Jemmapes-class ironclad
The Jemmapes class was a group of two coastal-defense ships built for the French Navy in the early 1890s. The class comprised  and  and were an improved version of the preceding , built for a higher speed with more modern Belleville boilers. They were armed with two turret-mounted  guns and were protected by armor up to  thick. Launched in 1892, the ships served with the Northern Squadron () of the French Navy. They operated along with the similar  and  as the Coastal Defence Division, being considered together "the most homogenous and dangerous squadron that one could meet at sea" by Vice Admiral Armand Bernard. They were struck in 1910 and, although Jemmapes had a brief respite as a hulk, they were both subsequently sold to be broken up.

Design and development
thumb|left|alt=Cutaway of the Jemmapes class from Brassey's Naval Annual|Plan view of the Jemmapes class
In the early 1880s, the  doctrine became popular in French naval circles. Key to this was the replacement of the battleship broadside with smaller vessels armed with torpedoes, such as smaller cruisers and torpedo boats, to defend France and attack enemy merchant shipping. To support these smaller vessels, a lesser number of powerful coastal defense ships were planned.

On 15 November 1888, the naval architect Louis de Bussy sent a note to the Ministry of the Navy () Jules François Émile Krantz on the newly-completed coastal defense ship . Krantz responded immediately with a request for a ship derived from Furieux but with more modern Belleville boilers to give a higher speed of . De Bussy submitted his design on 14 February 1889. The design proposal was accepted by the Board of Construction () on 26 February as meeting the criteria required, finalised on 2 July and approved on 6 July.

The ships of the Jemmapes class were longer than the Furieux with a overall length of ,  at the waterline and  between perpendiculars, but had a smaller beam of  at the waterline and a smaller mean draught of  at deep load. The vessels had a design displacement of , which increased to  in service. The complement numbered 299 sailors of all ranks.

The vessels were powered by two triple-expansion steam engines provided by St Denis that each drove one propeller shaft. Steam was provided by 16 coal-burning Lagrafel and d'Allest Belleville boilers. The power plant was rated at  at 108 rpm and a pressure of  at the boilers and  at the engines. While undertaking sea trials, Jemmapes reached a speed of  from  and Valmy reached  from . In service, speed was restricted as a bow wave was created at  which, by  became impossible to push forward, meaning this became the de facto maximum speed. The ships carried  of coal, which gave a range of  at a cruising speed of . The maximum load of coal was . Once in service, a range of  at  was claimed.

Armament and armor
Jemmapes and Valmy were armed with a main battery of two Canon de  Modèle 1887 guns in a two single-gun turrets, one forward of the superstructure and the other aft. The guns were manually-loaded and fired one round every five minutes, but this was sped up between 1900 and 1902 with new equipment. Secondary armament was provided by four  45-calibre M1891 QF guns mounted at the corners of the shelter deck. Defence from torpedo boats was provided by six Canon de  Modèle 1885 Hotchkiss guns and eight  Hotchkiss revolving cannons.

The ships had a full-length waterline armor belt that tapered from the maximum thickness of  amidships to  aft and  forward. The belt was  high amidships. The armor was hammered steel on the port side and compound armor on the starboard. The turrets were protected by  thick compound armor that was mounted on fixed bases  thick while the gun shields for the secondary armament was provided by hammered steel armor  thick. The main deck was protected by  thick iron plates. The laminated steel plates protecting the conning tower measured  in thickness. The armor was split between Schneider, who provided the steel, and Saint-Chamond, who provided the compound armor, except for the turret, which was completely supplied by the latter firm.

Modifications
During their lives, the ships had their armament modified. In 1906, the torpedo tubes were removed and by the following year six of the 37-mm Hotchkiss revolver cannons had been replaced by four additional 47-mm guns.

Construction and career
+ Construction data Name Shipyard Laid down Launched Commissioned Cost  , Saint-Nazaire and Saint-Denis 26 December 1889 27 April 1892 4 March 1895 £525,000  , Saint-Nazaire and Saint Denis 1889 6 October 1892 14 August 1895 £578,957

Jemmapes and Valmy were commissioned into the Northern Squadron () of the French Navy on 4 March and 14 August 1894 respectively, forming a small but formidable force within the French Navy. They were considered more than equal to their smaller German contemporaries, the  and . On 12 March 1895, as part of the naval budget debate, Vice Admiral Armand Bernard declared that the two ships of the class, alongside the related ironclads  and , were "the most homogenous and dangerous squadron that one could meet at sea". The ships' service lives were largely uneventful. Between 1 and 23 July 1895 and 6 to 26 July 1896, they took part in large naval exercises in the Atlantic Ocean alongside local defense forces in Brest, Cherbourg, Lorient and Rochefort.

At the end of the century, the vessels were part of the Coastal Defence Division alongside Amiral-Tréhouart and Bouvines. Meanwhile, French naval doctrine was changing and the focus on coastal defense was being replaced by one of larger sea-going warships. The size of ships was also increasing, and newer, more capable battleships entered service. Jemmapes was transferred to reserve in 1902, Valmy following in 1903. Valmy was the first to be struck, on 1 July 1910, Jemmapes following on 3 August. Valmy was put up for sale on 20 July 1911 and broken up. Jemmapes spent some time as a hulk before she being broken up on 5 November 1927.

Notes

References
 
 
 

 

Category:Coastal defense ship classes
Jemmapes-class ironclads
Category:Ships built in France
Category:Ship classes of the French Navy