Océan class ironclad
Encyclopedia
The Océan class
ironclads were a group of three wooden-hulled armored frigate
s built for the French Navy
in the mid to late 1860s. attempted to blockade Prussia
n ports in the Baltic Sea
in 1870 during the Franco-Prussian War
. participated in the French occupation of Tunisia
in 1881. was often used as the flagship
for the squadron she was assigned to. She was flagship of the Cherbourg Division, the Channel Division, Mediterranean Squadron and the Northern Squadron during her career. The ships were discarded during the 1890s.
as a improved version of the s. The ships were central battery ironclads with the armament concentrated amidships. For the first time in a French ironclad three watertight iron bulkhead
s were fitted in the hull. Like most ironclads of their era they were equipped with a metal-reinforced ram
.
The ships measured 87.73 metre overall, with a beam
of 17.52 metre. They had a maximum draft of 9.09 metre and displaced 7749 tonnes (7,626.6 LT). Their crew numbered between 750 and 778 officers and men. The metacentric height
of the ships was very low, between 1.7–2.2 ft (0.51816–0.67056 m).
. Their engines were powered by eight oval boiler
s. On sea trial
s the engines produced between 3600 ihp and the ships reached 13.5 knot. They carried 650 metric tons (639.7 LT) of coal which allowed them to steam for approximately 3000 nautical miles (5,556 km) at a speed of 10 knots (5.4 m/s). The Océan-class ships were barque
or barquentine
-rigged with three masts and had a sail area around 2000 sqm.
s on the upper deck, one gun at each corner of the battery, with the remaining guns on the battery deck below the barbettes. The original armament consisted of four 240 millimetres (9.4 in) guns in the barbettes, and on the battery deck, four 194 millimetres (7.6 in) and four 164 millimetres (6.5 in) guns. This was upgraded in Océan to four 274 millimetres (10.8 in) guns in the barbettes and eight 240 millimetres (9.4 in) on the battery deck before she was commissioned. The two later ships, Marengo and Suffren, were armed with 274-millimeter guns in the barbettes, and four 240-millimeter guns and seven 138 millimetres (5.4 in) on the battery deck.
The 18-caliber
274-millimeter Modéle 1870 gun fired an armor-piercing
, 476.2 pounds (216 kg) shell while the gun itself weighed 22.84 long tons (23.2 t). The gun fired its shell at a muzzle velocity
of 1424 ft/s (434 m/s) and was credited with the ability to penetrate a nominal 14.3 inches (36.3 cm) of wrought iron
armour at the muzzle. The armor-piercing shell of the 19-caliber 240-millmeter Modele 1870 gun weighed 317.5 pounds (144 kg) while the gun itself weighed 15.41 long tons (15.7 t). It had a muzzle velocity
of 1624 ft/s (495 m/s) and was credited with the ability to penetrate a nominal 14.4 inches (366 mm) of wrought iron
armour at the muzzle. The 138-millimeter gun was 21 calibers long and weighed 2.63 long tons (2.7 t). It fired a 61.7 pounds (28 kg) explosive shell
that had a muzzle velocity of 1529 ft/s (466 m/s). The guns could fire both solid shot
and explosive shells.
By 1885 all of the 138-millimeter guns were replaced by four or six 120 millimetres (4.7 in) guns. At some point the ships received a dozen 37 millimetres (1.5 in) Hotchkiss 5-barrel revolving guns
. They fired a shell weighing about 500 g (1.1 lb) at a muzzle velocity of about 610 m/s (2,001.3 ft/s) to a range of about 3200 metres (3,499.6 yd). They had a rate of fire of about 30 rounds per minute. The hull was not recessed to enable any of the guns on the battery deck to fire forward or aft. However, the guns mounted in the barbettes sponson
ed out over the sides of the hull did have some ability to fire fore and aft. Late in the ships' careers four above-water 356 millimetres (14 in) torpedo tube
s were added.
of wrought iron
. The sides of the battery itself were armored with 160 millimetres (6.3 in) of wrought iron. The barbette armor was 150 millimetres (5.9 in) thick. The unarmored portions of their sides were protected by 15 millimetre (0.590551181102362 in) iron plates. Gardiner says that the barbette armor was later removed to improve their stability, but this is not confirmed by any other source.
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. 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 on 13 February 1881 and bombarded the Tunisian port of Sfax
in July 1881 as part of the French occupation 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.
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 Ragusa
later that month under the command of Vice Admiral
Seymour
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
. 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.
Ship class
A ship class is a group of ships of a similar design. This is distinct from a ship-type, which might reflect a similarity of tonnage or intended use. For example, the is a nuclear aircraft carrier of the Nimitz class....
ironclads were a group of three wooden-hulled armored frigate
Frigate
A frigate is any of several types of warship, the term having been used for ships of various sizes and roles over the last few centuries.In the 17th century, the term was used for any warship built for speed and maneuverability, the description often used being "frigate-built"...
s built for the French Navy
French Navy
The French Navy, officially the Marine nationale and often called La Royale is the maritime arm of the French military. It includes a full range of fighting vessels, from patrol boats to a nuclear powered aircraft carrier and 10 nuclear-powered submarines, four of which are capable of launching...
in the mid to late 1860s. attempted to blockade Prussia
Prussia
Prussia was a German kingdom and historic state originating out of the Duchy of Prussia and the Margraviate of Brandenburg. For centuries, the House of Hohenzollern ruled Prussia, successfully expanding its size by way of an unusually well-organized and effective army. Prussia shaped the history...
n ports in the Baltic Sea
Baltic Sea
The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...
in 1870 during the Franco-Prussian War
Franco-Prussian War
The Franco-Prussian War or Franco-German War, often referred to in France as the 1870 War was a conflict between the Second French Empire and the Kingdom of Prussia. Prussia was aided by the North German Confederation, of which it was a member, and the South German states of Baden, Württemberg and...
. participated in the French occupation of Tunisia
French occupation of Tunisia
The French conquest of Tunisia occurred in two phases in 1881: the first consisting of the invasion and securing of the country before the signing of a treaty of protection, and the second consisting in the suppression of a rebellion...
in 1881. was often used as the flagship
Flagship
A flagship is a vessel used by the commanding officer of a group of naval ships, reflecting the custom of its commander, characteristically a flag officer, flying a distinguishing flag...
for the squadron she was assigned to. She was flagship of 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 ironclads were designed by Henri Dupuy de LômeHenri Dupuy de Lôme
Stanislas Charles Henri Dupuy de Lôme was a French naval architect. He was the son of a naval officer and was born in Ploemeur near Lorient, Brittany, in western France. He was educated at the École Polytechnique...
as a improved version of the s. The ships were central battery ironclads with the armament concentrated amidships. For the first time in a French ironclad three watertight iron bulkhead
Bulkhead (partition)
A bulkhead is an upright wall within the hull of a ship or within the fuselage of an airplane. Other kinds of partition elements within a ship are decks and deckheads.-Etymology:...
s were fitted in the hull. Like most ironclads of their era they were equipped with a metal-reinforced ram
Naval ram
A naval ram was a weapon carried by varied types of ships, dating back to antiquity. The weapon consisted of an underwater prolongation of the bow of the ship to form an armoured beak, usually between six and twelve feet in length...
.
The ships measured 87.73 metre overall, with a beam
Beam (nautical)
The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...
of 17.52 metre. They had a maximum draft of 9.09 metre and displaced 7749 tonnes (7,626.6 LT). Their crew numbered between 750 and 778 officers and men. The metacentric height
Metacentric height
The metacentric height is a measurement of the static stability of a floating body. It is calculated as the distance between the centre of gravity of a ship and its metacentre . A larger metacentric height implies greater stability against overturning...
of the ships was very low, between 1.7–2.2 ft (0.51816–0.67056 m).
Propulsion
The Océan-class ships had one horizontal return connecting rod compound steam engine driving a single propellerPropeller
A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and a fluid is accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's...
. Their engines were powered by eight oval boiler
Boiler (steam generator)
A boiler or steam generator is a device used to create steam by applying heat energy to water. Although the definitions are somewhat flexible, it can be said that older steam generators were commonly termed boilers and worked at low to medium pressure but, at pressures above this, it is more...
s. On sea trial
Sea trial
A sea trial is the testing phase of a watercraft . It is also referred to as a "shakedown cruise" by many naval personnel. It is usually the last phase of construction and takes place on open water, and can last from a few hours to many days.Sea trials are conducted to measure a vessel’s...
s the engines produced between 3600 ihp and the ships reached 13.5 knot. They carried 650 metric tons (639.7 LT) of coal which allowed them to steam for approximately 3000 nautical miles (5,556 km) at a speed of 10 knots (5.4 m/s). The Océan-class ships were barque
Barque
A barque, barc, or bark is a type of sailing vessel with three or more masts.- History of the term :The word barque appears to have come from the Greek word baris, a term for an Egyptian boat. This entered Latin as barca, which gave rise to the Italian barca, Spanish barco, and the French barge and...
or barquentine
Barquentine
A barquentine is a sailing vessel with three or more masts; with a square rigged foremast and fore-and-aft rigged main, mizzen and any other masts.-Modern barquentine sailing rig:...
-rigged with three masts and had a sail area around 2000 sqm.
Armament
These ships had their main armament mounted in four barbetteBarbette
A barbette is a protective circular armour feature around a cannon or heavy artillery gun. The name comes from the French phrase en barbette referring to the practice of firing a field gun over a parapet rather than through an opening . The former gives better angles of fire but less protection...
s on the upper deck, one gun at each corner of the battery, with the remaining guns on the battery deck below the barbettes. The original armament consisted of four 240 millimetres (9.4 in) guns in the barbettes, and on the battery deck, four 194 millimetres (7.6 in) and four 164 millimetres (6.5 in) guns. This was upgraded in Océan to four 274 millimetres (10.8 in) guns in the barbettes and eight 240 millimetres (9.4 in) on the battery deck before she was commissioned. The two later ships, Marengo and Suffren, were armed with 274-millimeter guns in the barbettes, and four 240-millimeter guns and seven 138 millimetres (5.4 in) on the battery deck.
The 18-caliber
Caliber (artillery)
In artillery, caliber or calibredifference in British English and American English spelling is the internal diameter of a gun barrel, or by extension a relative measure of the length....
274-millimeter Modéle 1870 gun fired an armor-piercing
Armor-piercing shot and shell
An armor-piercing shell is a type of ammunition designed to penetrate armor. From the 1860s to 1950s, a major application of armor-piercing projectiles was to defeat the thick armor carried on many warships. From the 1920s onwards, armor-piercing weapons were required for anti-tank missions...
, 476.2 pounds (216 kg) shell while the gun itself weighed 22.84 long tons (23.2 t). The gun fired its shell at a muzzle velocity
Muzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...
of 1424 ft/s (434 m/s) and was credited with the ability to penetrate a nominal 14.3 inches (36.3 cm) of wrought iron
Wrought iron
thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...
armour at the muzzle. The armor-piercing shell of the 19-caliber 240-millmeter Modele 1870 gun weighed 317.5 pounds (144 kg) while the gun itself weighed 15.41 long tons (15.7 t). It had a muzzle velocity
Muzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...
of 1624 ft/s (495 m/s) and was credited with the ability to penetrate a nominal 14.4 inches (366 mm) of wrought iron
Wrought iron
thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...
armour at the muzzle. The 138-millimeter gun was 21 calibers long and weighed 2.63 long tons (2.7 t). It fired a 61.7 pounds (28 kg) explosive shell
Shell (projectile)
A shell is a payload-carrying projectile, which, as opposed to shot, contains an explosive or other filling, though modern usage sometimes includes large solid projectiles properly termed shot . Solid shot may contain a pyrotechnic compound if a tracer or spotting charge is used...
that had a muzzle velocity of 1529 ft/s (466 m/s). The guns could fire both solid shot
Round shot
Round shot is a solid projectile without explosive charge, fired from a cannon. As the name implies, round shot is spherical; its diameter is slightly less than the bore of the gun it is fired from.Round shot was made in early times from dressed stone, but by the 17th century, from iron...
and explosive shells.
By 1885 all of the 138-millimeter guns were replaced by four or six 120 millimetres (4.7 in) guns. At some point the ships received a dozen 37 millimetres (1.5 in) Hotchkiss 5-barrel revolving guns
Hotchkiss gun
The Hotchkiss gun can refer to different products of the Hotchkiss arms company starting in the late 19th century. It usually refers to the 1.65-inch light mountain gun; there was also a 3-inch Hotchkiss gun...
. They fired a shell weighing about 500 g (1.1 lb) at a muzzle velocity of about 610 m/s (2,001.3 ft/s) to a range of about 3200 metres (3,499.6 yd). They had a rate of fire of about 30 rounds per minute. The hull was not recessed to enable any of the guns on the battery deck to fire forward or aft. However, the guns mounted in the barbettes sponson
Sponson
Sponsons are projections from the sides of a watercraft, for protection, stability, or the mounting of equipment such as armaments or lifeboats, etc...
ed out over the sides of the hull did have some ability to fire fore and aft. Late in the ships' careers four above-water 356 millimetres (14 in) torpedo tube
Torpedo tube
A torpedo tube is a device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units installed aboard surface vessels...
s were added.
Armor
The Ocean-class ships had a complete 178–203 mm (7–8 in) waterline beltBelt armor
Belt armor is a layer of heavy metal armor plated on to or within outer hulls of warships, typically on battleships, battlecruisers and cruisers, and on aircraft carriers converted from those types of ships....
of wrought iron
Wrought iron
thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...
. The sides of the battery itself were armored with 160 millimetres (6.3 in) of wrought iron. The barbette armor was 150 millimetres (5.9 in) thick. The unarmored portions of their sides were protected by 15 millimetre (0.590551181102362 in) iron plates. Gardiner says that the barbette armor was later removed to improve their stability, but this is not confirmed by any other source.
Construction
| Ship | Builder | Laid down | Launched | Commissioned | Fate |
|---|---|---|---|---|---|
| Arsenal de Brest Brest, France Brest is a city in the Finistère department in Brittany in northwestern France. Located in a sheltered position not far from the western tip of the Breton peninsula, and the western extremity of metropolitan France, Brest is an important harbour and the second French military port after Toulon... |
July 1865 | 15 October 1868 | 21 July 1870 | Condemned 1894 | |
| Arsenal de Toulon Toulon Toulon is a town in southern France and a large military harbor on the Mediterranean coast, with a major French naval base. Located in the Provence-Alpes-Côte-d'Azur region, Toulon is the capital of the Var department in the former province of Provence.... |
July 1865 | 4 December 1869 | 1872 | Condemned 1896 | |
| Arsenal de Cherbourg | July 1866 | 26 December 1872 | 1 March 1876 | Condemned 1897 |
Service
During the Franco-Prussian WarFranco-Prussian War
The Franco-Prussian War or Franco-German War, often referred to in France as the 1870 War was a conflict between the Second French Empire and the Kingdom of Prussia. Prussia was aided by the North German Confederation, of which it was a member, and the South German states of Baden, Württemberg and...
of 1870–71 Océan was assigned to the Northern Squadron that attempted to blockade
Blockade
A blockade is an effort to cut off food, supplies, war material or communications from a particular area by force, either in part or totally. A blockade should not be confused with an embargo or sanctions, which are legal barriers to trade, and is distinct from a siege in that a blockade is usually...
Prussian ports on the Baltic until recalled on 16 September 1870 and ordered to return to Cherbourg. 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 on 13 February 1881 and bombarded the Tunisian port of Sfax
Sfax
Sfax is a city in Tunisia, located southeast of Tunis. The city, founded in AD 849 on the ruins of Taparura and Thaenae, is the capital of the Sfax Governorate , and a Mediterranean port. Sfax has population of 340,000...
in July 1881 as part of the French occupation 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
Kronstadt
Kronstadt , also spelled Kronshtadt, Cronstadt |crown]]" and Stadt for "city"); is a municipal town in Kronshtadtsky District of the federal city of St. Petersburg, Russia, located on Kotlin Island, west of Saint Petersburg proper near the head of the Gulf of Finland. Population: It is also...
in 1891. She was reduced to reserve the following year and sold in 1896.
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 Ragusa
Dubrovnik
Dubrovnik is a Croatian city on the Adriatic Sea coast, positioned at the terminal end of the Isthmus of Dubrovnik. It is one of the most prominent tourist destinations on the Adriatic, a seaport and the centre of Dubrovnik-Neretva county. Its total population is 42,641...
later that month under the command of Vice Admiral
Vice Admiral
Vice admiral is a senior naval rank of a three-star flag officer, which is equivalent to lieutenant general in the other uniformed services. A vice admiral is typically senior to a rear admiral and junior to an admiral...
Seymour
Beauchamp Seymour, 1st Baron Alcester
Admiral Frederick Beauchamp Paget Seymour, 1st Baron Alcester, GCB was a British naval commander. He was Commander-in-Chief of the Channel Fleet between 1874 and 1877 and of the Mediterranean Fleet between 1880 and 1883....
of the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
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
Ulcinj
Ulcinj is a coastal resort town and municipality in Montenegro. The town of Ulcinj has a population of 10,828 of which the majority are Albanians...
to Montenegro
Montenegro
Montenegro Montenegrin: Crna Gora Црна Гора , meaning "Black Mountain") is a country located in Southeastern Europe. It has a coast on the Adriatic Sea to the south-west and is bordered by Croatia to the west, Bosnia and Herzegovina to the northwest, Serbia to the northeast and Albania to the...
. 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.