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 12-inch (305 mm) calibre, a secondary armament of six to eighteen quick-firing guns of between 4.7 inches (119 mm) and 7.5 inches (191 mm) 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 8-inch (203 mm) 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 Satsuma, originally designed with twelve 12-inch (305 mm) 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 USS Michigan, 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 naval battles could, and likely would, be fought at long distances. The newest 12-inch (305 mm) guns had longer range and fired heavier shells than a gun of 10-inch (254 mm) or 9.2-inch (234 mm) calibre. Most historians also cite advantages in 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.
In naval battles of the 1890s the decisive weapon was the medium-calibre, typically 6-inch (152 mm), 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 3,900 metres (4,300 yd) and most of the fighting occurred at 2,000 metres (2,200 yd). 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.[b]
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 4,000 yards (3,700 m). Both British and American admirals concluded that they needed to engage the enemy at longer ranges. In 1900, Admiral Sir John "Jackie" Fisher, commanding the Royal Navy Mediterranean Fleet, ordered gunnery practice with 6-inch guns at 6,000 yards (5,500 m). By 1904 the US Naval War College was considering the effects on battleship tactics of torpedoes with a range of 7,000 yards (6,400 m) to 8,000 yards (7,300 m).
The range of light and medium-calibre guns was limited, and accuracy declined badly at longer range.[c] 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 engaged the Imperial Japanese Navy in one of the longest-range gunnery duels to date – over 8 miles (13 km) – during the Battle of the Yellow Sea. The Russian battleships were equipped with Liuzhol range finders with an effective range of 4,000 metres (4,400 yd) and the Japanese ships had Barr & Stroud range finders that reached out to 6,000 metres (6,600 yd), but both sides still managed to hit each other with 12-inch (305 mm) main battery fire at 8 miles (13 km). 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 9.2-inch (234 mm) or 10-inch (254 mm). 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-dreadnoughts classes included the British King Edward VII and Lord Nelson; Russian Andrei Pervozvanny; Japanese Katori, Satsuma, and Kawachi; American Connecticut and Mississippi; French Danton; Italian Regina Elena; and Austro-Hungarian Radetzky class.
The design process for these ships often included discussion of an 'all-big-gun one-calibre' alternative.[d] The June 1902 issue of Proceedings of the US Naval Institute contained comments by the US Navy's leading gunnery expert Prof. P.R Alger proposing a main battery of eight 12-inch (305 mm) guns in twin turrets. In May 1902, the Bureau of Construction and Repair submitted a design for the battleship with twelve 10-inch guns in twin turrets, two at the ends and four in the wings. Lt. Cdr. H. C. Poundstone submitted a paper to President Roosevelt in December 1902 arguing the case for larger battleships. In an appendix to his paper, Poundstone suggested a greater number of 11-inch (279 mm) and 9-inch (229 mm) guns was preferable to a smaller number of 12-inch and 9-inch. 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 11-inch or 12-inch 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 1902–03 for "a powerful 'all big-gun' armament of two calibres, viz. four 12-inch and twelve 9.2-inch guns." The Admiralty decided to build three more King Edward VIIs (with a mixture of 12-inch, 9.2-inch and 6-inch (152 mm)) in the 1903–04 naval construction programme instead. The all-big-gun concept was revived for the 1904–05 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 6-inch (152 mm) or 8-inch (203 mm) guns with weapons of 9.2-inch (234 mm) or 10-inch (254 mm) 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 South Carolina class, for example, William Sims and Homer 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.[e] Some historians today hold that a uniform calibre was particularly important because the risk of confusion between shell-splashes of 12-inch (305 mm) 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.[f] Nevertheless, the likelihood of engagements at longer ranges was important in deciding that the heaviest possible guns should become standard, hence 12-inch (305 mm) rather than 10-inch (254 mm).[g]
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 24 knots (28 mph/44 km/h). 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.
Building the first dreadnoughts
In Japan, the two battleships of the 1903–04 programme were the first in the world to be laid down as all-big-gun ships, with eight 12-inch (305 mm) guns. The armour of their design was considered too thin, demanding a substantial redesign. The financial pressures of the Russo-Japanese War and the short supply of 12-inch guns—which had to be imported from the United Kingdom—meant these ships were completed with a mixture of 12-inch and 10-inch (254 mm) armament. The 1903–04 design retained traditional triple-expansion steam engines, unlike Dreadnought.
The dreadnought breakthrough occurred in the United Kingdom in October 1905. The new First Sea Lord, John "Jackie" Fisher had long been an advocate of new technology in the Royal Navy and had recently been convinced of the idea of an all-big-gun battleship.[h] Fisher is often credited as the creator of the dreadnought and the father of the United Kingdom's great dreadnought battleship fleet, an impression he himself did much to reinforce. It has been suggested Fisher's main focus was on the arguably even more revolutionary battlecruiser and not the battleship.
Shortly after taking office, Fisher set up a Committee on Designs to consider future battleships and armoured cruisers. The Committee's first task was to consider a new battleship. The specification for the new ship was a 12-inch main battery and anti-torpedo-boat guns but no intermediate calibres, and a speed of 21 kn (39 km/h) which was two or three knots faster than existing battleships. The initial designs intended twelve 12-inch guns, though difficulties in positioning these guns led the chief constructor at one stage to propose a return to four 12-inch guns with sixteen or eighteen of 9.2-inch (234 mm). After a full evaluation of reports of the action at Tsushima compiled by an official observer, Captain Pakenham, the Committee settled on a main battery of ten 12-inch guns, along with twenty-two 12 pounders as secondary armament. The Committee also gave Dreadnought steam turbine propulsion, which was unprecedented in a large warship. The greater power and lighter weight of turbines meant the 21-knot (24 mph/39 km/h) design speed could be achieved in a smaller and less costly ship than if reciprocating engines had been used. Construction took place quickly; the keel was laid on 2 October 1905, the ship was launched on 10 February 1906, and completed on 3 October 1906—an impressive demonstration of British industrial might.
The first US dreadnoughts were the two South Carolina-class ships. Detailed plans for these were worked out in July–November 1905, and approved by the Board of Construction on 23 November 1905. Building was slow; specifications for bidders were issued on 21 March 1906, the contracts awarded on 21 July 1906 and the two ships were laid down in December 1906, after the completion of the Dreadnought.