Britain’s last battlecruiser – designing the ‘Mighty Hood’

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Matthew Wright

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I'm a New Zealand historian with a life-long interest in matters military, particularly naval engineering. My books have principally been published by Penguin Random House. I'm a Fellow of the Royal Historical Society at University College, London.
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For around twenty years HMS Hood was the largest warship in the world and symbol of the might of the Royal Navy.

Her loss in May 1941 – with the deaths of 1,415 officers and men – was a human tragedy. That will be covered in the next article; in this one we look at Hood‘s design during a period of discovery about warship performance, and bitter debate between designers and admirals on the back of it.

hms hood

HMS Hood in Australian waters, 1924. Public domain, via Wikipedia.

Hood‘s origins can be traced to early 1915 when the Admiralty asked the Director of Naval Construction, Sir Eustace Tennyson d’Eyncourt, to develop a battleship with the same main armament as the battleship Queen Elizabeth, but higher speed, reduced draft, and increased freeboard. D’Eyncourt asked his assistant E. L. Attwood to prepare designs. Then reports emerged of German battlecruisers of unprecedented power, and the Commander in Chief of the Grand Fleet, Admiral Sir John Jellicoe, asked for battlecruisers to counter them. The Admiralty concurred, and Attwood’s final design was 860 feet long with standard displacement of 36,000 tons, 8-inch armour belt, eight 15-inch guns, and small-tube boilers for 32 knots. The belt was sloped to increase the angle of a striking shell.

Orders were placed for four, named after famous admirals. The first – Hood, commemorating Samuel Hood (1724-1816) – was laid down on 31 May 1916, the same day three British battlecruisers were lost to magazine explosions in the Battle of Jutland. Explanations had to be found, and work on Hood was halted. The Admiralty discovered multiple causes, including faulty munitions handling procedures, stowing munitions outside magazines, and flash-protection inadequacies. Lessons were also drawn about discontinuous armour thickness and the need for better deck armour against plunging fire. All these issues were systemic across the fleet, but the overall scale of battlecruiser protection was part of the problem.

britain's last battlecruiser

Midships section of HMS Hood as re-designed. Public domain.

Hood was consequently re-designed with thicker main belt and better horizontal protection, spread over three decks, together adding around 5000 tons. Jellicoe was still concerned by the proximity of the magazine crowns to the upper deck. Further, he insisted: ‘Distance of magazines from the ship’s side appears to have been neglected’. Jellicoe was a formidable expert, part of the committee that developed the original Dreadnought in 1905, and he was driven by close analysis of the engineering issues that had destroyed his ships. But D’Eyncourt retorted that Hood was ‘much better protected than any previous ship built or designed for any Navy of which the particulars are known’.* This was true. Although classified a battlecruiser, Hood was better armoured than any battleship of 1916. But Jellicoe, too, had fair points in light of the Jutland experience.

the mighty hood

HMS Hood in Auckland harbour, New Zealand, 1924. Kinnear, James Hutchings, 1877-1946 :Negatives of Auckland shipping, boating and scenery. Ref: 1/2-015263-F. Alexander Turnbull Library, Wellington, New Zealand. /records/23240158

Work on Hood re-started on 1 September 1916 to the new design, further modified in 1917 with another 600 tons of armour. The remaining ‘Admirals’ were suspended. Then in mid-1918, live firings against a full-scale test structure showed that Hood’s improved deck armour was vulnerable. Part of this was due to shell fusing developed to defeat multi-deck armour; and in a report of 26 September 1919 the Director of Naval Ordinance reported that Hood‘s magazines were vulnerable to ‘plunging fire at [illegible range] unless the ship were rebuilt with a deck of thick homogeneous armour plate.’* This was not possible. However, 3 inches of armour was added around the magazine crowns.**

The Admiralty shortly decided to finish Hood, cancel the other ‘Admirals’, and focus on designs that took better advantage of war lessons. However, the ‘Washington’ Treaty of 1922 intruded, with the result that Hood became Britain’s last battlecruiser. She was completed in 1920 with displacement of 41,125 tons light (46,680 tons deep), length of 860 feet and beam of 104 feet, but the improvements left her sitting 4 feet lower than intended, and that got worse as equipment was added over the years. But she had speed; although expected to reach 31 knots after re-design, Hood achieved 32.07 on trials.

hms hood

HMS Hood at sea, late 1930s. Her low freeboard aft (with rising shear-line) is evident. Public domain, via IWM non-commercial license, http://www.iwm.org.uk/collections/item/object/205224389

Hood’s size struck chords the public, a repute cemented by her 1923-24 world tour as part of the ‘Special Service Squadron’. She was given a major refit in 1929-31, but it was 1938 before a rebuild was proposed. The style of reconstruction applied to the battlecruiser Renown was the likely model, with more deck armour, ‘tower’ superstructure, dual-purpose secondary battery, enhanced AA weaponry, updated fire-control, renewed boilers and better aircraft facilities.  The rebuild would have restored some reserve buoyancy but not fully cured the deck armour concerns. Nor could it fix the fact that Hood‘s cordite stores were above the shell rooms. However, plans were never finalised. War broke out in 1939 and Hood’s only modifications were to her anti-aircraft armament. Her worn-out steam plant affected her speed, but she could not be taken out of service for major overhaul until a number of King George V class battleships were available.

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For what followed – including the irony of the Admiralty’s concern about her deck armour, given the likely cause of her sinking – watch for the second article.

Don’t forget to check out my book on twentieth century naval design and history, Dreadnoughts Unleashed, available on Kindle.

Copyright © Matthew Wright 2017

*ADM 1-9210
**ADM 1-9226

3 Comments

  1. A glimpse into naval history – Matthew Wright on 09/03/2017 at 2:30 PM

    […] Why two parts? Well, I had a lot to say – and the story, anyway, breaks into two. First is the way this ship was designed at a time of rapid transformation in design philosophy- which had its sequel for Hood in an open spat between the Admiralty’s design office and the top admiral of the day.  You can read that here: http://www.navygeneralboard.com/britains-last-battlecruiser-designing-the-mighty-hood/ […]

  2. GP Cox on 09/03/2017 at 9:51 PM

    Happily, I own Dreadnaughts Unleashed, but I regret it is on hold untold I finish the 3 other books I am in the middle of. If it is even half as good as your other work – I am greatly looking forward to it!!

    • Matthew Wright on 09/11/2017 at 5:25 PM

      Thank you for buying the book – hope you enjoy it!

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