H.M. WAR STEAMER ALEXANDRA.

Globe, Volume IV, Issue 327, 30 June 1875, Page 3

H.M. WAR STEAMER ALEXANDRA.

The following information concerning this powerful addition to her Majesty’s navy will prove interesting to many readers. From the London Mail we learn that: —“The Alexandra has been built on the model of the Hercules, but is more powerful both in armour and armament. Thus she will carry on her sides, in the most vulnerable parts, armour-plating of twelve inches thick, and on other parts, of as much as nine inches and ten inches thick. The Hercules nowhere carries more than nine inches of armour, and when it is considered that in the strength of her armour the Hercules has four times the advantage of the Warrior, and that the strength of the armour of the Alexandra is as seven to four compared with the Hercules —in other words, is nearly twice as great as that of the Hercules, and seven times as great as that of the Warrior— we can form an estimate not only of the enormous resisting power of this last addition to our ironclad fleet, but of her superiority to other vessels of her class. As in the case of the Hercules, the Alexandra has, fitted outside, a, skin plating of H inch thick, a teak backing of ten and twelve inches, with the usual longitudinal girders. Altogether, the total protection of this vessel, at its most vital parts, consists of about fourteen inches of iron, of which one thickness is twelve inches solid ; aud it is hardly an exaggeration that, of its class, it is the most powerful vessel yet constructed. Passing, however, from its power of defence and resistance to attack, it will be found that in its armament it is as superior to the Hercules, its prototype, as in its armour. It will carry at least two 25-ton guns and two 18-ton guns, on what corresponds to the central or principal battery of the Hercules ; on the upper deck eight or ten 18-ton guns, and in addition, fore and aft, will probably carry two or four chase guns, as is the case in the armament of the Hercules. In her central battery the Hercules carries eight 18ton guns, two 12-ton guns fore and aft, and fourGA-tongunsontheupperdeck. Itwasconsidered a triumph of constructive power when it was found possible to carry these 18ton guns, throwing 4001 b projectiles on a broadside battery; and it was considered essential for the 23-ton gun batteries that they should be constructed on the turret principle ; but our great objection to the broadside, sea-going ironclad has vanished with the capacity it has now been found possible to give the Alexandra, of carrying a battery of 25-ton guns. It is doubtful whether the speed of the Alexandra will be greater than that of the Hercules or of other sea-going ironclads. The Hercules has attained a speed of 14'691 knots an hour, but this is good work and very difficult to improve on. It is not generally understood that every additional knot gained by any vessel after a certain point has been reached, means, not a proportionate, but a most disproportionate, and even extravagant, increase of steam power. Thus, a horse-power of 4045 gave a result in a trial of the engines of the Hercules of 12.123 knots; but it required no less a horse-power than 8529 to give a result of 14.691 knots an hour; and to fgain an extra knot, by increasing the speed to 15 knots, would mean a still greater addition to the horse-power of the engines. If, therefore, the Alexandra can maintain really a speed of 14 knots she will be a fast vessel. So far as is known there are no vessels afloat which are superior to the Alexandra as sea-going ironclads, except the Kaiser and the Deutschland, belonging to the German navy. The Kaiser was launched recently, but the Deutschland will not be ready for at least another year. Both ships are smaller than the Alexandra, but their armour is almost equivalent in protective power, and their armament will hardly be inferior, as it will consist of eight 22-ton Krupp steel breech-loading guns, and four smaller guns.