HMS Ace (P414) was an Amphion-class submarine of the Royal Navy, constructed during World War II but never completed for active service. Laid down on December 3, 1943, at Devonport Dockyard, she was launched on March 14, 1945. Although intended for the Pacific campaign, her construction was halted due to the war’s end, and she was subsequently used as a target ship. In June 1950, she was sent to Smith & Houston in Port Glasgow, Scotland, to be broken up, with her hull repurposed for explosives testing beforehand. The Amphion class was designed as a successor to the T-class submarines, optimized for Pacific operations, though most were not finished before hostilities concluded. HMS Ace measured approximately 279 feet 3 inches (85.12 m) in length overall, with a beam of 22 feet 3 inches (6.78 m) and a draught of 17 feet 3 inches (5.26 m). Her displacement was 1,385 tons on the surface and 1,620 tons submerged. Powered by diesel-electric propulsion, she had two shafts and was equipped with Admiralty 6-cylinder engines, which provided a maximum surface speed of 18.5 knots, though Ace’s speed was slightly reduced to 17.5 knots due to engine limitations, with a power output of 3,400 bhp. She also carried two electric motors generating 1,200 shp for submerged operation, with a maximum submerged speed of 8 knots. Her armament included ten 21-inch torpedo tubes—four on the bow, two on the exterior bow, two on the stern, and two exterior stern—carrying a total of 20 torpedoes. For surface combat and defense, she was equipped with three 0.303 machine guns, a single Oerlikon 20mm cannon, and a QF 4-inch Mk XXII deck gun. The vessel's pressure hull was circular and tinplated, offering an operational diving depth of up to 500 feet, with a test depth of 600 feet, though structural integrity would be compromised below 200–300 feet. HMS Ace's service was limited; after WWII, she served primarily as a target ship and was ultimately dismantled in 1950. Her design and construction reflect the transitional nature of late-war submarine development in the Royal Navy.

This description has been generated using GPT-4.1-NANO based on the Vessel's wikidata information and then modified by ShipIndex.org staff.