Compound armour
Encyclopedia
Compound armour was a type of armour
used on warship
s in the 1880s. By the end of the decade it had been rendered obsolete by nickel
-steel armour.
plates on top of several inches of teak
to absorb the shock of projectile impact. A typical installation consisted of four to five inches of iron backed by thirty-six inches of solid wood timbers.
Various experiments were carried out in order to improve the armour, which included breaking up the armour into a laminate of several thinner layers of iron with wood between them, as well as various experiments with cast vs. wrought iron. In all of these experiments, simple blocks of wrought iron consistently proved to provide the best protection.
There had been several attempts to improve on iron with the addition of harder steels on the face, but these all failed for the same reason as the earlier laminate experiments; the ability for the armour to spread sideways into its softer backing allowed it to be penetrated more easily. In the case of steel facing, the problem was that the steel would not adhere well to the underlying iron, allowing it to shift or separate entirely.
In 1876 a competition was held by the Italian Navy
at Spezia to trial new armours. By that point conventional iron armours had to be 22 inches (558.8 mm) thick to stop contemporary naval artillery. The hands-down winner was a new soft steel from the French firm of Schneider et Cie, but this proved to be prone to breaking when stressed, making it less useful in naval applications.
low-carbon wrought iron plate. The front plate was intended to break up an incoming shell, whilst the rear plate would catch any splinters and hold the armour together if the brittle front plate shattered.
Steel plates positioned in front of iron plates had been tried unsuccessfully, for example in a trial by the Italian Navy
at Spezia in 1876. The problem of weld
ing them together was solved independently by two Sheffield
engineers, A. Wilson of John Brown & Company
and J. D. Ellis of Cammell Laird
. Wilson's technique, invented in 1877, was to pour molten steel onto a wrought iron plate, whilst Ellis' was to position the two plates close together and pour molten steel into the gap. In both cases, the plate formed was rolled down to about half of the original thickness. The steel front surface formed about one-third of the thickness of the plate.
Compound armour was initially much better than either iron or steel plates, about a 25% improvement. Throughout the decade continuous improvements were made in techniques for manufacturing both compound armour and steel armour. Nevertheless by the end of the decade all-steel plates had decisively edged ahead of compound armour, and the latter had become obsolete. Two major reasons for this were the introduction of forged chrome
-steel shot in 1886 and the discovery of nickel-steel alloys in 1889 which proved particularly effective as armour plate.
For instance, a trial by the French Navy
at Gavre in 1880 found compound armour superior to all-steel plates. An 1884 trial in Copenhagen
found that there was little difference between the two types, although compound armour was subsequently ordered by the Danish Navy, probably because it was cheaper. At the same time a similar trial to select the armour of the Italian
battleship
Lepanto saw 20 inches (508 mm) compound armour plate demolished by two shots of the 10-inch calibre guns which were to be fitted to the ship, whilst the same projectiles were shattered by 20 inches of French
Creusot steel plate.
Vehicle armour
Military vehicles are commonly armoured to withstand the impact of shrapnel, bullets, missiles, or shells, protecting the personnel inside from enemy fire. Such vehicles include tanks, aircraft, and ships....
used on warship
Warship
A warship is a ship that is built and primarily intended for combat. Warships are usually built in a completely different way from merchant ships. As well as being armed, warships are designed to withstand damage and are usually faster and more maneuvrable than merchant ships...
s in the 1880s. By the end of the decade it had been rendered obsolete by nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
-steel armour.
Prior armours
Prior to the 1880s, all naval armour plating was made from uniform homogeneous 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...
plates on top of several inches of teak
Teak
Teak is the common name for the tropical hardwood tree species Tectona grandis and its wood products. Tectona grandis is native to south and southeast Asia, mainly India, Indonesia, Malaysia, and Burma, but is naturalized and cultivated in many countries, including those in Africa and the...
to absorb the shock of projectile impact. A typical installation consisted of four to five inches of iron backed by thirty-six inches of solid wood timbers.
Various experiments were carried out in order to improve the armour, which included breaking up the armour into a laminate of several thinner layers of iron with wood between them, as well as various experiments with cast vs. wrought iron. In all of these experiments, simple blocks of wrought iron consistently proved to provide the best protection.
There had been several attempts to improve on iron with the addition of harder steels on the face, but these all failed for the same reason as the earlier laminate experiments; the ability for the armour to spread sideways into its softer backing allowed it to be penetrated more easily. In the case of steel facing, the problem was that the steel would not adhere well to the underlying iron, allowing it to shift or separate entirely.
In 1876 a competition was held by the Italian Navy
Regia Marina
The Regia Marina dates from the proclamation of the Kingdom of Italy in 1861 after Italian unification...
at Spezia to trial new armours. By that point conventional iron armours had to be 22 inches (558.8 mm) thick to stop contemporary naval artillery. The hands-down winner was a new soft steel from the French firm of Schneider et Cie, but this proved to be prone to breaking when stressed, making it less useful in naval applications.
Compound armour
Compound armour was made from two different types of steel; a very hard but brittle high-carbon steel front plate backed by a more elasticElastomer
An elastomer is a polymer with the property of viscoelasticity , generally having notably low Young's modulus and high yield strain compared with other materials. The term, which is derived from elastic polymer, is often used interchangeably with the term rubber, although the latter is preferred...
low-carbon wrought iron plate. The front plate was intended to break up an incoming shell, whilst the rear plate would catch any splinters and hold the armour together if the brittle front plate shattered.
Steel plates positioned in front of iron plates had been tried unsuccessfully, for example in a trial by the Italian Navy
Regia Marina
The Regia Marina dates from the proclamation of the Kingdom of Italy in 1861 after Italian unification...
at Spezia in 1876. The problem of weld
Weld
Weld most commonly refers to a joint formed by welding.Weld may also refer to:-People:* Weld family, an extended family of New England** Theodore Dwight Weld** Tuesday Weld* Weld-Blundell family* Cecil Weld-Forester, 1st Baron Forester...
ing them together was solved independently by two Sheffield
Sheffield
Sheffield is a city and metropolitan borough of South Yorkshire, England. Its name derives from the River Sheaf, which runs through the city. Historically a part of the West Riding of Yorkshire, and with some of its southern suburbs annexed from Derbyshire, the city has grown from its largely...
engineers, A. Wilson of John Brown & Company
John Brown & Company
John Brown and Company of Clydebank was a pre-eminent Scottish marine engineering and shipbuilding firm, responsible for building many notable and world-famous ships, such as the , the , the , the , the , and the...
and J. D. Ellis of Cammell Laird
Cammell Laird
Cammell Laird, one of the most famous names in British shipbuilding during the nineteenth and twentieth centuries, came about following the merger of Laird, Son & Co. of Birkenhead and Johnson Cammell & Co. of Sheffield at the turn of the twentieth century.- Founding of the business :The Company...
. Wilson's technique, invented in 1877, was to pour molten steel onto a wrought iron plate, whilst Ellis' was to position the two plates close together and pour molten steel into the gap. In both cases, the plate formed was rolled down to about half of the original thickness. The steel front surface formed about one-third of the thickness of the plate.
Compound armour was initially much better than either iron or steel plates, about a 25% improvement. Throughout the decade continuous improvements were made in techniques for manufacturing both compound armour and steel armour. Nevertheless by the end of the decade all-steel plates had decisively edged ahead of compound armour, and the latter had become obsolete. Two major reasons for this were the introduction of forged chrome
Chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
-steel shot in 1886 and the discovery of nickel-steel alloys in 1889 which proved particularly effective as armour plate.
For instance, a trial by 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...
at Gavre in 1880 found compound armour superior to all-steel plates. An 1884 trial in Copenhagen
Copenhagen
Copenhagen is the capital and largest city of Denmark, with an urban population of 1,199,224 and a metropolitan population of 1,930,260 . With the completion of the transnational Øresund Bridge in 2000, Copenhagen has become the centre of the increasingly integrating Øresund Region...
found that there was little difference between the two types, although compound armour was subsequently ordered by the Danish Navy, probably because it was cheaper. At the same time a similar trial to select the armour of the Italian
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
battleship
Battleship
A battleship is a large armored warship with a main battery consisting of heavy caliber guns. Battleships were larger, better armed and armored than cruisers and destroyers. As the largest armed ships in a fleet, battleships were used to attain command of the sea and represented the apex of a...
Lepanto saw 20 inches (508 mm) compound armour plate demolished by two shots of the 10-inch calibre guns which were to be fitted to the ship, whilst the same projectiles were shattered by 20 inches of French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
Creusot steel plate.