-History of H.M.S. Hood-
What Changes are Suggested in Naval Construction, Etc.,
Battle Cruisers - Armour

Written by Colonel JFC Fuller, DSO & transcribed by Mike Nottage
Updated 08-Apr-2019

The following originally appeared in The Navy Society's "The Naval Review" of 1921. It has been transcribed for us by Mike Nottage.

Chainbar divider

The degree of abovewater armour protection that should be given to battle cruisers cannot be determined, unless it is clear what role they are intended to fill.  The chief function usually ascribed to battle cruisers before the war, and the one to which it is believed their original inception is due, was to pierce the enemy’s cruiser screen, obtain information of his battle fleet, and keep touch with it.  When our battle cruisers first appeared their strongest opponents in this work were the armoured cruisers of the day, so the protection given them was of the class usual to armoured cruisers.  The same protection was ample also to enable them to pulverise with impunity any armoured or light cruisers that came within their range of vision, either in the main theatre of operations, or on the distant trade routes. 

There was a tendency before the war to allot an additional function to battle cruisers; that of  working as a fast armoured division of the fleet and joining in the battleship action, on the assumption that their great superiority of speed would enable them to obtain a favourable tactical position for using their heavy guns.  Neither British nor German battle cruisers were ever thoroughly tested during the war in action against heavy battleships, but German battle cruisers had a touch of it, and suffered severely, whilst inflicting correspondingly little damage to our battleships.  The fact is, that though the guns of battleships and battle cruisers are both equally effective at extreme visibility range, the ships armoured only on the scale of armoured cruisers are bound to be outmatched when hitting begins, their great speed then being no compensation for their lighter armour.  The use of battle cruisers against battleships cannot be justified except in emergencies, and in special tactical situations, when the battleships are already so heavily engaged elsewhere as to be unable to reply effectively. 

If battle cruisers should be required to engage battleships unaided, as part of their normal duties, they must be heavily armoured; they then cease to be cruisers at all, and can only be classed as fast battleships.  If the original high speed characteristic of battle cruisers is retained in this fast battleship, she necessarily becomes so large and expensive a vessel that the provision of each one of them must mean reducing the number of those of the more normal types necessary to complete our fleet for its special strategical functions.  Such a battleship could be usefully employed tactically in a fleet action to reinforce any heavy division in a widespread action; she would make an ideal fleet flagship for a Commander-in-Chief who believes that he should have the power of throwing in a powerful reserve at any point of the battle, after he has left the control of affairs to the squadron leaders.  A squadron of such ships would of course, make an ideal “fast division,” but it is questionable whether their tactical value would justify the enormous expense incurred in obtaining the speed. 

To revert to the battle cruiser proper, this, after all is only the old armoured cruiser improved and adapted to the principle of the single calibre big gun type, that originated in the Dreadnought.  Experience confirms that if a navy possess battle cruisers, and uses them either offensively with his fleet, or for independent offensive action, other battle cruisers are the only type that can bring them to action.  It follows that our battle cruisers should be at least as well protected as those of a potential enemy, whatever their respective armament may be.  In this respect, the chief lesson of the war was the serious disadvantage of the absence of armour above the main deck of our early battle cruisers, although it was possessed by the natural opponents, the German battle cruisers.