Amiral Duperré was an ironclad barbette ship built for the French Navy in the 1870s and 1880s; she was the first vessel of that type built by France. She carried her main battery of four guns individually in open barbette mountings, which offered increased fields of fire compared to earlier central battery ships, though they were less well protected. Amiral Duperré was ordered as part of a French naval construction program aimed at countering the growth of the Italian fleet, which had begun work on the very large ironclads of the and es in the early 1870s. The Italian vessels, armed with guns, prompted public outcry in France that pressured the navy to develop larger guns for its own ships. Amiral Duperrés design served as the basis for several follow-on classes, including the and es.
The ship served with the Mediterranean Squadron for most of her active career. In the 1880s and 1890s, the ship took part in numerous training exercises. She suffered an accidental explosion in one of her main guns, though reports of the timing and casualties vary. Amiral Duperré was reduced to the Reserve Division in 1895, serving as its flagship for the next three years. The ship continued to regularly participate in training maneuvers with the rest of the squadron. By the late 1890s, more modern pre-dreadnought battleships began to enter service, and in 1898, she was transferred to the Northern Squadron, based in the English Channel. In 1901, the ship was withdrawn from service to be modernized as part of a program to upgrade the ironclads still in service, though by the time work was completed after 1905, Amiral Duperré saw no further active duty. Instead, she was struck from the naval register in 1909 and subsequently broken up.
Design
In the aftermath of the Franco-Prussian War of 1870–1871, the French Navy embarked on a construction program to strengthen the fleet in 1872. The initial ships followed the same general pattern as the ships built in the 1860s, but by the early 1870s, the French design staff in the (Board of Construction) had to grapple with the challenges posed by technological developments and foreign construction programs.
In the early 1870s, the Italian (Royal Navy) had begun its own expansion program under the direction of Benedetto Brin, which included the construction of several very large ironclad warships of the and es, armed with 100-ton guns. The French initially viewed the ships as not worthy of concern, though by 1877, public pressure over the new Italian vessels prompted the Navy to order Amiral Duperré. The public outcry also forced the French to design new steel guns to compete with the gigantic Italian guns; the Model 1870 gun was quickly surpassed by the Model 1875, which was installed aboard Amiral Duperré.
As the power of guns continued to grow, thicker armor was needed to protect the ships; the full side armor of earlier ironclads could not be thickened without prohibitively increasing displacement. This led to intense discussions in France (and in foreign navies) as to the best way to protect new capital ships; in France, designers considered (de-armoring) their next generation of ironclads. This involved eliminating most of the side armor of the hull and concentrating a sufficient thickness at the waterline only. Guns would be placed in lightly armored barbettes on the upper deck. The French decision was driven by a desire to protect their ships' ability to maneuver, as the unarmored ends of the citadel ships could be easily damaged and flooded. They viewed the ram as a decisive weapon, and a vessel that could no longer maneuver effectively would easily fall victim to a ramming attack. The French differed from their British and Italian counterparts, who decided to shorten the length of their belt armor to save the weight necessary to thicken the remaining portion of armor.
Work on the design began with French Naval Minister Charles de Dompierre d'Hornoy's order for the to prepare two options for the new first-class ironclad on 20 October 1873. Work on the project was led by the Director of Material, Victorin Sabattier. One of the options, a combination barbette and central battery ship, was developed further into the . The other, which carried all of its heavy guns in barbettes on the upper deck, went through a series of alterations and Sabattier eventually submitted it to Léon Martin Fourichon, who was then the naval minister, on 8 March 1876. Fourichon approved it on 5 August, and the contract for the vessel was awarded on 4 December. Apart from the main battery arrangement, the ship was in most respects similar to the Dévastations.