page_title: HMS Dreadnought (1906)
section_title: Armament
hierarchical_section_title: HMS Dreadnought (1906) / Description / Armament
caption_attribution_description: Photograph showing 2 QF 12 pounder 18 cwt guns mounted on the roof of X turret, HMS Dreadnought (1906).
context_page_description: HMS Dreadnought was a Royal Navy battleship that revolutionised naval power. Dreadnought's name, and the class of battleships named after her, means "fear nothing". Dreadnought's entry into service in 1906 represented such an advance in naval technology that her name came to be associated with an entire generation of battleships, the "dreadnoughts", as well as the class of ships named after her. Likewise, the generation of ships she made obsolete became known as "pre-dreadnoughts". Admiral Sir John "Jacky" Fisher, First Sea Lord of the Board of Admiralty, is credited as the father of Dreadnought. Shortly after he assumed office, he ordered design studies for a battleship armed solely with 12 in guns and a speed of 21 knots. He convened a "Committee on Designs" to evaluate the alternative designs and to assist in the detailed design work.
  Dreadnought was the first battleship of her era to have a uniform main battery, rather than having a few large guns complemented by a heavy secondary armament of smaller guns. She was also the first capital ship to be powered by steam turbines, making her the fastest battleship in the world at the time of her completion.
context_section_description: Dreadnought mounted ten 45-calibre BL 12 in (300 mm) Mark X gun in five twin Mark BVIII gun turrets. Three turrets were located along the centreline of the ship, with the forward turret ('A') and two aft turrets ('X' and 'Y'), the latter pair separated by the torpedo control tower located on a short tripod mast. Two wing turrets ('P' and 'Q') were located port and starboard of the forward superstructure respectively.
  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. On bearings 1° ahead or astern she could fire six guns, although she would have inflicted blast damage on the superstructure.
  The guns could initially be depressed to −3° and elevated to +13.5°, although the turrets were modified to allow 16° of elevation during the First World War. They fired 850 lb (390 kg) projectiles at a muzzle velocity of 2,725 ft/s (831 m/s); at 13.5°, this provided a maximum range of 16,450 yd (15,040 m) with armour-piercing (AP) 2 crh shells. At 16° elevation, the range was extended to 20,435 yd (18,686 m) using the more aerodynamic, but slightly heavier, 4 crh AP shells. The rate of fire of these guns was one to two rounds per minute. The ships carried 80 rounds per gun.
  The secondary armament consisted of twenty-seven 50-calibre, 3 in (76 mm) 12-pounder 18 cwt Mark I guns positioned in the superstructure and on turret tops. The guns had a maximum depression of −10° and a maximum elevation of +20°. They fired 12.5 lb (5.7 kg) projectiles at a muzzle velocity of 2,600 ft/s (790 m/s); this gave a maximum range of 9,300 yd (8,500 m). Their rate of fire was 15 rounds per minute. The ship carried three hundred rounds for each gun.
  The original plan was to dismount the eight guns on the forecastle and quarterdeck and stow them on chocks on the deck during daylight to prevent them from being damaged by muzzle blast from the main guns. Gun trials in December 1906 proved that this was more difficult than expected and the two port guns from the forecastle and the outer starboard gun from the quarterdeck were transferred to turret roofs, giving each turret two guns. The remaining forecastle guns and the outer port gun from the quarterdeck were removed by the end of 1907, which reduced the total to twenty-four guns. During her April–May 1915 refit, the two guns from the roof of 'A' turret were reinstalled in the original positions on the starboard side of the quarterdeck. A year later, the two guns at the rear of the superstructure were removed, reducing her to twenty-two guns. Two of the quarterdeck guns were given high-angle mounts for anti-aircraft duties and the two guns abreast the conning tower were removed in 1917.
  A pair of QF 6-pounder Hotchkiss AA guns on high-angle mountings were mounted on the quarterdeck in 1915. They had a maximum depression of 8° and a maximum elevation of 60°. The guns fired a 6 lb (2.7 kg) shell at a muzzle velocity of 1,765 ft/s (538 m/s) at a rate of fire of 20 rounds per minute. They had a maximum ceiling of 10,000 ft (3,000 m), but an effective range of only 1,200 yd (1,100 m). They were replaced by a pair of QF 3-inch 20 cwt guns on high-angle Mark II mounts in 1916. These guns had a maximum depression of 10° and a maximum elevation of 90°. They fired a 12.5 lb (5.7 kg) shell at a muzzle velocity of 2,500 ft/s (760 m/s) at a rate of 12–14 rounds per minute. They had a maximum effective ceiling of 23,500 ft (7,200 m).
  Dreadnought carried five 18 in (460 mm) submerged torpedo tubes in three compartments. Each compartment had two torpedo tubes, one on each broadside, except for the stern compartment which only had one torpedo tube. The forward torpedo room was forward of 'A' turret's magazine and the rear torpedo room was abaft 'Y' turret's magazine. The stern torpedo compartment was shared with the steering gear. Twenty-three Whitehead Mark III* torpedoes were carried between them. In addition six 14 in (356 mm) torpedoes were carried for her steam picket boats.
caption: 12-pounder guns mounted on 'X' turret; note the sighting hoods on the turret roof.
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