Devastation-class battleship

HMS Devastation in 1896
Class overview
Builders:	HM Royal Dockyard, Portsmouth HM Royal Dockyard, Pembroke
Succeeded by:	HMS Dreadnought (1875)
Cost:	Devastation: £354,000 Thunderer: £358,500
Built:	1869–1877
In service:	1874-1905
In commission:	1873-1909
Planned:	2
Completed:	2
Retired:	2
Scrapped:	2
General characteristics
Displacement:	9,330 t (9,183 long tons)
Length:	307 ft (94 m) oa 285 ft (87 m) pp
Beam:	62 ft 3 in (18.97 m)
Draught:	26 ft 8 in (8.13 m)
Propulsion:	As built: Devastation: 2 × Penn 2-cyl trunk direct-acting steam engines turning 2 screws Thunderer: 2 × Humphry's 2-cyl trunk direct-acting steam engines turning 2 screws 8 × rectangular boilers 1890/92 Rebuild: 2 × Maudslay 3-cyl VTE steam engines turning 2 screws 8 × cylindrical locomotive type boilers
Speed:	As built: 6,640 ihp (4,950 kW) ND / 13.84 kn (25.63 km/h; 15.93 mph) 1890/92 Rebuild: 7,000 ihp (5,200 kW) ND / 14 kn (26 km/h; 16 mph)
Range:	1,800 tons of coal 5,980 nautical miles @ 10 knots 12 days with steam for full speed
Complement:	410
Armament:	As built: Devastation: 4 × 12 inch RML of 35 tons Mk I naval gun on sliding carriages Thunderer: 2 × 12 inch RML of 35 tons Mk I naval gun on sliding carriages 2 × 12.5 inch RML of 38 tons Mk I or II naval gun on sliding carriages 1890/92 Rebuild: 4 × 10-inch 32 calibre (25.4 cm) breech-loading naval guns mounted in twin Mark II Turrets 6 × 6-pounder 8-hundredweight [2.244” 40 calibre (57 mm)] quick-fire Mark I naval gun on Mark I* low-angle single mounts 8 × Hotchkiss 3-pounder [1.85” 40 calibre (47 mm)] quick-fire Mark I naval gun on twelve Mark I* low-angle single mounts 5-7 × Nordenfelt multi-barrel guns on pedestal mounts 2 × Gardner light machine guns 2 × Whitehead 14-inch (36 cm) torpedo tubes (fixed below waterline)
Armour:	Type: wrought iron with teak or oak backing Sides: 12 and 10 in (300 and 250 mm) Breastwork: 12 and 10 in (300 and 250 mm) Turrets: 14 and 12 in (360 and 300 mm) Backing: 16–18 inches (410–460 mm) teak or oak Deck: 3 and 2 in (76 and 51 mm)

The two British Devastation-class battleships of the 1870s, HMS Devastation and HMS Thunderer, were the first class of ocean-going capital ship that did not carry sails, and the first which mounted the entire main armament on top of the hull rather than inside it.

The ships were designed by Sir Edward Reed, whose concept was to produce short, handy ships of medium size as heavily armed as possible with a good turn of speed, that could attack and destroy an opponent without much risk of being damaged during the process.

The Admiralty Design Board set forth the requirements for the ocean-going monitors. These included the requirement of two twin 12-inch gun turrets capable of firing 600-pound shells with a 280-degree firing arc. The turrets would require 14-inch armour protection, with the machinery spaces and shell rooms protected by 12-inch-thick armour. Further, to reduce the interference with the main guns, no masts or sails were needed. The ships would need two steam engines for security and a minimum 12-knot speed. The trans-Atlantic concept was changed to a coastal defence ship, so a very low freeboard of 4 feet 6 inches (1.37 metres) was specified.

The loss of HMS Captain in September 1871 led to concerns about the stability of turret ships, and a special committee was set up to determine the safety of turret ships. Changes to the design were recommended. The freeboard of the design was increased to 10 feet 9 inches (3.28 metres). Another change 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 heel. This greatly improved the crew comfort by adding extra accommodation 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-foot-long (2.7 m) model of Devastation was tested in a water tank, and subsequently with an 18-foot-long (5.5 m) 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 back and forth across the deck 18 times. Other tests involved taking it to sea to look for rough weather, in one trial waves of 20 to 26 feet (6 to 8 m) were encountered which gave the ship a 14-degree roll either way.

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Wikipedia