RV Calypso is a former British Royal Navy minesweeper converted into a research vessel for the oceanographic researcher Jacques-Yves Cousteau, equipped with a mobile laboratory for underwater field research. It was severely damaged in 1996, and was planned to undergo a complete refurbishment in 2009-2011. It is named after the Greek mythological figure Calypso.

The British millionaire and former MP, Thomas Loel Guinness bought Calypso in July 1950 and leased her to Cousteau for a symbolic one franc a year. He had two conditions, that Cousteau never ask him for money and that he never reveal his identity, which only came out after Cousteau's death. Cousteau restructured and transformed the ship into an expedition vessel and support base for diving, filming and oceanographic research. One of the more unusual expeditions involving the vessel was a survey of Abu Dhabi waters conducted by Cousteau on behalf of British Petroleum (BP) in 1954 - the first and last time it was used for an oil survey.

Calypso carried advanced equipment, including one and two-man mini submarines developed by Cousteau, diving saucers, and underwater scooters. The ship was also fitted with a see-through "nose" and an observation chamber 3 metres (9.8 ft) below the waterline, and was modified to house scientific equipment and a helicopter pad. The Calypso underwater camera is named after this ship.

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