HMS Unrivalled ( P45 ) HMS " Unrivalled " ( P45 ) was a " U " - class submarine built for the Royal Navy during World War II . So far she has been the only ship of the Royal Navy to bear the name " Unrivalled " . Completed in 1942 , the boat spent most of the war in the Mediterranean . She sank a number of small merchant ships and naval auxiliaries , but major success eluded her during the war . Too small and slow for the post - war environment , " Unrivalled " was scrapped in 1946 . Design and description . HMS " Unrivalled " was one of the second group of " U " - class submarines ordered on 23 August 1940 . These submarines differed from their predecessors in that they were lengthened by " to give a more streamlined shape aft and to improve the flow of water over the propellers . " The submarine was long and abeam . " Unrivalled " had a single hull with internal ballast tank s and had a draft of when surfaced . She displaced while submerged , but only on the surface . The submarine was equipped with two diesel engines and twin General Electric electric motors — for surfaced and submerged running , respectively . They were coupled together with a diesel - electric transmission . " Unrivalled " had a surface speed of up to and could go as fast as while underwater . The boat could carry up to of diesel fuel , giving her a range of at . Her electric motors and batteries provided a range of at while submerged . HMS " Unrivalled " was equipped with four bow torpedo tube s and could carry eight torpedo es . The submarine was also armed with a QF Mk I gun deck gun . She had a crew of 33 men . Career . HMS " Unrivalled " was ordered on 23 August 1940 as part of the 1940 naval construction programme from Vickers - Armstrong at Barrow - in - Furness . She was laid down on 12 May 1941 , launched on 16 February 1942 and commissioned on 3 May 1942 . Apart from a work - up patrol in the Norwegian Sea , she spent the bulk of the war in the Mediterranean . While working up , " Unrivalled " fired a torpedo at what was thought to be a submerged enemy submarine . Only the periscope was sighted , and the torpedo was fired in the direction detected by the hydrophone s , but no German submarine was in the area . Whilst in service in the Mediterranean , she sank a number of small merchantmen and small naval auxiliary vessels with both torpedoes and gunfire . These included the Italian auxiliary submarine chaser O 97 / " Margherita " , the Italian merchants " Maddalena " , " Mostaganem " and " Pasubio " , the Italian tugs " Genova " and " Iseo " , the Italian sailing vessels " Triglav " , " Albina " , " Margherita " , " Sparviero " and " Ardito " , the German auxiliary submarine chasers " UJ 2201 / Bois Rose " and " UJ 2204 / Boréal " , the Italian tanker " Bivona " , the small Italian merchant " Santa Mariana Salina " , the Italian auxiliary minesweeper " R 172 / Impero " and the small Italian vessel " San Francisco di Paola A " . " Unrivalled " also damaged the on 3 December 1942 , but neither sank or damaged any Axis ships after 28 July 1943 . During Operation Husky in July 1943 , she was stationed offshore to mark the landing beaches for the 1st Canadian Infantry Division . The boat survived the war , but was too slow for requirements and was not retained after the war . She was scrapped at Briton Ferry , Wales , beginning on 22 January 1946 .