French submarine Turquoise (1908)

The Émeraude class were built as part of the French Navy's 1903 building program to a Maugas single-hull design.[1] The submarines displaced 395 metric tons (389 long tons) surfaced and 427 metric tons (420 long tons) submerged. They had an overall length of 44.9 meters (147 ft 4 in), a beam of 3.9 meters (12 ft 10 in), and a draft of 3.8 meters (12 ft 6 in). They had an operational diving depth of 40 meters (130 ft). Their crew numbered 2 officers and 23 enlisted men.[2]

For surface running, the boats were powered by two Sautter-Harlé 300-metric-horsepower (296 bhp; 221 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 300-metric-horsepower electric motor. They could reach a maximum speed of 11.26 knots (20.85 km/h; 12.96 mph) on the surface and 8.5 knots (15.7 km/h; 9.8 mph) underwater. The Émeraude class had a surface endurance of 2,000 nautical miles (3,700 km; 2,300 mi) at 7.3 knots (13.5 km/h; 8.4 mph) and a submerged endurance of 100 nmi (190 km; 120 mi) at 5 knots (9.3 km/h; 5.8 mph).[3]

The boats were armed with four internal 450-millimeter (17.7 in) torpedo tubes, two in the bow and two in the stern, for which they carried six torpedoes.[4] Turquoise and her sister Topaze were the first French submarines to be equipped with a deck gun when they were fitted with a single 37-millimeter (1.5 in) gun in August 1915.[1]

Turquoise was laid down in October 1903[5] at the Arsenal de Toulon, launched on 3 August 1908 and commissioned on 10 December 1910.[6]

During World War I, Turquoise was sunk in the Dardanelles off Nagara Point, Ottoman Empire, on 30 October 1915. She was refloated by Ottoman forces on 3 November 1915 and taken into the Ottoman Navy as Müstecip Onbaşı,[7] and returned in 1918.

• Borton, Donald E.; Griffith, Frank G.; Kemp, Paul J.; Layman, R. D. & Rich, North (1988). "Question 19/87". Warship International. XXV (2): 210–212. ISSN 0043-0374.
• Caruana, Joseph (1989). "Question 19/87". Warship International. XXVI (2): 206. ISSN 0043-0374.
• Couhat, Jean Labayle (1974). French Warships of World War I. London: Ian Allan. ISBN 0-7110-0445-5.
• Gardiner, Robert & Gray, Randal (1985). Conway's All The World's Fighting Ships 1906–1921. London: Conway Maritime Press. ISBN 0-85177-245-5.
• Garier, Gérard (2002). A l'épreuve de la Grande Guerre. L'odyssée technique et humaine du sous-marin en France (in French). 3–2. Bourg-en-Bresse, France: Marines édition. ISBN 2-909675-81-5.
• Garier, Gérard (1998). Des Émeraude (1905-1906) au Charles Brun (1908–1933). L'odyssée technique et humaine du sous-marin en France (in French). 2. Bourg-en-Bresse, France: Marines édition. ISBN 2-909675-34-3.