Specifications
The submarine used a compressed-air engine, propelled by stored compressed air powering a reciprocating engine. The air was contained in 23 tanks holding air at 12.5 bar (1.25 MPa, 180 psi), taking up a huge amount of space (153 m³/5,403 ft³), and requiring the submarine to be of unprecedented size. The engine had a power of 60 kW (80 hp), and could propel the submarine for 5 nm (9 km), at a speed of 4 kts (7.2 km/h).
Compressed air was also used to empty its ballast tanks, which had a volume of 53 m³ (1,872 ft³). Ballast was 212 t (234 tons), including a security ballast of 34 t (37 tons).
The submarine was armed with a ram to break holes in the hull of enemy ships, and an electrically-fired spar torpedo, fixed at the end of a pole.
The submarine was 43 m (140 ft) long and 381 t (420 tons) in displacement.
A support ship, the Cachalot, followed her in order to resupply the compressed air necessary to her propulsion.
A small lifeboat (8 x 1.7 m/26 x 5.6 ft) was provided for the escape of the 12-man complement.
Read more about this topic: French Submarine Plongeur