For other ships of this name see HMS Hood (disambiguation).
HMS Hood (pennant number 51) was a battlecruiser of the Royal Navy. She was one of four Admiral-class battlecruisers ordered in mid-1916 under the Emergency War Programme. Although the design was drastically revised after the Battle of Jutland, it was realised that there were serious limitations even to the revised design; for this reason, and because of evidence that the German battlecruisers that they were designed to counter were unlikely to be completed, work on her sister ships was suspended in 1917. As a result, Hood was Britain's last completed battlecruiser. She was named after the 18th century Admiral Samuel Hood.

History
Construction of Hood began at the John Brown & Company shipyards in Clydebank, Scotland, on 1 September 1916. Following the loss of three British battlecruisers at the Battle of Jutland, 5,000 tons of extra armour and bracing was added to Hood's design. The intention behind this change was to give her protection against 15 inch (381 mm) guns, such as her own— in theory moving her to the status of a true battleship. This led to some describing her as the first fast battleship, since the Hood appeared to have improvements over the revolutionary Queen Elizabeth-class battleships. To add to the confusion, Royal Navy documents of the period often describe any battleship with a speed of over about 24 knots (44 km/h) as a battlecruiser, regardless of the amount of protective armour. Classification as a battlecruiser notwithstanding, she was the largest capital ship in the British fleet at the time of her commissioning; Hood was much longer than any other British capital ship and only marginally lighter (at full load) than Britain's heaviest ever battleship, HMS Vanguard, which was not commissioned until 1946.
However, the reworking was hurried and incomplete and hence flawed. Only the forward cordite magazines were moved below the shell rooms — cordite explosions destroyed the Royal Navy battlecruisers lost at Jutland. The combination of the deck and side armour did not provide continuous protection against shells arriving at all angles. Most seriously, the deck protection was flawed — spread over three decks, it was designed to explode an incoming shell on impact with the top deck, with much of the energy being absorbed as the exploding shell had to penetrate the armour of the next two decks. The development of effective time delay shells at the end of World War I made this scheme much less effective, as the intact shell would penetrate layers of weak armour and explode deep inside the ship. In addition, she was grossly overweight compared to her original design, making her a wet ship with a highly stressed structure. It was seriously suggested that she should be scrapped before she was launched; the post-war economy drive made replacing her impossible however.
Construction on her sister ships HMS Anson, Howe, and Rodney was stopped in March 1917, although work continued on Hood. Two factors were at work regarding this decision. Firstly, the German ships to which the class were a response were never completed. Secondly, the flaws in her protection and design were apparent: the repeated redesigns of the sister ships did not solve them. Instead, a series of studies leading to the N3 battleship and G3 battlecruiser designs was started.
She was launched on 22 August 1918 by the widow of Admiral Sir Horace Hood, a Jutland casualty and distant relative of the famous Lord Hood for whom the ship was named. After fitting out and trials, she was commissioned on 15 May 1920, under Captain Wilfred Tomkinson, and became flagship of the British Atlantic Fleet's Battle Cruiser Squadron. She had cost £6,025,000 to build. With her conspicuous twin funnels and lean profile, Hood was widely considered a very graceful warship.

Construction

Principal characteristics
Hood's protection accounted for 33% of her displacement; a high proportion by British standards, although less than was usual in contemporary German designs (for example, 36% for the battlecruiser SMS Hindenburg). It was apparently proposed to extend the new plating to the whole of the upper deck, removing the conning tower, torpedo tubes and four 5.5 in guns as weight compensation; in the event, only the areas above the magazines were reinforced. As completed, Hood remained susceptible to plunging fire and bombs, and had no margin of protection against the next generation of heavy guns.
The main armament turrets had a frontal armour thickness of 15 in (381 mm), side armour of 11 to 12 in (280 to 305 mm) and a roof of 5 in (127 mm). For protection against torpedoes she was given an "anti-torpedo bulge", an air-filled space backed by an inner reinforced wall. It was a new and effective solution for World War I ships and a common solution to counteract the weight increases that would be otherwise needed for ships built between the two World Wars.

Main belt: 12 in (305 mm) between A and Y barbettes; forward extension 5 to 6 in (127 to 152 mm); aft extension 6 in (152 mm);
Middle belt: 7 in (178 mm) between A and Y barbettes; forward extension 5 in (127 mm);
Upper belt: 5 in (127 mm) amidships, extending forward to A barbette, with a short 4 in (102 mm) extension aft.
Forecastle deck: 1.75 to 2 in (44 to 51 mm);
Upper deck: 2 in (51 mm) over magazines; 0.75 in (19 mm) elsewhere;
Main deck: 3 in (76 mm) over magazines; 1 in (25 mm) elsewhere; plus 2 in (51 mm) slope meeting bottom of main belt;
Lower deck (forward and aft): 3 in (76 mm) over propeller shafts; 2 in (51 mm) magazine crowns; 1 in (25 mm) elsewhere. Protection

Weapons
Hood was fitted with the BL 15 inch Mark I (381 mm) /42 gun of 1912. This was the then standard weapon of British capital ships and was already mounted on the Queen Elizabeth-class, Revenge-class, Renown-class and other classes of ships. Hood was the first, and in the event the only ship to carry these guns in the Mark II twin mounting.

289 Common Pointed Capped shells (CPC), weight 1,920 lb (871 kg)
672 Armour-Piercing Capped (APC), weight 1,920 lb (871 kg)
30 shrapnel (forward turrets only), weight 1,920 lb (871 kg)
82 practice rounds. Main armament
The secondary (low angle) guns were BL 5.5 inch Mark I (140 mm) /50. These were designed in 1913 for two modified Town-class cruisers being built for the Greek Navy. This gun was 13 cwt (660 kg) lighter than the standard BL 6 inch Mark XII gun and fired a projectile 15 lb (6.8 kg) lighter and therefore easier to handle, allowing for a higher rate of fire. The Greek ships were completed for the Royal Navy as HMS Birkenhead and Chester, introducing this weapon into British service. They were shipped on shielded CP Mark II single mounts capable of elevating from -5 to +30 degrees, and fired 82 lb (37 kg) shells at a rate of 6 to 10 rounds per minute. The muzzle velocity was 2,725 ft/s (830 m/s), giving an effective range of 17,770 yards (16.2 km). The high position of the mountings along the upper deck and the forward shelter deck allowed them to be worked in a seaway, less obstructed by waves and spray.
These guns were removed during the Hood's refit in 1940, after which their magazines were used for 4 inch (102 mm) anti-aircraft ammunition.

Secondary armament
Hood's original anti-aircraft armament consisted of four QF 4 inch (102—mm) L/45 Mark V guns on mountings HA Mark III. These were joined in 1937 by four twin mountings HA/LA Mark XIX for the 1934 model QF 4 inch L/45 Mark XVI gun and the single guns were replaced with a further three Mark XIX mountings in 1940. The mounting could elevate from -10 to +80 degrees able to engage both aircraft and vessels. This gun fired a 31 lb (15 kg) shell at 2,660 ft/s (811 m/s) for an effective range of 18,150 yd (16.6 km). In 1931 a pair of octuple mountings Mark VIII for the QF 2 pounder Mark VIII (40 mm) gun were added, a third mount being added in 1937. Two quadruple mountings Mark I for the 0.5 inch Vickers Mark III (12.7 mm) machine gun were added in 1933 with a further two mountings added in 1937. To these were added 5 Unrotated Projectile (UP) launchers— 20-barrelled launchers for 3 inch (76 mm) rockets that shot their warheads out on three parachutes on lengths of cable that could snag aircraft.

Anti-aircraft armament
Two 21 inch (533 mm) torpedo tubes were mounted amidships on either side, a remainder of shorter range engagements expected during the Great War, but augmented with 4 more in 1940.

Torpedo armament
Hood carried aircraft for part of her service life. She embarked a flight of seaplanes, initially Fairey Flycatchers, then Fairey F3 Fs from 1929 to 1933. At first there were flying-off platforms fitted to "B" and "X" turrets so that wheeled aircraft could be launched from the ship, but these were soon removed as floatplanes became more reliable. A rotatable catapult was installed at the very rear (quarterdeck) of the ship along with a crane for recovery of the plane in 1929, but it was frequently awash when under way and was removed in 1932.
As befitted a vessel her size, Hood carried a large number of small boats, both sailing boats (a 42 ft (12.8 m) launch, 36 ft (11 m) sailing pinnace, 32 ft (9.8 m) cutter, 30 ft (9.1 m) gig, 27 ft (8.2 m) whaler and a 16 ft (4.9 m) dinghy) and powered boats (50 ft (15.2 m) steam pinnace, 45 ft (13.7 m) steam pinnace, 45 ft (13.7 m) and 35 ft (10.7 m) Admiral's barges, 45 ft (13.7 m) motor launch, 35 ft (10.7 m) and 25 ft (7.6 m) motor- and "fast" motor- boats of hard chine construction and a 16 ft (4.9 m) motor dinghy)

Aircraft and boats
In the inter-war years she was the largest warship in the world at a time when the British public felt a close affinity with the Royal Navy. Her name and general characteristics were familiar to most of the public, and she was popularly known as the Mighty Hood. Because of her fame, she spent a great deal of time on cruises and "flying the flag" visits to other countries. In particular she took part in a world-wide cruise between November 1923 and September 1924 in company with HMS Repulse and several smaller ships. This was known as the Cruise of the Special Service Squadron, and it was estimated that 750,000 people visited Hood during that cruise. The future First Sea Lord John H. D. Cunningham served aboard her as navigator for a period in 1920. In 1931 her crew took part in the Invergordon Mutiny.
She was given a major refit from 17 May 1929 to 16 June 1930, and was due to be modernised in 1941 to bring her up to a standard similar to that of other modernised World War I-era capital ships. Ironically, her status as the Royal Navy's finest capital ship meant that her material condition gradually deteriorated due to her near-constant active service, and by the end of the 1930s she was in poor condition and in need of refitting. The outbreak of war made it impossible to remove her from service, and as a consequence she never received the scheduled update. Her condition meant, among other things, that she was unable to attain her top designed speed.

Inter-war service
Hood was transferred to the Mediterranean Fleet in July 1936. In June 1939, she joined the Home Fleet's Battle Cruiser Squadron at Scapa Flow; when war broke out later that year, she was employed principally in patrolling the vicinity of Iceland and the Faroes 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. As the flagship of Force H, she took part in the destruction of the French Fleet at Mers-el-Kebir in July 1940, Hood firing 56 rounds of 15 inch shells during the thirty minute action. they were rescued about two hours after the sinking by the destroyer HMS Electra.
The dramatic loss of such a well-known symbol of British naval power had a great effect on many people; some later remembered the news as the most shocking of World War II. Following the loss of the Hood, the Royal Navy concentrated all available resources in pursuit of Bismarck and Prinz Eugen; although Prinz Eugen escaped, Bismarck was eventually sunk after being brought to battle again on 27 May 1941.

World War II
The official Admiralty communiqué on the loss, broadcast on the day of the sinking, reported that: "during the … action, HMS Hood … received an unlucky hit in a magazine and blew up." and examined both Goodall's theory and others (see below). The Board came to a conclusion almost identical to that of the first board, expressed as follows.
That the sinking of Hood was due to a hit from Bismarcks 15 inch shell in or adjacent to Hoods 4 inch or 15 inch magazines, causing them all to explode and wreck the after part of the ship. The probability is that the 4 inch magazines exploded first.

Boards of Enquiry into the sinking
The exact cause of the loss of HMS Hood remains a subject of debate. The principal theories can be summarised as follows.
An extensive review of each of these theories (except that of Preston) is given in Jurens. Such unprotected stowage could have been detonated either by the boat-deck fire or by a shell from Bismarck.
The ship was blown up by her own guns. At the second board, eyewitnesses reported unusual types of discharge from the Hood's 15 inch (381 mm) guns, suggesting that a shell could have detonated within the gun, causing an explosion within the gunhouse. It is possible that, under the stress of combat, the safety measures, introduced after the disasters at Jutland to prevent such an explosion reaching the magazines, could have failed. Modern Theories on the Sinking
The wreck of Hood was discovered in 3,000 metres of water in July 2001 by an expedition funded by UK-based Channel Four Television and ITN and led by shipwreck hunter David Mearns. In 2002, the site officially became a war grave by its designation the British government as a protected place under the Protection of Military Remains Act.
Hood's wreck lies on the seabed in pieces among two debris fields. The eastern field includes the tiny amount of the stern which survived the magazine explosion as well as the surviving section of the bow and some smaller remains such as the screws. The 4 inch (102 mm) fire director lies in the western debris field. The heavily armoured conning tower is located by itself a distance from the main wreck. The amidships section, the most massive part of the wreck to survive the explosions, lies south of the eastern debris field in a large impact crater. The starboard side of the amidships section is missing down to the inner wall of the fuel tanks; this has been interpreted as indicating the path of the explosion through the starboard fuel tanks. It is further supposed that the small debris fields are the fragments from the after hull where the magazines and turrets were located, since that section of the hull was totally destroyed in the explosion. The fact that the bow section separated just forward of A turret provoked the suggestion that a secondary explosion might have occurred in this area; however, the forensic assessment by Jurens has dismissed this theory.
The forward section remains upright on the seabed, with the amidship section keel up. Of interest is the stern section which actually rises from the seabed at an angle. This position clearly shows the rudder locked into a port turn, confirming that orders had been given (just prior to the aft magazines detonating) to change the ship's heading and bring the aft turrets 'X' and 'Y' to bear on the German ships.

See also

Bradford, Ernle (1959). The Mighty Hood. Cleveland: World.  An overall history, including her peace-time career.
Coles, Alan; Briggs, Ted (1985). Flagship Hood: The Fate of Britain's Mightiest Warship. London: Robert Hale. ISBN 0-7090-2024-4.  Ted Briggs was one of the three survivors of Hood's loss.
Northcott, Maurice P. (1975). Hood: Design and Construction. London: Bivouac Books Ltd. ISBN 0-85680-009-0.  A shorter work giving technical details of her construction.
Roberts, John (1989). Anatomy of the Ship: The Battlecruiser Hood. London: Conway Maritime. ISBN 0851772501.  A lengthy work giving great detail on her construction.
Taylor, Bruce (2005). The Battlecruiser HMS Hood: An Illustrated Biography, 1916-1941. London: Chatham.  The complete history of her career, functioning and people based on in-depth research from original sources.
Kemp, Paul J. (1991). Bismarck and Hood: Great Naval Adversaries. London: Arms and Armour Press.  Includes pictures of the Hood, and description of the Battle off Iceland.
Lt Cdr. Timothy J. Cain (1959). HMS Electra. London: Frederick Muller, LTD.. ISBN 0-86007-330-0.  Includes accounts of the survivor rescue effort.
Breyer, Siegfried (1973). Battleships and Battlecruisers 1905-1970. Garden City, New York: Doubleday and Company.  (originally published in German as Schlachtschiffe und Schlachtkreuzer 1905-1970, J.F. Lehmanns, Verlag, Munchen, 1970). Contains various line drawings of the ship as designed, as built, in her final (as sunk) configuration, and the proposed 1941 refit.
Mearns, David; White, Rob (2001). Hood and Bismarck: The Deep Sea Discovery of an Epic Battle. London: Channel 4.  Describes the expedition to find the wreck of the Hood, as well as its current state.
Steve Wiper, Warship Pictorial #20: H.M.S. Hood (Classic Warships Publishing, Tucson, Arizona, 2003), Contains pictures of the Hood during construction, including pictures of the launching.
Antonio Bonomi, Stretto di Danimarca, 24 maggio 1941, printed on "Storia Militare" magazine, December 2005.
Norman Friedman, Battleship Design and Development 1905-1945, Conway Maritime Press 1978; ISBN 0-85177-135-1.
VE Tarrant, King George V Class Battleships, Arms and Armour Press, 1991. ISBN 1-85409-524-2.