The Collingwood class is continued. though by vessels of a larger displacement, a some what superior type of battle-ship being presented by the Trafalgar and Nile in 1886. Most demands are well met in this class, but the secondary battery is somewhat weak. It was originally designed to be composed of eight 5-in. guns in broadside, without any protection, but was changed to six 4-72-in. rapid-fire guns behind 4 in. of armor. The irresistible logic of events had at this time forced the displacement above 14.000 tons; the water-line de fense continued about the same. Few, if any, armored vessels with complete or partial water line belts have these of sufficient depth to give proper protection when rolling. This defect is minimized, of course, in the large ships of from 13,000 to 15,000 tons displacement, which were not found to roll appreciably in any sea-way that permitted ordinary vessels to work their guns.
In the barbette ships there was greater freeboard nt the ends, four heavy guns placed high above water in two separate barbettes, and a central battery, containing an auxiliary arma ment identical with that provided for in the turret ships. In the strength of the protective armor arc the ammunition-tubes, and in the general protection of the loading arrangements and gun mountings the English type of barbette (Fig. 2) is held to be far superior to that to be found in most foreign war-ships. It was decided, however, in view of the great development of high explosives, that in any new designs for barbette ships the proportion of the length at the water-line protected by the belt of armor should be increased, and that the armored bar bette towers should be carried down far enough to prevent the possibility of the bursting of shells under the revolving gun-platforms.
Before proceeding to build new ships a most animated and prolonged discussion arose in 1888 in England, in which the leading naval architects participated, and which brought forth a great number of new features that are to be found in the battle-ships at present under con struction. The adoption of the redoubt system, when it is associated with a long central battery containing a powerful auxiliary armament, enables a very appreciable increase to be made in the defense of the turret base, the turret guns, and all the loading appliances, as compared with what is possible when the continuous citadel is adopted. The defense afforded by the side armor fitted above the belt is re-enforced by continuous coal-bunkers which, when filled, contribute to the defense, and, when empty, form cellular compartments in rear of the armor. During the first half of this past decade it was but rarely that the projectile energy
was entirely expended in making a cretin hole through either compound or steel plates, the results usually obtained being a fractured plate and broken projectile. In conseqenee, except in competitive trials of different plates of the dimensions under exactly similar circum stances, all calculations or comparisons were too unreliable to be of value, the outcome being to leave the question of the relative merits of compound and steel armor an open one. Such have been the improvements in the quality of metal and in the processes of manufacture, and the conditions have varied so much from preceding ones, that the entire subject of armor must now be somewhat differently treated, and the outcome of trials that occurred before the middle of the decade set aside as hardly pertinent to the question.
The improvements in the quality and in the manufacture of projectiles have been relatively much greater than in that of plates, and armor-piereing projectiles are now produced which, so far as compound and steel plates are concerned, can from their perfection of quality, toughness, and temper, be fairly dominated as unbreakable and undeformable. As soon as such projectiles were obtained, a fairly approximate method of comparing, under certain fixed conditions, the resisting powers of different plates to penetration was arrived at. Armor trials have thus far been conducted nailer conditions exceedingly unfavorable to the plate, more so than would probably ever occur in actual warfare. The gnu has every advantage: a steady platform and is normal impact at a short range on an immovable target, so rigidly braced as to receive the full effect of the energy stored up in the projectile.
In 1888 a Camtnel compound plate. S ft. by 6 ft. by 101 ft. thick, was tested in competition with it number of English-made compouml and steel plates, and not only proved superior to all its competitors, but gave better results than had ever before been obtained front a compound plate under similar conditions. The most important point brought out in regard to this late was the decided uniformity of the metal of which it was composed, this being evidenced by the nearly equal penetration of the three Holtzcr 100 lb. armor-picreing projec tiles, having a striking energy of 2,723 foot-tons, and the similar amount of work done on each. they all breaking in about the same manner. The iron Palliser projectiles broke up against the hard steel face with but slight penetration.