T Class: Large Patrol Submarine
This class was ordered under the 1940/41 and 1942 building programmes. Most of the 1941 and all the 1942 orders were of fully welded construction.
Like the Group 3 S class boats, the T's entered the war late but served in Home waters, the Mediterranean Sea, the Indian Ocean and fitted for the Tropics with Air Conditioning, in the Pacific.
The groups successes included the dispatching of 6 submarines and 3 Cruisers plus thousands of tons of merchant shipping.
The longest patrol accomplished by any British submarine during WW11, was in 1945 when Tantalus remained at see for 55 days covering 11,500 nautical miles.
Only one boat P311, was lost during the war. Terrapin was so badly damaged, she had to be scrapped but she had survived a sustained attack and returned to base.
Following the war the group suffered two losses. In 1950 Truculent was sunk after a collision and in 1968 Totem, renamed Dakar and sold to the Israeli Navy, was lost with all hands in the Mediterranean Sea.
The 1950's saw many changes to the T class design. Modifications for trials in streamlining and acoustics were made. For some, an increase in length achieved by cutting the boat in two just aft of the engine room and inserting a new piece of hull.
HMS/m Tiptoe, commissioned in April 1944 became the last boat of this group to be paid off in August 1969.