The Admiral-class battlecruisers were to have been a class of four British Royal Navy battlecruisers built near the end of World War I. Their design began as an improved version of the s, but it was recast as a battlecruiser after Admiral John Jellicoe, commander of the Grand Fleet, pointed out that there was no real need for more battleships, but that a number of German battlecruisers 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 to have consisted of , Anson, Howe, and Rodney — all names of famous admirals — but the other 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, 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 of the Battlecruiser Squadron of the Atlantic Fleet. She served as the flagship of the Special Service Squadron during its round-the-world cruise in 1923–1924. Hood was transferred to the Mediterranean Fleet in 1936 and spent much of the next few years on Non-Intervention Patrols during the Spanish Civil War, returning to the United Kingdom before the beginning of World War II 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, based at Gibraltar, 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 as they attempted to break out into the North Atlantic. In the subsequent Battle of the Denmark Strait, the aft magazines of Hood exploded, sinking her within five minutes of opening fire.
Design and description
In 1915 the Admiralty was considering the next generation of warship to follow the Queen Elizabeth-class battleships. The Director of Naval Construction (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 Queen Elizabeth by 22% by widening the ship to and lengthening it to ; this had the consequence of restricting the ships to use only one dock in Rosyth and two in Portsmouth. Large anti-torpedo bulges were fitted, and the secondary armament of twelve guns of a new design was mounted on the forecastle deck. The resulting high freeboard gave the design a greater ratio of reserve buoyancy to displacement than in any previous British dreadnought. The design's stretched hull form also gave her an estimated speed of , about faster than Queen Elizabeth had been able to reach in service. The First Sea Lord, Admiral Sir Henry Jackson, responded on 6 December that such a large ship might 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 , 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 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 in comparison with 'B' and 'C2' was only in length, but draught increased by . 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 Queen Elizabeth. In addition the new five-inch gun was rejected in favour of the existing gun.