The dreadnought was the predominant type of battleship of the 20th century. The revolutionary HMS Dreadnought of 1906 adopted an 'all-big-gun' armament and steam turbine propulsion; her impact was so great that battleships built after her were referred to as 'dreadnoughts' and earlier battleships became known as pre-dreadnoughts. The only other major advance in kind was the US Navy design with all main turrets on the centerline of the ship.
The concept of an all-big-gun ship had been in circulation for several years prior to Dreadnought's construction, and the Imperial Japanese Navy had even begun work on an all-big-gun battleship, the Satsuma, in 1904. The arrival of the dreadnoughts sparked a new arms race, principally between Britain and Germany but reflected worldwide, as the new class of warships became a crucial symbol of national power.
Technical development continued rapidly through the dreadnought era, with rapid changes in armament, armour, and propulsion, meaning that ten years after Dreadnoughts commissioning much more powerful ships were being built. These more powerful vessels were known as super-dreadnoughts'. The only pitched battle between fleets of dreadnoughts was the Battle of Jutland, an indecisive clash that reflected Britain's continuing strategic dominance. Most of the dreadnoughts were scrapped or scuttled after the end of World War I, though some of the most advanced super-dreadnoughts continued in service through World War II.
The term "dreadnought" gradually dropped from use after World War I, as the pre-dreadnoughts and the first generations of dreadnoughts were scrapped. However, all battleships built since then shared some of the characteristics of the dreadnought. "Dreadnought" can also be used to encompass battlecruisers, the other type of ship resulting from the dreadnought revolution.
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 firepower and range of their battleships. Most pre-dreadnoughts had a main armament of four heavy guns of 12-inch (30 cm), and a secondary armament of six to eighteen quick-firing ('rapid-firing' in US nomenclature) guns of 4.7-7.5 inch (12-19 cm), supplemented by a range of smaller weapons. Some designs had an intermediate battery of 8-inch (20.3 cm) guns. By 1903, however, serious proposals for an all-big-gun armament were circulated in several countries.
All-big-gun designs were begun almost simultaneously in three navies. The Imperial Japanese Navy authorised Satsuma, designed with twelve 12-inch guns, in 1904, and she was laid down in May 1905. The Royal Navy began the design of HMS Dreadnought in January 1905; she was laid down in October. The United States Navy gained authorisation for USS Michigan, carrying eight 12-inch guns, in March 1905, and she was laid down in May 1906.
The exact reasons for the move to an all-big-gun design are still a matter of some controversy. The newest, fast-firing 12-inch (305 mm) guns had more long-range firepower than a gun of 10-inch or 9.2-inch calibre. It is often stated mixed-calibre guns prevented accurate fire control because of the potential for confusion between shell-splashes of different calibre. However, more recent work suggests that shell-splashes and salvo firing were not of much importance in decision-making.
The pre-dreadnought battleships combined heavy-calibre ship-killing guns, typically of 12 inch, with a secondary and tertiary armament able to generate a hail of fire destroying the less protected parts of enemy ships. At the Battle of the Yalu River (1894) and the Battle of Santiago de Cuba (1898), this hail of fire destroyed most of the vessels of the defeated side. At Santiago, none of the four U.S. battleships present scored a single hit with their 12- and 13-inch guns. These were short-range engagements. At Yalu River, the victorious Japanese did not open fire until the range had closed to 3,000 yards; naval gunnery was still too inaccurate to score hits at a longer range.
By the early 1900s, British and American admirals expected that future battleships would engage at considerably longer ranges. They would need to do so, because torpedo ranges were increasing; for example, in 1903, the US ordered a torpedo effective to 4,000 yards. Both British and American admirals concluded they needed to engage the enemy at longer ranges. In 1900, Jackie Fisher, commanding the Royal Navy Mediterranean Fleet, ordered gunnery practice with the 6-inch guns at 6,000 yards. By 1904, the U.S. Naval War College was considering the effects on battleship tactics of 7-8,000 yard range torpedoes.
At the short ranges expected for combat in the 1890s, lighter guns had good accuracy; combined with their high rate of fire, this produced the lethal 'hail of fire' effect. As ranges increased, the accuracy of light and medium-calibre guns declined more rapidly than that of heavier weapons. "Moreover at long ranges gunners had to 'spot' the fall of shot to correct their aim... The longer the range, the lower the maximum theoretical rate of spotted fire."
The early years of the 20th century saw the effective range of heavy guns increase. This had been established during gunnery exercises by 1904, and then validated during the action at Tsushima in 1905.
One approach to making more powerful battleships was to reduce the secondary battery, and substitute additional heavy guns: typically 9.2- or 10-inch. These ships, described as 'all-big-gun mixed-calibre' or later 'semi-dreadnought', included the British King Edward VII and Lord Nelson classes, the French Danton class, and the Japanese battleship Satsuma. The design process for these ships often included discussion of a pure, 'all-big-gun one-calibre', alternative.
The June issue of Proceedings of the US Naval Institute contained an article by US Navy's leading gunnery expert Prof P.R Alger proposing a main battery of eight 12-inch guns in twin turrets. Future chief constructor David W. Taylor responded, suggesting battleships of the future would be powered with steam turbines. In May 1902, the Bureau of Construction and Repair (BuC&R) submitted a design for the Mississippi-class 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 and 9-inch guns was preferable to a smaller number of 12-inch and 9-inch. The Naval War College and BuC&R developed these ideas in studies between 1903 and 1905. Wargame studies begun in July 1903 "showed that a battleship armed with twelve 11- or 12-inch guns hexagonally arranged would be equal to three or more of the conventional type.
In the British navy, the same trend occurred. A design had also 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. However, the Admiralty decided to build three more King Edwards (with a mixture of 12-inch, 9.2-inch and 6-inch) in the 1903-04 programme instead. The 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.
The replacement of the 6-inch or 8-inch guns with weapons of 9.2-inch or 10-inch calibre improved the striking power of a battleship, particularly at longer ranges. However, making the move to a uniform calibre of heavy guns offered a number of additional benefits.
A uniform heavy-gun armament offered advantages for logistics and damage control. When the U.S. was considering whether to have a mixed-calibre main armament for the South Carolina class, for example, Sims and Poundstone stressed the advantages of homogeneity in terms of ammunition supply and the transfer of crews from the disengaged guns to replace wounded gunners..
A uniform calibre of gun meant streamlined 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. It is often argued a uniform calibre was particularly important because the risk of confusion between shell-splashes of 12-inch and lighter guns, which is held to make accurate ranging difficult. More recent investigation suggests firecontrol in 1905 was not advanced enough to use the salvo-firing technique where this confusion might be important; 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 the heaviest possible guns should become standard, hence 12-inch rather than 10-inch.
Furthermore, 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 fire one round every four minutes; by 1902, two rounds per minute was usual. In October 1903, 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-in guns, protected by 12-inch armour, and having a speed of 24 knots (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 overcame the principal objection to 12-inch guns and laid the foundations for future advances in fire control.
In Japan, the two battleships of the 1903-4 Programme were in fact the first to be laid down as all-big-gun designs, with eight 12-inch guns. However, the design had armour which 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 Britain meant these ships were completed with a mixed 10- and 12-inch armament. The 1903-4 design also retained traditional triple-expansion steam engines.
The dreadnought breakthrough occurred in Britain in the October of 1905. The new First Sea Lord, Jackie Fisher had long been an advocate of new technology in the Royal Navy and had recently been converted to the idea of an all-big-gun battleship.
Fisher is often credited as the creator of the dreadnought and the father of Britain's great dreadnought battleship fleet, an impression he himself did much to reinforce. However, it is now seriously suggested Fisher's main interest was in developing the battlecruiser and not the battleship. One of Fisher's first actions on coming to office was to 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 21-knot speed (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 9.2-inch. After a full evaluation of reports of the action at Tsushima compiled by an official observer, Captain William Christopher Pakenham, the Committee settled on a main battery of ten 12-inch guns, along with twenty-two 12-pounders (3 inch, 76 mm) as her secondary armament. The Committee also took the adventurous step of giving Dreadnought steam turbine propulsion. This was unprecedented in a large warship. The greater efficiency of the turbines meant the 21-knot design speed could be achieved in a smaller and cheaper ship.
Construction took place at a remarkable rate; her keel was laid on 2 October 1905, she was launched on 10 February 1906, and she was completed on 3 October 1906—an impressive demonstration of British industrial might. The new ship was named Dreadnought, preserving the name of a ship stricken the previous year.
The first US dreadnoughts were the South Carolina class. Detailed plans for these were worked out in July-November 1905, and approved by the Board of Construction on 23 November 1905. However, building was slow; specifications for bidders were issued on 21 March 1906, and the two ships were laid down in December 1906, after the completion of the Dreadnought.
The inevitable consequence of demands for ever greater speed, striking power, and endurance meant displacement and hence cost of dreadnoughts tended to increase. Dreadnought size was only eventually limited by the Washington Naval Treaty in 1922, when an upper limit of 35,000 tons was agreed; in subsequent years a number of treaty battleships were commissioned designed to build up to this limit. Once war came on the horizon again, however, the race towards bigger and bigger battleships resumed.
The defining characteristic of the dreadnought was the 'all-big-gun' armament: a large number of very heavy guns. The number and size of guns in the main battery could vary. Dreadnought herself mounted ten 12-inch guns; 12-inch armament had been standard in the pre-dreadnought and this continued the first generation of dreadnought battleships, though the German Navy continued to use 11.1-inch guns in its first class of dreadnoughts, the Nassaus.
As dreadnoughts developed, there were continuing demands for more firepower to match or outpace the likely enemy. This meant either more powerful heavy guns, a greater number of such guns, or an arrangement which meant the same number of guns could be better used.
Dreadnoughts also carried lighter weapons. Many early dreadnoughts carried only very light guns designed to fend off enemy torpedo boats. However, the calibre and weight of secondary armament tended to increase, as the range of torpedoes and the staying power of the destroyers expected to carry them also increased. From the end of World War I onwards, battleships had also to be equipped with anti-aircraft armament, typically a large number of light guns.
Dreadnoughts also very frequently carried torpedo tubes themselves. In theory, a line of battleships so equipped could unleash a potentially devastating volley of torpedoes on an enemy line steaming a parallel course. In practice, however, carrying torpedoes presented many risks, while torpedoes fired from battleships scored very few hits.
The effectiveness of the guns depended in part on the layout of the turrets. Dreadnought, and the British ships which immediately followed her, carried five turrets: one forward and two aft on the centreline of the ship, and two in the 'wings' next to the superstructure. This allowed three turrets to fire ahead and four on the broadside. Nassau and the first few classes of German dreadnoughts adopted a 'hexagonal' layout, with one turret each fore and aft and four wing turrets; this meant more guns were mounted in total, but the same number could fire ahead or broadside as with Dreadnought.
Dreadnought designs experimented with different layouts. An alternative was to mount the centre turrets en echelon. The British Neptune class staggered the wing turrets, so all ten guns could fire on the broadside, a feature copied by the German Kaiser class. This, however, risked blast damage to parts of the ship which the guns fired over, and put great stress on the ship's frame.
The solution which imposed the least stress on the ship's hull was to put all the turrets on the centreline. This meant the main battery could fire on the broadside, but fewer could fire end-on. It also meant the hull would be longer, and the armoured belt would have to be heavier or thinner; the deep, heavily-armoured magazines which served each turret also interfered with the distribution of boilers and engines. Agincourt carried fourteen 12-inch guns in seven centreline turrets, more heavy guns than any other dreadnought, but was not considered a success for these reasons.
An improved centreline layout involved raising some turrets so they could fire over a turret immediately forward or astern of them. The U.S. Navy adopted this feature with their very first dreadnoughts, the South Carolinas. Other navies were slower to do so, because of fears about the impact of the blast of the raised guns on the lower turret. Raised turrets also raised the centre of gravity of the ship, potentially reducing stability; for this reason it was impossible for more than two turrets to superfire, one forward and one aft. The most common superfiring arrangement was eight guns, with two turrets forward and two aft, allowing four guns to fire on either end and eight on a broadside. This was adopted as early as the South Carolinas, spread to the Royal Navy with the Orions, and by World War II was standard.
The alternative to more turrets was to put more guns into each turret. Economising on the number of turrets meant the ship could be shorter or could devote more space to machinery. On the other hand, it meant a higher proportion of the main battery could be put out of action by a single lucky enemy hit. It also reduced the rate of fire slightly, due to interference between guns. The first nation to adopt the triple turret was Italy, with their first Dreadnought, the Dante Alighieri, soon followed by Russia with her Gangut class (also her first dreadnoughts),, the Austro-Hungarian Tegetthoff class, the U.S.'s Nevada class, and after World War I by the British G3 and N3 designs of 1921, and the first German triple-turreted capital ship, Scharnhorst. Several later designs used quadruple turrets, for instance the King George Vs. The quadruple turrets, however, often suffered from technical difficulties - most famously HMS Prince of Wales in her engagement with the Bismarck.
Another way to increase the striking power of a dreadnought was to increase the power of each gun. This could be done by increasing either the calibre of the weapon and hence the weight of shell, or by lengthening the barrel to increase muzzle velocity. Either of these offered the chance to increase range and armour penetration.
Both methods offered advantages and disadvantages. As guns fire, their barrels wear out, losing accuracy and eventually requiring replacement. At times, this became problematic; the U.S. Navy seriously considered stopping practice firing of heavy guns in 1910 because of the wear on the barrels. The higher the muzzle velocity, the more pronounced the problem of gun wear. Heavier shells are also affected less by air resistance, and so retain greater penetrating power at long range. The disadvantages of heavier guns were twofold: first, the guns and turrets required weighed much more; and second, heavier and slower shells needed to be fired at a higher angle for the same range.
Different navies approached the decision of calibre in different ways. The German navy, for instance, generally used a lighter calibre than the equivalent British ships, e.g. 12-inch calibre when the British standard was 13.5-inch. However, because German metallurgy was superior, the German 12-inch gun was superior to the British 12-inch in terms of shell weight and muzzle velocity; and because the German guns were lighter than the British 13.5-inch, German ships could afford more armour.
On the whole, however, the calibre of guns tended to increase. In the Royal Navy, the Orion class, launched 1910, used ten 13.5-inch guns, all on the centreline; the Queen Elizabeth class, launched 1913, used eight 15-inch guns. In all navies, the calibre of guns increased and the number of guns tended to decrease to compensate. The fewer guns needed meant distributing them became less of an issue, and centreline turrets became entirely the norm.
A further step change was planned for battleships designed and laid down at the end of World War I. The Japanese Nagato class in 1917 carried 16-inch guns, matched by the US Navy's Colorado class. Some designs went still further: the British "N3" class would have carried nine 18-inch guns, and the Japanese planned an un-named class, also with 18-inch armament. However, the Washington Naval Treaty meant these mammoth battleships never got off the drawing board.
The trend towards larger calibres was arrested by the Naval Treaties. The Washington Naval Treaty limited battleship guns at 16-inch (406 mm). Later treaties preserved this limit, though reductions of the limit to 11, 12, or 14 inches were proposed. The only battleships to break the limit were the Japanese Yamato class, begun in 1937 (after the treaty expired), which carried 460-mm (18.1-inch) main guns. By the middle of World War II, Britain was making use of 15-inch guns built as spares for the Queen Elizabeth class to arm the last British battleship, Vanguard.
A number of World War II-era designs were drawn up proposing another move towards gigantic armament. The German H-43 and H-44 designs proposed 508-mm (20-inch) guns, and there is evidence Hitler wanted calibres as high as 609-mm (24-inch); the Japanese 'Super Yamato' design also used 508-mm guns. None of these proposals went further than very preliminary design work.
The first dreadnoughts tended to have a very light secondary armament intended to protect them from torpedo boats. Dreadnought herself carried 12-pounder guns (3 in, 76 mm calibre); each of her twenty-two 12-pounders could fire at least 15 rounds a minute at any torpedo boat foolhardy enough to come close. The South Carolinas and other early American dreadnoughts were identically equipped. These very light guns tended to be mounted in unarmoured positions, high on the ship.
Other navies, whose earliest dreadnoughts were designed a few years later, tended to retain heavier guns in the secondary armament. Nassaus, for instance, carried twelve 150-mm (5.9 in) and sixteen 88-mm (3.9 in) guns, and subsequent German dreadnought classes followed her lead.. These heavier guns tended to be mounted in armoured barbettes on the main deck. After World War I, however, the secondary armament tended to be mounted in turrets on the upper deck and around the superstructure.
Those navies which initially only mounted light guns shortly increased the calibre of their secondary armament. The Royal Navy increased its secondary armament from 12-pounder to first 4-inch and then 6-inch guns, which were standard at the start of World War I.; the USA standardised on 5-inch calibre for the War but planned 6-inch guns for the ships designed just afterwards.
The secondary armament of dreadnoughts was, on the whole, unsatisfactory. A hit from a light gun could not be relied on to stop a destroyer. Heavier guns could not be relied on to hit a destroyer, as experience at the Battle of Jutland showed. The barbette mountings of heavier guns also proved problematic; being low in the hull, they proved liable to flooding, and on several classes some were removed and plated over. The only sure way to protect a dreadnought from destroyer or torpedo boat attack was to escort it with its own destroyer squadron.
Much of the displacement of a dreadnought was taken up by the steel plating of its armour. Designers spent much time and effort to provide the best possible protection for their ships against the various weapons they would be faced with. However, only so much weight could ever be devoted to protection, without compromising speed, firepower or seakeeping.
The bulk of a dreadnought's armour was concentrated around the armoured citadel. This 'citadel' was a box, armoured on all but one side, which contained the most important parts of the ship. The sides of the citadel were the 'armoured belt' of the ship, which started on the hull just in front of the forward turret and ran to just behind the aft turret. The ends of the citadel were two armoured bulkheads, fore and aft, which stretched between the ends of the armour belt. The 'roof' of the citadel was an armoured deck. Within the citadel were the boilers, engines, and the magazines for the main armament. A hit to any of these systems could cripple or destroy the ship.
The earliest dreadnoughts were intended to take part in a pitched battle against other battleships at ranges of up to 10,000 yards. In such an encounter, shells would fly on a relatively flat trajectory, and a shell would have to hit at or just about the waterline to damage the vitals of the ship. For this reason, the early dreadnoughts' armour was concentrated in a thick belt around the waterline; this was 11 in thick in Dreadnought. Behind this belt were arranged the ship's coal bunkers, to further protect the engineering spaces. In an engagement of this sort, there was also a lesser threat of indirect damage to the vital parts of the ship. A shell which struck above the belt armour and exploded could send fragments flying in all directions. These fragments were dangerous, but could be stopped by much thinner armour than an unexploded armour-piercing shell. To protect the innards of the ship from fragments of shells which detonated on the superstructure, much thinner steel armour was applied to the decks of the ship. Dreadnought carried a total of 2.5 in of deck armour on two decks.
While the thickest protection was reserved for the central citadel in all battleships, some navies also extended a thinner armoured belt and armoured deck to cover the ends of the ship, or extended a thinner armoured belt up the outside of the hull. This 'tapered' armour was used by the major European navies - Britain, Germany and France. This arrangement gave some armour to a larger part of the ship; for the very first dreadnoughts, when it was still likely that the medium-calibre guns of pre-dreadnoughts would be present in a fleet battle, this would be useful. However, it tended to result in the main belt being very short, sometimes below the waterline. The alternative was an 'all-or-nothing' protection scheme, developed by the U.S. Navy. The armour belt was tall and thick, but no side protection at all was provided to the ends of the ship or the upper decks. The armoured deck was also thickened. The 'all-or-nothing' system provided more effective protection against the very-long-range engagements of dreadnought fleets and was adopted outside the U.S. Navy after World War I.
During the evolution of the dreadnought, armour schemes changed to reflect the greater risk of plunging shells from long-range gunfire, the increasing threat from both bombs dropped by aircraft and the need to protect battleships more adequately from torpedoes and mines.
The threat of plunging fire and bombing meant later designs carried a greater thickness of steel on the armoured deck, and the amount of protection devoted to the deck increased much more rapidly than did the amount in the main belt. For instance, Yamato carried a 16.5 in main belt, as opposed to Dreadnoughts 11 in but a deck as thick as 9 in against Dreadnoughts 2 in. The main belt itself was increasingly angled inwards to give a greater effective thickness against low-angle shells.
The final element of the protection scheme of the first dreadnoughts was the subdivision of the ship below the waterline into several watertight compartments. If the hull was holed - by shellfire, mine, torpedo, or collision - then, in theory, only one area would flood and the ship could survive. To make this precaution even more effective, many dreadnoughts had no hatches between different underwater sections, so that even a surprise hole below the waterline need not sink the ship. However, there were still a number of instances where flooding spread between underwater compartments.
The greatest evolution in dreadnought protection came with the development of the Anti-torpedo bulge and torpedo belt, both attempts to protect against underwater damage by mines and torpedoes. The purpose of underwater protection was to absorb the force of a detonating mine or torpedo well away from the final watertight hull. This meant an inner bulkhead along the side of the hull, which was generally lightly armoured to capture splinters, separated from the outer hull by one or more compartments. The compartments in between were either left empty, or filled with coal, water or fuel oil.
Dreadnoughts were propelled by two to four screw propellors. Dreadnought herself, and all British dreadnoughts, had screw shafts driven by steam turbines. However, the first generation of dreadnoughts built in other nations used the slower triple-expansion steam engine which had been standard in pre-dreadnoughts.
Turbines offered more power than reciprocating engines for the same volume of machinery. It was this which persuaded the Royal Navy to use turbines in the Dreadnought; it helped that Charles Parsons, the inventor of the turbine, offered a guarantee on the new machinery. Another often-mentioned advantage of turbines, their cleanliness and superior reliability, is largely illusory. By 1905, improved designs of reciprocating engine were available which made the reciprocating engine reliable and easy to work with.
Turbines were not without disadvantages. At slower, cruising speeds turbines were markedly less fuel-efficient than reciprocating engines. This was of particular importance for navies which required a long range at cruising speeds - and hence for the U.S. Navy, which even in the early 1900s was planning to cruise across the Pacific to engage the Japanese in the Philippines. This was the reasoning behind the American decision to abandon turbines after installing them in North Dakota (ordered 1907, launched 1908); it was not until Nevada (ordered 1911, launched 1914) that turbines were rehabilitated for U.S. dreadnoughts.
This disadvantage of the turbine was eventually overcome. The solution which eventually was generally adopted was the geared turbine, where gearing reduced the rotation rate of the propellors and hence increased efficiency. However, this solution required technical precision in the gears and hence was difficult to implement.
One alternative was the turbo-electric drive where the steam turbine generated electrical power which then drove the propellors. This was particularly favoured by the U.S. Navy, which used it from all dreadnoughts from late 1915-1922. The advantages of this method were its low cost, the opportunity for very close underwater compartmentation, and good astern performance. The disadvantages were that machinery was heavy and vulnerable to battle damage, particularly the effects of flooding on the electrics.
Turbines were never replaced in battleship design. Diesel engines were eventually considered by a number of powers, as they offered very good endurance and an engineering space taking up less of the length of the ship. However, they were also heavier, took up a greater vertical space, offered less power, and were considered unreliable.
The first generation of dreadnoughts used coal to fire the boilers which fed steam to the turbines. Coal had been in use since the very first steam warships, but had many disadvantages; it was labour-intensive to pack coal into the ship's bunkers and then feed it into the boilers, which became clogged with ash; coal produced thick black smoke which gave away the position of a fleet. In addition, coal was very bulky and had comparatively low thermal efficiency. Coal was, however, quite inert and could be used as part of the ship's protection scheme.
Oil-fired propulsion had many advantages for naval architects and officers at sea alike. It reduced smoke, making ships less vulnerable. It could be fed into boilers automatically, rather than needing a complement of stokers to do it by hand. Oil has roughly twice the thermal content of coal, which meant that the boilers themselves could be smaller, and that for the same volume of fuel carried an oil-fired ship would have much greater range.
These benefits meant that as early as 1901 Fisher was pressing the advantages of oil fuel. There were one or two technical problems with oil-firing, connected with the different distribution of the weight of oil fuel compared to coal, and the problems of pumping viscous oil.. However, the main problem with using oil for the battlefleet was that, with the exception of the USA, every major navy would have to import its oil. This meant that a number of navies adopted 'dual-firing' boilers which could use coal sprayed with oil; British ships so equipped, which included dreadnoughts, could even use oil alone at up to 60% power.
Given the USA's plentiful oil and its demand for long-ranged ships, it is no surprise that the U.S. Navy was the first to wholeheartedly adopt oil-firing, deciding to do so in 1901; the Nevada class, ordered 1911. Britain was not far behind, deciding in 1912 to use oil exclusively in the Queen Elizabeth class; the shorter British design and building times that the first oil-fired battleships in both fleets went to sea at nearly exactly the same time. Britain planned to revert to mixed firing with the subsequent Revenge class, at the cost of some speed - but Fisher, returned to office in 1914, insisted that all of the boilers should be oil-fired. Other major navies retained mixed coal-and-oil firing until the end of World War I.
The dreadnought was developed as a move in an international battleship arms-race which had begun in the 1890s. Most navies paused their building programmes for a few years while imbibing the technical lessons required to build dreadnoughts of their own. After this brief period, the battleship race accelerated once more, in spite of the ships' great cost. Possession of modern battleships was not only vital to naval power, but as with nuclear weapons today, represented a nation's standing in the world. Germany, France, Russia, Italy, Japan and Austria all began dreadnought programmes, and second-rank powers including Turkey, Argentina, Brazil, and Chile commissioned dreadnoughts to be built in British and American yards.
The building of the Dreadnought coincided with increasing tension between Britain and Germany. Germany had begun to build a large battlefleet in the 1890s, as part of a deliberate policy to challenge British naval supremacy. With the conclusion of the Entente Cordiale between Britain and France in April 1904, it became increasingly clear that Britain's principal naval enemy would be Germany. This rivalry gave rise to the two largest dreadnought fleets of the pre-war period.
The first German response to Dreadnought came with the Nassau class, laid down in 1907, followed by the Helgoland class in 1909. Together with two battlecruisers — a type for which the Germans had less admiration than Fisher, but which could be built under authorisation for armored cruisers, rather than capital ships — these classes gave Germany a total of ten modern capital ships built or building in 1909. While the British ships were somewhat faster and more powerful than their German equivalents, a 12:10 ratio fell very short of the 2:1 ratio that the Royal Navy wanted to maintain.
In 1909, the British Parliament authorised an additional four capital ships, holding out hope Germany would be willing to negotiate a treaty about battleship numbers. If no such solution could be found, an additional four ships would be laid down in 1910. Even this compromise solution meant (when taken together with some social reforms) raising taxes enough to prompt a constitutional crisis in Britain in 1909-10.
In 1910, the British eight-ship construction plan went ahead, including four Orion-class super-dreadnoughts, and augmented by battlecruisers purchased by Australia and New Zealand. In the same period of time, Germany laid down only three ships, giving Britain a superiority of 22 ships to 13. The British resolve demonstrated by their construction programme led the Germans to seek a negotiated end to the arms race. While the Admiralty's new target of a 60% lead over Germany was near enough to Tirpitz's goal of cutting the British lead to 50%, talks foundered on the question on whether British Commonwealth battlecruisers should be included in the count, as well as non-naval matters like the German demands for recognition of her ownership of Alsace-Lorraine.
The pace of the dreadnought race stepped up in both nations' 1910 and 1911 budgets, with Germany laying down four capital ships each year and Britain five. The tensions came to a head following the German Naval Law of 1912. This proposed a fleet of 33 German battleships and battlecruisers, outnumbering the Royal Navy in home waters. To make matters worse, the Austro-Hungarian Fleet was building 4 dreadnoughts, while the Italians had four and were building two more. Against such threats, the Royal Navy could no longer guarantee vital British interests. Britain was faced with a choice of building more battleships, withdrawing from the Mediterranean, or seeking an alliance with France. Further naval construction was unacceptably expensive at a time when social welfare provision was making calls on the budget. Withdrawing from the Mediterranean would mean a huge loss of influence, weakening British diplomacy in the Mediterranean and shaking the stability of the British Empire. The only acceptable option, and the one taken by First Lord of the Admiralty Winston Churchill, was to overturn a hundred years of splendid isolation and seek an alliance with France.
In spite of these important strategic consequences, the 1912 Naval Law had little bearing on the battleship force ratios. Britain responded by laying down ten new super-dreadnoughts in her 1912 and 1913 budgets—ships of the Queen Elizabeth and Revenge classes, which introduced a further step change in armament, speed and protection—while Germany laid down only five, focusing resources on the Army.
Smaller than Dreadnought at 16,000 tons standard displacement, they carried eight 12-inch (305 mm) guns in four twin turrets arranged in superfiring pairs fore and aft along the centerline. This arrangement gave South Carolina (and her sister Michigan) a broadside equal Dreadnought's without requiring the cumbersome wing turrets. The superfiring (superimposed) arrangement was not proven until after South Carolina went to sea, and it was initially feared the weakness of the previous Virginia-class would recur. Half of the first ten U.S. dreadnoughts used the older and less efficient reciprocating engines rather than turbines, which made many U.S. battleships slower than their British counterparts, but gave them much greater range, something of great importance for operations in the Pacific.
With the defeat of the Russians, the Japanese navy became concerned about the potential for conflict with the USA. Japanese theorist Sato Tetsutaro developed the concept of a fleet at a minimum 70% of the U.S.'s. This would enable the Japanese navy to win two decisive battles, the first early in a war, against the U.S. Pacific Fleet, and the second against the U.S. Atlantic Fleet which would inevitably be despatched as reinforcements.
Japan's first priority was to refit the pre-dreadnoughts she had captured from Russia, and to complete Satsuma and Aki. Like the South Carolinas, the Satsumas were designed before Dreadnought, but financial shortages resulting from the Russo-Japanese War delayed her completion and resulted in her carrying a mixed armament, so she was known as a semi-dreadnought. These were followed by a modified Aki-type: Kawachi and Settsu, which were laid down in 1909 and complete in 1912, and were armed with four 12-inch/50, eight 12-inch/45, ten 6-inch/45, and eight 4.7-inch/40. "Although nominally dreadnoughts, these ships did not have a really uniform main battery, since the guns differed in length, and therefore in performance, particularly at very long range. This would have made fire control very difficult.
Compared to the other major naval powers, France was slow to start building dreadnoughts, instead finishing the planned Danton-class of pre-dreadnoughts, laying down five in 1907 and 1908. It was not until September 1910 the first of the Courbet-class was laid down, making France the eleventh nation to enter the dreadnought race. The dreadnought race saw France drop from second to fifth in terms of naval power; however, the closer alliance with Britain made these reduced forces more than adequate for French needs.
Even though Cuniberti had promoted the idea of an all-big-gun battleship in Italy well before Dreadnought, it took until 1909 for Italy to lay down one of her own. The construction of Dante Alighieri was prompted by rumours of Austro-Hungarian dreadnought building. A further five Dreadnoughts of the Cavour- and Andrea Doria-class followed as Italy sought to maintain its lead over Austria-Hungary. These ships remained the core of Italian naval strength until World War II. The subsequent Caracciolo class were cancelled on the outbreak of WWI.
In January 1909, Austro-Hungarian admirals circulated a document calling for a fleet of four dreadnoughts. However, a constitutional crisis in 1909-10 meant no construction could be approved. In spite of this, two dreadnoughts were laid down by shipyards on a speculative basis, and later approved along with an additional two. The resulting ships, all Tegetthoff-class, were to be accompanied by a further four ships, but these were cancelled on the outbreak of World War I.
In June 1909, the Russian Empire laid down four Gangut-class dreadnoughts for the Baltic Fleet and in 1911 three more Imperatritsa Mariya-class dreadnoughts for the Black Sea. Taking lessons from Tsushima, and influenced by Cuniberti, they ended up more closely resembling Fisher's battlecruisers than Dreadnought, and proved badly flawed.
Spain commissioned three dreadnoughts of the España-class, laying the first down in 1909. The Españas were the lightest dreadnoughts ever built. While built in Spain, the construction was reliant on British assistance.
Brazil managed the remarkable achievement of being the third country with a dreadnought under construction, laying down two in British shipyards in 1907. This sparked a small-scale arms race in South America, as Argentina and then Chile commissioned dreadnoughts. Argentina placed orders in American yards and Chile in Britain; both of Chile's two battleships were purchased by the British on the outbreak of war. One was later returned to the Chilean government.
The Netherlands intended by 1912 to replace its fleet of pre-dreadnought armoured ships with a modern fleet comprising at least five dreadnoughts. Constant fiddling with the designs and slow political decision making meant the ships were not ordered until the summer of 1914, when the outbreak of World War I put an end to the ambitious fleet plan.
Turkey ordered two dreadnoughts from British yards, which were seized by the British, while Greece's, ordered from Germany, was taken over by the Germans. The main armament, ordered in the United States, consequently equipped a class of British monitors. Greece in 1914 purchased two pre-dreadnoughts from the United States Navy, renaming them Kilkis and Limnos in Royal Hellenic Navy service.
The seizure of the two Turkish dreadnoughts, Reshadiye and Sultan Osman I(ex-HMS Erin and Agincourt) nearing completion in 1914 in Britain, resulted in far-reaching international repercussions. The Turks were outraged by the British move and the Germans saw an opening. Through skillful diplomacy and by handing over the battlecruiser Goeben and the cruiser Breslau, the Germans maneuvered the Ottoman Empire into joining the Central Powers.
Even after Dreadnought commissioned, battleships continued to grow in size, guns, and technical complexity countries vied to have the best ships. By 1914 Dreadnought was obsolete.
The arrival of super-dreadnoughts is not as clearly identified with a single ship in the same way as the dreadnought era. However, it is commonly held to start with the British Orion-class, and for the German navy with Königs. What made them "super" was the unprecedented jump in displacement (2,000–tons) compared to the previous class, the introduction of the heavier 13.5-inch (343 mm) gun, and the distribution of all the main armament on the centreline. Thus, in the four years between Dreadnought and Orion, displacement had increased by 25%, and weight of broadside had doubled.
British super-dreadnoughts were joined by other nations as well. In Japan, two Fuso-class super-dreadnoughts were laid down in 1912, followed by the Ises in 1914, with both classes carrying twelve 14-inch (356 mm) guns. In 1917, the Nagato-class was ordered, the first dreadnoughts to mount guns, making them the arguably most powerful warships in the world. All were increasingly built from Japanese rather than imported components. In France, the Courbets were followed by three super-dreadnoughts of the Bretagne class; another five Normandies were cancelled on the outbreak of World War One.
The later super-dreadnoughts, principally the Queen Elizabeth class, dispensed with "Q" turret, so weight and volume were freed up for larger, oil-fired boilers. Oil had many advantages as a fuel over coal. It had more energy density than coal, and its liquid form vastly simplified refuelling arrangements; oil required no stokers, and emitted much less smoke, aiding gun laying and making the ships less visible on the horizon. The new 15 inch (381 mm) gun gave greater firepower in spite of the loss of a turret, and there was a thicker armour belt and improved underwater protection. The class had a 25 knot (46 km/h) design speed, and they were considered the first fast battleships.
The design weakness of super-dreadnoughts, which distinguished them from post-World War I designs, was armour disposition. Their design placed emphasis on vertical protection, needed in short range battles. These ships were capable of engaging the enemy at 20,000 metres, but were vulnerable to the high angle ("plunging") fire at such ranges. Post-war designs typically had 5 to 6 inches (130 to 150 mm) of deck armour to defend against this. The concept of zone of immunity became a major part of the thinking behind battleship design. Lack of underwater protection was also a weakness of these pre-World War I designs which were developed only as the threat of the torpedo became real.
The United States Navy's "standard"-type battleships, beginning with the Nevada class, or "Battleship 1912", were designed with long-range engagements and plunging fire in mind; the first of these was laid down in 1912, five years before Jutland taught the dangers of long-range fire to European navies. Important features of the standard battleships were "all or nothing" armour and "raft" construction, a philosophy under which only the parts of the ship worth giving the thickest possible protection were worth armouring at all, and enough reserve buoyancy should be contained within the resulting armored "raft" to keep afloat the entire ship in the event the unarmored bow and stern were thoroughly riddled and flooded. This design was proven in battle at the Naval Battle of Guadalcanal, when an ill-timed turn by South Dakota silhouetted her to Japanese guns. Though she suffered a terrible battering and her bow and stern were riddled and thoroughly flooded, her "raft" remained untouched and she remained both afloat and fully operational at the end of action.
The First World War was almost an anticlimax for the great dreadnought fleets. There was no decisive clash of modern battlefleets to compare with Tsushima. The role of battleships was marginal to the great land struggle in France and Russia; it was equally marginal to the First Battle of the Atlantic.
By virtue of geography, the Royal Navy could keep the German High Seas Fleet bottled up in the North Sea with relative ease. Both sides were aware, because of the greater number of British dreadnoughts, a full fleet engagement would result in a British victory. The German strategy was therefore to try to provoke an engagement on favourable terms: either inducing a part of the Grand Fleet to enter battle alone, or to fight a pitched battle near the German coast, where friendly minefields, torpedo boats, and submarines could even the odds.
The first two years of war saw conflict in the North Sea limited to skirmishes by battlecruisers at the Battle of Heligoland Bight and Battle of Dogger Bank, and raids on the English coast. In the summer of 1916, a further attempt to draw British ships into battle on favourable terms resulted in a clash of the battlefleets at Jutland; it was indecisive.
In the other naval theatres, there were no decisive pitched battles. In the Black Sea, Russian and Turkish battleships skirmished, but nothing more. In the Baltic, action was largely limited to convoy raiding and the laying of defensive minefields. The Adriatic was in a sense the mirror of the North Sea: the Austro-Hungarian dreadnought fleet remained bottled up by British and French blockading fleets. And in the Mediterranean, the most important use of battleships was in support of the amphibious assault at Gallipoli.
The course of the war also illustrated the vulnerability of battleships to cheaper weapons. In September 1914, the U-boat threat to capital ships was demonstrated by successful attacks on British cruisers, including the sinking of three elderly British armoured cruisers by the German submarine U-9 in less than an hour. Mines continued to prove a threat when the recently commissioned British super-dreadnought Audacious struck one and sank the next month. By the end of October, British strategy and tactics in the North Sea had changed to reduce the risk of U-boat attack. While Jutland was the only major clash of battleship fleets in history, the German plan for the battle relied on U-boat attacks on the British fleet; and the escape of the German fleet from the superior British firepower was affected by the German cruisers and destroyers closing on British battleships, causing them to turn away to avoid the threat of torpedo attack. Further near-misses from submarine attacks on battleships and casualties amongst cruisers led to growing paranoia in the Royal Navy about the vulnerability of battleships.
For the German part, the High Seas Fleet determined not to engage the British without the assistance of submarines, and since submarines were more needed for commerce raiding, the fleet stayed in port for the remainder of the war. Other theatres equally showed the role of small craft in damaging or destroying dreadnoughts. The two Austrian dreadnoughts lost in 1918 were the casualties of torpedo boats and of frogmen.
In Britain, the British government's moratorium on battleship building and the return of Jackie Fisher to the Admiralty in 1914 meant a renewed focus on the battlecruiser. The final units of the Revenge and Queen Elizabeth classes were completed. The last two battleships of the Revenge class were redesigned as battlecruisers of the Renown class. Fisher followed these ships with the even more extreme Courageous class ; very fast and heavily-armed ships with minimal, 3-inch armour, called 'large light cruisers' to get around a Cabinet ruling against new capital ships. Fisher's mania for speed culminated in his plan for 'HMS Incomparable', a mammoth, lightly-armoured battlecruiser.
In Germany, two units of the pre-year Bayern class were gradually completed, but the other two laid down were still unfinished by the end of the War. The Mackensen class battlecruisers, designed in 1914-15, were begun but never finished.
In spite of the lull in battleship building, the years 1917-1922 saw the threat of a renewed naval arms race between Britain, Japan and the USA. The Battle of Jutland exerted a huge influence over the designs produced in this period.
The first ships which fit into this picture are the British Admiral class battlecruisers, designed in 1916. Jutland finally persuaded the Admiralty that lightly-armoured battlecruisers were too vulnerable, and therefore the final design of the Admirals incorporated much increased armour, increasing displacement to 42,000 tons.
However, the initiative in creating the new arms race lay with the Japanese and United States navies. The United States Naval Appropriations Act 1916 authorised the construction of 156 new ships, including ten battleships and six battlecruisers. For the first time, the United States Navy was threatening the British global lead.. This programme was started slowly (in part because of a desire to learn lessons from Jutland), and never fulfilled entirely: however the new American ships, the Colorado class battleship and Lexington class battlecruiser, took a qualitative step above the British Queen Elizabeths and Admirals by mounting 16-inch guns.
At the same time the Imperial Japanese Navy was finally gaining authorisation for its 'eight-eight' battlefleet. The Nagato class, authorised in 1916, carried eight 16-inch guns like their American counterparts. The next year's naval bill authorised two more battleships and two more battlecruisers. This time the battleships, the Kaga class carried ten 16-inch guns. The battlecruisers, the Amagi class, also carried ten 16-inch guns and were designed to be capable of 30 knots, capable of beating both the British Admiral and the USN's Lexington-class battlecruiser..
Matters took a further turn for the worse in 1919 when Woodrow Wilson proposed a further expansion of the United States Navy, asking for funds for an additional ten battleships and six battlecruisers in addition to the completion of the 1916 programme (the South Dakota class not yet started). In response, the Diet of Japan finally agreed to the completion of the 'eight-eight fleet', incorporating a further four battleships class.. These ships, the Kii would displace 43,000 tons; the next design, the Number 13 class, would have carried 18-inch guns. Many in the Japanese Navy were still dissatisfied, calling for an 'eight-eight-eight' fleet with 24 modern battleships and battlecruisers.
The British, impoverished by World War I, faced the possibility of becoming the world's third naval power. No ships had been begun since the Admiral class, and of those only HMS Hood had been completed. A British Admiralty plan of June 1919 outlined a post-war fleet with 33 battleships and eight battlecruisers, which could be built and sustained for £171M a year; in practice only £84M was available. The Admiralty then demanded, as an absolute minimum, a further eight battleships. These would have been 'G3' battlecruiser design, with 16-inch guns and high speed, and the 'N3' battleship, with 18-inch guns.
Instead of this cripplingly expensive expansion programme, the major naval powers concluded the Washington Naval Treaty in 1922. The Treaty laid out a list of ships, including most of the older dreadnoughts and almost all the newer ships under construction, which were to be scrapped or otherwise put out of use. It furthermore declared a 'building holiday' during which no new battleships or battlecruisers were to be laid down. The ships which survived the treaty, including the most modern super-dreadnoughts of all three navies, formed the bulk of international capital ship strength through the 1920s and 1930s and, with some modernisation, into World War II. The ships built under the terms of the Treaty to replace outdated vessels are known as treaty battleships.
Most of the German dreadnought fleet was scuttled at Scapa Flow by its crews in 1919; the remainder were handed over as war prizes.
From this point on, 'dreadnought' became less widely used. Most pre-dreadnought battleships were scrapped or hulked after the World War I, so the term 'dreadnought' became less necessary. Many capital ships were rebuilt, and while still sometimes referred to as dreadnoughts, were the battleships used in World War II.