian Navy and was adopted later that year.

Improvements over the corvette design included improved accommodation which was markedly better. The twin engines gave only three more knots of speed but extended the range of the ship to nearly double that of a corvette at 7200 nmi at 12 knots. Among other lessons applied to the design was an armament package better designed to combat U-boats including a twin 4-inch mount forward and 12-pounder aft. 15 Canadian frigates were initially fitted with a single 4-inch gun forward but with the exception of HMCS Valleyfield (K329), they were all eventually upgraded to the double mount. For underwater targets, the River-class frigate was equipped with a Hedgehog anti-submarine mortar and depth charge rails aft and four side-mounted throwers.

River-class frigates were the first Royal Canadian Navy warships to carry the 147B Sword horizontal fan echo sonar transmitter in addition to the irregular ASDIC. This allowed the ship to maintain contact with targets even while firing unless a target was struck. Improved radar and direction-finding equipment improved the RCN's ability to find and track enemy submarines over the previous classes.

Canada originally ordered the construction of 33 frigates in October 1941. The design was too big for the shipyards on the Great Lakes so all the frigates built in Canada were built in dockyards along the west coast or along the St. Lawrence River. In all Canada ordered the construction of 60 frigates including ten for the Royal Navy that transferred two to the United States Navy.

War service
After working up in Bermuda, Stettler returned to Halifax where she was assigned to local escort group EG 16. She remained with the group when it transferred to Londonderry in March 1945. She escorted convoys to and from Gibraltar twice, otherwise remaining on patrol in the waters around the United Kingdom.

In June 1945, Stettler returned to Canada from Europe, the last Canadian warship to do so. Upon her return she began a tropicalization refit at Shelburne for possible service in the southern Pacific Ocean. This meant adding refrigeration and water-cooling capabilities and changing the camouflage. The refit was cancelled in August 1945 due to the surrender of Japan. Stettler was paid off 9 November 1945 and laid up.

Postwar service
After the war, Stettler was sold to private interests. However she was recovered when the Royal Canadian Navy decided to refit old River-class frigates. She underwent conversion to a Prestonian-class frigate and was recommissioned 27 February 1954 with the new pennant number 311. She transferred to the west coast and remained in service there until 31 August 1966 when she was paid off. She was sold to Capital Iron & Metals Ltd. of Victoria, British Columbia and scrapped there in 1967.