| Warrior. | Inflexible. | |
| Weight of gun | 4¾ tons. | 80 tons. |
| Length | 10 feet. | 26 feet 9 inches. |
| Calibre | 8 inches. | 16 inches. |
| Powder charge | 16 pounds. | 450 pounds. |
| Weight of projectile | 68 ” | 1700 ” |
| Energy at 1000 yards | 452 foot-tons. | 26,370 foot-tons. |
| Penetration of 4½ inches of wrought-iron at short range | None. | ... |
| Penetration of wrought-iron at 1000 yards | ... | 23 inches. |
The term energy, when employed to indicate the work that a gun can perform, is expressed in foot-tons, and signifies that the amount developed is sufficient to raise the given weight in tons to the height of one foot. The piercing power of the Inflexible’s projectile was, under the same conditions of charge and range, sufficient to penetrate twenty-five feet of granite and concrete masonry, or thirty-two feet of the best Portland cement.
When the thickness of armor-plating increased, gun-makers tried to overcome the resistance by giving greater energy to the shot. As this required large charges of powder and very long guns, muzzle-loaders became impracticable on shipboard, and were supplanted by breech-loaders. From this stage guns developed greatly in power until, in 1882, those designed for the Benbow were to weigh 110 tons, to be 43 feet long and 16¾ inches in calibre, and with 900 pounds of powder and an 1800-pound projectile were to develop 54,000 foot-tons, or an energy sufficient to penetrate thirty-five inches of unbacked wrought-iron at one thousand yards. The guns for the latest English ships, the Trafalgar and the Nile, weigh 67 tons, are 36 feet 1 inch in length and 13½ inches in calibre, and with a 520-pound charge and a 1250-pound projectile are expected to develop 29,500 foot-tons, or an energy sufficient to penetrate an iron target twenty-two and a half inches thick at a thousand yards. These results apparently show a retrogression in power, but a comparison of the Inflexible’s and Trafalgar’s batteries proves that the more modern gun of the latter weighs 13 tons less, is 2½ inches smaller in calibre, fires a shot 450 pounds lighter, and yet develops an energy greater by 3000 foot-tons.
This gain is mainly due to the improvements made with powder and projectiles. In 1883 a 403-pound Whitworth steel shell penetrated a wrought-iron target eighteen inches thick backed by thirty-seven inches of well-packed wet sand, one and a half inches of steel, various balks of timber, and sixteen feet more of sand. When the projectile was recovered after this stratified flight it was found to be practically uninjured. On the Continent, where breech-loaders were favored earlier than in England or with ourselves, the heaviest rifles afloat are the 75-ton, 16.54-inch calibre, French, and the 106 tons, 17-inch Italian guns. These are, however, not the largest pieces designed, for there is an 120-ton Krupp gun, and the French have projected one which will weigh 124 tons, be 18.11 inches in calibre, and fire a 2465-pound projectile—over a ton—with a powder charge of 575 pounds. A comparison of the Krupp 120-ton gun with the 110-ton Armstrong shows that the former is more powerful; that its projectile is much heavier, and the initial velocity and pressure are smaller. The results at the recent test were as follows:
| Armstrong. | Krupp. | |
| Charge | 850 pounds | 847 pounds. |
| Shot | 1800 ” | 2315 ” |
| Velocity | 2150 feet | 1900 feet. |
| Pressure | 19.9 tons | 18.8 tons. |
| Energy | 57,679 foot-tons | 67,928 foot-tons. |
From the Warrior to the Inflexible the evolution of design was based upon a principle that sought the best results for the offence in small, powerful batteries, with all-around fire and armor protection; and for the defence, in thick armor carried over the vitals of the ship. This was satisfied by larger weights of armor and a smaller ratio of armored part to total surface. Wrought-iron armor was also replaced by compound, with a corresponding gain of twenty per cent. for equal thicknesses, and at present all-steel plates, of which great things may reasonably be expected, are now employed by France and Italy. In 1861 the Minotaur was belted throughout her 400 feet of length with 1780 tons of armor, or with a weight nearly double that given to the Warrior two years before. The Inflexible has 3280 tons, and the Trafalgar 4230 tons, of which 1040 are fitted horizontally. The maximum thickness of the Warrior’s wrought-iron armor is 4½ inches, of the Devastation’s, 12 inches, and of the Inflexible’s 24 inches; the compound (iron steel-faced) armor of the Trafalgar is 18 and 20 inches thick, and the Baudin and Formidable have 21.7 inches in solid plates of steel. These, of course, are some of the dry-as-dust figures before referred to, and they are cited only to assist a comparison, their mere enumeration having no scientific value, because the disposition and character of the plates are unconsidered.
To meet this development of offence and defence many changes in design have been adopted. The broadside system of the first armored ships was followed in 1863-1867 by a belt and battery type, wherein the principal guns, much reduced in number, were carried in a box battery amidships, and given a fore-and-aft fire by means of recessed ports or outlying batteries. In 1869 the Admiralty adopted the breastwork monitor, a low free-boarded structure, which was plated from stem to stern in the region of the water-line, and had in its central portion an armored breastwork that carried at each end a revolving turret. In 1870 this type was pronounced unsafe, and after a careful investigation by a special committee on design certain modifications were recommended. These did not affect materially the essential features of Sir Edward Reed’s plan, for the complete water-line belt and the central armored battery were retained; and to-day many of the critics who then denounced it claim that, after all, it is the true type of an ideal battle-ship.
In 1872 the Italian naval authorities accepted the conclusions of the British committee, and laid down the first central-citadel battle-ships, now known as the Duilio and Dandolo; and about the same time Mr. Barnaby, the new Chief Constructor of the British Navy, brought forward a similar design in the Inflexible. The engines, boilers, and the bases of two turrets in this vessel are protected by an armored box-shaped citadel, from the extremities of which a horizontal armored deck extends fore and aft below the water-line; above this deck an armored superstructure completes the free-board, and has its unprotected spaces at the water-line, subdivided into numerous water-tight compartments. This ship met with so much hostile criticism that a committee was appointed to investigate the charges, but in the end the Admiralty plans were officially sustained.
The French, with characteristic ability and independence, have in the mean time made many notable departures from their first types of broadside ships. Believing in the association of heavy guns with light ones—mixed armaments, as they are called—the central armored casemate of wholly protected guns has been rejected in order to give a maximum thickness of plating at the water-line. The largest guns are mounted en barbette—that is, in towers which protect the gun mechanism, and permit the pieces to be fired, not through port-holes, but over the rim of armored parapets. The French constructors reason, and with justice, that no single shot from a heavy gun should be wasted, and that, in addition to an extended range, gun captains must be enabled, by keeping their eyes upon the enemy, to select the best opportunity for firing. With broadside pieces this is impossible, for apart from the limited range, and the obscurity caused by the smoke, the port-holes through which the sighting has necessarily to be done are almost choked by the gun-muzzles. Turrets have their objections also, because the poisonous gases which formerly escaped wholly from the muzzle will, as soon as the breech is opened, rush into the turret and make it almost uninhabitable. Often after one discharge the air becomes stifling, and in the Duilio it deteriorated so quickly as to be unfit for respiration until a part of the turret-roof had been lifted. Then, again, structural difficulties not easily overcome in the turret are simplified in the barbette, as the latter, with equal gun facilities, weighs fifty per cent. less, and at the same time escapes all those chances of disablement which a well-placed shot is almost sure to cause in any revolving system. At sea the chance of hitting the gun is never great, and the main things to protect are the gun machinery and the gunners; the armored wall of the barbette tower does this for the former, and the latter have a fair fighting chance afforded by the gun-shield. Of course war is not deer-stalking, and the patriot who wants to go into battle so fully protected as to be in no danger had better stop playing sailor or soldier, and take to the woods before the fighting begins. In addition to the heavy ordnance, the French mount a number of lighter pieces, and carry powerful secondary batteries of rapid fire and machine-guns; and sufficient armor defence is given by a belt at the water-line, an armored deck, and a glacis and parapet for the barbette. It is quite probable that these purely military terms may seem odd when applied to ships, but they are the only ones which can exactly explain what is meant, and, after all, they show how much a battle-ship has become a floating, transferable fortress.
The Italians were not altogether satisfied with the Duilio, as she lacked the high speed and coal endurance which they deem essential in any Mediterranean naval policy; so in 1878 they adopted an idea advanced some years before in England, and startled the world with the Italia type. In this ship protection is given, not by vertical or side armor, but by an armored deck, between which and the deck above there is a very minute subdivision of the water-line space. The system is based upon the theory that the power to float must be obtained, not by keeping our projectiles, but by so localizing their effect as to make any penetration practically harmless. The Italia’s heavy guns are carried in a central armored redoubt, at a height of thirty-three feet above the water-line, and with their machinery and fittings weigh over two thousand tons. This fact shows the magnitude of the task accepted by her designer, for it means that a load nearly equal to the total weight of a first-class line-of-battle ship of the last century has to be sustained at this great elevation. Besides the main battery of four 106-ton guns, eighteen six-inch breech-loading guns are carried—twelve in broadside on the upper battery deck, four in the superstructure before and abaft the redoubt, and two under cover at the extremities of the spar-deck. The redoubt is protected by seventeen inches of compound iron, inclined twenty-four degrees from the vertical; and the complete armored deck, which is nearly three inches thick, dips forward to strengthen the ram, curves aft to cover the steering gear, and, at the ship’s sides, extends six feet below the water-line.