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Devastation Class Battleship | align="center" colspan="2"| | | lign ="center" style="color: white; height: 30px; background: navy no-repeat scroll top left;"|General Characteristics | align ="center" style="color: white; height: 30px; background: navy no-repeat scroll top left;"|RN Ensign | | isplacement: | 9188 tons | | ength: | 285 ft | | eam: | 62fr 3 inches | | raught: | Maximum 27 ft 6 inches | | ropulsion: | Two coal fired Penn trunk engines, 2 screws; | | peed: | 13 knots maximum | | ange: | 4700 miles | | omplement: | 410 | | rmament: | Four 12 inch rifled muzzle-loading guns mounted in two turrets | | rmour: | 15 inch armour on turrets, 12 inches partial belt reducing to 10 inches at ends, 3 inch curved deck | The two British Devastation-class battleships of the 1870s were the first class of ocean-going capital ship which did not carry sails, and the first which mounted the entire main armament on top of the hull rather than inside it. For the first fifteen years of their lives, they were the most powerful warships in the world. The genesis of the design was a request by the First Sea Lord Hugh Childers to the head of ship design at the Admiralty, Edward Reed in early 1869 for a large breastwork monitor which could steam from Queenstown (now Cobh) in Ireland to Halifax in Canada. He responded in February 1869 with an outline design, but complained that the upper limit on displacement of 3000 tons was insufficient and suggested that 4000 tons was more practical. At a meeting shortly afterwards of the Admiralty board it was agreed that the ship should have two 12 inch guns firing 600-pound shells mounted in each of two turrets protected by 14 inches of armour, which would each have a 280 degree field of fire. The turrets would be mounted on the centre-line one of which would be in front of the superstructure and one behind it. The ship would be protected by a 12 inch thick armour belt around the waterline. A very low freeboard of 4 feet 6 inches was agreed since the ship was now intended for coastal service in waters around the United Kingdom or service in the relatively calm Mediterranean. Twin steam engines and twin screws were felt necessary for security, and there was a strong feeling that masts and sails should be dispensed with. This was in part due to problems with masted turret warships, where the standing rigging for the masts interferred with the field of fire of the turrets, but their absence meant that the vessel could not operate far away from friendly coaling stations. A replica of the proposed turret was constructed and tested at Shoeburyness in May 1872. The 11 inch armour plate backed by 15 inches of teak and a 1.25 metal inch skin resisted hits from a 25 ton gun firing at a range of 200 yards, although one shot hit a joint between plates and opened a gap 7 inches wide but did not penetrate. The main belt was 12 inches of armour reducing to 10 inches at the ends, and backed by 18 inches of teak. The loss of HMS Captain in 1870 led to concerns about the stability of turret ships, and a committee was set up to determine whether Devestation would be safe. One effect of this was to extend the armoured breastwork with unarmoured structure to the sides of the ship and carried aft to improve the stability at large angles of heal. This greatly improved the crew comfort by adding extra accomodation and especially latrines, but since it was not armoured would have been riddled in a battle reducing the stability of the vessel. In 1871 a 9 feet long model of Devastation was tested in a water tank, and subsequently with an 18 feet long version. Once Devastation was completed, tests could be carried out with the real ship. This included building up a roll of 7 degrees by having 400 men run backwards and forwards across the deck 18 times. Other tests involved taking it to sea to look for rough weather, in one trial waves of 20-26 feet were encountered which gave the ship a 14 degree roll either way. References David Brown, Warrior to Dreadnought: Warship development 1860-1905, Chatham Publishing.
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