The ironclad warship was a major type of armored vessel in the second half of the 19th century and the early 20th. It preceded the battleship and it had a hybrid propulsion system, which consisted of both steam engine and sails. It was fitted with strong, iron plates on the sides of hull as armor protection. It was armed with either an artillery turret mounting one heavy caliber naval gun and/or a row of muzzle-loading guns that fired from gunports in the upper hull. Ironclads were the biggest and strongest ships of the navy at that time and were used in naval battles with enemy armored ships and in operations against coastal fortresses. The idea of plating ships of the major types with armor had originated a long time ago. But it was only after the Battle of Sinope (1853), in which a Russian squadron under the command of Admiral P. S. Nakhimov destroyed the Turkish fleet with incendiary bombs, that the necessity of replacing wooden sailing ships with iron ships equipped with steam engines became a conviction shared by all navies. The construction of warships with iron hulls led to the wide use of armor to protect the thin iron side and deck from artillery shells.
The ironclad was developed from ships of the Monitor type, which were first used in 1862 in the Civil War in North America. Monitors were usually armed with two heavy caliber cannon (up to 280 mm) placed on a revolving armored turret and had a very low but carefully assigned freeboard. Subsequent development included an increase in the caliber, in the number of cannon, and in the height of freeboard. In Russia the first big ironclad ship, Petr Velikiy, was laid down in 1869 and launched in 1872. It had a water displacement of 10,100 tons and was considered the most powerful and sea-worthy ironclad of its time. In the Russian Navy a distinction was made between squadron ironclads (for battles on the open sea) and coast defense ironclads (for action in inshore regions). Potemkin, which became famous through its participation in the Revolution of 1905-07, was a type of squadron ironclad. One of the mightiest squadron ironclads was the Andrei Pervozvannyi (laid down in 1905, launched in 1906; water displacement, 17,400 tons: speed, 18 knots; four 305-mm guns of the main caliber; side armor, 70-216 mm).
A typical coast defense ironclad warship was the Admiral Seniavin (commissioned in 1896; water displacement, 4,790 tons; speed, 16 knots; four 254-mm guns of the main caliber; side armor, 152-254 mm). The experience of the Russo-Japanese War of 1904-05 revealed that the number of guns of the main caliber was insufficient, that the calibers of the auxiliary artillery varied too much, that the armor plating of the ironclads was too weak, and that their ability to survive was too poor. Therefore the construction of ironclads was discontinued after the Russo-Japanese War; many navies of the world began building battleships instead. In some navies, mainly in the Scandinavian countries, a small number of ironclads were retained until the end of World War II and in the Swedish Navy, until the middle of the 1950’s. Several ironclads, for example in the Norwegian Navy, participated in combat action in offshore regions at the beginning of World War II.
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| HMS Achilles, the second ironclad warship in service with the Royal Navy. |