The Battlecruiser HMS Hood

 [Drawings by Stefan Dramiński]

Until the outbreak of World War II the battlecruiser Hood was the world’s largest warship and, as many believed, the finest one ever built. She inspired awe not just because of her sheer size but also because of the power of her armament.

It is no wonder she quickly became to be known as the “Mighty Hood”. Her end was sudden and violent: she exploded and sank after a short battle with the German battleship Bismarck. Only three of her crew survived.
The Grand Fleet warships of the World War I era had many deficiencies. Their low freeboard combined with the placement of the medium battery guns in casemates put the ships in danger of flooding and made the low-mounted guns virtually unusable in rough sea conditions. It was clear that the new generation of ships would have to feature high freeboard and gun batteries mounted high above the waterline. In October 1915 the Board of Admiralty instructed the Director of Naval Construction to begin work on the new, experimental warship design. The new ship was to be a modified Queen Elizabeth design with the draught reduced by 50 percent. Additionally, the new class would feature enhanced armor protection below the waterline to improve its survivability. However, in February 1916 the plan to design a fast battleship was questioned by Admiral John Jellicoe, who believed that the Royal Navy already had a clear advantage over other nations in that category of warships. What Jellicoe proposed instead was the design and construction of heavily armed battlecruisers which could match the capabilities of the new German Mackensen class warships. On February 17 the Admiralty designers submitted six different proposals for warships armed with eight 15 inch (381 mm) main guns, or with four to eight 18 inch (456 mm) weapons and protected by 8 to 10 inch (203 – 254 mm) armor. Two more design concepts of warships featuring 15 inch main battery guns were submitted on March 27. After the most promising design had been selected, the construction of four vessels was given a green light. In April the Admiralty placed an order for construction of the battlecruiser HMS Hood at John Brown & Co. in Clydebank, Scotland. The other three ships were to be built at Cammell Laird in Birkenhead (HMS Howe), Fairfield in Govan (HMS Rodney) and at Armstrong Whitworth in Elswick (HMS Anson). The order for the construction of the latter was placed in July 1916. Since the new battlecruisers were all named after British admirals, the new warships became to be referred to as the “Admiral” class. Displacing as much as 36 200 tons, the new vessels were expected to reach the speeds of 32 knots. However, the installation of heavy 140 and 381 mm guns necessitated the reduction of the ships’ protective armor. In fact it was barely heavier than the armor of the Minotaur class cruisers – the vessels which were only half the size of the new battlecruisers.

Area around “B” turret barbette. Note the after breakwater and vents.  [Drawings by Stefan Dramiński]

The Hood was laid down on May 31, 1916, but her construction was almost immediately halted following the tough lessons learned from the battle of Jutland that took place on that very day. In the battle three Royal Navy battlecruisers (Indefatigable, Queen Mary and Invincible) were lost after the well-placed German shells penetrated their hulls causing massive explosions of the ships’ ammunition magazines. The commission tasked with investigating the tragic incident established that the root cause was inadequate armor protection of the ships’ decks and ammunition magazines. The findings led to the introduction of a series of modifications to the design of the new battlecruiser, which made the vessel appear more like a battleship. The thickness of the main armor plates was increased by about 50 percent, the 203 mm main armor belt was replaced with 305 mm of armor and the thickness of horizontal armor protection rose from 137 mm to 161 mm. Ammunition magazines also received enhanced armor plating. The 5 000 tons of additional weight reduced the ship’s projected top speed from 32 knots to 31 knots. However, during sea trials in 1920 she did manage to reach the top speed of 32.07 knots. In fact the Hood would consistently achieve speeds of over 30 knots until about 1941 when they dropped to 28 knots due to her deteriorating condition. The battlecruiser was powered by four sets of Brown-Curtis steam turbines which received steam from 24 Yarrow small tube 3 drum boilers installed in four boiler rooms.
The Hood was laid down once more on September 1, 1916. The changes to the design introduced in the aftermath of the battle of Jutland were followed by more modifications added throughout the construction period. HMS Hood had overall length of 860 ft, 7 in (262.3 m), the beam of 104 ft, 2 in (31.8 m) and draught of 32 ft (9.8 m). She was therefore 30 m longer and 4 m wider than the older class of battlecruisers. The weight of added armor plating increased the Hood’s draught by 4 feet (1.2 m) and lowered the freeboard, which led to frequent flooding of the ship’s decks. In rough sea conditions, or whenever the warship was steaming at full speed, the sea water would enter the crew’s living quarters through ventilation shafts making the ship’s interior permanently damp. This, combined with poor ventilation, made many of the battlecruiser’s crew suffer from tuberculosis.