Ironclad warship
An ironclad was a steam-propelled warship protected by steel or iron armor constructed from 1859 to the early 1890s. The ironclad was developed as a result of the vulnerability of wooden warships to explosive and incendiary shells. The first ironclad battleship,, was launched by the French Navy in November 1859, narrowly preempting the British Royal Navy. However, Britain built the first completely iron-hulled warships.
Ironclads were first used in warfare in 1862 during the American Civil War, when they operated against wooden ships, and against each other at the Battle of Hampton Roads in Virginia. Their performance demonstrated that the ironclad had replaced the unarmored ship of the line as the most powerful warship afloat. Ironclad gunboats became very successful in the American Civil War.
Ironclads were designed for several uses, including as high-seas battleships, long-range cruisers, and coastal defense ships. Rapid development of warship design in the late 19th century transformed the ironclad from a wooden-hulled vessel that carried sails to supplement its steam engines into the steel-built, turreted battleships and cruisers familiar in the 20th century. This change was pushed forward by the development of heavier naval guns, more sophisticated steam engines, and advances in ferrous metallurgy that made steel shipbuilding possible.
The quick pace of change meant that many ships were obsolete almost as soon as they were finished and that naval tactics were in a state of flux. Many ironclads were built to make use of the naval ram, the torpedo, or sometimes both, which several naval designers considered the important weapons of naval combat. There is no clear end to the ironclad period, but toward the end of the 1890s, the term ironclad dropped out of use. New ships were increasingly constructed to a standard pattern and designated as battleships or armored cruisers.
Development
The ironclad became technically feasible and tactically necessary because of developments in shipbuilding in the first half of the 19th century. According to naval historian J. Richard Hill: "The had three chief characteristics: a metal-skinned hull, steam propulsion and a main armament of guns capable of firing explosive shells. It is only when all three characteristics are present that a fighting ship can properly be called an ironclad." Each of these developments was introduced separately in the decade before the first ironclads.Steam propulsion
In the 18th and early 19th centuries, fleets had relied on two types of major warship, the ship of the line and the frigate. The first major change to these types was the introduction of steam power for propulsion. While paddle steamer warships had been used from the 1830s onward, steam propulsion only became suitable for major warships after the adoption of the screw propeller in the 1840s.Steam-powered screw frigates were built in the mid-1840s, and at the end of the decade the French Navy introduced steam power to its line of battle. Napoleon III's ambition to gain greater influence in Europe required a sustained challenge to the British at sea. The first purpose-built steam battleship was the 90-gun in 1850. Napoléon was armed as a conventional ship-of-the-line, but her steam engines could give her a speed of, regardless of the wind conditions: a potentially decisive advantage in a naval engagement.
The introduction of the steam ship-of-the-line led to a building competition between France and Britain. Eight sister ships to Napoléon were built in France over a period of ten years, but the United Kingdom soon managed to take the lead in production. Altogether, France built ten new wooden steam battleships and converted 28 from older ships of the line, while the United Kingdom built 18 and converted 41.
Explosive shells
The era of the wooden steam ship-of-the-line was brief, because of new, more powerful naval guns. In the 1820s and 1830s, warships began to mount increasingly heavy guns, replacing 18- and 24-pounder guns with 32-pounders on sailing ships-of-the-line and introducing 68-pounders on steamers. Then, the first shell guns firing explosive shells were introduced following their development by the French Général Henri-Joseph Paixhans. By the 1840s they were part of the standard armament for naval powers including the French Navy, Royal Navy, Imperial Russian Navy and United States Navy.It is often held that the power of explosive shells to smash wooden hulls, as demonstrated by the Russian destruction of an Ottoman squadron at the Battle of Sinop, spelled the end of the wooden-hulled warship. The more practical threat to wooden ships was from conventional cannon firing red-hot shot, which could lodge in the hull and cause a fire or ammunition explosion. Some navies even experimented with hollow shot filled with molten metal for extra incendiary power.
Iron armor
The use of wrought iron instead of wood as the primary material of ships' hulls began in the 1830s; the first "warship" with an iron hull was the gunboat Nemesis, built by Jonathan Laird of Birkenhead for the East India Company in 1839. There followed, also from Laird, the first full-sized warship with a metal hull, the 1842 steam frigate Guadalupe for the Mexican Navy. The latter ship performed well during the Naval Battle of Campeche, with her captain reporting that he thought that there were fewer iron splinters from Guadalupes hull than from a wooden hull.Encouraged by the positive reports of the iron hulls of those ships in combat, the Admiralty ordered a series of experiments to evaluate what happened when thin iron hulls were struck by projectiles, both solid shot and hollow shells, beginning in 1845 and lasting through 1851. Critics like Lieutenant-general Sir Howard Douglas believed that the splinters from the hull were even more dangerous than those from wooden hulls and the tests partially confirmed this belief. What was ignored was that with of wood backing, the iron would stop most of the splinters from penetrating and that relatively thin plates of iron backed by the same thickness of wood would generally cause shells to split open and fail to detonate.
The early experimental results seemed to support the critics and party politics came into play as the Whig First Russell ministry replaced the Tory Second Peel Ministry in 1846. The new administration sided with the critics and ordered that the four iron-hulled propeller frigates ordered by the Tories be converted into troopships. No iron warships would be ordered until the beginning of the Crimean War in 1854.
Following the demonstration of the power of explosive shells against wooden ships at the Battle of Sinop, and fearing that his own ships would be vulnerable to the Paixhans guns of Russian fortifications in the Crimean War, Emperor Napoleon III ordered the development of light-draft floating batteries, equipped with heavy guns and protected by heavy armor. Experiments made during the first half of 1854 proved highly satisfactory, and on 17 July 1854, the French communicated to the British Government that a solution had been found to make gun-proof vessels and that plans would be communicated. After tests in September 1854, the British Admiralty agreed to build five armored floating batteries on the French plans.
The French floating batteries were deployed in 1855 as a supplement to the wooden steam battle fleet in the Crimean War. The role of the battery was to assist unarmored mortar and gunboats bombarding shore fortifications. The French used three of their ironclad batteries in 1855 against the defenses at the Battle of Kinburn on the Black Sea, where they were effective against Russian shore defences. They would later be used again during the Italian war in the Adriatic in 1859. The British floating batteries and arrived too late to participate to the action at Kinburn. The British planned to use theirs in the Baltic Sea against the well-fortified Russian naval base at Kronstadt.
The batteries have a claim to the title of the first ironclad warships but they were capable of only under their own power: they operated under their own power at the Battle of Kinburn, but had to be towed for long-range transit. They were also arguably marginal to the work of the navy. The brief success of the floating ironclad batteries convinced France to begin work on armored warships for their battlefleet.
Early ironclad ships and battles
By the end of the 1850s it was clear that France was unable to match British building of steam warships, and to regain the strategic initiative a dramatic change was required. The result was the first ocean-going ironclad,, begun in 1857 and launched in 1859. Gloires wooden hull was modelled on that of a steam ship of the line, reduced to one deck, and sheathed in iron plates thick. She was propelled by a steam engine, driving a single screw propeller for a speed of. She was armed with thirty-six rifled guns. France proceeded to construct 16 ironclad warships, including two sister ships to Gloire, and the only two-decked broadside ironclads ever built, and.The Royal Navy had not been keen to sacrifice its advantage in steam ships of the line, but was determined that the first British ironclad would outmatch the French ships in every respect, particularly speed. A fast ship would have the advantage of being able to choose a range of engagement that could make her invulnerable to enemy fire. The British specification was more a large, powerful frigate than a ship-of-the-line. The requirement for speed meant a very long vessel, which had to be built from iron. The result was the construction of two s; and. The ships had a successful design, though there were necessarily compromises between 'sea-keeping', strategic range and armor protection. Their weapons were more effective than those of Gloire, and with the largest set of steam engines yet fitted to a ship, they could steam at 14.3 knots. Yet the Gloire and her sisters had full iron-armor protection along the waterline and the battery itself.
The British Warrior and Black Prince were obliged to concentrate their armor in a central "citadel" or "armoured box", leaving many main deck guns and the fore and aft sections of the vessel unprotected. The use of iron in the construction of Warrior also came with some drawbacks; iron hulls required more regular and intensive repairs than wooden hulls, and iron was more susceptible to fouling by marine life.
By 1862, navies across Europe had adopted ironclads. Britain and France each had sixteen either completed or under construction, though the British vessels were larger. Austria, Italy, Russia, and Spain were also building ironclads. However, the first battles using the new ironclad ships took place during the American Civil War, between Union and Confederate ships in 1862. These were markedly different from the broadside-firing, masted designs of Gloire and Warrior. The clash of the Italian and Austrian fleets at the Battle of Lissa, also had an important influence on the development of ironclad design.