HMS Cook was a Bay-class frigate of the Royal Navy, primarily serving as a survey vessel in the Pacific Ocean from 1950 to 1964. Originally ordered in 1943 from William Pickersgill & Sons Ltd. as a Loch-class frigate named Loch Mochrum, her construction was later modified, and she was laid down in November 1944 as Admiralty Job Number 4813. Launched on 24 September 1945 as Pegwell Bay, her contract was subsequently terminated, and she was towed to HM Dockyard Devonport for conversion into a survey ship. Conversion work began in February 1948 and was completed in July 1950, during which she was stripped of main armaments and fitted with additional accommodations, offices for hydrographic work, boats, and Type 972 survey radar. Renamed HMS Cook with pennant number A307, she was commissioned for sea trials in June 1950. She was primarily engaged in hydrographic survey work along the west coast of Scotland, with notable missions including surveys in the Gold Coast in 1953 and participation in the Coronation Fleet Review that same year. In 1955, she conducted trials of the Decca Two Range Survey System, which used radio signals from shore stations for precise positioning. In 1957, HMS Cook embarked on a voyage to the Pacific to observe the British thermonuclear test "Operation Grapple" in May. Following this, she conducted extensive survey operations in Fiji, the Solomon Islands, New Britain, and around the Philippines, including gravimetric and magnetic measurements, depth sounding, and chart corrections. She also visited Australia, Singapore, and other Pacific islands for refits and survey work, often upgrading her equipment and facilities. In 1963, HMS Cook was involved in a grounding incident off Suva, which caused significant damage. After temporary repairs, she returned to the UK, but her captain was court-martialed for hazarding the ship. She was decommissioned on 1 May 1964 and placed into reserve. Throughout her service, HMS Cook played a vital role in maritime surveying, providing critical hydrographic data and supporting British interests across the Pacific region.

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