During the 1930s, the Admiralty of Great Britain decided to replace the existing overseas patrol submarines of the Oberon, Parthian, and Rainbow classes, which had performed poorly. Despite the emphasis placed by the Royal Navy on surface vessels, construction began in 1934-35 on the Royal Navy’s T Class (or Triton Class) of diesel-electric submarines.
These new submarines were subjected to strict design guidelines. They required a strong armament and a patrol duration of at least 42 days for long-distance service. In addition, they were limited by the London Naval Treaty to a total of 16,500 tons of new construction. The Admiralty built 53 new subs with a displacement of about 1,575 tons each just before and during World War II.
The first T-class subs were 275 feet long and built with a distinctive bulbous bow to accommodate the external forward torpedo tubes. However, the bow shape adversely affected the speed while surfaced, prompting the Admiralty to build nine slightly modified T-class submarines with a more streamlined bow shape and the external bow tubes moved further back.
Although the T-class submarines achieved acceptable success against enemy subs during the war, sinking 13 enemy submarines including six Italian, four German, and three Japanese, the record is marred by an early disastrous incident. In September 1939, the crew of the HMS Triton sighted another submarine just off the coast of Norway. When the boat did not respond to radio communications, the Triton fired two torpedoes and sank the first British submarine lost during WWII, the HMS Oxley.
[Featured image by Stewart Bale Ltd via Wikimedia Commons | Cropped and scaled | CC Public Domain]