
Churchill-class submarine

The three Repeat "Valiant"-class submarines, sometimes known as the "Churchill" class, were nuclear-powered fleet submarines which served with the Royal Navy from the 1970s until the early 1990s. The "Churchill" class was based on the older , but featured many internal improvements. 
The lead vessel was named after the former Prime Minister and First Lord of the Admiralty Winston Churchill. was the most famous of the class, sinking the Argentinian cruiser during the 1982 Falklands War. , this is the only instance of a nuclear-powered submarine of any nation sinking an enemy ship by torpedo.
Design.
The "Churchill"s carried a crew of 103 and had a full load displacement of 4,900 tons whilst dived. They were long, had a beam of and a draught of . Their single pressurized water-cooled reactor supplied steam to two English Electric geared turbines, producing a total of for the single shaft and resulting in a maximum of submerged. Like all nuclear-powered submarines the "Churchill" class could remain submerged almost indefinitely, with supplies of food being the only limiting factor. One Kelvin Type 1006 surface-search radar was fitted. The ships were built with a Type 2001 sonar array, but this was replaced in the late 1970s with a Type 2020 array and a Type 2026 towed array. Weapons included Mk VIII torpedoes, Mk 24 Tigerfish torpedoes, and Sub-Harpoon anti-ship missiles. Six torpedo tubes fired from the bow.
HMS "Churchill" evaluated both the American Mark 48 torpedo and the UGM-84 Harpoon missile, though only the latter was adopted by the Royal Navy. She was decommissioned in 1990 and is laid up at Rosyth awaiting disposal.
In 1981 became the first British submarine to carry the Sub-Harpoon missile. She was decommissioned in 1992 and is at Devonport Dockyard serving as a museum ship.
Service history.
 was the most famous of the class, sinking the Argentinian cruiser during the 1982 Falklands War. She did not fire again during the war, but provided valuable help to the British task force by using her monitoring equipment to track Argentine aircraft departing the mainland. After the war "Conqueror" returned to Faslane; the sinking of "General Belgrano" had provoked controversy in Britain and "Conqueror" was criticised for flying the Jolly Roger on returning to port, as Royal Navy submarines customarily did on returning after scoring a kill. She the only nuclear-powered submarine of any nationality to have engaged an enemy ship with torpedoes. She was decommissioned in 1990 and is laid up at Devonport awaiting disposal. "Conqueror"s periscopes can be viewed at the Royal Navy Submarine Museum in Gosport.