In an attempt to close the “air gap” in the middle of the Atlantic convoy routes, in 1943 the British Admiralty added flight decks to 14 former tankers and five former grain ships to allow them to operate as small aircraft carriers. These Merchant Aircraft Carriers or MAC ships, carried either three planes on deck in the case of the tankers or four with a hangar in the case of the grain ships. The aircraft used was the Fairey Swordfish or “Stringbag, originally designed as a biplane torpedo bomber, and famously used as such during the hunt for the BISMARCK and the British air raid on the Italian fleet at Taranto, but now employed as an anti-submarine aircraft.
A Royal Naval Air Service base, HMS SEABORN, was established at RCAF Dartmouth and spare Swordfish were held there for use on the eastbound MAC ships. In 1946, SEABORN closed and the Admiralty donated the 22 Swordfish there to the RCN, one of which also ended up at STAR as a static training aircraft.
Source: Hamilton Naval Heritage - Naval history and heritage of Hamilton and HMCS STAR
A Royal Navy Swordfish in torpedo bomber configuration