Pluviôse-class submarine

The Pluviôse class of submarines was a group of submarines built for the French Navy prior to World War I. There were eighteen vessels in this class, of the Laubeuf type. One was accidentally lost prior to the outbreak of war; the others saw action, and four more were lost during hostilities. All were stricken in 1919.

Naming
The French Navy built 34 Laubeuf-type submarines between 1906 and 1911. These are usually described as two classes, of which the Pluviôse class was one, the other being the Brumaire class. (Another source treats the vessels as one group, divided by the yards that built them) The boats had two naming schemes; the earlier vessels were named after the months of the French Revolutionary calendar, and the later ones after French scientists. However the difference is not reflected in the class division; nine boats of the Pluviose class were named for the months, and nine for scientists.

Design
The Pluviôse class were Laubeuf type submarines, following the Laubeuf standard design of double hull and dual propulsion systems (as were the Brumaire class). The Pluviôse boats had electric motors for underwater propulsion, and are usually listed as having steam engines for surface propulsion, though in practice this was mixed. The earlier boats had steam engines (preferred by Laubeuf in the early stages as he felt petrol engines (favoured by his rival JP Holland) were unsafe; however, later Laubeuf type submarines, such as the Circé class, predecessors to the Pluviôse and Brumaire classes, had used diesel engines, and later Pluviôse boats had diesels.

Construction
The Pluviôse class were ordered in the 1905 programme and the first vessels were laid down in 1906. They were built at three of the French Navy’s dockyards, at the Arsenals of Cherbourg, Rochefort and Toulon. The first of the class, Pluviôse, was launched in May 1907, and the last, Gay Lussac in March 1910.

Armament
The Pluviôse class submariens were armed with 17.7 inch torpedoes, of which eight were carried. They had one 17.7 inch torpedo tube mounted in the bow, with one torpedo loaded and one carried as a reload, and six carried externally. Of these two were in Drzewiecki drop-collars and four in external cradles alongside the conning tower, two trained forward and two aft.

Service history
The Pluviôse class were acknowledged to be good sea boats and saw action throughout the First World War on patrol and close blockade duty. Of the eighteen built, five were lost. One (Vendémiaire) was accidentally lost prior to the war, in 1912. Two others (Floréal, Priarial) were lost accidentally during the conflict. Two others (Monge, Fresnel) were lost in action.