By 1904 studies reinforced by battle experience in the Spanish-American and Russo-Japanese wars indicated that fire from large guns at longer ranges was more effective than mixed-battery fire closer in. Effectively increasing range depended upon abandoning the multiple-caliber pattern of previous battleship armament in favor of a single-caliber armament. Several navies reached this conclusion simultaneously, but the British were the first to produce such a ship, HMS Dreadnought, completed in 1906. Displacing about 18,000 tons, it carried 10 12-inch guns; its only other armament consisted of three-inch weapons intended to fight off destroyers. The Dreadnought gave its name to an entirely new class of battleships of the most advanced design. Unlike its immediate German and American contemporaries, the Dreadnought had steam turbines in place of reciprocating engines. These enabled it to attain a speed of 21 knots, which was hitherto achieved only by cruisers. Thus, in mobility as well as in size, the Dreadnought began a new era.
In the years between the world wars, ships continued to become larger and more expensive to build and maintain. Ships of comparable size and power to the Dreadnought were labeled 'Battlecruisers' or even 'Heavy Cruisers' by the 1940's.