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APPENDIX B.

WARSHIPS AND SIGNALS.

HERE are ten principal classes of vessels in the United States navy, distinguished one from another by the differences in their uses and by their strength and speed. The general principle underlying their construction is that a vessel which is not strong enough to fight one of her own size must be fast enough to run away. Any vessel which is inferior in armament, and has no compensating superiority in speed, is outclassed. The same is true of any vessel which is equal in armament, but inferior in speed to an adversary.

The size of a vessel is measured by its displacement. This displacement is the number of tons of water she will push aside to make room for herself. A vessel of ten thousand tons will take engines of a certain weight and power to drive her at a given speed, and the larger the engine the larger the boilers and the greater the supply of coal required. Now, if it is necessary to give this vessel heavy protective armour and big guns, the additional weight of this equipment must be saved somewhere else, and usually in the engine-room, reducing the speed of the vessel. Following out this principle, it will be found that the fastest ships carry the lightest armament, and that those which carry the biggest guns in their batteries and the thickest armour on their sides are comparatively slow, the extreme variation among vessels of the same displacement being about eight or nine miles an hour.

In the matter of attack and defence, vessels are distinguished by the number and weight of the guns they carry, and by the distribution and thickness of their armour. Protective armour is of two kinds, that which surrounds the guns, so as to protect them from the enemy's fire, and that which protects the motive-power of the ship, so as to prevent the engines from being rendered useless.

The maximum of guns and armour and the minimum of speed are to be found in the first-class battle-ship, which is simply a floating fortress, so constructed that she need never run away, but can stand up and fight as long as her gun turrets revolve. The general plan of construction in a battle-ship is to surround the engines, boilers, and magazines with a wall of Harveyized steel armour eighteen inches or so thick, and seven or eight feet high, which extends about four feet below the water-line and three feet above it. This armour belt is not only on the sides of the ship, but is carried across it fore and aft, immediately in front of and behind the space occupied by the engines and magazines, and the whole affair is covered with a solid steel roof three or four inches thick. Outside this central fortress, and extending from it clear to the bow and stern at each end, is a protective deck of steel, three inches thick, which is placed several feet below the water-line. Everything above this deck and outside this fortress might be shot away, and the vessel would still float and fight.

On the roof of the fortress are placed the turrets containing the big guns. The largest of these guns, 13-inch calibre, weigh about sixty tons each, and will carry a shell weighing eleven hundred pounds about twelve miles. The turrets are circular, as a rule, large enough to hold two guns, and are made of face-hardened steel from fifteen to eighteen inches thick. They revolve within a barbette or ring of steel eighteen inches thick, which protects the machinery by

which the guns are trained. Farther back on the roof of the fortress are other and lighter turrets made of 8-inch steel and carrying 8-inch guns, and at other places are stationed rapid-fire guns of lighter calibre, protected by thinner armour than that of the main belt.

If all this secondary battery is stripped off, leaving nothing but the turrets with the big guns, and these are brought down close to the water, and the armour belt is reduced to seven or eight inches in thickness, the type of vessel known as the monitor is reached. It is simply a battle-ship on a reduced scale. Such vessels are very slow and cannot stand rough weather, on account of their low freeboard. The speed of the monitors is seldom more than twelve or fourteen miles an hour, and they are intended to act in coast defence, usually in connection with shore-batteries. The best types in the navy are the Terror and the Puritan.

The speed of a battle-ship is about eighteen miles an hour. The best specimen in the navy is the Indiana, declared by its admirers to be the most powerful battle-ship afloat. Second-class battle-ships, like the Texas, are smaller vessels, usually about seven thousand tons, and they have a much lighter armour belt, about twelve inches, and do not carry so heavy an armament as ships of the first class. The Maine was a second-class battle-ship. Her largest guns were of 10-inch calibre; her armour was twelve inches thick, and her turrets were eight inches thick only.

The first step in reducing the armament from that of the battle-ship proper, at the same time increasing the speed, produces the armoured cruiser. This type of vessel may carry no guns of more than 8-inch calibre, and the armour belt is reduced to three or four inches in thickness. Instead of the roof over the armour belt, the protective deck is carried all over the ship, but it is not flat, nor is it of equal

thickness, as in a battle-ship. On the top and in the middle it is three inches thick, but the sides are six inches and they slope abruptly to below the water-line. Between these sloping sides and the thin armour belt coal is stored, so that a shell would have to penetrate the outer belt, six or eight feet of coal, and a sloping belt of steel six inches thick, the total resistance of which is calculated to be equal to a solid horizontal armour plate fifteen inches thick.

A cruiser is not supposed to fight with a battle-ship, because it could not accomplish anything with its 8-inch guns against the 18-inch armour of its heavier rival, while one well-directed shot from the 12-inch guns of a battle-ship or monitor would probably sink any armoured cruiser afloat. For this reason the cruiser must be faster than the battleship, so that she can run away, and the weight that is saved in the armour belt and big guns is therefore put into the engine-room. The average speed of an armoured cruiser is about twenty-four miles an hour, and the best types of this class in the navy are probably the Brooklyn and New York.

Some vessels, like the Spaniard Vizcaya, are about half way between a battle-ship and a cruiser, having the heavy guns of the former and the speed of the latter. The Vizcaya, although a cruiser, carried 11-inch guns with a 12-inch armour belt, and had a speed of twenty-three miles an hour.

The next step in reducing armament and increasing speed, produced the protected cruiser, which carries no armour belt, but retains the protective deck, upon the sloping sides of which is stored the coal. The turrets disappear altogether, and there is usually only one 8-inch gun, the battery being principally made up of 4-inch rapidfire guns and 6, 4, and 1-pounders. As this class of vessel is not able to cope with the armoured cruiser, it must be faster, for the general principle holds good that the weaker the vessel becomes in point of offensive weapons or defensive

armour, the greater the necessity that she should be able to run away. The best types of the protected cruiser in the navy may be found in the Columbia and Minneapolis, which have a speed of about twenty-seven miles an hour.

The weakest class of all is composed of the unprotected cruisers, which have neither armour-belt nor protective deck, and carry only light batteries of rapid-fire guns. When these vessels are slow, like the Detroit, they are intended for long voyages and for duty in foreign countries, and are of little use in a sea fight. The very fast unprotected cruiser, like the American line steamers, St. Paul and St. Louis, attach little importance to their armament, and rely for protection upon stowing the coal behind the place occupied by the armour belt in other vessels. All the beautiful wood-work, which was so much admired in these vessels, was ripped out to make room for these coal-bunkers, which are sufficient to protect them from anything but the heaviest guns. On account of their extreme weakness as fighters, these cruisers are necessarily the fastest of all the large vessels, and can run away from anything. For this reason no concern was felt for the Paris by those who knew the principles which govern the safety of modern vessels.

The various types of cruisers are not expected to fight with any but vessels of their own class, which they may encounter in the discharge of similar duties, such as scouring the seas as the advance guard of the slower line of battle-ships, preying upon or escorting merchant vessels, blockading ports, and acting as convoys for troop-ships. Gunboats are simply light-draught cruisers, and are intended for use in shallow waters and rivers.

Torpedo-boats, as their name implies, depend entirely upon the torpedo as the weapon of attack, and they carry no guns except a very few light-calibre rapid-fires to keep off small boats. Their success depends on their ability