Alma class ironclad
Encyclopedia
The Alma class ironclads were a group of seven wooden-hulled, armored corvette
s built for the French Navy
in the mid to late 1860s. Three of the ships attempted to blockade Prussia
n ports in the Baltic Sea
in 1870 during the Franco-Prussian War
. Three others patrolled the North Sea
and the Atlantic, while the last ship was enroute to Japan
when the war began and blockaded two small Prussian ships in a Japanese harbor. Afterwards they alternated periods of reserve and active commissions, many of them abroad. Three of the ships participated in the French occupation of Tunisia
in 1881 while another helped to intimidate the Vietnam
ese Government into accepting status as a French protectorate
and played a small role in the Sino-French War
of 1884–85.
as improved versions of the armored corvette suitable for foreign deployments. Unlike their predecessor the ships were true central battery ironclads as they were fitted with armored transverse bulkhead
s. The original plan for these ships was to have a two-deck battery with four 194 millimetres (7.6 in) guns on the battery deck and four 164 millimetres (6.5 in) guns mounted above them on the upper deck, one gun at each corner of the battery. This design was changed to substitute four barbette
s for the upper battery, but the addition of armored bulkheads proved to be very heavy and the rear pair of barbettes had to be deleted to save weight. In partial compensation the 164-millimeter guns in the barbettes were replaced by an additional pair of 194-millimeter guns. Like most ironclads of their era they were equipped with a metal-reinforced ram
.
The ships were built from the same general plan, but differed amongst themselves. They measured 68.75–69.03 m (225.6–226.5 ft) between perpendiculars, with a beam
of 13.94–14.13 m (45.7–46.4 ft). The ships had a mean draft of 6.26–6.66 m (20.5–21.9 ft) and displaced 3569–3889 t (3,512.6–3,827.6 LT). Their crew numbered 316 officers and men.
s. On sea trial
s the engine produced between 1585 ihp and the ships reached 10.48 knot. Unlike the single funnels of the others, and had two funnels, mounted side-by-side. The ships carried 250 metric tons (246.1 LT) of coal which allowed the ship to steam for 1310–1620 nmi (2,426.1–3,000.2 ) at a speed of 10 knots (5.4 m/s). They were barque
-rigged with three masts and had a sail area between 1338 sqm.
ed out over the sides of the ship. The four 120 millimetres (4.7 in) guns were also mounted on the upper deck. is the only ship positively known to have exchanged her 194 mm guns for newer Modèle 1870 guns. The armor-piercing
shell of the 20-caliber
Mle 1870 gun weighed 165.3 pounds (75 kg) while the gun itself weighed 7.83 long tons (8 t). The gun fired its shell at a muzzle velocity
of 1739 ft/s (530 m/s) and was credited with the ability to penetrate a nominal 12.5 inches (31.8 cm) of wrought iron
armour at the muzzle. The guns could fire both solid shot
and explosive shells
.
waterline belt
, approximately 2.4 metres (7.9 ft) high. The sides of the battery itself were armored with 120 millimetres (4.7 in) of wrought iron and the ends of the battery were closed by bulkheads of the same thickness. The barbette armor was 100 millimetres (3.9 in) thick, backed by 240 millimetres (9.4 in) of wood. The unarmored portions of their sides were protected by 15 millimetre (0.590551181102362 in) iron plates.
of 1870–71 Thétis, Jeanne d'Arc and Armide were assigned to the Northern Squadron that attempted to blockade
Prussian ports on the Baltic until ordered to return to Cherbourg on 16 September 1870. Montcalm, Atalante, and Reine Blanche cruised the North Sea
and Montcalm later watched a Prussian corvette in Portuguese waters. Alma was enroute to the Far East
when the war began and she blockaded a pair of Prussian corvettes in Yokohama
harbor once she arrived at Japan
.
After the end of the war many of the ships were placed in reserve or sent to foreign stations, often as the flagship. During the Third Carlist War
of 1872–76 Thétis, Reine Blanche and Jeanne d'Arc spent time in Spanish waters where they could protect French citizens and interests. In 1875 the latter ship rammed and sank the dispatch vessel Forfait. On 3 July 1877 Thétis rammed Reine Blanche who had to be run ashore to prevent her from sinking.
Further abroad Reine Blanche and Alma bombarded the Tunisian port of Sfax
in July 1881 as part of the French occupation of Tunisia. Atalante participated in the Battle of Thuan An
in August 1883. This was an attack by the French on the forts defending the mouth of the Perfume River
, leading to the Vietnam
ese capital of Huế
in an attempt to intimidate the Vietnamese government. During the Sino-French War of 1884–85 the ship was in Huế in early September 1884, but she carried Admiral Amédée Courbet
to Keelung
, Taiwan
on 23 September.
Corvette
A corvette is a small, maneuverable, lightly armed warship, originally smaller than a frigate and larger than a coastal patrol craft or fast attack craft , although many recent designs resemble frigates in size and role...
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. Three of the ships 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...
. Three others patrolled the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
and the Atlantic, while the last ship was enroute to Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
when the war began and blockaded two small Prussian ships in a Japanese harbor. Afterwards they alternated periods of reserve and active commissions, many of them abroad. Three of the ships 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 while another helped to intimidate the Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...
ese Government into accepting status as a French protectorate
Protectorate
In history, the term protectorate has two different meanings. In its earliest inception, which has been adopted by modern international law, it is an autonomous territory that is protected diplomatically or militarily against third parties by a stronger state or entity...
and played a small role in the Sino-French War
Sino-French War
The Sino–French War was a limited conflict fought between August 1884 and April 1885 to decide whether France should replace China in control of Tonkin . As the French achieved their war aims, they are usually considered to have won the war...
of 1884–85.
Design and description
The Alma-class ironcladsIronclad is the all-encompassing term for armored warships of this period. Armored corvettes were originally designed for the same role as traditional wooden corvettes, but this rapidly changed as the size and expense of these ships caused them to be used as second-class armored ships. 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 improved versions of the armored corvette suitable for foreign deployments. Unlike their predecessor the ships were true central battery ironclads as they were fitted with armored transverse 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. The original plan for these ships was to have a two-deck battery with four 194 millimetres (7.6 in) guns on the battery deck and four 164 millimetres (6.5 in) guns mounted above them on the upper deck, one gun at each corner of the battery. This design was changed to substitute four barbette
Barbette
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 for the upper battery, but the addition of armored bulkheads proved to be very heavy and the rear pair of barbettes had to be deleted to save weight. In partial compensation the 164-millimeter guns in the barbettes were replaced by an additional pair of 194-millimeter guns. 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 were built from the same general plan, but differed amongst themselves. They measured 68.75–69.03 m (225.6–226.5 ft) between perpendiculars, 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 13.94–14.13 m (45.7–46.4 ft). The ships had a mean draft of 6.26–6.66 m (20.5–21.9 ft) and displaced 3569–3889 t (3,512.6–3,827.6 LT). Their crew numbered 316 officers and men.
Propulsion
The Alma-class ships had a single horizontal return connecting-rod steam engine driving a single propeller. Their engine was powered by four oval boilerBoiler (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 engine produced between 1585 ihp and the ships reached 10.48 knot. Unlike the single funnels of the others, and had two funnels, mounted side-by-side. The ships carried 250 metric tons (246.1 LT) of coal which allowed the ship to steam for 1310–1620 nmi (2,426.1–3,000.2 ) at a speed of 10 knots (5.4 m/s). They 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...
-rigged with three masts and had a sail area between 1338 sqm.
Armament
The ships mounted four of their 194-millimeter Modèle 1864 breech-loading guns in the central battery on the battery deck. The other two 194-millimeter guns were mounted in barbettes on the upper deck, sponsonSponson
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 ship. The four 120 millimetres (4.7 in) guns were also mounted on the upper deck. is the only ship positively known to have exchanged her 194 mm guns for newer Modèle 1870 guns. The 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...
shell of the 20-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....
Mle 1870 gun weighed 165.3 pounds (75 kg) while the gun itself weighed 7.83 long tons (8 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 1739 ft/s (530 m/s) and was credited with the ability to penetrate a nominal 12.5 inches (31.8 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 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
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...
.
Armor
The Alma-class ships had a complete 150 millimetres (5.9 in) wrought ironWrought 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...
waterline belt
Belt 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....
, approximately 2.4 metres (7.9 ft) high. The sides of the battery itself were armored with 120 millimetres (4.7 in) of wrought iron and the ends of the battery were closed by bulkheads of the same thickness. The barbette armor was 100 millimetres (3.9 in) thick, backed by 240 millimetres (9.4 in) of wood. The unarmored portions of their sides were protected by 15 millimetre (0.590551181102362 in) iron plates.
Construction
| Ship | Builder | Laid down | Launched | Commissioned | Fate |
|---|---|---|---|---|---|
| Lorient Lorient Lorient, or L'Orient, is a commune and a seaport in the Morbihan department in Brittany in north-western France.-History:At the beginning of the 17th century, merchants who were trading with India had established warehouses in Port-Louis... |
1 October 1865 | 26 November 1867 | 1870 | Sold May 1893 | |
| Rochefort Rochefort, Charente-Maritime Rochefort is a commune in southwestern France, a port on the Charente estuary. It is a sub-prefecture of the Charente-Maritime department.-History:... |
1865 | 12 April 1867 | 1868 | Used in gunnery trials 1886 | |
| Cherbourg | June 1865 | 9 April 1868 | 1869 | Condemned 1887 in Saigon | |
| Cherbourg | 1865 | 28 September 1867 | 1869 | Condemned 28 August 1883 | |
| Rochefort | 26 October 1865 | 16 October 1868 | 1869 | Condemned 2 April 1891 | |
| Lorient | 1865 | 10 March 1868 | 1869 | Condemned 12 November 1884 | |
| 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.... |
1865 | 22 August 1867 | 1868 | Hulk Hulk (ship) A hulk is a ship that is afloat, but incapable of going to sea. Although sometimes used to describe a ship that has been launched but not completed, the term most often refers to an old ship that has had its rigging or internal equipment removed, retaining only its flotational qualities... ed after 1885 |
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 Thétis, Jeanne d'Arc and Armide were 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 ordered to return to Cherbourg on 16 September 1870. Montcalm, Atalante, and Reine Blanche cruised the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
and Montcalm later watched a Prussian corvette in Portuguese waters. Alma was enroute to the Far East
Far East
The Far East is an English term mostly describing East Asia and Southeast Asia, with South Asia sometimes also included for economic and cultural reasons.The term came into use in European geopolitical discourse in the 19th century,...
when the war began and she blockaded a pair of Prussian corvettes in Yokohama
Yokohama
is the capital city of Kanagawa Prefecture and the second largest city in Japan by population after Tokyo and most populous municipality of Japan. It lies on Tokyo Bay, south of Tokyo, in the Kantō region of the main island of Honshu...
harbor once she arrived at Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
.
After the end of the war many of the ships were placed in reserve or sent to foreign stations, often as the flagship. During the Third Carlist War
Third Carlist War
The Third Carlist War was the last Carlist War in Spain. It is very often referred to as the Second Carlist War, as the 'second' had been small in scale and almost trivial in political consequence....
of 1872–76 Thétis, Reine Blanche and Jeanne d'Arc spent time in Spanish waters where they could protect French citizens and interests. In 1875 the latter ship rammed and sank the dispatch vessel Forfait. On 3 July 1877 Thétis rammed Reine Blanche who had to be run ashore to prevent her from sinking.
Further abroad Reine Blanche and Alma 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. Atalante participated in the Battle of Thuan An
Battle of Thuan An
The Battle of Thuan An was a clash between the French and the Vietnamese during the period of early hostilities of the Tonkin Campaign...
in August 1883. This was an attack by the French on the forts defending the mouth of the Perfume River
Perfume River
The Perfume River is a river that crosses the city of Huế, in the central Vietnamese province of Thừa Thiên Huế.-Etymology:In the autumn, flowers from orchards upriver from Huế fall into the water, giving the river a perfume-like aroma....
, leading to the Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...
ese capital of Huế
Hue
Hue is one of the main properties of a color, defined technically , as "the degree to which a stimulus can be describedas similar to or different from stimuli that are described as red, green, blue, and yellow,"...
in an attempt to intimidate the Vietnamese government. During the Sino-French War of 1884–85 the ship was in Huế in early September 1884, but she carried Admiral Amédée Courbet
Amédée Courbet
Anatole-Amédée-Prosper Courbet was a French admiral who won a series of important land and naval victories during the Tonkin campaign and the Sino-French War .-Early years:...
to Keelung
Keelung
Keelung City is a major port city situated in the northeastern part of Taiwan. It borders New Taipei and forms the Taipei–Keelung metropolitan area, along with the Taipei and New Taipei. Nicknamed the Rainy Port for its frequent rain and maritime role, the city is Taiwan's second largest seaport...
, Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
on 23 September.