Dreadnought
The dreadnought was the predominant type of battleship in the early 20th century. The first of the kind, the Royal Navy's, had such an effect when launched in 1906 that similar battleships built after her were referred to as "dreadnoughts", and earlier battleships became known as pre-dreadnoughts. Her design had two revolutionary features: an "all-big-gun" armament scheme, with an unprecedented number of heavy-calibre guns, and steam turbine propulsion. As dreadnoughts became a crucial symbol of national power, the arrival of these new warships renewed the naval arms race between the United Kingdom and Germany. Dreadnought races sprang up around the world, including in South America, lasting up to the beginning of World War I. Successive designs increased rapidly in size and made use of improvements in armament, armour, and propulsion throughout the dreadnought era. Within five years, new battleships outclassed Dreadnought herself. These more powerful vessels were known as "super-dreadnoughts". Most of the original dreadnoughts were scrapped after the end of World War I under the terms of the Washington Naval Treaty, but many of the newer [|super-dreadnoughts] continued serving throughout World War II.
Dreadnought-building consumed vast resources in the early 20th century, but there was only one battle between large dreadnought fleets. At the Battle of Jutland in 1916, the British and German navies clashed with no decisive result. The term dreadnought gradually dropped from use after World War I, especially after the Washington Naval Treaty, as virtually all remaining battleships shared dreadnought characteristics; it can also be used to describe battlecruisers, the other type of ship resulting from the dreadnought revolution.
Origins
The distinctive all-big-gun armament of the dreadnought was developed in the first years of the 20th century as navies sought to increase the range and power of the armament of their battleships. The typical battleship of the 1890s, now known as the "pre-dreadnought", had a main armament of four heavy guns of calibre, a secondary armament of six to eighteen quick-firing guns of between calibre, and other smaller weapons. This was in keeping with the prevailing theory of naval combat that battles would initially be fought at some distance, but the ships would then approach to close range for the final blows, when the shorter-range, faster-firing guns would prove most useful. Some designs had an intermediate battery of guns. Serious proposals for an all-big-gun armament were circulated in several countries by 1903.All-big-gun designs commenced almost simultaneously in three navies. In 1904, the Imperial Japanese Navy authorized construction of, originally designed with twelve guns. Work began on her construction in May 1905. The Royal Navy began the design of HMS Dreadnought in January 1905, and she was laid down in October of the same year. Finally, the US Navy gained authorization for, carrying eight 12-inch guns, in March 1905, with construction commencing in December 1906.
The move to all-big-gun designs was accomplished because a uniform, heavy-calibre armament offered advantages in both firepower and fire control, and the Russo-Japanese War of 1904–1905 showed that future naval battles could, and likely would, be fought at long distances. The newest guns had longer range and fired heavier shells than a gun of calibre. Another possible advantage was fire control; at long ranges guns were aimed by observing the splashes caused by shells fired in salvoes, and it was difficult to interpret different splashes caused by different calibres of gun. There is still debate as to whether this feature was important.
Long-range gunnery
In naval battles of the 1890s the decisive weapon was the medium-calibre, typically, quick-firing gun firing at relatively short range; at the Battle of the Yalu River in 1894, the victorious Japanese did not commence firing until the range had closed to, and most of the fighting occurred at. At these ranges, lighter guns had good accuracy, and their high rate of fire delivered high volumes of ordnance on the target, known as the "hail of fire". Naval gunnery was too inaccurate to hit targets at a longer range.By the early 20th century, British and American admirals expected future battleships would engage at longer distances. Newer models of torpedo had longer ranges. For instance, in 1903, the US Navy ordered a design of torpedo effective to. Both British and American admirals concluded that they needed to engage the enemy at longer ranges. In 1900, Admiral John Fisher, commanding the Royal Navy Mediterranean Fleet, ordered gunnery practice with 6-inch guns at. By 1904 the US Naval War College was considering the effects on battleship tactics of torpedoes with a range of.
The range of light and medium-calibre guns was limited, and accuracy declined badly at longer range. At longer ranges the advantage of a high rate of fire decreased; accurate shooting depended on spotting the shell-splashes of the previous salvo, which limited the optimum rate of fire.
On 10 August 1904 the Imperial Russian Navy and the Imperial Japanese Navy had one of the longest-range gunnery duels to date—over during the Battle of the Yellow Sea. The Russian battleships were equipped with Lugeol range finders with an effective range of, and the Japanese ships had Barr & Stroud range finders that reached out to, but both sides still managed to hit each other with fire at. Naval architects and strategists around the world took notice.
All-big-gun mixed-calibre ships
An evolutionary step was to reduce the quick-firing secondary battery and substitute additional heavy guns, typically. Ships designed in this way have been described as 'all-big-gun mixed-calibre' or later 'semi-dreadnoughts'. Semi-dreadnought ships had many heavy secondary guns in wing turrets near the centre of the ship, instead of the small guns mounted in barbettes of earlier pre-dreadnought ships.Semi-dreadnought classes included the British and ; the Japanese,, and ; French ; and Austro-Hungarian es.
The design process for these ships often included discussion of an 'all-big-gun one-calibre' alternative. The June 1902 issue of Proceedings of the US Naval Institute contained comments by the US Navy's leading gunnery expert, P. R. Alger, proposing a main battery of eight guns in twin turrets. In May 1902, the Bureau of Construction and Repair submitted a design for the battleship with twelve guns in twin turrets, two at the ends and four in the wings. Lt. Cdr. Homer C. Poundstone submitted a paper to President Theodore Roosevelt in December 1902 arguing the case for larger battleships. In an appendix to his paper, Poundstone suggested a greater number of guns was preferable to a smaller number of. The Naval War College and Bureau of Construction and Repair developed these ideas in studies between 1903 and 1905. War-game studies begun in July 1903 "showed that a battleship armed with twelve guns hexagonally arranged would be equal to three or more of the conventional type."
The Royal Navy was thinking along similar lines. A design had been circulated in 1902–1903 for "a powerful 'all big-gun' armament of two calibres, viz. four and twelve guns." The Admiralty decided to build three more King Edward VIIs in the 1903–1904 naval construction programme instead. The all-big-gun concept was revived for the 1904–1905 programme, the Lord Nelson class. Restrictions on length and beam meant the midships 9.2-inch turrets became single instead of twin, thus giving an armament of four 12-inch, ten 9.2-inch and no 6-inch. The constructor for this design, J. H. Narbeth, submitted an alternative drawing showing an armament of twelve 12-inch guns, but the Admiralty was not prepared to accept this. Part of the rationale for the decision to retain mixed-calibre guns was the need to begin the building of the ships quickly because of the tense situation produced by the Russo-Japanese War.
Switch to all-big-gun designs
The replacement of the guns with weapons of calibre improved the striking power of a battleship, particularly at longer ranges. Uniform heavy-gun armament offered many other advantages. One advantage was logistical simplicity. When the US was considering whether to have a mixed-calibre main armament for the, for example, William Sims and Poundstone stressed the advantages of homogeneity in terms of ammunition supply and the transfer of crews from the disengaged guns to replace gunners wounded in action.A uniform calibre of gun also helped streamline fire control. The designers of Dreadnought preferred an all-big-gun design because it would mean only one set of calculations about adjustments to the range of the guns. Some historians today hold that a uniform calibre was particularly important because the risk of confusion between shell-splashes of 12-inch and lighter guns made accurate ranging difficult. This viewpoint is controversial, as fire control in 1905 was not advanced enough to use the salvo-firing technique where this confusion might be important, and confusion of shell-splashes does not seem to have been a concern of those working on all-big-gun designs. Nevertheless, the likelihood of engagements at longer ranges was important in deciding that the heaviest possible guns should become standard, hence 12-inch rather than 10-inch.
The newer designs of 12-inch gun mounting had a considerably higher rate of fire, removing the advantage previously enjoyed by smaller calibres. In 1895, a 12-inch gun might have fired one round every four minutes; by 1902, two rounds per minute was usual. In October 1903, the Italian naval architect Vittorio Cuniberti published a paper in Jane's Fighting Ships entitled "An Ideal Battleship for the British Navy", which called for a 17,000-ton ship carrying a main armament of twelve 12-inch guns, protected by armour 12 inches thick, and having a speed of. Cuniberti's idea—which he had already proposed to his own navy, the Regia Marina—was to make use of the high rate of fire of new 12-inch guns to produce devastating rapid fire from heavy guns to replace the 'hail of fire' from lighter weapons. Something similar lay behind the Japanese move towards heavier guns; at Tsushima, Japanese shells contained a higher than normal proportion of high explosive, and were fused to explode on contact, starting fires rather than piercing armour. The increased rate of fire laid the foundations for future advances in fire control.