French submarine Esturgeon

Esturgeon was one of 20 Naïade-class submarines built for the French Navy at the beginning of the 20th century.

Sister ship Thon
History
France
Name	Esturgeon
Ordered	3 April 1901
Builder	Arsenal de Toulon
Laid down	26 April 1902
Launched	4 January 1904
Commissioned	12 April 1904
Stricken	8 December 1914
Fate	Sold for scrap, 1 February 1913
General characteristics
Class & type	Naïade-class submarine
Displacement	70 t (69 long tons), (surfaced) 74 t (73 long tons) (submerged)
Length	23.7 m (77 ft 9 in)
Beam	2.3 m (7 ft 7 in)
Draft	2.6 m (8 ft 6 in)
Installed power	65 PS (64 bhp; 48 kW) (petrol engine) 70 PS (69 bhp; 51 kW) (electric motor)
Propulsion	1 × shaft; diesel-electric powertrain 1 × benzol engine 1 × electric motor
Speed	7.2 knots (13.3 km/h; 8.3 mph) (surfaced) 5.3 kn (9.8 km/h; 6.1 mph) (submerged)
Range	200 nmi (370 km; 230 mi) at 5.5 knots (10.2 km/h; 6.3 mph) (surfaced) 30 nmi (56 km; 35 mi) at 4.1 kn (7.6 km/h; 4.7 mph) (submerged)
Test depth	30 m (98 ft)
Complement	9
Armament	2 × single 450 mm (17.7 in) torpedo launchers

Design and description

The Naïade class was designed by Gaston Romazotti, an early French submarine engineer and director of the Arsenal de Cherbourg to a specification for a small coastal-defense submarine. They were of a single-hull design, derived from the first French submarine, Gymnote, but with a Diesel–electric powertrain.^[1] The hull was constructed of Roma-bronze, a copper alloy devised by Romazotti to resist corrosion better than steel.^[2] The submarines had a surfaced displacement of 70 long tons (71 t) and 74 long tons (75 t) submerged. They measured 23.7 metres (77 ft 9 in) long overall with a beam of 2.3 metres (7 ft 7 in) and draught of 2.6 metres (8 ft 6 in). The crew numbered nine men.^[3]

The Naïade's were equipped with a variable-pitch propeller and two auxiliary side-thrusting propellers (French: hélices auxiliaires évolueurs). On the surface, the propeller shaft was driven by two dynamos powered either by the Panhard et Levassor four-cycle benzol engine designed to produce 65 brake horsepower (48 kW) or the batteries used underwater. Speeds attained during the boats' sea trials reached up to 8.2 knots (15.2 km/h; 9.4 mph) from 104 bhp (78 kW). Underwater power for the Naïades was provided by a Société Éclairage Électrique electric motor rated at 70 shaft horsepower (52 kW) and intended to give them a maximum speed of 6 knots (11 km/h; 6.9 mph). Speeds during their sea trials were disappointing at only 5.3 knots (9.8 km/h; 6.1 mph) from 92 shp (69 kW). They were designed to have a range of 30 nautical miles (56 km; 35 mi) at 4.1 knots (7.6 km/h; 4.7 mph) submerged and 200 nautical miles (370 km; 230 mi) at 5.5 knots (10.2 km/h; 6.3 mph) on the surface. The Naïade class were armed with two external single 450-millimetre (17.7 in) torpedo launchers, one aimed forward and the other aft.^[4]

Construction and career

Esturgeon was ordered on 3 April 1901 and laid down on 26 April 1902 at the Arsenal de Toulon. The boat was launched on 4 January 1904 and commissioned on 8 December.^[5]