THE ARMOUR PROTECTION OF CRUISERS.

Auckland Star, Volume XXXIV, Issue 2, 2 January 1903, Page 2

THE ARMOUR PROTECTION OF CRUISERS.

IMPORTANT, DEPARTURE IN BRITISH PRACTICE.

Tbe new British cruisere, as described in "Engineering," to be known as the Duke of Edinburgh class, are to have citadels-, as distinct from the scattered casemate system, and when one recalls, continues ''Engineering," that we have, since first adopting the system, of casemates in 1889, fitted 800 of these, and that in some 30 ships now building there are 380 casemates, ft is important to inquire how far this change is justified. The casemate system was first introduced, and greatly appreciated, because it secured, for, a minimum of weight, a complete protection to each gun crew and gun mechanism from .the attack of~ common shelL The face .of the casemate was usually made of armour equal to resisting penetration from a shot delivered by a gun of a calibre corresponding to that protected by the casemate. But the rear walls were made of only one-half, and in some cases of one-third, this thickness, the theory being that a large percentage of the shell would pass direct across the ship—i.e., at right angles—and tha.t even those which might cross diagonally, and thus -be liable to strike the rear of the casemate opposite to the broadside attacked, would have their force spent and their charge exploded by contact with the shell plating or bulwarks. There has, however, been a considerable development in armour-piercing shell during the past ten years, and the result has been to make such diagonal shots, even at long range, capable of very considerable destructive power when exploding near to, or against,, the rear plating of such a casemate. To make the armour on all sides of maximum thickness, it has been considered, would involve a weight which might be more satisfactorily utilised if disposed entirely on the broadside, so that that part of the shell of the ship between the casemates might be completely armoured. The United States have, more than any other Power, accepted this condition, and in their recent siiips 70 per cent of their guns are thus protected in box batteries or citadels. France, on the other hand, has preferred to put the secondary guns in turrets, which offers advantages in isolation; nearly 70 per cent, of her guns are disposed in way. In Russia, however, there is greater variety, in the systems adopted, and barely 50 per cent, of the secondary guns are in turrets, while the remaining weapons are equally distributed between casemates and box batteries. Germany utilises all three methods in al most equal proportions, although in later siiips the citadel system finds favour. Britain, on the other hand, has practically all the guns within casemetns, the only departures being in the case of the ships of the King Edward class. The citadel system, while enabling the guns, and therefore the armour, to be concentrated within a comparatively small area, may also confer the advantage of greater arc of training for the majority of the ally all the guns within casements', the system. In the new British cruisers, adds "Engineering," the citadel will extend for about three-fifths of the length of the vessel, and the side plating will be of 6in cemented armour from about sft below the water line right up to the main deck. On the water line, however, there will be forward and abaft the citadel, to the bow and the stern, armour-plating tapering from 4in to 3in in thickness, the usual armoured bulkheads forming the bow and stern thwartship walls of the citadel The armoured deck will, as hitherto, be 'Sußßid epis eqj jo taojjoq aq; o} p9Ajt» thus increasing the effective protectloa on the broadside against gun attack.