The Battle-class trawlers were a class of naval trawlers built for and used by the Royal Canadian Navy (RCN) during the First World War. Between the wars, some remained in RCN service, but most were transferred to the Department of Marine and Fisheries, where they performed a number of functions, including working as lightships and fisheries patrol vessels. During the Second World War, a number of these trawlers were re-acquired by the RCN, but all the navy's Battle-class trawlers were decommissioned soon after the war. A number of the class remained in civilian government and commercial service for years after the war, although most had been disposed of by the early 1960s.
Armentières at Vancouver on 27 May 1933
Thiepval as fisheries patrol ship in the Hecate Strait
HMS Revenge underway
Naval trawlers are vessels built along the lines of a fishing trawler but fitted out for naval purposes; they were widely used during the First and Second World Wars. Some—known in the Royal Navy as "Admiralty trawlers"— were purpose-built to naval specifications, others adapted from civilian use. Fishing trawlers were particularly suited for many naval requirements because they were robust vessels designed to work heavy trawls in all types of weather, and had large clear working decks. A minesweeper could be created by replacing the trawl with a mine sweep. Adding depth charge racks on the deck, ASDIC sonar below, and a 3-inch (76 mm) or 4-inch (102 mm) gun in the bow equipped the trawler for anti-submarine duties.
First World War naval trawler, HMT Swansea Castle
Second World War naval trawler, HMT Lancer
A naval trawler's gun crew mans a 12-pounder (76-mm) Mk V gun on the forecastle
HMT Northern Sky pitching and rolling at slow speed along her patrol lines. Operating off Iceland, this trawler made the last attack of the Second World War on a U-boat.