Admiral class battlecruiser
Encyclopedia
The Admiral-class battlecruisers were a class
Ship class
A ship class is a group of ships of a similar design. This is distinct from a ship-type, which might reflect a similarity of tonnage or intended use. For example, the is a nuclear aircraft carrier of the Nimitz class....

 of four British Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 battlecruiser
Battlecruiser
Battlecruisers were large capital ships built in the first half of the 20th century. They were developed in the first decade of the century as the successor to the armoured cruiser, but their evolution was more closely linked to that of the dreadnought battleship...

s designed near the end of World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

. Their design began as a improved version of the s, but it was recast as a battlecruiser after Admiral John Jellicoe
John Jellicoe, 1st Earl Jellicoe
Admiral of the Fleet John Rushworth Jellicoe, 1st Earl Jellicoe, GCB, OM, GCVO was a British Royal Navy admiral who commanded the Grand Fleet at the Battle of Jutland in World War I...

, commander of the Grand Fleet, pointed out that there was no real need for more battleships, but that a number of German battlecruisers
Mackensen class battlecruiser
The Mackensen class was the last class of battlecruisers to be built by Germany in World War I. The class was to have comprised four ships: Mackensen, the name ship, Graf Spee, Prinz Eitel Friedrich, and Fürst Bismarck. None of the vessels were completed, as shipbuilding priorities were redirected...

 had been laid down that were superior to the bulk of the Grand Fleet's battlecruisers and the design was revised to counter these. The class was going to consist of , Anson, Howe, and Rodney - all names of famous Admirals - but the latter three ships were suspended as the material and labour required to complete them was needed for higher-priority merchantmen and escort vessels. Their designs were updated to incorporate the lessons from the Battle of Jutland
Battle of Jutland
The Battle of Jutland was a naval battle between the British Royal Navy's Grand Fleet and the Imperial German Navy's High Seas Fleet during the First World War. The battle was fought on 31 May and 1 June 1916 in the North Sea near Jutland, Denmark. It was the largest naval battle and the only...

, but the Admiralty eventually decided that it was better to begin again with a clean-slate design so they were cancelled in 1919. No more battlecruisers would be built due to the arms limitations agreements of the interbellum.

Hood, however, was sufficiently advanced in construction that she was completed in 1920 and immediately became flagship
Flagship
A flagship is a vessel used by the commanding officer of a group of naval ships, reflecting the custom of its commander, characteristically a flag officer, flying a distinguishing flag...

 of the Battlecruiser Squadron
Battlecruiser Squadron (United Kingdom)
The Battlecruiser Squadron was a Royal Navy squadron of battlecruisers that saw service from 1919 to the early part of the Second World War.- Formation :...

 of the Atlantic Fleet. She served as the flagship of the Special Service Squadron during its round-the-world cruise in 1923–24
Cruise of the Special Service Squadron
In 1923-24, HMS Hood and the Special Service Squadron sailed around the world on The Empire Cruise, visiting many ports of call in the countries which had fought together during the First World War. The Squadron departed Devonport on 27 November 1923 and headed for Sierra Leone...

. Hood was transferred to the Mediterranean Fleet
Mediterranean Fleet
Several countries have or have had a Mediterranean Fleet in their navy. See:* Mediterranean Fleet * French Mediterranean Fleet* Mediterranean Squadron * United States Sixth Fleet...

 in 1936 and spent much of the next few years on Non-Intervention Patrol
Non-Intervention Committee
During the Spanish Civil War, several countries followed a principle of non-intervention, which would result in the signing of the Non-Intervention Agreement in August 1936 and the setting up of the Non-Intervention Committee, which first met in September...

s during the Spanish Civil War
Spanish Civil War
The Spanish Civil WarAlso known as The Crusade among Nationalists, the Fourth Carlist War among Carlists, and The Rebellion or Uprising among Republicans. was a major conflict fought in Spain from 17 July 1936 to 1 April 1939...

, returning to the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 before the beginning of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 and the Battlecruiser Squadron of the Home Fleet.

Hood spent most of the early part of the war patrolling against German commerce raiders and escorting convoys. Flagship of Force H
Force H
Force H was a British naval formation during the Second World War. It was formed in 1940 to replace French naval power in the western Mediterranean that had been removed by the French armistice with Nazi Germany....

, based at Gibraltar
Gibraltar
Gibraltar is a British overseas territory located on the southern end of the Iberian Peninsula at the entrance of the Mediterranean. A peninsula with an area of , it has a northern border with Andalusia, Spain. The Rock of Gibraltar is the major landmark of the region...

, she bombarded French ships during the attack on Mers-el-Kébir. In May 1941 Hood and the battleship were ordered to intercept the and the heavy cruiser
Heavy cruiser
The heavy cruiser was a type of cruiser, a naval warship designed for long range, high speed and an armament of naval guns roughly 203mm calibre . The heavy cruiser can be seen as a lineage of ship design from 1915 until 1945, although the term 'heavy cruiser' only came into formal use in 1930...

  as they attempted to breakout into the North Atlantic. In the subsequent Battle of the Denmark Strait
Battle of the Denmark Strait
The Battle of the Denmark Strait was a Second World War naval battle between ships of the Royal Navy and the German Kriegsmarine, fought on 24 May 1941...

 Hoods aft magazine
Magazine (artillery)
Magazine is the name for an item or place within which ammunition is stored. It is taken from the Arabic word "makahazin" meaning "warehouse".-Ammunition storage areas:...

s exploded, sinking her within five minutes of opening fire.

Design and description

In 1915 the Admiralty
Admiralty
The Admiralty was formerly the authority in the Kingdom of England, and later in the United Kingdom, responsible for the command of the Royal Navy...

 was considering the next generation of warship to follow the Queen Elizabeth-class battleships. The Director of Naval Construction
Director of Naval Construction
The Director of Naval Construction was a senior British civil servant post in the Admiralty, that part of the British Civil Service that oversaw the Royal Navy. The post existed from 1860 to 1966....

 (DNC), Sir Eustace Tennyson-d'Eyncourt, was given instructions to prepare designs for a new battleship. The design should: "take the armament, armour and engine power of Queen Elizabeth as the standard and build around them a hull which should draw as little water as was considered practicable and safe, and which should embody all the latest protection and improvements against underwater attack." The design ('A') was submitted to the Admiralty on 30 November for consideration. The DNC had been able to reduce the draught in comparison to the Queen Elizabeth by 22% by widening the ship to 104 feet (31.7 m) and lengthening it to 810 feet (246.9 m); this had the consequence of restricting the ships to use only one dock in Rosyth
Rosyth
Rosyth is a town located on the Firth of Forth, three miles south of the centre of Dunfermline. According to an estimate taken in 2008, the town has a population of 12,790....

 and two in Portsmouth
Portsmouth
Portsmouth is the second largest city in the ceremonial county of Hampshire on the south coast of England. Portsmouth is notable for being the United Kingdom's only island city; it is located mainly on Portsea Island...

. Large anti-torpedo bulge
Anti-torpedo bulge
The anti-torpedo bulge is a form of passive defence against naval torpedoes that featured in warship construction in the period between the First and Second World Wars.-Theory and form:...

s were fitted, and the secondary armament of twelve 5 inches (13 cm) guns of a new design was mounted on the forecastle deck. The resulting high freeboard
Freeboard (nautical)
In sailing and boating, freeboardmeans the distance from the waterline to the upper deck level, measured at the lowest point of sheer where water can enter the boat or ship...

 gave the design a greater ratio of reserve buoyancy to displacement than in any previous British dreadnought
Dreadnought
The dreadnought was the predominant type of 20th-century battleship. The first of the kind, the Royal Navy's had such an impact when launched in 1906 that similar battleships built after her were referred to as "dreadnoughts", and earlier battleships became known as pre-dreadnoughts...

. The design's stretched hull form also gave her an estimated speed
Hull speed
Hull speed, sometimes referred to as displacement speed, is the speed of a boat at which the bow and stern waves interfere constructively, creating relatively large waves, and thus a relatively large value of wave drag...

 of 26.5 knots (14.4 m/s), about 2.5 knots (1.4 m/s) faster than the Queen Elizabeth had been able to reach in service. The First Sea Lord, Admiral
Admiral
Admiral is the rank, or part of the name of the ranks, of the highest naval officers. It is usually considered a full admiral and above vice admiral and below admiral of the fleet . It is usually abbreviated to "Adm" or "ADM"...

 Sir Henry Jackson, responded on 6 December that one danger of such a large ship would be start a new arms race with the Americans that Britain could ill-afford, and that better deck protection was necessary to defeat plunging shells during long-range engagements.

The Admiralty asked for the design to be reworked ('B') with a maximum beam of 90 feet (27.4 m), but this was deemed unsatisfactory as it compromised the ship's underwater protection. A pair of revised designs was requested with the speed reduced to 22 knots (12 m/s) to allow the hull to be shortened to better fit in existing floating docks and the minimum possible draught. The first of the two ('C1') was to have full bulge protection and the second ('C2') to have the best bulge protection possible without exceeding Queen Elizabeths length. 'C1' was shortened by 100 feet (30.5 m) in comparison with 'B' and 'C2' was only 610 feet (185.9 m) in length, but draught increased by 1 in 3 in (0.381 m). In both proposals it had been necessary to reduce the number of guns in the secondary armament and reduce the thickness of the armour. The Admiralty was not pleased with either design and asked for a revised version of 'A' of the same draught, beam, armour and armament, but shortened and with the same speed as the Queen Elizabeth. In addition the new five-inch gun was rejected in favour of the existing 5.5 inches (14 cm) gun.

At least some of the designs were passed to Admiral John Jellicoe, commander of the Grand Fleet, who pointed out that there was no need for new battleships as the British superiority in numbers over the Germans was substantial, but that was not true for battlecruisers. Germany was known to be building three new s with an estimated speed approaching 30 knots (16.3 m/s) and a reported armament of 15.2 inches (39 cm) guns.These reports were incorrect; the German ships were designed for 28 knots (54.9 km/h) and 35 centimetres (13.8 in) guns. In addition there were four, not three ships in the class. See Campbell, pp. 58–59 These ships would be superior to all existing British battlecruisers, and those then under construction (the two and the three 'large light cruisers') were equally fast, but too thinly armoured to compete with them. He also remarked that his experience with the Queen Elizabeths had persuaded him that an intermediate speed between the battleships and the battlecruisers was of little use; he suggested that the design should be for either a 21 knots (11.4 m/s) battleship or a thirty-knot battlecruiser, preferably the latter.

The DNC prepared two new designs in response to Admiral Jellicoe's comments on 1 February 1916, each for a battlecruiser capable of thirty knots or better and armed with eight 15 inches (38 cm) guns. Design '1' displaced 39000 long tons (39,626 t) with two less inches in belt armour and a speed of thirty knots. It used the bulky large-tube boilers
Water-tube boiler
A water tube boiler is a type of boiler in which water circulates in tubes heated externally by the fire. Fuel is burned inside the furnace, creating hot gas which heats water in the steam-generating tubes...

 traditional in British capital ships, which explains why the design was 9000 long tons (9,144 t) larger than any of the previous battleship designs. Design '2' was essentially a repeat of the first design except that small-tube boilers were substituted. These were considerably smaller than the older type and saved 3500 long tons (3,556 t) over Design '1' and had one less foot of draught. These savings were substantial enough to overcome the Engineer-in-Chief's objections that they required more frequent and expensive repairs. The DNC was asked to submit four more designs using small-tube boilers which were submitted on 17 February. Design '3' was Design '2' with the machinery power increased to 160000 shp to boost the maximum speed to 32 knots (17.4 m/s) while the other designs had either four, six or eight 18 inches (46 cm) guns. Design '3' was selected as Admiral Jellicoe has specified that the minimum number of guns should be no less than eight as fewer caused problems in accurate fire control, and two alternatives were to be provided, one with a dozen 5.5-inch guns and the other with sixteen such guns. The latter proposal was selected on 7 April and orders were placed on 19 April for three ships (Hood, Howe and Rodney). The order for the fourth ship, Anson, was placed on 13 June.

was laid down on 31 May 1916, the same day as the Battle of Jutland
Battle of Jutland
The Battle of Jutland was a naval battle between the British Royal Navy's Grand Fleet and the Imperial German Navy's High Seas Fleet during the First World War. The battle was fought on 31 May and 1 June 1916 in the North Sea near Jutland, Denmark. It was the largest naval battle and the only...

. The loss of three British battlecruisers during that battle caused the work on all three ships to be suspended pending an investigation into possible design flaws. Admiral Jellicoe's investigation blamed the loss of the ships on faulty cordite handling procedures that allowed fires in the turrets or hoists to reach the ships' magazine
Magazine (artillery)
Magazine is the name for an item or place within which ammunition is stored. It is taken from the Arabic word "makahazin" meaning "warehouse".-Ammunition storage areas:...

s. It recommended anti-flash equipment be installed in magazines and handling rooms and the improvement of deck armour over the magazines to prevent plunging shells or fragments from reaching the magazines. The DNC and the Third Sea Lord opposed the latter, believing that there was no direct evidence that the magazines had been directly penetrated.

On 5 July the DNC submitted two revised designs for the Admiral-class ships. The first was a modification of the previous design with slight increases to the deck, turret, barbette, and funnel uptake armour, one-inch protection for the 5.5-inch ammunition hatches and hoists, and the number of electrical generators increased from four to eight. These changes increased the displacement by 1250 long tons (1,270 t) and draught by 9 inches (22.9 cm). The second design drastically improved the protection and converted the ships into fast battleships. The vertical armour was generally increased by 50% and the deck protection was slightly thickened as in the first design. These changes would have added another 4300 long tons (4,369 t) to the original design and increased the draught by 2 foot (0.6096 m), but would have cost half a knot in speed. This design would have been equal to the Queen Elizabeths, but 7 knots (3.8 m/s) faster and with much improved torpedo protection, although it was some 13000 long tons (13,209 t) larger than the older ships. After the DNC submitted the above designs, he was asked to consider variations with triple fifteen-inch turrets, and these were submitted on 20 July. The Admiralty chose the fast battleship design, and Hood was laid down again on 1 September.

Later that month Hoods armour scheme was slightly revised in light of further analysis of the results of Jutland and the deck armour was modestly increased in order to ensure that a minimum thickness of nine inches of armour would have to be penetrated by shells striking at angles of descent up to 30° from the horizontal. Further alterations were made in 1917 during her construction that increased the thickness of her turret faces and roofs. These changes, plus numerous others, increased her displacement by 600 long tons (610 t), her draught by 3 inches (7.6 cm) and reduced her speed to 31 knots (16.9 m/s). The changes continued during 1918 when the thickness of her magazine crowns was increased from one inch to two; the armour for the funnel uptakes above the forecastle deck was omitted in compensation. In May 1919 her main deck armour at the side abreast the magazines was increased to three inches (76 mm) , and four 5.5-inch guns and their ammunition were deleted in consequence. The next month plans were approved to increase the thickness of the main deck over the forward magazines to 5 inches (13 cm) and to 6 inches (15 cm) over the rear magazines; her four above water torpedo tubes and their protection were to be omitted and the wall of the torpedo control tower were to be reduced to a thickness of 1.5 inches (3.8 cm) to offset the armour's weight. However, the additional deck armour was never fitted and the torpedo tubes (less their protection) were retained.

Earlier in 1917, however, construction of Hoods three sisters had been suspended as the amount of labour and material they required would be better employed in the construction and repair of merchant ships and escorts needed to keep open Britain's lines of communication in the face of the U-boat blockade. Design work continued however, although Hood was too far advanced to incorporate these changes, and ultimately would have been extensive enough for the other three ships to constitute their own class. At the end of 1917 the suspended ships' design was modified to increase the thickness of the turret roofs to six inches (152 mm) , and (unspecified) alterations were made to the armoured bulkheads. These cost a total of 267 long tons (271 t) in displacement. Other changes were a redesigned bridge structure and moving the funnels closer together and the exchange in position between the fifteen-inch shellrooms and magazines. This latter change would have caused the hull's form to be filled out somewhat to accommodate the handling room of the rearmost turret at the cost of a slight loss in speed and ammunition storage.

Hood was the closest to completion and her construction was continued in case the Germans managed to complete any of their new battlecruisers. Admiral Beatty
David Beatty, 1st Earl Beatty
Admiral of the Fleet David Richard Beatty, 1st Earl Beatty, GCB, OM, GCVO, DSO was an admiral in the Royal Navy...

 continually pressed to have Hoods construction expedited and for her sisters to be restarted, but the War Cabinet
War Cabinet
A War Cabinet is a committee formed by a government in a time of war. It is usually a subset of the full executive cabinet of ministers. It is also quite common for a War Cabinet to have senior military officers and opposition politicians as members....

 refused to approve either measure as nothing could be sacrificed in the shipbuilding programme to this end. After the end of the war the three suspended ships were cancelled as they could not fully incorporate the lessons of the war.

General characteristics

The Admiral-class ships were significantly larger than their predecessors of the . They had an overall length of 860 feet (262.1 m), a beam
Beam (nautical)
The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...

 of 104 feet (31.7 m), and a draught of 31 in 6 in (9.6 m) at deep load. This was 110 feet (33.5 m) longer and 14 feet (4.3 m) wider than the smaller ships. They displaced 41200 long tons (41,861 MT) at load and 45620 long tons (46,352 MT) at deep load, over 13000 long tons (13,208.7 MT) more than the older ships. They had a metacentric height
Metacentric height
The metacentric height is a measurement of the static stability of a floating body. It is calculated as the distance between the centre of gravity of a ship and its metacentre . A larger metacentric height implies greater stability against overturning...

 of 4.6 feet (1.4 m) at deep load as well as a complete double bottom
Double bottom
A double bottom is a ship hull design and construction method where the bottom of the ship has two complete layers of watertight hull surface: one outer layer forming the normal hull of the ship, and a second inner hull which is somewhat higher in the ship, perhaps a few feet, which forms a...

.

Propulsion

The ships had four Brown-Curtis single-reduction geared steam turbine
Steam turbine
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884....

 sets, each of which drove one propeller shaft. They were arranged in three engine rooms. The forward engine room held the two turbines for the wing shafts, the middle compartment housed the turbines for the port inner shaft and the aft engine room contained the turbines for the starboard inner shaft. A cruising turbine was built into the casing of each wing turbine. The turbines were powered by twenty-four Yarrow
Yarrow Shipbuilders
Yarrow Limited , often styled as simply Yarrows, was a major shipbuilding firm based in the Scotstoun district of Glasgow on the River Clyde...

 small-tube boilers equally divided between four boiler rooms. They were designed to produce a total of 144000 shp at a working pressure of 235 psi (1,620,268 Pa), but achieved more than 151000 shp during Hoods trials, when she slightly exceeded her designed speed of 31 knots.

They were designed to normally carry 1200 long tons (1,219 t) of fuel oil
Fuel oil
Fuel oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash...

, but had a maximum capacity of 4000 long tons (4,064 t). At full capacity, Hood could steam at a speed of 14 knots for an estimated 7500 nautical mile. They had eight 175 kW dynamo
Dynamo
- Engineering :* Dynamo, a magnetic device originally used as an electric generator* Dynamo theory, a theory relating to magnetic fields of celestial bodies* Solar dynamo, the physical process that generates the Sun's magnetic field- Software :...

s, two diesel, two turbo-driven, and four reciprocating.

Armament

The Admiral-class ships mounted eight BL 15-inch Mk I guns in four twin hydraulically powered Mark II turrets, designated 'A', 'B', 'X' and 'Y' from front to rear. The guns could be depressed to −3° and elevated to 30°; they could be loaded at any angle up to 20°, although loading at high angles tended to slow the gun's return to battery. The ships carried 120 shells per gun. They fired 1920 pounds (871 kg) projectiles at a muzzle velocity
Muzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...

 of 2467 ft/s (751.9 m/s); this provided a maximum range of 29000 yd (26,518 m) with armour-piercing (AP)
Armor-piercing shot and shell
An armor-piercing shell is a type of ammunition designed to penetrate armor. From the 1860s to 1950s, a major application of armor-piercing projectiles was to defeat the thick armor carried on many warships. From the 1920s onwards, armor-piercing weapons were required for anti-tank missions...

 shells.

Their secondary armament consisted of sixteen BL 5.5-inch Mk I
BL 5.5 inch Mark I naval gun
The Breech Loading 5.5 inch Mk I was a naval gun used by the British Royal Navy during both World Wars.-Naval history:This weapon was developed by Coventry Ordnance Works in 1913 and offered to the Greek Navy as main armament for two new cruisers building at Cammell Laird...

 guns, which were mounted on pivot mounts on the forecastle deck, protected by gun shield
Gun shield
thumb|A [[United States Marine Corps|U.S. Marine]] manning an [[M240 machine gun]] equipped with a gun shieldA gun shield is a flat piece or section of armor designed to be mounted on a crew-served weapon such as a machine gun or artillery piece, or, more rarely, to be used with an assault rifle...

s. They were provided with 200 rounds per gun. The guns on their CPII mounts had a maximum elevation of 30°. They fired 82 pounds (37.2 kg) projectiles at a muzzle velocity of 2790 ft/s (850.4 m/s). Their maximum range was 17700 yd (16,184.9 m) at 30° elevation. Their rate of fire was twelve rounds per minute.

The Admiral-class ships were designed with four QF four-inch Mark V
QF 4 inch Mk V naval gun
The QF 4 inch Mk V gun was a Royal Navy gun of World War I which was adapted on HA mountings to the heavy anti-aircraft role both at sea and on land, and was also used as a coast defence gun.-Naval service:...

 anti-aircraft
Anti-aircraft warfare
NATO defines air defence as "all measures designed to nullify or reduce the effectiveness of hostile air action." They include ground and air based weapon systems, associated sensor systems, command and control arrangements and passive measures. It may be to protect naval, ground and air forces...

 guns. They had a maximum depression of -5° and a maximum elevation of 80°. They fired a 31 pounds (14.1 kg) high explosive shell at a muzzle velocity of 2387 ft/s (727.6 m/s) at a rate of ten to fifteen rounds per minute. The guns had a maximum ceiling of 31000 ft (9,448.8 m), but an effective range of much less.

Two 21 inches (53 cm)
British 21 inch torpedo
There have been several British 21-inch diameter torpedoes used by the Royal Navy since their first development just before the First World War.They were the largest size of torpedo in common use in the RN...

 submerged side-loading torpedo tube
Torpedo tube
A torpedo tube is a device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units installed aboard surface vessels...

s were fitted forward of 'A' turret and eight above-water side-loading Mark V tubes were intended to be mounted abreast the rear funnel on the upper deck, although only four of the latter were carried by Hood. They were loaded and traversed by hydraulic power; the submerged tubes were fired by compressed air while the above-water tubes used cordite charges. Thirty-two warheads could be accommodated in the two magazines in the hold forward of 'A' turret's shellroom. Hood carried Mark IV and IV* torpedoes, each which had a warhead of 515 pounds (234 kg) of TNT. They had three speed settings which governed their range; from 8000 yards (7,315 m) at 35 knots (19.1 m/s), 10000 yards (9,144 m) at 29 knots (15.8 m/s), and 13500 yards (12,344 m) at 25 knots (13.6 m/s).

Fire-control

The main guns of the Admiral-class ships were controlled from either of the two fire-control directors. The primary director was mounted above the conning tower
Conning tower
A conning tower is a raised platform on a ship or submarine, often armored, from which an officer can con the vessel; i.e., give directions to the helmsman. It is usually located as high on the ship as practical, to give the conning team good visibility....

 in an armoured hood and the other was in the fore-top on the foremast. 'B' turret could also control all the main gun turrets while 'X' turret could control the rear guns. Data from a 30 feet (9.1 m) rangefinder
Rangefinder
A rangefinder is a device that measures distance from the observer to a target, for the purposes of surveying, determining focus in photography, or accurately aiming a weapon. Some devices use active methods to measure ; others measure distance using trigonometry...

 in the armoured hood were input into a Mk V Dreyer Fire Control Table located in the Transmitting Station (TS) on the platform deck where they were converted into range and deflection data for use by the guns. The target's data were also graphically recorded on a plotting table to assist the gunnery officer in predicting the movement of the target. The fore-top was equipped with a 15 feet (4.6 m) rangefinder. Each turret was provided with a thirty-foot rangefinder in an armoured housing on the turret roof and a Dumaresq
Dumaresq
The Dumaresq is a mechanical calculating device invented around 1902 by Lieutenant John Dumaresq of the Royal Navy.The dumaresq is an analog computer which relates vital variables of the fire control problem to the movement of one's own ship and that of a target ship...

 analogue computer
Analog computer
An analog computer is a form of computer that uses the continuously-changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved...

 for local fire-control.

The secondary armament was primarily controlled by the 5.5-inch directors mounted on each side of the bridge. They were supplemented by the two additional control positions in the fore-top, which were provided with 9 feet (2.7 m) rangefinders. Each of these positions was equipped with a Dumaresq calculator for local control, but the spotting data were normally sent to the 5.5-inch TS on the lower deck much like the procedure for the fifteen-inch guns, except that the firing data were calculated by two Type F fire-control clocks (analog computers). The anti-aircraft guns were controlled by a simple 2 metre rangefinder mounted on the aft superstructure.

The torpedoes initially had a similar system where various rangefinders, especially the fifteen-foot rangefinder above the aft torpedo control tower, and deflection sights provided data to a Dreyer table in the torpedo TS adjacent to the 5.5-inch TS on the lower deck. However the Dreyer table was removed during Hoods 1929–1931 refit and the calculations were made in the torpedo control position in the bridge.

Armour

The waterline belt
Belt armor
Belt armor is a layer of heavy metal armor plated on to or within outer hulls of warships, typically on battleships, battlecruisers and cruisers, and on aircraft carriers converted from those types of ships....

 of the Admiral-class ships was 12 inches (30 cm) thick, angled 12° outwards partly to keep the belt inside the bulge structure and allow torpedo hits to vent to the atmosphere. This angle also increased the armor's relative thickness to horizontal, close-range fire, albeit at the cost of reducing its relative height which increased the chance of plunging shellfire going over or under it. This sloped belt made their armor comparable to the 13 inches (33 cm) found in the latest British dreadnoughts. It ran some 562 feet (171.3 m), from the forward edge of 'A' barbette to the middle of 'Y' barbette. Forward of this the belt thinned to six inches before further reducing to 5 inches (13 cm) and ending in a five-inch (127 mm) bulkhead
Bulkhead (partition)
A bulkhead is an upright wall within the hull of a ship or within the fuselage of an airplane. Other kinds of partition elements within a ship are decks and deckheads.-Etymology:...

 well short of the bow. Aft of the midships section the belt reduced to six inches (152 mm) ; it did not reach the stern, but terminated at a five-inch bulkhead. This belt had a height of 9 in 6 in (2.9 m), which 4 feet (1.2 m) was below the designed waterline. Above it was the seven-inch middle belt, 7 feet (2.1 m) high, and the five-inch upper belt, which was 9 feet (2.7 m) high. The middle belt stretched between 'A' and 'Y' barbettes, ending in four-inch transverse bulkheads at each end. The upper belt only ran from 'A' barbette to the end of the machinery spaces and ended in another four-inch transverse bulkhead. Five of Hoods decks were armoured with thicknesses varying from 0.75 to 3 in (1.9 to 7.6 ), with the greatest thicknesses over the magazines and the steering gear. Immediately adjacent to 'A' and 'Y' barbettes the main deck was five inches thick to protect the magazines.

The turret faces were fifteen inches thick while their sides ranged from 11 to 12 in (27.9 to 30.5 ) in thickness, and the roof was five inches thick. The barbettes had a maximum of twelve inches of armour, but were reduced in thickness in stages below decks, although the outer faces of 'A' and 'Y' barbettes were considerably thicker below decks than the other barbettes. The conning tower armour was nine to eleven inches thick, and it was the largest yet fitted to a British capital ship as it weighed 600 long tons (610 t). The primary fire-control director atop the conning tower was protected by an armoured hood. The face of the hood was six inches thick, its sides were two inches thick, and its roof was protected by three inches of armour. A communications tube with six-inch sides ran from the conning tower down to the lower conning position on the main deck. The three torpedo bulkhead
Torpedo bulkhead
A torpedo bulkhead is a type of armor common on the more heavily armored warships, especially battleships and battlecruisers of the early 20th century. It is designed to keep the ship afloat even if the hull was struck underneath the belt armor by a shell or by a torpedo...

s were 1.5 inches (3.8 cm), 1 inches (2.5 cm) and 0.75 inches (1.9 cm) thick.

The anti-torpedo bulge
Anti-torpedo bulge
The anti-torpedo bulge is a form of passive defence against naval torpedoes that featured in warship construction in the period between the First and Second World Wars.-Theory and form:...

s of the Admiral-class battlecruisers were the first fitted on a British capital ship to fully incorporate the lessons learned from a series of experiments begun before World War I. They consisted of an outer air space, an inner buoyancy space and the 1.5-inch protective bulkhead. The buoyancy space was filled with sealed steel crushing tubes intended to distribute the force of an explosion over as wide an area as possible as well as absorb as much of its force as possible. However, tests conducted after Hood was completed showed that filling the buoyancy space with water was equally as effective and considerably cheaper.

Ships

Ship Builder Namesake Laid down Launched Completed Fate
John Brown, Clydebank
Clydebank
Clydebank is a town in West Dunbartonshire, in the Central Lowlands of Scotland. Situated on the north bank of the River Clyde, Clydebank borders Dumbarton, the town with which it was combined to form West Dunbartonshire, as well as the town of Milngavie in East Dunbartonshire, and the Yoker and...

Viscount Hood
Samuel Hood, 1st Viscount Hood
Samuel Hood, 1st Viscount Hood was a British Admiral known particularly for his service in the American War of Independence and French Revolutionary Wars...

1 September 1916 22 August 1918 15 May 1920 align=right |Sunk 24 May 1941 by
Anson Armstrong Whitworth
Armstrong Whitworth
Sir W G Armstrong Whitworth & Co Ltd was a major British manufacturing company of the early years of the 20th century. Headquartered in Elswick, Newcastle upon Tyne, Armstrong Whitworth engaged in the construction of armaments, ships, locomotives, automobiles, and aircraft.-History:In 1847,...

, Elswick
Elswick, Tyne and Wear
Elswick is a ward of the city of Newcastle upon Tyne, England, in the western part of the city, bordering the river Tyne. One of the earliest references to the coal mining industry of the north east occurs in 1330, when it was recorded that the Prior of Tynemouth let a colliery, called Heygrove, at...

George Anson
George Anson, 1st Baron Anson
Admiral of the Fleet George Anson, 1st Baron Anson PC, FRS, RN was a British admiral and a wealthy aristocrat, noted for his circumnavigation of the globe and his role overseeing the Royal Navy during the Seven Years' War...

9 November 1916 Suspended 9 March 1917 Cancelled 27 February 1919
Howe Cammell Laird
Cammell Laird
Cammell Laird, one of the most famous names in British shipbuilding during the nineteenth and twentieth centuries, came about following the merger of Laird, Son & Co. of Birkenhead and Johnson Cammell & Co. of Sheffield at the turn of the twentieth century.- Founding of the business :The Company...

, Birkenhead
Birkenhead
Birkenhead is a town within the Metropolitan Borough of Wirral in Merseyside, England. It is on the Wirral Peninsula, along the west bank of the River Mersey, opposite the city of Liverpool...

Earl Howe
Richard Howe, 1st Earl Howe
Admiral of the Fleet Richard Howe, 1st Earl Howe KG was a British naval officer, notable in particular for his service during the American War of Independence and French Revolutionary Wars. He was the brother of William Howe and George Howe.Howe joined the navy at the age of thirteen and served...

16 October 1916 Suspended 9 March 1917 Cancelled 27 February 1919
Rodney Fairfield
Fairfield Shipbuilding and Engineering Company
The Fairfield Shipbuilding and Engineering Company, Limited was a British shipbuilding company in the Govan area on the Clyde in Glasgow. Fairfields, as it is often known, was a major warship builder, turning out many vessels for the Royal Navy and other navies through the First World War and the...

, Govan
Govan
Govan is a district and former burgh now part of southwest City of Glasgow, Scotland. It is situated west of Glasgow city centre, on the south bank of the River Clyde, opposite the mouth of the River Kelvin and the district of Partick....

Baron Rodney
George Brydges Rodney, 1st Baron Rodney
George Brydges Rodney, 1st Baron Rodney, KB was a British naval officer. He is best known for his commands in the American War of Independence, particularly his victory over the French at the Battle of the Saintes in 1782...

9 October 1916 Suspended 9 March 1917 Cancelled 27 February 1919

Service

Shortly after commissioning on 15 May 1920 Hood became flagship of the Battlecruiser Squadron of the Atlantic Fleet, under the command of Rear Admiral
Rear Admiral
Rear admiral is a naval commissioned officer rank above that of a commodore and captain, and below that of a vice admiral. It is generally regarded as the lowest of the "admiral" ranks, which are also sometimes referred to as "flag officers" or "flag ranks"...

 Sir Roger Keyes. She made a cruise to Scandinavian waters that year. She visited the Mediterranean in 1921 and 1922 to show the flag and to train with the Mediterranean Fleet, before sailing on a cruise to Brazil and the West Indies in company with the Battlecruiser Squadron.

In November 1923 Hood, accompanied by the battlecruiser and a number of s of the 1st Light Cruiser Squadron, set out on a world cruise
Cruise of the Special Service Squadron
In 1923-24, HMS Hood and the Special Service Squadron sailed around the world on The Empire Cruise, visiting many ports of call in the countries which had fought together during the First World War. The Squadron departed Devonport on 27 November 1923 and headed for Sierra Leone...

 from west to east via the Panama Canal
Panama Canal
The Panama Canal is a ship canal in Panama that joins the Atlantic Ocean and the Pacific Ocean and is a key conduit for international maritime trade. Built from 1904 to 1914, the canal has seen annual traffic rise from about 1,000 ships early on to 14,702 vessels measuring a total of 309.6...

. They returned home ten months later in September 1924. The Battlecruiser Squadron visited Lisbon in January 1925 to participate in the Vasco da Gama
Vasco da Gama
Vasco da Gama, 1st Count of Vidigueira was a Portuguese explorer, one of the most successful in the Age of Discovery and the commander of the first ships to sail directly from Europe to India...

 celebrations before continuing on the Mediterranean for exercises. Hood would continue this pattern of a winter training visit to the Mediterranean for the rest of the decade.

Hood was given a major refit from 1 May 1929 to 10 March 1931 and afterwards resumed her role as flagship of the Battlecruiser Squadron. Later that year her crew participated in the Invergordon Mutiny
Invergordon Mutiny
The Invergordon Mutiny was an industrial action by around 1,000 sailors in the British Atlantic Fleet, that took place on 15–16 September 1931...

 over pay cuts for the sailors. It ended peacefully and Hood returned to her home port afterwards. The Battlecruiser Squadron made a Caribbean cruise in early 1932. The next year she resumed her previous practice of a winter cruise in the Mediterranean. While enroute to Gibraltar for one of these cruises she collided with the battlecruiser on 23 January 1935, but was only lightly damaged. Hood participated in King George V's Silver Jublilee Fleet Review at Spithead
Spithead
Spithead is an area of the Solent and a roadstead off Gilkicker Point in Hampshire, England. It is protected from all winds, except those from the southeast...

 the following August. She was transferred to the Mediterranean Fleet shortly afterward and stationed at Gibraltar at the outbreak of the Second Italo-Abyssinian War
Second Italo-Abyssinian War
The Second Italo–Abyssinian War was a colonial war that started in October 1935 and ended in May 1936. The war was fought between the armed forces of the Kingdom of Italy and the armed forces of the Ethiopian Empire...

 and the Spanish Civil War
Spanish Civil War
The Spanish Civil WarAlso known as The Crusade among Nationalists, the Fourth Carlist War among Carlists, and The Rebellion or Uprising among Republicans. was a major conflict fought in Spain from 17 July 1936 to 1 April 1939...

. On 23 April 1937 she escorted three British merchantmen into Bilbao
Bilbao
Bilbao ) is a Spanish municipality, capital of the province of Biscay, in the autonomous community of the Basque Country. With a population of 353,187 , it is the largest city of its autonomous community and the tenth largest in Spain...

 harbour despite the presence of the Nationalist
Spanish State
Francoist Spain refers to a period of Spanish history between 1936 and 1975 when Spain was under the authoritarian dictatorship of Francisco Franco....

 cruiser that attempted to blockade the port. She returned to Portsmouth in January 1939 for an overhaul that lasted until 12 August.

World War II

In June 1939, she was assigned to the Home Fleet’s Battlecruiser Squadron while still refitting; when war broke out later that year, she was employed principally in patrolling the vicinity of Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

 and the Faroe Islands
Faroe Islands
The Faroe Islands are an island group situated between the Norwegian Sea and the North Atlantic Ocean, approximately halfway between Scotland and Iceland. The Faroe Islands are a self-governing territory within the Kingdom of Denmark, along with Denmark proper and Greenland...

 to protect convoys and intercept German raiders attempting to break out into the Atlantic. In September 1939, she was hit by a 250 kg (550 lb) aircraft bomb with minor damage. By early 1940 Hood's machinery was in dire shape and limited her best speed to 26.5 knots (14.4 m/s); she was refitted between 4 April and 12 June.

Hood and the aircraft carrier were ordered to Gibraltar to join Force H
Force H
Force H was a British naval formation during the Second World War. It was formed in 1940 to replace French naval power in the western Mediterranean that had been removed by the French armistice with Nazi Germany....

 on 18 June where Hood would become the flagship. As such, she took part in the destruction of the French Fleet at Mers-el-Kebir
Destruction of the French Fleet at Mers-el-Kebir
The Attack on Mers-el-Kébir, part of Operation Catapult and also known as the Battle of Mers-el-Kébir, was a naval engagement fought at Mers-el-Kébir on the coast of what was then French Algeria on 3 July 1940...

 in July 1940. Just eight days after the French surrender, the British Admiralty had issued an ultimatum to the French Fleet at Oran
Oran
Oran is a major city on the northwestern Mediterranean coast of Algeria, and the second largest city of the country.It is the capital of the Oran Province . The city has a population of 759,645 , while the metropolitan area has a population of approximately 1,500,000, making it the second largest...

 to ensure they would not fall into German or Italian hands. The terms were rejected and the Royal Navy opened fire on the French ships berthed there. The results of Hoods fire are not known exactly, but she damaged the , which was hit by four fifteen-inch shells and was forced to beach herself. Hood was straddled during the engagement by Dunkerque; shell splinters wounded two men. Dunkerques sister ship
Sister ship
A sister ship is a ship of the same class as, or of virtually identical design to, another ship. Such vessels share a near-identical hull and superstructure layout, similar displacement, and roughly comparable features and equipment...

  managed to escape from the harbour and Hood with several light cruisers gave chase, but gave up after two hours after Hood had dodged a salvo of torpedoes from the a French sloop and she had stripped a turbine reaching 28 knots (15.2 m/s).

Hood was relieved as flagship of Force H by Renown on 10 August after returning to Scapa Flow. After a short refit she resumed her previous role in patrolling against German commerce raiders and convoy escort. This lasted until January 1941 when she began a refit that lasted until March. Upon its completion she was ordered to sea in an attempt to intercept the German battleships and . Unsuccessful, she was ordered to patrol the Bay of Biscay
Bay of Biscay
The Bay of Biscay is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Brest south to the Spanish border, and the northern coast of Spain west to Cape Ortegal, and is named in English after the province of Biscay, in the Spanish...

 against any breakout attempt by the German ships from Brest
Brest, France
Brest is a city in the Finistère department in Brittany in northwestern France. Located in a sheltered position not far from the western tip of the Breton peninsula, and the western extremity of metropolitan France, Brest is an important harbour and the second French military port after Toulon...

. Hood was ordered to the Norwegian Sea
Norwegian Sea
The Norwegian Sea is a marginal sea in the North Atlantic Ocean, northwest of Norway. It is located between the North Sea and the Greenland Sea and adjoins the North Atlantic Ocean to the west and the Barents Sea to the northeast. In the southwest, it is separated from the Atlantic Ocean by a...

 on 19 April when the Admiralty received a false report that the had sailed from Germany. Afterwards she patrolled the North Atlantic before putting in to Scapa Flow on 6 May.

Battle of the Denmark Strait

On the evening of 21 May 1941 Hood and the newly-completed battleship sailed from Scapa Flow to join the heavy cruiser
Heavy cruiser
The heavy cruiser was a type of cruiser, a naval warship designed for long range, high speed and an armament of naval guns roughly 203mm calibre . The heavy cruiser can be seen as a lineage of ship design from 1915 until 1945, although the term 'heavy cruiser' only came into formal use in 1930...

s and patrolling the Denmark Strait
Denmark Strait
The Denmark Strait or Greenland Strait |Sound]]) is an oceanic strait between Greenland and Iceland...

 between Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...

 and Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

 on the news that Bismarck and the heavy cruiser had sortied into the North Atlantic. They had not yet reached the Strait when Suffolk spotted the German ships north of Iceland in the early evening on 23 May. Hood and Prince of Wales altered course and increased their speed to intercept. The British squadron spotted the Germans at 05:37 a.m., but the Germans were already aware of their presence. The British opened fire at 05:52 with Hood engaging Prinz Eugen, the lead ship in the German formation, and the Germans returned fire 05:55, both ships concentrating on Hood. Prinz Eugen (probably) was the first ship to score when a shell hit Hoods boat deck, between her funnels, and started a large fire among the ready-use ammunition for the anti-aircraft guns and rockets of the Unrotated Projectile
Unrotated Projectile
The Unrotated Projectile, or UP, was a short range rocket-firing anti-aircraft weapon developed for the Royal Navy to supplement the 2 pounder Pom-Pom gun due to a critical lack of close-range anti-aircraft weapons. It was used extensively by British ships during the early days of World War II...

mounts. Right before 06:00, while Hood was turning 20° to port to unmask her rear turrets, she was hit again on the boat deck by a shell from Bismarcks fifth salvo. The exact location and sequence of events is unknown, but her aft fifteen-inch magazines exploded. This broke her back and she sank with the loss of all but three of her crew.

External links

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