- Type: Research vessel
- Displacement: 402 tons
- Dimensions: 139 x 25 x 10 ft.
- Machinery: Diesel, twin screws, 580 hp = 10 knots
- Crew: 27
- Builder: Ballard Marine Railway, Seattle, 1942
- Service: Built as yard motor minesweeper YMS J-826, one of 561 constructed during World War II. Turned over to the Royal Navy, she operated out of Malta, Taranto, and Naples. Returned to U.S. Navy in 1947, but sold two years later to operate as a ferry between Malta and Gozo under the name Calypso. Purchased in 1950 by Lt.Cmdr. Jacques-Yves Cousteau, leader in the French development of SCUBA gear, as a research vessel. Over 46 years, the ship logged more than one million miles around the world. The ship carried the most modern equipment, including various submersiles and helicopters. She also sported a submerged observation bubble in the bow. The ship was featured in numerous publications and documentary films. On 8 Jan 1996 she was severely damaged in an accident at Singapore, and it was decided to replace her with a new, specially-designed vessel, the Calypso II.