The ''Lagrange''-class submarines were a class of four submarines built for the

French Navy The French Navy (french: Marine nationale, lit=National Navy), informally , is the maritime arm of the French Armed Forces and one of the five military service branches of France. It is among the largest and most powerful naval forces in th ...

during

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was List of wars and anthropogenic disasters by death toll, one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, ...

and the interwar period. Threeships of this type were built in the

Arsenal de Toulon The military port of Toulon (french: arsenal de Toulon) is the principal base of the French Navy and the largest naval base in the Mediterranean, sited in the city of Toulon. It holds most of France's force d'action navale, comprising the aircr ...

from 1913 to 1924, and onewas built at the

Arsenal de Rochefort The Arsenal de Rochefort was a French naval base and dockyard in the town of Rochefort. It was founded in 1665 and it was closed in 1926. In December 1665 Rochefort was chosen by Jean-Baptiste Colbert as a place of "refuge, defense and supply" fo ...

shipyard. Entering the French ''Marine Nationale'' from 1918 to 1924, the submarines served until the mid-1930s.

Design

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 s, using two Parsons

steam turbine A steam turbine is a machine that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Its modern manifestation was invented by Charles Parsons in 1884. Fabrication of a modern steam turb ...

s with a power of .Fontenoy, p. 89 During construction, though, the idea was abandoned and the ships were instead equipped with diesel engines. long, with a

beam Beam may refer to: Streams of particles or energy * Light beam, or beam of light, a directional projection of light energy ** Laser beam * Particle beam, a stream of charged or neutral particles **Charged particle beam, a spatially localized g ...

of and a draught of ,Couhat, p. 158-9 ''Lagrange''-class submarines could dive up to . The submarines had a surfaced displacement of and a submerged displacement of . Propulsion while surfaced was provided by two diesel motors built by Swiss manufacturer, Sulzer, and two electric motors.Gardiner, p. 212. The submarines' electrical propulsion allowed them to attain speeds of while submerged and on the surface. They had surfaced range of at and a submerged range of at . The ships were equipped with eight

torpedo tube A torpedo tube is a cylindrical device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units (also referred to as torpedo launchers) installed abo ...

s (fourin the bow; twostern and twoexternal), with a total of ten

torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, s ...

es and two guns. The crew of a ship comprised forty-sevenmen.

Ships

Of the four''Lagrange''-class submarines, threewere built in the

and one in the

.Jane, p. 198 The ships were

laid down Laying the keel or laying down is the formal recognition of the start of a ship's construction. It is often marked with a ceremony attended by dignitaries from the shipbuilding company and the ultimate owners of the ship. Keel laying is one ...

between 1913 and 1914 and launched between 1917 and 1924. The ships were named after French scholars:

Joseph-Louis Lagrange Joseph-Louis Lagrange (born Giuseppe Luigi LagrangiaPierre-Simon Laplace Pierre-Simon, marquis de Laplace (; ; 23 March 1749 – 5 March 1827) was a French scholar and polymath whose work was important to the development of engineering, mathematics, statistics, physics, astronomy, and philosophy. He summarized ...

Henri Victor Regnault Henri Victor Regnault (21 July 1810 – 19 January 1878) was a French chemist and physicist best known for his careful measurements of the thermal properties of gases. He was an early thermodynamicist and was mentor to William Thomson in ...

and the constructor of submarines

Gaston Romazzotti Gaston Romazotti was a French naval engineer of the late 19th and early 20th century, and an early designer of submarines. Early life Romazotti was born at Molsheim, in Bas-Rhin, in July 1855. After studying at the École Polytechnique and qualif ...

Service

Of the foursubmarines, only twowere commissioned before the end of

: ''Lagrange'' and ''Romazzotti'', which operated in the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

. From 1922 to 1923, the ships underwent a major refit in which they received new major conning towers,

bridges A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somethi ...

and

periscope A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position. In its simplest form, it consists of an outer case with ...

s. All ships served in the

until 1935 for ''Lagrange'' and 1937 for the other threeships.

References

Citations

* * * * {{DEFAULTSORT:Lagrange World War I submarines of France Submarine classes Ship classes of the French Navy