page_title: HMS Agincourt (1913)
section_title: Armament
hierarchical_section_title: HMS Agincourt (1913) / Design and description / Armament
caption_attribution_description: English: Sultan Osman I fitting out at Low Walker, after Brazil sold the ship to the Ottoman Empire, but before the British seized her.
context_page_description: HMS Agincourt was a dreadnought battleship built in the United Kingdom in the early 1910s. Originally part of Brazil's role in a South American naval arms race, she holds the distinction of mounting more heavy guns and more turrets than any other dreadnought battleship, in keeping with the Brazilians' requirement for an especially impressive design.
  Brazil ordered the ship in 1911 as Rio de Janeiro from the British company Armstrong Whitworth. However, the collapse of Brazil's rubber boom and a warming in relations with Argentina, the country's chief rival, led to the ship's sale while under construction to the Ottoman Empire. The Ottomans renamed her Sultan Osman I, after the empire's founder, and the ship was nearly complete when the First World War broke out. The British government seized her for use by the Royal Navy, together with another Ottoman dreadnought being constructed in Britain. This act caused resentment in the Ottoman Empire, as the payments for both ships were complete, and contributed to the decision of the Ottoman government to join the Central Powers.
  Renamed Agincourt by the Royal Navy, she joined the Grand Fleet in the North Sea.
context_section_description: Agincourt mounted fourteen BL 12-inch Mk XIII 45-calibre guns in seven twin hydraulically powered turrets, unofficially named after the days of the week, starting from Sunday, forward to aft. This was the largest number of turrets and heavy guns ever mounted on a dreadnought battleship. The guns could be depressed to −3° and elevated to 13.5°. They fired 850-pound (386 kg) projectiles at a muzzle velocity of 2,725 ft/s (831 m/s); at 13.5°, this provided a maximum range of just over 20,000 yards (18,000 m) with armour-piercing (AP) shells. During the war the turrets were modified to increase their maximum elevation to 16°, but this only extended the range to 20,435 yards (18,686 m). The rate of fire of these guns was 1.5 rounds per minute. When a full broadside was fired, "the resulting sheet of flame was big enough to create the impression that a battle cruiser had blown up; it was awe inspiring." No damage was done to the ship when firing full broadsides, despite the common idea that doing so would break the ship in half, but much of the ship's tableware and glassware did shatter when Agincourt fired her first broadside.
  As built, Agincourt mounted eighteen BL 6-inch Mk XIII 50-calibre guns. Fourteen were placed in armoured casemates on the upper deck and two each in the fore and aft superstructures, protected by gun shields. Two more were added abreast the bridge in pivot mounts protected by gun shields when the ship was purchased by the British. The guns could be depressed to −7° and elevated to 13°, later increased to 15°. They had a range of 13,475 yards (12,322 m) at 15° when firing a 100-pound (45 kg) shell with a muzzle velocity of 2,770 ft/s (840 m/s). Their rate of fire was about five to seven rounds per minute, but this dropped to about three rounds per minute after the ready ammunition was used up because the ammunition hoists were too slow or few to keep the guns fully supplied. About 150 rounds were carried per gun.
  Close-range defence against torpedo boats was provided by ten 3-inch (76 mm) 45-calibre quick-firing guns. These were mounted in the superstructure in pivot mounts and protected by gun shields. Agincourt also carried three 21-inch (533 mm) submerged torpedo tubes; one was on each beam and the last was in the stern. The water that entered the torpedo tubes when they were fired was discharged into the torpedo flat to facilitate reloading the tube and then pumped overboard. This meant that the torpedo crewmen would be operating in 3 feet (0.9 m) of water if rapid fire was required. Ten torpedoes were carried for them.
caption: Sultan Osman-ı Evvel, soon to become Agincourt, in the fitting-out stage of her construction
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