During the 1930s, the Royal Navy of Great Britain made the decision to replace its underperforming overseas patrol submarines of the Oberon, Parthian, and Rainbow classes. This led to the construction of the T Class submarines, also known as the Triton Class, starting in 1934-35.

The T Class submarines had strict design requirements, including a strong armament and the ability to patrol for at least 42 days for long-distance missions. The construction of these submarines was also limited to a total of 16,500 tons due to the London Naval Treaty. The Admiralty went on to build 53 T Class submarines, each weighing around 1,575 tons, just before and during World War II.

The initial T Class submarines were 275 feet long and featured a unique bulbous bow design to accommodate external forward torpedo tubes. However, this design adversely affected speed while surfaced. As a result, the Admiralty built nine slightly modified T Class submarines with a more streamlined bow shape and moved the external bow tubes further back.

During the war, the T Class submarines achieved a reasonable level of success against enemy submarines, sinking a total of 13 enemy subs, including six Italian, four German, and three Japanese vessels. However, their record is marred by a tragic incident that occurred in September 1939. The crew of HMS Triton mistakenly identified another submarine off the coast of Norway and, after receiving no response to their radio communications, fired two torpedoes, sinking the first British submarine lost in World War II, the HMS Oxley.

[Featured image by Stewart Bale Ltd via Wikimedia Commons | Cropped and scaled | CC Public Domain]