Capital Ship - Battleship / Battlecruiser

Battleship / Battlecruiser

The definition of "capital ship" was formalized in the limitation treaties of the 1920s and 30s in the Washington Naval Treaty, London Naval Treaty, and Second London Naval Treaty. This applied mainly to ships resulting from the dreadnought revolution; dreadnought battleships (also known first as dreadnoughts and later as battleships) and battlecruisers.

In the 20th century, especially in World Wars I and II, typical capital ships would be battleships and battlecruisers. All of the above ships were close to 20,000 tons displacement or heavier, with large caliber guns and heavy armor protection. Heavy cruisers, despite being important ships, were not considered capital ships.

An exception to the above in World War II was the Deutschland-class cruiser. Though this class was technically similar to a heavy cruiser, albeit with considerably heavier guns, they were generally regarded as capital ships (hence the British label "Pocket battleship"). The Alaska-class cruisers, despite being oversized heavy cruisers and not true battleships/battlecruisers, were also considered by some to be capital ships.

During the Cold War, a Soviet Kirov-class large missile cruiser had a displacement great enough to rival WWII-era capital ships, perhaps defining a new battlecruiser for that era. However, others consider the Kirov to be just a supersized guided-missile cruiser.