First maneuverable research submersible

Last updated: June 2, 2018 at 15:13 pm

The Diving Saucer DS-1 (Soucoupe plongeante SP-300) — Jacques-Yves Cousteau and engineer Jacques Mollard began designing small, maneuverable submersibles capable of being launched from the deck of a ship in the 1950s. Their two-man DS-1 was first tested (unmanned) to a depth of 600 m (1,968 ft) in the Mediterranean Sea in 1957 but it was lost when its tether snapped during ascent. A second saucer DS-2 (a.k.a. Denise in honour of the wife of Jean Mollard), was launched in 1959. It was deployed from Cousteau’s Calypso during expeditions all over the world, including the first exploration of the HMHS Britannic in 1976. Unlike current submersible designs, the DS-2 was propelled by water jets. Its maximum operating depth was 300 m (1,000 ft). As of January 2018, the DS-2 is no longer in use.

“Its propulsion consists of steerable, electrically powered water jets, allowing it to navigate in all directions, as well as turn about its vertical axis. To correct the attitude of the hull, the pilot can shift a liquid mercury ballast mass. The crew members enter the craft through a hatch on the top of the hull and lie prone side-by-side on mattresses to operate it, watching their surroundings through tilted portholes that let them come within a few centimeters of their subject. Electric lamps are fitted for night diving and to provide illumination for photography at extreme working depths. An electrically operated manipulator arm can be fitted at the front of the craft so that the craft can pick up objects for the crew to examine through the portholes. The steel pressure hull, nearly circular in plan form, is 2 metres (6 ft 7 in) in diameter and 1.43 metres (4 ft 8 in) high, able to resist a pressure of more than 90 kg/cm2 (1,300 psi), equivalent to a depth of nearly 900 metres (3,000 ft), although dives never exceed 300 metres (980 ft) for safety. Denise is naturally positively buoyant, and is weighted to negative buoyancy with ballast weights that can be jettisoned in an emergency. If the craft is within 100 metres (330 ft) of the surface, the crew can abandon it via the top hatch, provided they are equipped with emergency breathing apparatus.”¹

Shannon, Terry. 1965. Saucer In The Sea; The Story Of The Cousteau Diving Saucer In Pacific Coast Waters.
¹ SP-350 Denise. (2017, October 11). In Wikipedia, The Free Encyclopedia. Retrieved 15:43, January 3, 2018, from

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