Discoveries and Inventions of the Nineteenth Century

by Robert Routledge

Fig. 119.—Official Trial of “Harvey’s Sea Torpedo,” February, 1870.

When the torpedo has been launched over the vessel’s side, the latter being in motion, the torpedo immediately diverges clear of the ship; and when the buoys have also reached the water, the men working the reels pay out the line steadily, occasionally checking the torpedo to keep it near the surface, but avoiding a sudden strain upon the slacked tow-rope, which would cause the torpedo to dive, and in shallow water this might lead to the injury or loss of the torpedo. The torpedo can be gradually veered out to the distance required, at the same time that the safety-key is so managed that sufficient strain may be put upon it to prevent it from forming a long bight astern of the torpedo, but avoiding such a strain as would break the yarn holding the safety-key in its place. The distance to which the tow-line may be paid will depend upon the circumstances of the attack. More than 50 fathoms is, however, a disadvantage, as the long bight of tow-lines makes the torpedo drag astern. The torpedo can always be made to dive several feet below the surface by suddenly letting out two or three fathoms of tow-line. The torpedo vessel should, of course, be a steamer of considerable speed—able to outstrip when necessary all her antagonists, and, as a rule, it is found best to make the attack at night. Let us imagine two ships of war at anchor, and parallel to each other at perhaps a distance of 60 fathoms; and suppose that, under cover of darkness, a hostile torpedo vessel boldly steams up between them, having launched both its starboard and port torpedoes. In such a case neither ship could fire at the torpedo vessel for fear of injuring the other, while the torpedo vessel would in all probability succeed in bringing its floating mines into contact with both its enemies.

Fig. 120.—Model of Submarine Guns.

Another device for submarine attacks upon vessels on which much ingenuity has been expended is the submarine gun. It has been sought to propel missiles beneath the surface of the water, these missiles being usually provided with a charge which, on contact with the vessel’s side, would explode, and by making a hole below the water-line, cause the certain destruction of the ship. It is obvious that such a mode of attack would reach the only vulnerable parts of a thickly-plated ironclad, and therefore the project has been recently revived in several forms. Fig. [120] is taken from the photograph of a model of an invention of this kind. The guns which are to propel the submarine projectiles, have port-holes formed by valves in such a manner that the gun when loaded can be run out without allowing water to enter; it can then be fired while the muzzle is below the surface, and again drawn in without the port being at any time so opened that water can pour into the vessel. All contrivances of this kind have hitherto been failures; indeed, it does not appear possible that they could succeed, except at very close quarters, for the resistance offered by water to a body moving rapidly in it is extremely great, and, as we have already had occasion to state, the resistance increases as the square of the velocity, and probably in even a higher degree for very great velocities. Any one who will remember the effort it requires to move one’s hand quickly backwards and forwards through water will easily understand that the resistance it presents would, in a comparatively short space, check the speed of a projectile, however great that speed might be at first. A good many years ago Mr. Warner produced a great sensation by an invention which appears to have been essentially a floating torpedo. The cut below, Fig. [121], represents the result of an experiment publicly made by him off Brighton, in 1844, upon a barque, which was towed out by a steamer to a distance of a mile and a half from the shore. Mr. Warner was on board the steamer, and the barque was 300 yards astern. Five minutes after a signal had been made from the shore, the torpedo was caused to explode, striking the barque amidships, throwing up a large column of water and débris, shooting the mainmast clean out of the vessel, the mizen going by the board, and dividing the hull into two parts, so that she sank immediately. Yet this invention, though apparently so successful, does not seem to have ever been put in practice.

Fig. 121.—The Warner Experiment off Brighton.

The stationary torpedoes of the kind mostly used in the American Civil War were, as already stated, self-acting; that is, they exploded when touched by a passing vessel. They would now be more generally called self-acting mines, and are to be distinguished from that form of the weapon in which the explosion is determined by some manipulation on shore, such as the closing of an electric circuit, when the hostile vessel comes within the area of destructive action. This form receives the name of observation mines. Stationary mines are essentially instruments of defence, and as such are employed for the protection of rivers and harbours. The self-acting varieties usually contain a charge of 70 lbs. to 80 lbs. of gun-cotton, and are commonly arranged in lines. Of course, when the occasion for which such mines have been laid down is past, they must be removed, and the operation of picking them up is one of great danger. The observation mines, on the other hand, do not require immediate removal, and they can be taken up with little risk. In the British service the observation mine contains about 500 lbs. of gun-cotton, and a line of these is sometimes moored in a water-way, from 35 feet to 50 feet below the surface. The area of destructive action in this case is a circle of about 30 feet radius, and therefore a line of seven such mines laid across a channel at intervals of 120 feet apart would ensure the almost certain destruction of any war vessel of ordinary breadth that might attempt to pass up a river of 840 feet in width. This is about the distance across the Thames near the Tower of London, but the depth of the river there being only 12 feet at low-water and 33 feet at high-water, would not suffice to give effect to the full energy of so large a charge of gun-cotton; for it has been found that, for a given charge, there is a certain depth under water at which its explosion will produce the maximum effect, and this depth will be greater with heavier charges than with light ones. The regulation “observation mine” of the British service has a cylindrical case of stout plate-iron, 32 inches in diameter and 34 inches high, with domed ends. Within this gun-cotton is contained, in a wet condition, in a number of copper envelopes, which have holes for access of water to wet the charge from time to time as occasion requires, the wet condition being the safest for the carriage of gun-cotton. The centre of the case is a tin charged with some discs of dry gun-cotton, and the detonator required to bring about the explosion of the whole charge when the electrical contact is made, fires the fuze contained within the primer. These cases are arranged to have a certain buoyancy, and are moored with wire ropes to heavy iron sinkers, the mooring ropes being of such length as to keep the explosive case at the proper depth below the surface, and of sufficient strength to resist the force of the currents in the waterway. There is also another type of submarine mine, operated by an electric current, the circuit of which is closed by contact of a passing vessel, if at the time a battery on shore is included in the circuit. In this way the mines can be made harmless or dangerous for passing vessels at the will of the operator on shore. The passing vessel is made to complete the circuit by tilting over the cylindrical case so far that some mercury contained in a small part of it is upset, and makes the requisite metallic contact. This arrangement is known as the electro-contact mine.

In former pages of this article on torpedoes will be found representations of the effects produced by Whitehead’s torpedo, which, being automobile and travelling altogether under the surface of the water, was capable of being made a very formidable weapon of offence. When the earlier editions of this work were going through the press, it was understood that the Whitehead torpedo left much to be desired as regards speed, certainty of direction through the water, and perhaps in other points, the inventor being constantly engaged in effecting improvements. At that time particular pains were taken to keep secret the nature of the most important parts of the internal mechanism. The work of construction was carried on in a room with locked doors, blocked-out windows, and a military guard outside. The earlier experimental forms of this automobile torpedo were constructed in complete secrecy by the inventor himself, with the help of only one trusted, skilled mechanic and a boy, who was no other than Mr. Whitehead’s own son. The history of the invention is very interesting, and exemplifies the power of skill and perseverance to overcome a multitude of difficulties, the result being a machine which is simply a marvel of ingenuity and of delicate nicety of adaptation.

The first notion of the automobile torpedo appears to have occurred to an Austrian naval officer; but it took rather the form of a small vessel containing within itself some propelling power by which it could move along the surface of the water, its course being directed by ropes or guiding lines from the shore or from a ship. The fore part of the little vessel was to hold an explosive, to be fired automatically by the self-propelled torpedo coming into contact with the side of the hostile vessel. The propelling power, as first suggested, was clockwork, if that could be made efficient, or steam as an alternative. The Austrian authorities, however, considered that it would be impracticable to direct the course of the torpedo in the manner proposed, and that there were also great objections to each of the methods of obtaining motive power. The assistance of a thoroughly competent and skilful mechanician was then sought, and Mr. Whitehead, at that time the director of an engineering establishment at Fiume, devoted himself to solving the problem of devising a torpedo which should be able to travel beneath the surface of the water, and, when once started, should require no external guidance to keep it on its proper course. After some years of experimental labours, Mr. Whitehead produced the first form of the weapon with which his name is associated, but to this he has since added from time to time many ingenious improvements. A committee of experts having been appointed by the Austrian Government to test the capabilities of the new invention, it was made the subject of a long series of trials, after which the committee recommended its immediate adoption in the Austrian navy. The earlier form of the Whitehead torpedo had, however, the defect already mentioned, of being sometimes very erratic in its course; its speed was small (6 knots) compared with that of the more recent patterns (30 knots), and its range of travel proportionately less. The British Admiralty having invited Mr. Whitehead to visit England with some specimens of his invention, a committee was appointed to make complete trials of the capabilities of two weapons he had brought with him. Although by this time great improvements had been made on the original design, and in particular, Mr. Whitehead had almost completely overcome the difficulty of keeping the torpedo at a uniform depth during its course, by means of delicate adjustments in what we may call the steering chamber (to be presently mentioned), much remained to be accomplished before the weapon attained the perfection of the modern patterns. Indeed, the inventor may be said to have from time to time redesigned his contrivances, as when in 1876 the speed was increased to 18 knots, and again in 1884 more powerful engines brought up the speed to 24 knots. Further improvements have been made by Mr. Whitehead, who designed a new form of the weapon in 1889, and some of the more recent patterns can now show a speed of 30 knots or more. The committee appointed by the Admiralty to conduct experiments with the first pair of torpedoes brought to England, after having tested them in various ways for a period extending over six months, reported that they believed that “any maritime nation failing to provide itself with submarine locomotive torpedoes, would be neglecting a great source of power, both for offence and defence.” Upon this recommendation the Admiralty immediately purchased from Mr. Whitehead for £15,000 the secret of the internal mechanism of his invention and the rights of manufacturing it. The self-adjusting apparatus within the steering chamber, by means of which the torpedo was kept at its due depth, was then a jealously-guarded secret; but when the arrangement with Mr. Whitehead was effected, the Government immediately set about the manufacture of these torpedoes on a large scale. The artificers employed in making the Whitehead torpedoes were now numerous, and the internal structure of these weapons could not advantageously be altogether concealed from those who had to handle them on board of the ships, so that it inevitably happened that some details of their construction leaked out, and came into the possession of other powers, whereupon all the maritime states followed the example of Great Britain by providing their navies with Whitehead or some such form of locomotive torpedo. It is no part of our plan to enter into the mechanical minutiæ of the Whitehead torpedo. We may, however, give the reader such an idea of the external appearance and internal arrangement of the Whitehead torpedo as will enable him to appreciate to some extent the ingenuity and skill that have been brought to bear upon its construction.