The Battleship HMS Dreadnought

 [Drawings by Stefan Dramiński]

The first vessel designed to incorporate the new concept was the Japanese battleship Satsuma, whose construction began five months before Dreadnought was laid down. However, due to delays in gun production Satsuma carried only four 12 inch guns and a battery of twelve 10 inch weapons and thus fell short of being a full “all-big-gun” warship. In the meantime the U.S. Navy was lagging behind the British and did not start the construction of their own “all-big-gun” battleship until the fall of 1906 when the USS South Carolina was laid down.
The Royal Navy considered the speed of their new battleship to be a crucial issue. The common naval tactic of line-ahead involved a line of ships firing broadside at the opponent. If the ships were fast enough to cross the enemy line (“crossing the T”) they would be able to put all their guns to bear on the opposing ships, while the enemy could only use their forward-firing guns. It was therefore the speed that could make or break a naval engagement. Fisher also wanted to use the speed advantage to achieve an optimal distance from the target since firing the big guns at close ranges was less effective due to a flat trajectory of the shells.

Battleship's hull and superstructures seen from port side. [Drawings Stefan Dramiński]

 

Several years before, on June 26, 1897 a new type of propulsion was presented during the celebrations to mark Queen Victoria’s Diamond Jubilee. The ship equipped with the new system – a steam turbine developed by Charles Algernon Parsons – appeared at Spithead Navy Review along the warships of the Royal Navy. Turbinia demonstrated her extraordinary capabilities in an unauthorized run in which she accelerated to 34 knots leaving all Royal Navy vessels in her wake. The system was later successfully tested on HMS Viper and HMS Cobra, as well as on a number of passenger liners. The trials quickly convinced the Admiralty that the future belonged to the steam turbine propulsion. In fact the decision to use the turbines on Dreadnought was as controversial as the decision to arm the warship with heavy guns only. Steam turbines had many advantages: reduction of cost and weight, higher reliability, smaller dimensions and better fuel efficiency. However, the turbines were most effective at high speeds. To operate efficiently in lower speed regimes larger rotors were needed, which negated some of the weight savings. The use of turbine propulsion required four propellers instead of two. Regardless of the drawbacks, Parsons turbines were selected as the powerplant for the new battleship. They were installed in pairs in two engine rooms and each drove two propeller shafts. There was also an additional cruise turbine coupled with the two inner shafts, but it was later discarded. The steam was generated by 18 Babcock and Wilcox boilers with a working pressure of 250 psi (1 724 kPa). The powerplant was designed to deliver 23 000 shp, enough to accelerate the ship to 21 knots. During sea trials Dreadnought achieved 21.6 knots and the turbines delivered 27 010 shp.

Construction

The battleship was laid down on October 2, 1905 at Portsmouth Royal Dockyard in Hampshire. The choice of the shipyard was no coincidence as the Portsmouth was then considered the fastest shipbuilding facility in the world and therefore the only one that could possibly build a big battleship in under a year. The work was coordinated by Admiral Fisher and the shipyard’s chief designer Thomas Mitchell. Fisher’s plan to build the ship in less than a year required a well-coordinated effort of the Admiralty and Portsmouth’s staff. To meet the deadline the design of the hull was simplified as much as possible and the number of steel profiles and thickness of skin plates were reduced to the minimum. The efforts that had gone into the improvement of British warship designs since 1890 resulted in Dreadnought’s hull being only 450 tons heavier than the HMS Majestic – a warship built in 1894 – 1895 with a displacement that was as much as 3 000 tons lower than the new battleship.
The work on the new project began in earnest long before the official laying down ceremony at Portsmouth. In October 1905 the shipyard received some of the prefabricated components and other materials, including elements of the hull framework. Soon 1 100 staff went to work on Dreadnought working 11 hour shifts, six days per week. Before long the number of workers grew to 3 000 and coordinating such a massive workforce required a lot of effort from the shipyard’s management team.

A 12 pdr mount fitted on the forecastle.  [Drawings by Stefan Dramiński]
Dreadnought was officially launched on February 10, 1906 by King Edward VII. Following the launch the warship’s outfitting began in Dock 5. On July 2, 1906 Sir Reginald Bacon took command of the new warship. Bacon had been involved in the project for some time and was therefore an ideal candidate for the post. By commanding Dreadnought in a series of sea trials Sir Reginald would be in a perfect position to recommend changes and improvements to future warships of that class. There were two unknowns in the new design: the operation of the powerful steam turbines and the effects of firing broadside salvos of big 12 inch guns. It was feared that firing all eight guns simultaneously could result in damage to the ship’s structure, especially in the areas around the wing turrets. The first turbine tests were performed even before the battleship had been fully outfitted (September 17), while the hull inspection was carried out between September 24 and 28.
HMS Dreadnought had an overall length of 527 ft (160.6 m), beam of 82 ft, 1 in (25 m) and deep load draught of 29 ft, 7.5 in (9 m). The battleship displacement varied depending on the load from 18 100 long tons to 20 700 long tons.
The warship’s main battery consisted of 10 12’’/45 Mark X guns mounted in five twin turrets: three placed along the ship’s centerline (turrets “A”, “X” and “Y”) and two wing turrets (“P” and “Q”) located port and starboard of the forward superstructure. Dreadnought could deliver a broadside of eight guns between 60° before the beam and 50° abaft the beam. Beyond these limits she could fire six guns aft, and four forward. The guns fired 850 lb (390 kg) projectiles. Initially the maximum elevation of the main guns was 13.5°, but that was increased during the Great War to 16°. With the muzzle velocity of 831 m/s the guns’ range at 13.5° elevation was 17 990 yd (16 450 m), which increased to 20 435 yd (18 686 m) at 16° elevation.
Secondary armament consisted of twenty seven 50-caliber, 3-inch 12-pounder Mark I guns positioned on the forecastle deck and quarterdeck (2 and 3 mounts respectively), on superstructure decks (12 mounts) and on turret tops (10 mounts). The guns fired 12.5-pound (5.7 kg) projectiles at a muzzle velocity of 790 m/s and a rate of fire of 15 rounds per minute. The weapons’ maximum range was 9 300 yd (8 500 m).
In 1915 a pair of 6 pounder Hotchkiss AA guns were mounted on the quarterdeck , but those were later replaced with more effective 3 inch guns.

Compass platform on top of the superstructure. Note the compass, chart table and searchlight controls. [Drawings by Stefan Dramiński]


In addition to main and secondary guns Dreadnought carried five 18-inch (450 mm) submerged torpedo tubes in three compartments. Each compartment had two torpedo tubes, one on each broadside, except the stern compartment which only had one tube. The broadside tubes were mounted in the compartments behind the magazines of turret “A” and turret “Y”. The ship could carry a total of 23 Whitehead Mark III torpedoes.
Fisher did not care much for Dreadnought’s armor protection as he saw it mainly as additional weight reducing the battleship’s speed. Nonetheless, the vessel’s most critical areas were very well protected. The main armor belt was 11 in (279 mm) thick, tapering off to 7 in (178 mm) near its lower edge. Bow and stern extensions of the belt were respectively 6 in (152 mm) and 4 in (102 mm) thick. The citadel was enclosed by 8 in (203 mm) bulkheads. Additional 8 in belt was fitted above the main armor belt. The thickness of deck armor varied depending on location: 1.5 in (38 mm), 1.75 in (44 mm), 2 in (51 mm), 2.75 in (70 mm) and 3 in (76 mm). The turrets’ sides were protected by 11 in armor and the roofs featured 3 in armor plates. The barbettes’ armor was from 8 to 11 in thick, while the conning tower featured the same protection as the main gun turrets (11 in on the sides and 8 in on the top). Torpedo bulkheads were from 2 to 4 in thick. Originally Dreadnought was equipped with anti-torpedo nets, but those were removed in the beginning of World War I as they greatly reduced the ship’s speed and were deemed ineffective.
Dreadnought was the first warship in the Royal Navy fitted with electric instruments for communication between the fire control station and the turrets. There were two fire control stations on the battleship: at the head of the foremast and on a platform on the roof of the signal tower between the foremast and the forward funnel. Both stations were equipped with the 9 ft (2.7 m) Barr and Stround FQ-2 rangefinders. The firing data was calculated by a Dumaresq mechanical computer.

 

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3D21 Drednought

 

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