The Jacques Cousteau diving saucer is a unique type of diving technology invented and built by famous French oceanographer and explorer Jacques Cousteau in 1959. First used during his explorations aboard the Calypso at the end of the 1950s and early 1960s, it represented a small, saucer-shaped submarine capable of carrying up to two divers and reaching depths of about 400 meters. The official name of the diving saucer was SP-350 Denise, and the submarine was initially developed, tested and fine-tuned by Cousteau together with French engineer Jean Mollard.
One of the crowning achievements of Jacques Cousteau, the saucer was designed to counter the immense undersea pressures at depths of more than 1,000 feet, where divers could not reach by themselves using regular breathing equipment. This mini-submersible had a saucer shape with a diameter of 2.85 meters, and weighed about 3.5 tons due to its resilient steel hull. The design uses a simple and efficient jet propulsion system and a construction that allows the submersible to move like a squid. The small ship also used an electrically operated arm that allowed divers to pick up and interact with objects, examining them through the portholes.
The Jacques Cousteau diving saucer became a highly efficient means of conducting significant underwater research. The saucer was capable of a speed of 2 knots – or about 3.7 km/h – and was relatively easy to maneuver. Although it was capable of withstanding a pressure of up to 1,300 psi, equivalent to a depth of more than 900 meters, for safety reasons, Cousteau rarely allowed his divers to exceed depths of 300 meters. If the depth was beneath 100 meters and the divers were geared up with proper breathing equipment, they could easily abandon the Denise and swim up to the surface – in cases of extreme necessity.
Denise was designed to be positively buoyant and weighted down to negative buoyancy using ballast weights that can quickly be jettisoned in an emergency. The technology was groundbreaking at the time, especially since it allowed for the weights to be adjusted to the contents of the sub’s equipment. The onboard equipment regularly included a radio, two special underwater cameras, a tape recorder and a lighting system consisting of three adjustable independent lamps that could be moved into position to illuminate specific areas and objects at accurate angles. The Jacques Cousteau diving saucer remains to this day a pioneer in advanced diving technology as well as the first mini-submarine used for oceanographic exploration.