By the time that hostilities ended in 1945, submarine development during the later part of the war, particularly by the Germans had made the majority of existing submarines obsolete.The whole concept of the submarine was changing dramatically, particularly regarding underwater speed and endurance. Captured Type XXI and Type XXIII battery powered submarines achieved underwater speeds of 17 knots in trials, if only for short periods.

As a consequence, eight of the younger , all welded T Class boats were lengthened, by inserting a 20 foot parallel section of pressure hull aft of the engine room bulkhead, with two additional motors and a fourth battery, to increase underwater power and endurance. Also, all external projections were removed, and the hull and bridge structure streamlined.

29th August 1969 Tiptoe became the last operational T Class submarine to be paid off.