Triumph during repairs after she was damaged by a mine and Thetis during the extensive repairs following her sinking and subsequent salvage. Only six survived the war, less than half. Triton sunk in the Adriatic Sea on 18 December 1940 Thetis built at Cammell Laird. Sank during trials in 1939 with 99 dead. Thetis was salvaged and recommissioned as Thunderbolt in October 1940. Sunk by the Italian corvette Cicogna off Strait of Messina on 14 March 1942) Tribune, built at Scotts, Greenock, commissioned October 1939, scrapped 1947 Trident built at Cammell Laird, commissioned October 1939, scrapped 1946 Triumph built by Vickers, Barrow-in-Furness and commissioned May 1939. Lost, probably to Italian mines, on 14 January 1942 Taku scrapped 1946 Tarpon (probably sunk by German minesweeper M-6 on 14 April 1940) Thistle torpedoed by U-4 on 10 April 1940 off Norway Tigris (probably sunk by German ship UJ-2210 on 27 February 1943) Triad sunk by gunfire from the in the Gulf of Taranto on 15 October 1940 Truant wrecked 1946 on way to breakers Tuna scrapped 1946 Talisman lost in Mediterranean, probably to Italian mines, on 17 September 1942) Tetrarch, commissioned February 1940 the only boat completed with mine laying equipment. Lost in Mediterranean, probably to Italian mines, after 27 October 1941. Torbay built at Chatham, commissioned 1941, scrapped 1947. Group Two boats These seven vessels were all ordered under the 1939 War Emergency Programme. The first, Thrasher, was launched on 5 November 1940. The external bow torpedo tubes were moved seven feet aft to help with sea keeping. The two external forward-angled tubes just forward of conning tower were repositioned aft of it and angled backwards to fire astern, and a stern external torpedo tube was also fitted. This gave a total of eight forward-facing tubes and three rear-facing ones. All Group Two boats were sent to the Mediterranean, only Thrasher and Trusty returned. Tempest (sunk by the Italian Circe on 13 February 1942) Thorn (sunk by the Italian Pegaso on 6 August 1942) Thrasher Traveller (lost, probably to Italian mines, on 12 December 1942) Trooper (lost, probably to German mines, on 14 October 1943) Trusty Turbulent (possibly sunk by an Italian torpedo boat, or a mine in March 1943) During her career, she sank over 90,000 tons of enemy shipping. Group Three boats Wartime austerity meant that they lacked many refinements such as jackstaffs and guardrails, and had only one