automatically adjusts the depth at which the torpedo travels below the water, and other mechanism which ensures that it will keep going in the direction in which it was fired. Such a torpedo is now effective up to two miles, and it will traverse this distance in about six minutes.
Torpedoes are discharged from what are called “torpedo tubes” by means of compressed air. These tubes are to all intents and purposes, guns made of thin steel, the torpedo being put in at the breech. Those used on board torpedo boats or similar light fast craft are mounted on a swivel on the deck; in larger vessels they are usually placed below the waterline so as to be free from the serious consequences that would ensue if the tube were struck by the enemy’s shot, while a torpedo was in it. Torpedoes have also been invented which are steered by electricity.
The problem of protecting ships against torpedoes is a difficult one, and no satisfactory solution has yet been arrived at. All large warships, however, are provided with “torpedo nets” of thick iron wire, which are hung round her at the end of long poles, which, when not in use, are tied up alongside. But mechanism has been invented by which the torpedo will cut through the netting, if it encounters it, so that at present the torpedo is master of the situation, within its range. In fairly shallow water a torpedo will throw a column of water nearly 200 feet into the air, by the impulse of the gases generated by the explosion, and no ship yet built would be able to withstand its enormous shock.
Reference has already been made to the huge guns of the Inflexible, and to the improvements in both powder and guns made later on. The modern gun is what is called a “wire gun,” from its method of construction. Round a central tube of steel, several layers of immensely strong steel wire is tightly wound; a second steel tube is then slipped on above the wire, and as this tube is hot when first put on, when it cools it contracts and binds the layers of wire tightly together, forming a gun of very great strength—as, indeed, it would need to be, seeing that it has to withstand a pressure of over 16 tons to the square inch.
The projectiles fired from naval guns are of three kinds, solid shot for piercing the thickest armour,—as on the conning-tower, or barbettes; “armour piercing shell,” with very thick walls and small bursting charge, which can only penetrate armour, two-thirds of that piercible by solid shot; lastly, “common shell,” in which the shell walls are much thinner, and can thus only be used with effect against the lighter structures of the enemy. By placing a small “cap” of iron on the points of ordinary shot, “capped shot” are produced; and thus provided, they will pierce a much greater thickness of hard-faced armour than the ordinary ones. Against soft armour, however, they are not so efficient.
The armour of modern ships has also been greatly improved in resisting power. The Inflexible of 1881 was protected by wrought-iron plates 24 inches thick, which weighed 2,400 tons, or a fifth of her total weight, yet only a third of her length was protected. Soon after her completion, “compound” armour plates,—with a hard steel face on a backing of wrought-iron—were introduced, which enabled a third of the weight of the armour to be saved, yet leaving the amount of penetrability unchanged. Later on, “Harvey” armour, made of steel alloyed with nickel, still further reduced the weight, and recent improvements now make the best armour equal in resisting power to three times its thickness of wrought-iron. It may be mentioned also that the coal bunkers are now arranged so as to further protect the engines, being reckoned equivalent to about three inches of wrought-iron.
Facing page 464 are two “sections” of warships, which will, no doubt, interest the reader. The first is of an old steam battleship, such as the Marlborough, the other, that of a modern second-class cruiser, like the Minerva, which could blow the Marlborough to pieces before the latter could get her within the range of her guns. Notice the enormous difference in the space devoted to the engines and boilers. The modern vessel gives a general idea of the arrangement in all classes of modern warships. The conning-tower will be seen below the bridge, in front of the foremast. The magazines are at the bottom, right below the forward and aft guns, which in this type of vessel, are protected by a shield only, with armoured ammunition hoists going down from it; the barbettes of the more powerful vessels would simply be iron breast-works, extending all round these guns. The curved protective deck is also seen, about the waterline, and the projecting ram, while at the stern is the curiously shaped rudder, made in this form, because it takes less power to work, than that of the ordinary type.