HMS Queen Mary
HMS Queen Mary was the last battlecruiser built by the Royal Navy before the First World War. The sole member of her class, Queen Mary shared many features with the
Her wreck was discovered in 1991 and rests in pieces, some of which are upside down, on the bed of the North Sea. Queen Mary is designated as a protected place under the Protection of Military Remains Act 1986 as a war grave.
Design
Queen Mary's construction was ordered, together with the four battleships of the, under the 1910–11 Naval Programme. As was the usual pattern of the time, only one battlecruiser was ordered per naval programme. She differed from her predecessors of the Lion class in the distribution of her secondary armament and armour and in the location of the officers' quarters. Every capital ship since the design of the battleship in 1905 had placed the officers' quarters closer to their action stations amidships; after complaints from the Fleet, Queen Mary was the first battlecruiser to restore the quarters to their traditional place in the stern. In addition, she was the first battlecruiser to mount a sternwalk.Queen Mary, the only ship of her name ever to serve in the Royal Navy, was named for Mary of Teck, the wife of King George V. The Queen's representative at the ship's christening on 20 March 1912 was the wife of Viscount Allendale.
General characteristics
Slightly larger than the preceding Lion-class ships, Queen Mary had an overall length of, a beam of, and a draught of at deep load. The ship normally displaced and at deep load, over more than the earlier ships. She had a metacentric height of at deep load. In peacetime, the crew numbered 997 officers and ratings, but this increased to 1,275 during wartime.Propulsion
The ship had two paired sets of Parsons direct-drive steam turbines housed in separate engine rooms. Each set consisted of a high-pressure turbine driving an outboard propeller shaft and a low-pressure turbine driving an inner shaft. A cruising stage was built into the casing of each high-pressure turbine for economical steaming at low speeds. The turbines had a designed output of, more than her predecessors. On sea trials in May and June 1913, Queen Mary achieved more than, although she barely exceeded her designed speed of. The steam plant consisted of 42 Yarrow boilers arranged in seven boiler rooms. Maximum bunkerage was of coal and of fuel oil to be sprayed on the coal to increase its burn rate. Her range was at a speed of.Armament
Queen Mary mounted eight BL 13.5-inch Mk V guns in four twin hydraulically powered turrets, designated 'A', 'B', 'Q' and 'X' from bow to stern. The guns could be depressed to −3° and elevated to 20°, although the director controlling the turrets was limited to 15° 21' until prisms were installed before the Battle of Jutland in May 1916 to allow full elevation. They fired projectiles at a muzzle velocity of ; at 20° elevation, this provided a maximum range of with armour-piercing shells. The rate of fire of these guns was 1.5–2 rounds per minute. Queen Mary carried a total of 880 rounds during wartime for 110 shells per gun.Her secondary armament consisted of sixteen BL 4-inch Mk VII guns, most of which were mounted in casemates on the forecastle deck, unlike the arrangement in the Lion class. The guns could depress to −7° and had a maximum elevation of 15°. They fired projectiles at a muzzle velocity of at a maximum range of ; the ship carried 150 rounds per gun.
The ship was built without any anti-aircraft guns, but two guns were fitted in October 1914. One was a QF 6-pounder Hotchkiss gun and the other was a QF 3-inch 20 cwt, both on high-angle mountings. The Hotchkiss fired a shell at a muzzle velocity of. The three-inch gun fired a shell at a muzzle velocity of with a maximum effective ceiling of.
Two submerged torpedo tubes were fitted, one on each broadside. Fourteen Mk II*** torpedoes were carried, each of which had a warhead of of TNT. Their range was at or at.
Fire control
In February 1913, the Admiralty bought five sets of fire-control equipment from Arthur Pollen for comparative trials with the equipment designed by Commander Frederic Dreyer. One set was mounted in Queen Mary and consisted of a Argo rangefinder located on top of the conning tower that fed range data into an Argo Clock Mk IV located in the transmitting station below the conning tower. The clock converted the information into range and deflection data for use by the guns. The target's data was also graphically recorded on a plotting table to assist the gunnery officer in predicting the movement of the target. The aft torpedo director tower was the backup gunnery control position. All four turrets were provided with 9-foot rangefinders and 'B' and 'X' turrets were further outfitted to serve as auxiliary control positions.Fire-control technology advanced quickly during the years immediately preceding World War I, and the development of the director firing system was a major advance. This consisted of a fire-control director mounted high in the ship which electrically provided elevation and training angles to the turrets via pointers, which the turret crewmen only had to follow. The guns were fired simultaneously, which aided in spotting the shell splashes and minimized the effects of the roll on the dispersion of the shells. Queen Mary received her director before the Battle of Jutland.
Armour
The armour protection given to Queen Mary was similar to that of the Lions; her waterline belt of Krupp cemented armour was also thick between 'B' and 'X' turrets. It thinned to inches towards the ships' ends, but did not reach either the bow or the stern. In addition the ship was given an upper armour belt with a maximum thickness of six inches over the same length as the thickest part of the waterline armour, thinning to abreast the end turrets. Four-inch transverse bulkheads closed off the ends of the armoured citadel. High-tensile steel plating, cheaper than nickel-steel, but equally as effective, was used for the protective decks. The lower armoured deck was generally only thick except outside the citadel where it was. The upper armoured deck was situated at the top of the upper armour belt and was also only one inch thick. The forecastle deck ranged from.The gun turrets had nine-inch fronts and sides, while their roofs were thick. The barbettes were protected by nine inches of armour above the deck, but it thinned to above the upper armour deck and below it. The forward 4-inch guns were protected by three-inch sides and a two-inch high-tensile steel deck overhead. The conning tower sides were thick, with three-inch roofs and communication tubes. Her aft torpedo director tower was protected by six-inch walls and a three-inch cast steel roof. High-tensile steel torpedo bulkheads thick were fitted abreast the magazines and shell rooms. Her funnel uptakes were protected by high-tensile steel splinter armour thick on the sides and one inch thick on the ends between the upper and forecastle decks.