The ''Océan''-class ironclads were a class of three wooden-hulled armored
frigate
A frigate () is a type of warship. In different eras, the roles and capabilities of ships classified as frigates have varied somewhat.
The name frigate in the 17th to early 18th centuries was given to any full-rigged ship built for speed and ...
flagship
A flagship is a vessel used by the commanding officer of a group of naval ships, characteristically a flag officer entitled by custom to fly a distinguishing flag. Used more loosely, it is the lead ship in a fleet of vessels, typically the fi ...
for the Cherbourg Division, the Channel Division, Mediterranean Squadron and the Northern Squadron during her career. The ships were discarded during the 1890s.
Design and description
The ''Océan''-class
ironclad
An ironclad is a steam engine, steam-propelled warship protected by Wrought iron, iron or steel iron armor, armor plates, constructed from 1859 to the early 1890s. The ironclad was developed as a result of the vulnerability of wooden warships ...
s were designed by Henri Dupuy de Lôme as an improved version of the s. The ships were central battery ironclads with the armament concentrated amidships.de Balincourt and Vincent-Bréchignac 1975, p. 26 For the first time in a French ironclad three watertight iron bulkheads were fitted in the hull. Like most ironclads of their era they were equipped with a metal-reinforced ram.Campbell, p. 288
The ships measured overall, 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 grou ...
of . They had a maximum draft of and displaced . Their crew numbered between 750 and 778 officers and men. The metacentric height of the ships was very low, between . The ships were over-weight as completed; their draught so exceeded that designed for them that an increase of stability by ballast was impossible. The ''Océan''-class were reported to be able to carry all sail safely, were good sea-boats, steady and well-behaved, but lacking in stiffness (resistance to heeling).
propeller
A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...
using steam provided by eight oval boilers. On sea trials the engines produced between and the ships reached . They carried of coal which allowed them to steam for approximately at a speed of . The ''Océan''-class ships were barque or barquentine-rigged with three masts and had a sail area around .
Armament
The initial design was to have a main armament of four guns and four guns on the main deck in an armoured central battery, and four guns in open-topped armoured barbettes on the spar deck. In 1869, the armament was changed to four 24 cm guns in barbettes and either six or eight 24 cm guns in the battery, which was then changed to four 24 cm guns in barbettes and four cm guns in the battery, The ship's sides were not recessed, so the main deck guns could not fire fore or aft. But the barbettes were slightly sponsoned out over the sides of the hull. If the barbette guns were fired at angles smaller than 45 degrees from the keel-line, the crew had to be withdrawn from the extremities of the ship; for practical purposes, the arc of fire of each barbette was about 100 degrees. The main deck battery was above the waterline and the spar deck and barbette guns were above the waterline. The barbettes had steam-powered turntables.
They also had a secondary armament mounted on the broadside on the spar deck of six guns, the rear pair could be moved to the stern to fire aft.
The 18-
caliber
In guns, particularly firearms, caliber (or calibre; sometimes abbreviated as "cal") is the specified nominal internal diameter of the gun barrel Gauge (firearms) , bore – regardless of how or where the bore is measured and whether the f ...
27 cm Modéle 1870 gun had a caliber of 274 millimeters and fired an armor-piercing, shell while the gun itself weighed . The gun fired its shell at a
muzzle velocity
Muzzle velocity is the speed of a projectile (bullet, pellet, slug, ball/shots or shell) with respect to the muzzle at the moment it leaves the end of a gun's barrel (i.e. the muzzle). Firearm muzzle velocities range from approximately to i ...
of and was credited with the ability to penetrate a nominal of wrought iron armour at the muzzle. The armor-piercing shell of the 19-caliber 24 cm Modele 1870 gun had a caliber of 240 millimeters weighed while the gun itself weighed . It had a
muzzle velocity
Muzzle velocity is the speed of a projectile (bullet, pellet, slug, ball/shots or shell) with respect to the muzzle at the moment it leaves the end of a gun's barrel (i.e. the muzzle). Firearm muzzle velocities range from approximately to i ...
of and was credited with the ability to penetrate a nominal of wrought iron armour at the muzzle. The 138-millimeter gun was 21 calibers long and weighed . It fired a explosive shell that had a muzzle velocity of . The guns could fire both solid shot and explosive shells.
By 1885 all of the 138-millimeter guns were replaced by four or six guns.Silverstone, p. 62 At some point the ships received a dozen Hotchkiss 5-barrel revolving guns. They fired a shell weighing about at a muzzle velocity of about to a range of about . They had a rate of fire of about 30 rounds per minute. Late in the ships' careers four above-water torpedo tubes were added.
Armor
The ''Ocean''-class ships had a complete waterline belt of wrought iron. The sides of the battery itself were armored with of wrought iron. The barbette armor was thick. The unarmored portions of their sides were protected by iron plates. Gardiner and Gibbons say that the barbette armor was later removed to improve their stability, but this is not confirmed by any other source.
File:French Ironclad Ocean plan view.png, Armour and armament distribution on the ''Océan'' class
File:French Ironclad Ocean barbette (without explanation).png, Barbette of the ''Océan'' class A Upper deck a Backing B Barbette b Inner skin C Pivot hollow for supply of ammunition D Ring revolving on pivot E Rollers G Slide and carriage I Platform for working gun K Toothed rack L, M, N, O Turning gear
File:French Ironclad Ocean hull section.png, Section through the hull of French ''Ocean''-class ironclad showing side armour and decks
File:Marengo (1869) Marius Bar.jpg, ''Marengo'' on 26 May 1888
File:Suffren (1873).jpg, ''Suffren'' circa 1875
Ships
Initial cost
The American, Chief Engineer
James Wilson King
James Wilson King (1818 – June 6, 1905) Thomas Brassey gave the cost of the ''Marengo'' as £280,000, and the ''Suffren'' as £260,400.
Service
During the Franco-Prussian War of 1870–71 ''Océan'' was assigned to the Northern Squadron that attempted to blockade Prussian ports on the Baltic until recalled on 16 September 1870 and ordered to return to Cherbourg.de Balincourt and Vincent-Bréchignac 1975, p. 30 Afterward she was assigned to the Evolutionary Squadron until 1875 when she was placed in reserve. ''Océan'' was recommissioned in 1879 for service with the Mediterranean Squadron. She had a lengthy refit in 1884–85 and was assigned to the Northern Squadron after it was completed. Around 1888 the ship was transferred back to the Mediterranean Squadron until she was reduced to reserve around 1891. ''Océan'' was assigned to the Gunnery School that same year and later became a training ship for naval apprentices before being condemned in 1894.
''Marengo'' was running her sea trials when the Franco-Prussian War began and was immediately put in reserve. She was recommissioned in 1872 for service with the Mediterranean Squadron until 1876 when she was again placed in reserve. On 2 October 1880 the ship was recommissioned and assigned to the Mediterranean Squadron. ''Marengo'' was transferred to the Levant Squadron (french: Division Navale du Levant) on 13 February 1881 and bombarded the Tunisian port of Sfax in July 1881 as part of the French conquest of Tunisia. She remained in the Mediterranean until she was assigned to the Reserve Squadron in 1886. In 1888 ''Marengo'' became the flagship of the Northern Squadron and led the squadron during its port visit to Kronstadt in 1891. She was reduced to reserve the following year and sold in 1896.de Balincourt and Vincent-Bréchignac 1975, pp. 26–27
''Suffren'' was placed into reserve after she completed her sea trials and was not commissioned until 1 March 1876 when she became flagship of the Cherbourg Division. Throughout her career the ship was often used as a flagship because of her spacious admiral's quarters. On 1 September 1880 the ship was assigned to the division that participated in the international naval demonstration at
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later that month under the command of Vice Admiral
Seymour
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...
of the Royal Navy in an attempt to force the Ottoman Empire to comply with the terms of the Treaty of Berlin and turn over the town of Ulcinj to Montenegro.McCarthy, pp. 56–58 ''Suffren'' was reduced to reserve in 1881 and not recommissioned until 23 August 1884 when she was assigned to the Northern Squadron. The ship was transferred to the Mediterranean Squadron about 1888 and remained there until paid off in 1895 and condemned in 1897.