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 or incendiary shells. The first ironclad battleship, Gloire, 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 (as in the case with smaller ships and later torpedo boats), 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.

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 (ironclad) 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.^{[citation needed]}

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 Napoléon in 1850. Napoléon was armed as a conventional ship-of-the-line, but her steam engines could give her a speed of 12 knots (22 km/h; 14 mph), regardless of the wind conditions: a potentially decisive advantage in a naval engagement.^{[citation needed]}

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.