French ironclad Amiral Duperré

Side and top views of Amiral Duperré

Amiral Duperré was 97.48 m (319 ft 10 in) long at the waterline, with a beam of 20.4 m (66 ft 11 in) and a draft of 8.43 m (27 ft 8 in). She displaced 11,030 long tons (11,210 t). Her hull featured a pronounced ram bow and had a short forecastle deck that extended from the stem to the forward main battery guns. A small conning tower was placed between the forward barbettes and a secondary tower was placed aft, between the stern barbettes. Her hull was divided by sixteen watertight transverse bulkheads and several longitudinal bulkheads. Her transverse metacentric height was about 0.61 m (2 ft). She was fitted with three pole masts equipped with spotting tops for her main battery guns. The crew consisted of 660 officers and enlisted men.

Her propulsion machinery consisted of two vertical compound steam engines, each driving a screw propeller, with steam provided by twelve coal-burning fire-tube boilers. The boilers were vented through a pair of large funnels located side-by-side just aft of the conning tower. Her engines were rated to produce 7,300 indicated horsepower (5,400 kW) for a top speed of 14 knots (26 km/h; 16 mph). Coal storage amounted to 787 long tons (800 t). Amiral Duperré was designed with a sailing rig to supplement the steam engines,[4] though it was removed before she was completed.[5]

Her main armament consisted of four 340 mm (13.4 in), 18-caliber guns mounted in individual barbette mounts, two side-by-side forward, one amidships, and one aft, the latter pair on the centerline. These guns were supported by a secondary battery of one 163 mm (6.4 in) and fourteen 138 mm (5.4 in) guns, all carried in individual pivot mounts. The 163 mm gun was placed in the bow as a chase gun, while the 138 mm weapons were located in an unarmored gun battery in the main deck, seven guns per broadside. For defense against torpedo boats, she carried eighteen 37 mm (1.5 in) 1-pounder Hotchkiss revolver cannon, all in individual mounts. Her armament was rounded out with four 356 mm (14 in) torpedo tubes in above-water mounts.[4]

Sketch of Amiral Duperré, including a depiction of the forward barbettes

The ship was protected with wrought iron armor; her belt extended for the entire length of the hull from 0.46 m (1 ft 6 in) above the waterline to 2.01 m (6 ft 7 in) below. It was 559 mm (22 in) thick amidships, tapering to 406 mm (16 in) on the bottom edge, while the bow and stern were protected by 254 mm (10 in) at the waterline. A lower 152 mm (6 in) section extended down at the bow to reinforce the ram. An armor deck connected to the belt at its top and was 61 mm (2.4 in) of mild steel on a layer of 18 mm (0.7 in) plating. The barbettes for the main battery were 305 mm (12 in) thick and the supporting tubes were 100 mm (4 in); the gun shields were 51 mm (2 in). Her conning tower had 38 mm (1.5 in) of mild steel on the sides. Conway's All The World's Fighting Ships notes that "she was very vulnerable above [the waterline] and would not have stood much chance against HMS Inflexible."[4]

At some point in Amiral Duperré's career, three of her main battery guns were replaced with the slightly longer 21-caliber M1881 variant of the 340 mm gun, though she retained one of the shorter, original weapons. The ship's anti-torpedo-boat battery was revised early in her career, and by 1895, she was equipped with a pair of 9-pounder guns and forty guns ranging from 47 mm (1.9 in) 3-pounder Hotchkiss guns to 37 mm revolver cannon. She also had her masts reduced to two, which were fitted with two fighting tops apiece.[4]

Amiral Duperré was withdrawn from service in 1901 to be modernized, along with many other French capital ships of the period. The ship received new water-tube boilers and her engines were overhauled. The center 340 mm gun and its barbette were removed, and an armored battery of 163 mm guns was installed in their place.[6]

The keel for Amiral Duperré was laid down at the Société Nouvelle des Forges et Chantiers de la Méditerranée shipyard in La Seyne-sur-Mer outside of Toulon in January 1877. She was launched in September 1879 and fitting-out work was completed by 1883.[4] The ship thereafter served in the Mediterranean Squadron. On 2–3 March 1886, she took part in experiments with torpedo boats to determine the effectiveness of various attack angles. Later on the 3rd, Amiral Duperré and the ironclads Colbert, Friedland, Redoutable, Suffren, and Dévastation conducted shooting practice using the old ironclad Armide as a target. They fired at a range of 2,700 to 4,600 m (3,000 to 5,000 yd) and scored 22 percent hits with cast iron practice shells, though they conducted the test under unrealistic conditions, with Armide anchored in a calm sea.[7][8] The year's large-scale maneuvers were held off Toulon from 10 to 17 May, and they tested the effectiveness of torpedo boats in defending the coastline from a squadron of ironclads, whether cruisers and torpedo boats could break through a blockade of ironclads, and whether a flotilla of torpedo boats could intercept ironclads at sea.[9]

Illustration of Amiral Duperré c. 1889

Another major set of exercises was held from 2 to 12 June at Ajaccio on the island of Corsica; Amiral Duperré and several other ironclads simulated a fleet attacking the port, which was defended by a coastal defense ship, three cruisers, and twenty torpedo boats. The ironclad squadron thereafter sailed to Oran, French Algeria, for another round of maneuvers that began on 25 June. During these exercises, the ironclads simulated an enemy fleet passing through the Strait of Gibraltar to attack the French Mediterranean coast; torpedo boats attempted to intercept them off Majorca. From the year's maneuvers, the French concluded that the torpedo boats of the day were not sufficiently powerful enough to achieve any of the goals that had been assigned to them, particularly further from coast, but nevertheless still posed significant threats to blockading warships. These lessons spurred the development of larger torpedo boats better able to operate at sea.[10]

In May 1887, Amiral Duperré took part in exercises to practice convoy escort; the French Army kept significant forces in French North Africa, and these units would have to be transported back to Europe in the event of a major conflict. The ship was assigned to escort a convoy of four simulated troop ships, along with Colbert and the ironclads Courbet and Indomptable. A squadron of cruisers and torpedo boats was tasked with intercepting the convoy. The convoy used bad weather to make the passage, as heavy seas kept the torpedo boats from going to sea.[11]

At some point, one of the ship's main guns accidentally exploded, blowing its breech, though reports conflict over the timing and the results of the incident. According to the contemporary journal The Naval Annual, the explosion took place on 13 December 1888 and killed six men from the gun crew. That report offered two explanations, as different experts faulted the brown powder propellant charge, which was believed to have decayed, or defects in the steel breech, as the guns carried by Amiral Duperré were among the earliest steel-built guns in French service.[12] But the historian Theodore Ropp stated that it was the result of an increased propellant charge. By the early 1880s, the French had developed more effective, slower-burning propellants, and had bored out the chambers of existing guns to accept larger charges of the new powder. Amiral Duperré's gun was the only weapon that had been modified to have failed. And according to Ropp, no men were killed in the accident.[13]

Scale model on display at the Musée de la Marine in Paris

Amiral Duperré served in the 1st Division of the Mediterranean Squadron in 1890, along with the two Amiral Baudin-class ironclads. She took part in the annual fleet maneuvers that year in company with her division-mates and six other ironclads, along with numerous smaller craft. Amiral Duperré served as part of the French force during the maneuvers, which lasted from 30 June to 6 July.[14] During the 1890 fleet maneuvers, the ship served in the 1st Division of the 1st Squadron of the Mediterranean Fleet. At the time, the division also included the ironclads Courbet and Formidable. The ships concentrated off Oran, French Algeria on 22 June and then proceeded to Brest, France, arriving there on 2 July for combined operations with the ships of the Northern Squadron. The exercises began four days later and concluded on 25 July, after which Amiral Duperré and the rest of the Mediterranean Fleet returned to Toulon.[15] The ship remained in service with the Mediterranean Fleet in 1892, which by that time had been joined by the three Marceau-class ironclads.[16] She participated in the 1893 maneuvers, again as part of the 2nd Division in company with Amiral Baudin and the ironclad Hoche. The maneuvers included an initial period of exercises from 1 to 10 July and then larger-scale maneuvers from 17 to 28 July.[17]

In late January 1895, Amiral Duperré and the protected cruiser Sfax took part in an experimental bombardment of a simulated coastal fortification on Levant Island. The test lasted six hours and was carried out over the course of three days, so that the effect of shelling could be studied throughout the experiment. It involved over a thousand shots between the two ships, firing calibers ranging from 10 to 34 cm (3.9 to 13.4 in). Neither ship was able to significantly damage the fortifications, though several of the guns were damaged and shell fragments would have inflicted casualties among gun crews. The French determined that an excessive amount of ammunition was required to neutralize the guns, and had the fortification been returning fire, both ships likely would have been seriously damaged. Amiral Duperré suffered an accidental explosion in one of her magazines on 13 May after the compartment became overheated from the adjacent boiler room. Only one shell detonated and the resulting fire was quickly suppressed by the crew.[18][19] By that year, Amiral Duperré had been reduced to the Reserve Squadron of the Mediterranean Fleet, along with the ironclad Richelieu and three of the Terrible-class ironclads. She served as its flagship through 1896.[20][21]

Amiral Duperré later in her career

She remained in the Reserve Squadron in 1898, by which time the French Navy had begun rebuilding several of its older ironclads. As a result, the only other members of the unit were Indomptable and Dévastation.[22] She took part in the fleet maneuvers the following year, which lasted from 5 to 25 July. She served as the flagship of Rear Admiral Godin during the maneuvers.[23] Later that year, she was transferred to the Northern Squadron in the English Channel, along with the two Amiral Baudins, Dévastation, Courbet, and Redoutable, since more modern pre-dreadnought battleships built in the mid-1890s had entered service by that time.[24]

Two of these new battleships—Carnot and Masséna—joined Amiral Duperré in the Northern Squadron in 1900, which at that time also included Formidable, Redoutable, and Amiral Baudin.[25] In June and July that year, she participated in extensive joint maneuvers conducted with the Mediterranean Fleet. The Northern Squadron initially held its own maneuvers in Brest, which included a simulated blockade of the squadron in Brest, after which the squadron made mock attacks on the island of Belle Île and nearby Quiberon. In early July, the squadron met the Mediterranean Squadron off Lisbon, Portugal before the two units steamed north to Quiberon Bay and entered Brest on 9 July. Amiral Duperré and the rest of the Northern Squadron were tasked with attacking Cherbourg two days later. The maneuvers concluded with a naval review in Cherbourg on 19 July for President Émile Loubet.[26] While at sea for gunnery practice on 14 December, her starboard forward gun broke free in inclement weather and swung around, striking the bridge and causing significant damage to it and the fore mast. No crewmen were injured in the accident.[27]

Amiral Duperré remained in the unit through early 1901,[28] but she was withdrawn from service later that year to be reconstructed.[29] The work proceeded slowly, and as late as 1905, additional funds had been included in the year's budget to complete the installation of new boilers.[30] Despite the refit, Amiral Duperré saw no further service. By that time, more pre-dreadnoughts had been built, displacing those that had been built in the 1890s to the Northern and Reserve Divisions.[31][32][33] She was struck from the naval register in 1909,[4] and was broken up for scrap at some point thereafter.[34]