The armored cruiser was a naval cruiser protected by armor on its sides as well as on the decks and gun positions. This class was used from around 1875 until mid-World War I, and in auxiliary roles in the 1930s and even during World War II.

The development of the explosive shell gun in the mid-1800s made the use of armor inevitable, despite its cost and weight, and armored cruisers began to appear in large Western navies.

History

The first armored cruiser was the British Shannon (1875). Early armored cruisers had a usual displacement of around 6,000 - 12,000 tons and a speed of 18 to 20 knots (33 to 37 km/h). This type reached its zenith in 1906-1908 with displacements of 14,000-16,000 tons and speeds of 22 to 23 knots (41 to 43 km/h). Typical armament was either 2 or 4 large-calibre guns, usually 8 to 10 in (203 to 254 mm) and some dozen guns of calibre 6in (152mm) or similar.

For example, the first Russian Ryurik (1895) had 4 x 8 in (203 mm) guns, 16 x 6 in (152 mm) guns and 6 x 4.7 in (120 mm) guns and the French Victor Hugo (1904) had 4 x 9.4 in (194 mm) guns and 16 x 7.5 in (164 mm) guns. The British HMS Monmouth was an exception, with a weak armament of only 14 guns of 6 in (152 mm). The last armored cruisers had a stronger armament, like the British HMS Warrior (1905) - 6 x 9.2 in (234 mm) guns and 4 x 7.5 in (190 mm) guns; the German SMS Blucher (1909) - 12 x 8.2 in (210 mm) guns and 6 x 5.9 in (150 mm) guns; and the second Russian Ryurik (1909, British-built) had 4 x 10 in (254 mm) guns, 8 x 8 in (203 mm) guns and 20 x 4.7 in (120 mm) guns.

Armored cruisers were the chief combatants in two naval battles: the Battle of Ulsan in the Russo-Japanese War, and the Battle of Coronel in World War I, and played important supporting roles in other battles of the period. On the other hand, the Battle of the Falkland Islands and the Battle of Jutland showed that their armor was insufficient to allow them to take on capital ships. The last armored cruisers were built around 1910, after technological developments allowed the type to evolve alongside battleships by including a uniform main gun armament and increasing their speeds. They were eventually known as battlecruisers.

Armored cruisers in the US Navy

The first armored cruiser of the United States Navy was the USS Maine, whose explosion 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 slowness compared to other cruisers, and weakness versus the first-line battleships of the time.

New York (Armored Cruiser No. 2), 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 (Armored Cruiser No. 3) was an improved version of the New York design.

Shortly after the Spanish-American War, the Navy built six Pennsylvania class armored cruisers, almost immediately followed by five of the Tennessee class .

On 17 July 1920, all existing US armored cruisers were merged with protected cruisers in a single class "cruiser" with hull classification symbol "CA", bringing to an end the use of the term in the US.

One armored cruiser still exists: Giorgios Averoff, preserved in Greece.