|  | 
| History | 
|---|
| France | 
|---|
| Owner | Cousteau Society | 
| Port of registry | France | 
| Launched | 1959 | 
| Maiden voyage | 1959 | 
| Homeport | Marseille, France | 
| Identification | SP-350 | 
| Nickname(s) | Denise | 
| Status | Decommissioned | 
| General characteristics | 
|---|
| Type | Submarine | 
| Displacement | 3.8 tonnes | 
| Length | 2.75 m (9 ft 0 in) | 
| Beam | 2.75 m (9 ft 0 in) | 
| Draught | 1.5 m (4 ft 11 in) | 
| Propulsion | Electric water jet | 
| Speed | 1 knot | 
| Endurance | 96 hours (one person) | 
| Test depth | 1,000 m (3,300 ft) | 
| Complement | 2 | 
| Crew | 2 | 
The SP-350 Denise, famous as the "Diving saucer" (Soucoupe plongeante), is a small submarine designed to hold two people, and is capable of exploring depths of up to 400 metres (1,300 ft). It was invented by Jacques-Yves Cousteau and engineer Jean Mollard at the French Centre for Undersea Research.  It was built in the year 1959 and usually operated from Cousteau's ship, the Calypso.