BANK.) It will be seen, therefore, that the answer to the air menace to sea-borne commerce is, under certain conditions, the sea-borne aeroplane and the escort vessel with anti-aircraft guns, and to the submarine menace the convoy system, the armed escort and the array of surface submarine-hunters. It has also been demonstrated that the security against these new foes, as against the older sur face raider, depends entirely on the existence of a surface navy, the most important unit of which is the "predominant surface ship"—the battleship. So well was this realized after the War that there seemed danger that the principal naval powers would embark on a race to produce the most powerful type of warship afloat. The good sense and good will of the respective governments and their naval advisers, however, effected a check on such ruinous competition and by the Washington Treaty (q.v.) battleships are now limited both in size and numbers. A further attempt to effect limitations in size was made by the British representatives at the naval conference at Geneva in 1927, but, although the Japanese representatives were favourably disposed towards the proposal, the United States delegates were unable to subscribe to them. In this connection, however, it should be realized that whatever limitations are imposed on the battleship by international concessions, the principle of the "predominant surface ship" re mains. This type of warship might, by agreement, become the ton or even the 5,000 ton cruiser, but, with each reduction in tonnage . the capabilities, offensive and defensive, of the ship must necessarily decline, and with them the sense of sea security. It is for this reason that responsible naval opinion is disinclined to reduce drastically the characteristics of the modern battleship.
The modern battleship is the lineal descendant of the "ships of the line" of Nelson's day of which the "Victory," now jealously preserved in H.M. dockyard at Portsmouth, was the most famous example. Such ships are at the head of the many types of ships forming a navy. They are fitted with the most powerful arma ment available and form the main striking force in a naval war.
The history of the modern battleship, apart from the adoption of all improvements in materials and methods due to general sci entific advance, is one of continuous rivalry between guns and armour, and when we speak of guns we must also include the shells which are fired from the guns, as a shell to do great damage must not only be fired to hit the target but must also be strong enough to penetrate the armour (q.v.) and explode inside the ship with devastating effect. With the gradual advance in the power of ord nance it has been necessary to provide more and more efficient protection to enable the battleship to withstand the shot and shell of the enemy, and the size of each new ship laid down increases as the power of the gun increases. The climax of this development is shown on the table of the latest battleships of the five great Naval Powers at the end of this article. Owing to the Washington Treaty, a limit of displacement of 35,000 tons is now imposed on all future capital ships.
Ships of the British Navy up to the year 186o were still being built of wood with broadside guns, after the manner of the "Vic tory." For the next ten years, 41" wrought iron plates were used as armour on the sides of these vessels. This armour was proof against shot from the 68 pdr. gun at a range of ioo yards, this being the largest gun in use at this period. In 1859, the "Warrior," an iron armoured ship was started. She was 38o ft. long, 9,200 tons displacement, and rather more than one half her length was covered with 44" wrought iron plates. The armament was all on the broadside and she was armed with the new Armstrong 10o pdr. gun. The ship was fully rigged and her single-screw machinery gave her a speed of 141 knots. There was great opposition to building a war vessel of iron, and it is narrated that the First Lord of the Admiralty remarked to the builder: "I often wonder how I mustered sufficient courage to order the construction of such a novel vessel," to which the builder replied : "I often won der how I mustered sufficient courage to undertake the construc tion of such a novel vessel." The "Warrior" was, of course, fully rigged; her single screw machinery was of sufficient power to propel her at a speed of 14a knots.
The "Warrior" and her sister ship, the "Black Prince," were succeeded by the "Achilles," Minotaur," "Agincourt" and "Nor thumberland" of the same general type. The "Minotaur" was a vessel 40o ft. long, and of 10,690 tons displacement, with the armour extending the whole length, thus protecting the vulnerable steering gear, and having a maximum thickness of 54". These vessels proved too long to be handy under sail, and the next step was the production of a shorter and handier ship, the "Bellero phon," 30o ft. long, 7,5 5o tons. Vessels on somewhat similar lines continued until about 1875, and as the series progressed fewer guns of greater size were carried and these were placed in a bat tery amidships with thick armour on the sides. Thus, "Teme raire" in 1877 had a belt of 11" armour with 8" on the midship battery, her armament being 4-1I", 4-10", and 6-4" guns.
The revolving armoured turret, mounted in a low freeboard Monitor came prominently to notice during the American Civil War, when Ericsson's "Monitor" with a turret containing 2-I 1" guns, defeated the Confederate vessel "Merrimac." Revolving armoured turrets were first introduced into the British Navy in the "Royal Sovereign" in 1862 ; this ship was a 3-deck line-of battle ship, cut down to a height of about 7 ft. above the water and fitted with armoured turrets and side armour; but the "Mon arch," designed in 1866, and the "Captain," were the two first iron turret ships built as such for the Royal Navy; both were full rigged ships. The type-vessel for the turret ship was, however, the "Devastation," laid down in 1869, in which the armament con sisted of 4-35 ton guns contained in 2 revolving turrets of 14" thickness, placed on the middle line. Sails were definitely aban doned and the propelling machinery was duplicated. The armour belt had a maximum thickness of i 2", tapering to 8" at the ends. She was 285 ft. in length, 9,32o tons displacement, and had a speed of 14.2 knots. The "Devastation" type continued for the next 20 years, but owing to the rapid increase in the power of the large guns, the protecting armour had to be successively increased in thickness, and a stage was eventually reached, when, owing to limitations of weight, the area of side that could be armoured had to be confined to the most vulnerable portion of the ship amid ships, where the machinery and the heavy guns were situated. The wrought-iron armour plates had then become i 2" thick, and even with this thickness two layers had to be provided in some cases to give the necessary protection. Compound armour con sisting of a wrought-iron plate with a steel face welded on was introduced about 1873, the steel face being hardened to break up projectiles, while the tough wrought-iron back prevented the cracking and shattering of the plate. With such armour a lesser thickness would give the same protection. Successive improve ments in the manufacture of this armour increased its value as compared with wrought iron, from 1.25 to 1 . 7, and it was used in the British Navy up to 1889. Ships of the "Devastation" type carried a few heavy guns and no secondary armament. They had comparatively low freeboard and were greatly inferior to present day ships in their power of keeping the sea. The last of the type were the "Admiral" class, of which 6 were built. They were 325 ft. long and 9,50o tons displacement, and had an armour belt 18" thick at the waterline, only 7' 6" broad over rather less than half the length. The armament consisted of 4—I2" guns, arranged in 2 barbettes at the end of the armoured citadels, with a secondary armament of six 6" guns. Speed was i62 knots. This class was much criticised, chiefly on account of the extent of the unpro tected side abreast the 6" guns and the insufficiency of the area of the protected side of the citadel. It was rightly contended that a light vessel armed with many comparatively small quick-firing guns could quickly riddle the whole of their upper works and put them out of action. Up to this period the general idea had been to keep the displacement so that it should not exceed io,000 tons, and to keep the dimensions so small that the ship should be capa ble of ramming in a fleet action. As a result of the controversies aroused, and the natures of the ships which other nations started to build, a radical departure was made in the "Royal Sovereign" Class of 1889. The length of the ship was substantially in creased and the displacement raised to 14,15o tons. A secondary armament of i o-6" guns in armoured casemates was provided. Above the waterline belt of armour i i" thick the side to the main deck was plated of 4" nickel steel armour to give protection against small quick-firing guns. These ships were followed by the "Ma jestic" Class, in the design of which all the experience gained by trials at sea of the "Admiral" and "Royal Sovereign" Classes was embodied. A new and powerful type of 12" gun and a new style of mounting was available for them, also for the armour an im proved type of manufacture known as the Harvey process was adopted. This armour was of steel, homogeneous and with a hard face obtained by chilling. It was more efficient than the com pound armour previously employed, its efficiency compared with wrought iron being 1.8 to 2.2. The vessels were of high freeboard, ft. long and 14,90o tons displacement. The armour protection was arranged on a new principle. The belt was 9 inches in thick ness, but it was carried up to the main deck a total depth of 15 feet. The protective deck was level at the middle line and sloped down at the side to the bottom of the armour below water, being 3 inches thick on the flat and 4 inches on the slope. This arrange ment reflected the influence of the larger quick-firing guns; al though the protection at the waterline was not sufficient to keep out the heaviest projectiles, it was backed up by the deck inside.
These vessels, which carried an armament of 4-12" guns and 12-6" guns in armoured casemates, had a speed of 17 knots; they proved to be very satisfactory in every respect and formed the type from which all British battleships and many of other coun tries were built over the years which elapsed before the "Dread nought" era started in 1905. Improvements in details were made in the successive classes as technical science progressed, i.e., water tube boilers in "Canopus" Class (1897), Krupp type of armour instead of Harvey in "Formidable" Class 0900), 4-9.2" guns in shields in addition to other armament in "King Edward VII." (1902).
The modern Navy starts with the "Dreadnought," which ship was the outcome of an Admiralty Committee appointed in Decem ber 1904 to review the types of fighting ships which the Board of Admiralty proposed to adopt for future building. The members of the Committee were naval and civilian officers of large and varied experience, and Admiral Sir John (later Lord) Fisher was appointed Chairman. Experience of earlier vessels in the Channel and Atlantic Fleets and the lessons of the naval actions in the Russo-Japanese War of i9o4-5 were taken into account and pointed to the great importance of increasing the number of the heavy long range gun. The advisability of extra speed was recog nised and to obtain it propulsion by turbine machinery was adopted, it having been experimented with in several small war ships and used in fast passenger vessels. The design as finally adopted was 49oft. long and i 7,90o tons displacement, armament I0-12" guns in 5 turrets, three on the centre line and two at the sides abreast the mast, no secondary armament of 6" guns, but 24 I2pdrs. to deal with torpedo attack. The thickest armour was I I" and the belt and deck followed the arrangement of previous ships. The turbine machinery developed 23,00o H.P. on 4 shafts, giving a speed of 21 knots. About one-third of her fuel supply consisted of oil fuel. Laid down in October 1905, she was coni pleted and commissioned in December 1906, and immediately pro ceeded on long-distance trials in the Atlantic to test the turbine machinery for reliability and endurance. From this time onward till the World War, British battleships followed on progressively without departing from, the essential principles of the type.
This type was followed in all its main features in the ships laid down up to the year 1908, namely, the "Superb," "Bellerophon" and "Temeraire," "St. Vincent," "Vanguard" and "Collingwood"; but io to 12 4in. guns replaced the 12-pounders. In the "Neptune" and "Hercules" laid down in 1909 the five turrets were disposed differently. In the latter ship the length had increased to 5 i of t. and the displacement to 20,000 tons. In the next group of ships, "Orion," "Monarch," "Conqueror" and "Thunderer," the i 2in. gun gives way to the 13.5in. gun, all disposed on the centre line, two pairs forward, two pairs aft, in each case the pair nearer amid ships firing over the adjacent pair, and a fifth pair right amidships. "King George V.," "Centurion," "Ajax" and "Audacious" (1910 I I) were similar but slightly larger, the standard speed of 21 knots being maintained. These vessels were 555ft. long and 23,000 tons. The next step was the "Iron Duke" Class, four in number, the "Iron Duke" herself being the flagship of Admiral Jellicoe while he was in command of the Grand Fleet. In these ships i o 13.5in. guns were retained, but 12 6in. guns replaced the 4in. as the secondary armament. The armour belt of 12in. maximum thickness is carried to the upper deck with a battery above for io of the 6in. guns. The length of ship was increased to 58oft. and the displacement to 25,00o tons, the speed remaining at 21 knots.
The ships of the "Queen Elizabeth" Class were laid down in 1912 and completed in the first year of the World War. This class, five in number, formed a division of fast battleships of 25 knots requiring 75,00o H.P. The length was 600 ft. and displace ment 27,50o tons. The calibre of the main armament was in creased to I5in. and the number of guns reduced to eight, two pairs at each end. The armour belt had a maximum thickness of 13in., the armour being carried to the upper deck, with a battery above for 12 of the 16 6in. guns carried. The other four 6in. guns were removed later. In this class of ship oil fuel was exclusively employed, with very great advantages especially as regards en durance. An internal bulkhead gin. in thickness was fitted as a protection against torpedo explosion; "Bulges" are now being fitted to increase this protection still further. The ships of the "Royal Sovereign" Class, five in number, were laid down 1913-14 and completed in 1916. These vessels were designed for a speed of 23 knots and had four i5in. guns with 14 6in. guns.
No ship of the battleship class, as distinct from battle-cruisers, was laid down for the British Navy between 1914 and December 1922, when "Nelson" and "Rodney," designed to displacement limit agreed to at the Washington Conference, were commenced.