_ CHAPTER TWENTY ONE. MODERN ENGINES OF WAR
For many centuries after the invention of gunpowder, little change took place in the weapons used in naval warfare, the chief developments being in the way of better workmanship and material, and the production of guns of larger size.
About the end of the eighteenth century, however, the period from which so many of our modern improvements begin to date, inventors began to plan new and improved methods of disposing of the enemy. About the year 1770, the American Bushnell conceived the idea of what his fellow-countryman Fulton afterwards called the "torpedo." This weapon consisted of a case of powder which was to be attached to the bottom of the enemy's ship by the aid of a submarine boat, leaving it to explode later on by means of a clock inside.
The submarine boat was actually made in 1775; it was egg-shaped in form, and held one man. It was propelled through the water by means of a screw propeller, worked by manual power; a similar screw, arranged vertically, enabled the boat to rise or sink at will. With this boat, during the War of Independence, he, or some other operator, succeeded in getting under a British man-of-war lying at anchor near New York. Without her crew having the slightest suspicion of his presence, he attempted to screw his torpedo to her bottom, but his auger encountered what appeared to be a bar of iron. When shifting to another position he lost the ship altogether, and being unable to find her again was forced to cast off the torpedo and make away, as the clock-work inside had been arranged to explode soon afterwards. And about an hour later the crew of the warship were first roused to their danger by the explosion of the torpedo at no great distance from them, and they were the more alarmed as they were wholly unable to account for it.
In the beginning of the nineteenth century another American, named Fulton, having borrowed Bushnell's ideas, came over to Europe and endeavoured to get the French government to take up his plans for submarine warfare. After long delay he was at length given the sum of 10,000 francs, with which he successfully constructed a submarine boat. In this boat he remained under water for more than four hours, and having been required to blow up a small vessel had no difficulty in getting under her and in blowing her to pieces with his torpedo. The torpedo in a highly developed form is now one of the most important weapons in naval tactics.
In spite of the success of Fulton's experiments, his plans were not adopted, either by Napoleon or by the British Admiralty, to whom Fulton afterwards offered them. The great European wars having been brought to an end by the downfall of Napoleon, the torpedo for a while sunk into oblivion, although during the Crimean war the Russians used submarine mines to protect their harbours. But during the American Civil War the torpedo was again brought to the front, and the Southerners, or "Confederates," used vast numbers of them, to the great damage of the Northerners, or "Federals."
At first these torpedoes proved so harmless--so few exploding out of the hundreds laid--that the Federal officers paid little attention to them. But as the war went on, better methods of exploding them were devised, and vessel after vessel was sunk in a few minutes, often with great loss of life. Some of these were sunk by submarine mines fired by electricity, others by floating torpedoes drifted down by the current or tide; others again by torpedoes at the end of a long spar carried in a small launch. In one instance, a submarine boat was employed, propelled by a screw worked by eight men. Instead of running just beneath the surface, however, her crew insisted on keeping the hatchway just above water, and open, with the result that the wave caused by the explosion of her torpedo rushed in and swamped her, so that she went to the bottom with all on board.
Another night a large frigate was blockading Charleston harbour when a _David_--as these torpedo boats were then called--was seen approaching. The frigate, which carried a crew of 700 men, slipped her cable and made off at full speed, although she was only being attacked by a small launch, manned by four men, armed with a few pounds of powder extended on a spar in front of her! In spite of a fierce fusillade aimed at her, not a shot struck the _David_, which returned in safety to Charleston.
The Russo-Turkish War afforded several additional examples of the same kind, which, as already mentioned, had not a little to do with the alteration in naval design and tactics that took place during the last two decades of the nineteenth century.
Torpedoes were of three kinds: the first were really submarine mines, and were placed in a river channel, being fired by electricity when the vessel came over them. The second kind was the floating or Harvey's torpedo, consisting of a long narrow, but deep wooden case from 44 to 60 inches in length, which contained 30 to 80 pounds of gunpowder, inside a copper lining. It had two levers projecting on the outside, which, on striking an object, set off the explosive inside. This torpedo was used in two ways: the first by setting it adrift on a river, or where there was a well-marked current setting towards the enemy's ships, when the current carried it to its destination; the other way was by towing it at night, by means of a long line, across the bows of an enemy's ship; it exploded whenever it came in contact with the ship.
The third kind of torpedo was practically a Harvey's torpedo attached to a long boom, or pole, about 28 feet long. This was carried at the gunwale of a fast steam launch at night; on nearing the enemy's ship this boom was pushed forward so as to bring the torpedo ten feet below the surface and well in advance of the boat. The torpedo exploded when it struck the ship, and to prevent the torpedo-boat from being sunk by the huge wave raised by the explosion, it had to be covered in front by a shield.
The experiences of the two wars already mentioned showed the difficulty of dealing with torpedo boats at night, and "search lights" are now installed on all modern warships. These consist of an electric arc lamp of 25,000 candle-power, combined with a reflector, which concentrates the light so that it brilliantly lights up objects at a great distance. Torpedo boats can be readily discovered when a mile or more distant and, at the same distance from the light, the rays are so powerful that a newspaper can be read with the greatest ease.
Torpedo attack, however, has been revolutionised by the invention of "Whitehead's torpedo," which can be used from a distance. In shape it is exactly like a huge cigar, 12 to 18 inches in diameter, and 6 to 10 feet long. At the head is the explosive; behind this is a reservoir containing air compressed to an enormous pressure, which drives engines contained in a third compartment, and which in their turn work a screw propeller at the back of the torpedo. There is also mechanism which 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. _