Lagrange-class submarine

The Lagrange-class submarines were constructed as part of the French fleet's expansion programmes from 1913 to 1914. The ships were designed by Julien Hutter, who slightly modified his previous project, the {{sclass|Dupuy de Lôme|submarine|1}}s, using two Parsons steam turbines with a power of {{Convert|2000|hp|lk=in|0|abbr=on}}.Fontenoy, p. 89 During construction, though, the idea was abandoned and the ships were instead equipped with diesel engines.

{{Convert|75.2|m|ftin|abbr=on}} long, with a beam of {{Convert|6.3|m|ftin|abbr=on}} and a draught of {{Convert|3.6|m|ftin|abbr=on}},Couhat, p. 158-9 Lagrange-class submarines could dive up to {{Convert|50|m|ft|0|abbr=on}}. The submarines had a surfaced displacement of {{Convert|920|LT|t|0|lk=on}} and a submerged displacement of {{Convert|1318|LT|t|0|lk=on}}. Propulsion while surfaced was provided by two{{Nbsp}}{{Convert|2600|hp|0|abbr=on}} diesel motors built by Swiss manufacturer, Sulzer, and two{{Nbsp}}{{Convert|1640|hp|0|abbr=on}} electric motors.Gardiner, p. 212. The submarines' electrical propulsion allowed them to attain speeds of {{Convert|11|kn|lk=in}} while submerged and {{Convert|16.5|kn}} on the surface. They had surfaced range of {{convert|4300|nmi|km|lk=in}} at {{convert|10|kn|km/h}} and a submerged range of {{convert|125|nmi|km}} at {{convert|5|kn|km/h}}.

The ships were equipped with eight{{Nbsp}}{{Convert|450|mm|in}} torpedo tubes (four{{Nbsp}}in the bow; two{{Nbsp}}stern and two{{Nbsp}}external), with a total of ten{{Nbsp}}torpedoes and two{{Nbsp}}{{Convert|75|mm|in}} guns. The crew of a ship comprised forty-seven{{Nbsp}}men.{{cite web|url=http://www.naval-history.net/WW1NavyFrench.htm|title=French Navy, World War 1|first=Gordon|last=Smith|website=www.naval-history.net}}

Of the four{{Nbsp}}Lagrange-class submarines, three{{Nbsp}}were built in the Arsenal de Toulon and one in the Arsenal de Rochefort.Jane, p. 198 The ships were laid down between 1913 and 1914 and launched between 1917 and 1924. The ships were named after French scholars: Joseph-Louis Lagrange, Pierre-Simon Laplace, Henri Victor Regnault and the constructor of submarines Gaston Romazzotti.

Of the four{{Nbsp}}submarines, only two{{Nbsp}}were commissioned before the end of World War I: Lagrange and Romazzotti, which operated in the Mediterranean Sea.

From 1922 to 1923, the ships underwent a major refit in which they received new major conning towers, bridges and periscopes. All ships served in the Mediterranean Sea until 1935 for Lagrange and 1937 for the other three{{Nbsp}}ships.

{{reflist|30em}}

• {{cite book|last=Couhat|first=Jean Labayle|title=French Warships of World War I|year=1974|publisher=Ian Allan|location=London|isbn=0-7110-0445-5}}
• {{cite book|last=Fontenoy |first= Paul E.|title=Submarines: An Illustrated History of Their Impact|publisher= ABC-CLIO Publishing|year=2007|isbn=978-1-85109-563-6}}
• {{cite book|last1=Gardiner |first1=Robert|last2=Gray |first2= Randal |title=Conway's All the World's Fighting Ships 1906–1921|publisher=Conway Maritime Press|location=London|year=1985|isbn=978-0-85177-245-5}}
• {{cite book|last=Moore |first=John |title=Jane's Fighting Ships of World War I|location=London|year=1990}}

{{Lagrange-class submarine}}

{{WWI French ships}}

{{DEFAULTSORT:Lagrange}}

Category:World War I submarines of France

Category:Submarine classes

Category:Ship classes of the French Navy