The armored cruiser was a type of warship of the late 19th and early 20th centuries. Like other types of cruiser, the armored cruiser was a long-range, independent warship, capable of defeating any ship apart from a battleship, and fast enough to outrun any battleships it encountered.
The first armored cruiser was HMS Shannon, launched in 1875. Like other early armored cruisers, she combined sail and steam propulsion. However, by the 1890s cruisers had abandoned sail propulsion and took on a modern appearance. The size of armored cruisers varied; the largest were as large and expensive as battleships.
The armored cruiser was distinguished from other types of cruiser by its belt armor-thick iron (or later steel) plating on much of the hull to protect the ship from shellfire from enemy guns. This protection method was widely used on battleships. However, for many decades it proved difficult to design an effective armored cruiser which combined an armored belt with the long range and high speed required to fulfill the cruiser's mission. In the 1880s and early 1890s, many navies preferred to build protected cruisers instead. It was often possible to build cruisers which were faster and better all-round using this type of ship, which relied on a lighter armored deck to protect the vital parts of the ship.
In 1908 the development of the armored cruiser culminated in the battlecruiser. The new type of ship combined a radically more powerful armament similar to that of a dreadnought battleship with fast steam turbine engines, rapidly superseding the armored cruiser. At around the same time, the term 'light cruiser' came into use for small cruisers with armored belts.
Armored cruisers were widely used in World War I, though by this stage they were generally regarded as second-class ships. Most of the surviving armored cruisers were scrapped under the terms of the Washington Naval Treaty of 1922, which imposed limits on warships and defined a cruiser as a ship of 10,000 tons or less carrying guns of 8-inch caliber or less – rather smaller than many of the large armored cruisers. A handful survived in one form or another until World War II.
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The armored cruiser was first developed in the 1870s as an attempt to combine the virtues of the armored ironclad warship and the fast and long-ranged, but unarmored, cruisers of the time. The first ocean-going ironclads had been launched around 1860, and both French and British navies had built classes of relatively small ironclad warships, designed for long-range colonial service and using both sail and steam propulsion. Examples of this kind of "station ironclad" include the British Audacious and French Belliqueuse classes.[1] However, these ships were too slow to raid enemy commerce or hunt down enemy commerce raiders. These missions of commerce raiding and commerce protection were filled by frigates or corvettes, also powered by both sail and steam. Without the additional weight of armor, these ships could reach speeds of up to 16 or 17 knots. Examples of the most powerful armored cruisers of the 1860s include the British Inconstant, the U.S. Navy's Wampanoag and the French Duquesne.[2]
The Russian navy was the first to produce an armored warship intended for commerce raiding, with the General Admiral, begun in 1870 and launched in 1873, often referred to as the first armored cruiser.[3] She and her sister Gerzog Edinburgski were a new threat to British commerce in the event of war.[4] The British responded with Shannon, begun in 1873 and launched in 1875, and followed by two ships of the Nelson class.
These early armored cruisers looked like cut-down versions of the ironclads of the time. Since sail propulsion was still vital for a long-ranged ship, the armored cruisers were required to carry a full sailing rig. As sailing ships required a high freeboard and a large degree of stability, the use of armored turrets as used on monitors and some battleships was ruled out, because a turret was a very heavy weight high in the ship. Consequently armored cruisers retained a more traditional broadside arrangement. Their armor was distributed in a thick belt around the waterline along most of their length; the gun positions on deck were not necessarily armored at all. They were typically powered by double-expansion steam engines fed by boilers which generated steam at perhaps 60 or 70 psi pressure, which gave relatively poor efficiency and short range under steam. Their short steaming range could have been improved if less weight had been devoted to masts and rigging, but not to so far that they would ever reach the desired range under coal.
The British navy was never very happy with these early armored cruisers. They were too slow to deal with fast cruisers, Shannon making 12.25 knots and Nelson 14 knots, and not armored well enough to take on a first-class battleship.[5] At this stage, it was still novel to distinguish between the concepts of armored cruiser and second-class battleship, and the designer of the British ships felt they fulfilled both roles.[6]
A battle in May 1877 between the British unarmored cruiser Shah and the Peruvian monitor Huáscar demonstrated the need for more and better-protected cruisers. Shah and the smaller wooden corvette Amethyst hit Huáscar more than 50 times without causing significant damage. The Peruvian ship had an inexperienced crew unused to its cumbersome machinery, and managed to fire only six rounds, all of which missed.[7] The engagement demonstrated the value of cruisers with armor protection.[6]
During the 1870s the size and power of armor-piercing guns increased rapidly. This caused problems for the designers of armored ships of all kinds, both battleships and cruisers. Even if a ship was designed with enough armor to protect it against the current generation of guns, it was likely that within a few years new guns powerful enough to penetrate its armor would be developed.
Consequently naval designers tried a novel method of armouring their ships. The vital parts of a ship - its engines, boilers, and magazines, together with enough of the hull to keep the ship stable in the event of damage - could be positioned underneath an armored deck just below the waterline. Since this deck would only be struck very obliquely by shells, it could be rather less thick and heavy than belt armor. While the sides of the ship would be entirely unarmoured, this protection scheme could be just as effective as an armored belt which would not stop shellfire.[8] Cruisers with armored decks and no side armor became known as protected cruisers, and superseded armored cruisers in the 1880s and the beginning of the 1890s.[9]
The first ship to make use of an armored deck was the armored cruiser Shannon. She relied principally on her vertical citadel armor for protection, with the armored deck covering a relatively short section of the hull forward from the armored citadel to the bows. However, by the end of the 1870s ships could be found with full-length armored decks and little or no side armor. The Italian Italia class of very fast battleships had armored decks and guns but no side armor. The British used a full-length armored deck in their Comus class of corvettes started in 1878; however the Comus class were designed for colonial service and were only capable of 13 knots speed, not fast enough for commerce protection or fleet duties.
The breakthrough for the protected cruiser design came with the Chilean cruiser Esmeralda, designed and built by the British firm Armstrong, at their Elswick yard. Esmeralda had a high speed of 18 knots, and dispensed entirely with sails. Her armament of two 10in and six 6in guns appeared very powerful for her size. Her protection scheme, inspired by the Italia class, included a full-length protected deck up to 2in thick, and a cork-filled cofferdam along her sides. Esmeralda set the tone for cruiser construction for the years to come, with "Elswick cruisers" on a similar design being constructed for Italy, China, Japan, Argentina, Austria and the United States.[10]
The French navy adopted the protected cruiser wholeheartedly in the 1880s. The Jeune Ecole school of thought, which proposed a navy composed of fast cruisers for commerce raiding and torpedo-boats for coast defense, was particularly influential in France. The first French protected cruiser was the Sfax, laid down in 1882, and followed by six classes of protected cruiser – and no armored cruisers until the Dupuy de Lôme, laid down in 1888 but not finished until 1895. Dupuy de Lôme was a revolutionary ship, being the first French armoured cruiser to dispose entirely of masts, and sheathed in steel armour. However, she and two other were not sufficiently seaworthy, and their armor could be penetrated by modern quick-firing guns. Thus from 1891–7 the French reverted to the construction of protected cruisers.[11]
The British Royal Navy was equivocal about which protection scheme to use until 1887. The large Imperieuse class, begun in 1881 and finished in 1886, were built as armored cruisers but were often referred to as protected cruisers. While they carried an armored belt some 10 in thick, the belt only covered a 140 ft of the 315 ft length of the ship, and was submerged below the waterline at full load. The real protection of the class came from the armored deck 4 in thick, and the arrangement of coal bunkers to prevent flooding. These ships were also the last armored cruisers to be designed with sails. However, on trials it became clear that the masts and sails did more harm than good; they were removed and replaced by a single military mast with machine guns.[12]
The next class of small cruisers in the Royal Navy, the Mersey class, were protected cruisers, but the Royal Navy then returned to the armored cruiser with the Orlando class, begun in 1885 and completed in 1889. However in 1887 a comparison of the Orlando type judged them inferior to the protected cruisers[6] and the Royal Navy built exclusively protected cruisers, including some very large, fast ships like the 14,000-ton Powerful class.
The only major naval power to retain a preference for armored cruisers during the 1880s was Russia. The Russian Navy laid down four armored cruisers and one protected cruiser during the decade, all being large ships with sails.[13]
The late 1890s saw the development of a new generation of armored cruisers, many of which were as large and expensive as the pre-dreadnought battleships of the time. These cruisers combined long range, high speed, and an armament approaching that of battleship with enough armour to protect them against the quick-firing guns which were regarded as the most important weapons afloat at the time.
This was made possible by the introduction of Case-hardened steel armor – first Harvey armor and then crucially Krupp armor - which meant it was finally possible to put a useful armor belt on a large cruiser [11] The Jeanne d'Arc, laid down in 1896, displaced 11,000 tons, carried a mixed armament of 7.6in and 5.5in guns, and had a 6in belt of Harvey armor over her machinery spaces.[11] In response, the British returned to armoured cruiser construction in 1898, with the Cressy class. The 6in belt of Krupp steel on these ships was expected to keep out armour-piercing shells from a 6in quick-firing gun at likely battle ranges. The weight of the belt armor was 2,500 tons, as compared to the 1,809 tons on the otherwise similar Diadem class. Given that the armour on the Cressy class was actually very similar to that of the Canopus class of battleships, this was readily accepted.[14]
The first armored cruiser of the United States Navy was the USS Maine, whose destruction in 1898 triggered the Spanish-American War. Launched in 1889, she had 7 to 12 inches (178 to 305 mm) of armor around the sides ('belt armor'), and 1 to 4 inches (25 to 102 mm) on the decks. She was redesignated as a 'second class battleship' in 1894, an awkward compromise reflecting that she was slower than other cruisers, and weaker than the first-line battleships of the time.
New York, launched in 1895, was less well protected than Maine, with 3 inches (76 mm) of belt armor, and 3 to 6 inches (76 to 152 mm) of deck armor. The Brooklyn was an improved version of the New York and Olympia designs.
Shortly after the Spanish-American War, the Navy built six Pennsylvania-class armored cruisers, almost immediately followed by four of the Tennessee class. Collectively these ten ships were referred to as the 'big ten'.
Armored cruisers were used with success in the line of battle by the Japanese at the Battle of Tsushima in 1905. Of the battle damage received by the Japanese, the armored cruiser Nisshin received the second-most hits after the battleship Mikasa. Nisshin was hit 13 times, including six 12-inch (300 mm) hits. Nisshin managed to stay in line throughout the battle, validating the hopes of the designer: a cruiser able to stand in the line of battle. The performance of the Japanese armored cruisers during the Battle of Tsushima, and that of Nisshin in particular, likely led to a boom in the construction of armored cruisers in the world's navies.
The last armored cruisers were built around 1910 . At this time they were rapidly being outclassed by new technological developments such as the all big gun dreadnought battleship powered by steam turbine engines, and the adoption of oil firing meant that new construction could no longer rely on the protection afforded by coal bunkers. Armored cruisers were directly replaced in battle fleets by the larger, faster and better-armed battlecruisers. The large armored cruiser was therefore rendered obsolete, and only light cruisers were built from that point on. Remaining armored cruisers were used in patrolling and minor roles until the end of World War II.
Among the last armored cruisers built was the German SMS Blücher. Though it was perhaps the best of that type of ship, it was not up to par with the new battlecruisers. She was considered to be an intermediate stage toward the future German battlecruiser, being larger, faster and more heavily armed than all preceding armored cruisers, though smaller than subsequent battlecruisers. Blücher was completed in part because the British had misled the Germans on the Invincibles' specifications, and she was too far advanced in her construction once the actual design of the British battlecruisers was known.
The Battle of Coronel, which had occurred shortly before the Battle of the Falkland Islands, was one of the last battles involving armored cruisers as the chief adversaries; all subsequent engagements were dominated by dreadnought-era battleships and battlecruisers. Unlike pre-dreadnoughts, armored cruisers still played an active role in World War I due to their high speeds, and were often used against dreadnought-type vessels, where they fared poorly.
For instance, at the Falkland Islands engagement, SMS Scharnhorst and Gneisenau were sunk by the battlecruisers HMS Invincible and Inflexible. The German commander Vice-Admiral Maximilian von Spee had already considered the Royal Australian Navy flagship HMAS Australia superior to his force of armored and light cruisers. At the Falkland Islands encounter, while the German gunnery was mostly accurate, they failed to inflict serious damage on the British battlecruisers, which turned the tide of battle once they started hitting von Spee's ships.
During the Battle of Dogger Bank, the SMS Blücher was crippled by a shell from a British battlecruiser, which slowed Blücher to 17 knots. This forced Admiral Hipper to make the decision to sacrifice the armored cruiser (which was sunk with great loss of life) and let his more modern and valuable battlecruisers escape.
HMS Warrior, Defence and Black Prince were lost at the Battle of Jutland when they inadvertently came into sight and range of the German Navy's battle line, which included several battlecruisers and dreadnought battleships.
After the end of World War I, many of the surviving armoured cruisers were sold for scrap. The Washington Naval Treaty of 1922 placed strict limits on the numbers of "capital ships" possessed by the navies of the great powers. A "capital ship" was defined as any vessel of over 10,000 tons displacement or with guns over 8in calibre, and several more armoured cruisers were decommissioned to comply with the terms of the treaty. The London Naval Treaty of 1930 introduced further limits on cruiser tonnage. Only a small number of armored cruisers survived these limitations, though a handful saw action in World War II.
One late-design armored cruiser still exists: Georgios Averof, constructed in 1909–1911, is preserved as a museum in Greece.
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