The Development of Navies During the Last Half-Century/Chapter 10
CHAPTER X.
TORPEDO WARFARE.
Early Application of the Torpedo in America—The Fish Torpedo-Development by Mr Whitehead—Introduction of Torpedo Boats, and their Process—Submarine Boats—Protection against Torpedoes—Nets—Electric Search Lights—Torpedo Boat Destroyers—Sinking of 'Blanco Encalada.'
The torpedo as a weapon of practical utility first came prominently into notice during the American Civil War. To disable a vessel by exploding underneath her a large mass of gunpowder, contained in a water-tight case, had long been a project of enthusiasts, but the difficulty of obtaining an efficient mechanical arrangement for ignition, and keeping the whole apparatus in order when immersed for any length of time, had, up to the period mentioned, prevented any striking success being achieved by this means. Small submarine mines, with a chemical fuse or some clockwork apparatus for their ignition, were laid down in the Baltic during the Russian War, but were in most cases fished up by our ships without exploding. One, however, did explode on the poop of the flagship, after much handling to ascertain the method of ignition; but as the charge was small few of the spectators were injured. When the Southern Confederacy seceded from the United States in 1861, one of the first steps of its naval department was to form a torpedo section to protect approaches to places liable to attack by the Northern fleet. Such energy and ingenuity was shown by this branch of the department, and so little was at first understood of this new mode of warfare by the enemy, that a number of his vessels were sunk by submarine mines. From henceforth it was evident this weapon could not be despised with impunity.
Of course, these mines, being moored or placed on the bottom, only acted if the ship came into their vicinity; and if not covered by guns bearing on the area they protected, could be fished for or destroyed by boats before the vessels advanced. A further development, therefore, was made in taking the mine to the hostile ship by means of a boat. A charge of powder was placed at the end of a long pole, carried in the bows of the boat, which under cover of darkness then sought its victim. On arriving alongside the ship the pole and charge were immersed and the explosive ignited by an electric wire when in contact with the bottom of the vessel. In the confusion that followed the assailant had a fair chance of escape. A most daring gallant, and successful attack was thus made on the Confederate ship 'Albemarle,' by an officer of the Northern navy named Gushing, in a small steamboat. At the moment of the explosion his own craft sank, but he escaped by swimming, and returned unhurt with the news.
This method of attack then came into favour, but so great was the risk of discovery when close, and the consequent danger of being sunk by the fire of the ship attacked, that ideas turned in the direction of a torpedo which could be discharged at a vessel from a moderate distance. This resulted in the fish torpedo. The original conception was that of a small sort of boat propelled along the surface and carrying a charge of gunpowder in the bow. An Austrian officer broached this idea to Mr Whitehead, an English civil engineer settled in that country. From this crude proposal he developed the wonderful piece of mechanism now universally known as the Whitehead torpedo. First, he had to fix upon his mode of propulsion. He selected compressed air, working a small engine and a screw in the tail of his fish, as in an ordinary vessel. Steam would condense, and had other disadvantages; gunpowder gas could not be controlled; electricity was not applicable. The result has shown that his choice was a good one. Then he determined that his torpedo should travel under water. An explosion on the surface and against the water line of a ship would have little effect, because most of the gas generated would escape into the air. Immersed, the surrounding water confines the gas and compels it to exert all its energy against the bottom of the ship. If the charge is large enough, this pent-up energy is irresistible. It was desirable, therefore, that the torpedo should strike a ship a certain distance below the water line, keeping this depth during its passage. Now, any vessel containing compressed air has an appreciable weight added to it, but as the air is allowed to escape the vessel is lightened to a corresponding extent. Consequently a torpedo propelled by this motive power would, as the air escaped after doing its work, be continually getting lighter, and if started 10 ft. under water would soon come to the surface and finish its course in this position. This had to be corrected and provided for by special machinery. The torpedo must travel throughout its run in the same horizontal plane. The method by which Mr Whitehead obtains this effectually is the most ingenious part of his invention. It was long kept a secret, but has recently been made public. The general principle is to utilise the pressures due to different depths of water to actuate horizontal rudders, so that the torpedo is steered upwards or downwards as its tendency is to sink or rise.
In the foremost end of the torpedo the explosive is carried, originally gunpowder but now gun cotton, as being so much more powerful, its ignition being effected by the impact of the nose of the torpedo on any hard substance, which forces a pointed striker against a detonating cap.
So constructed, we have an iron or steel fish-shaped body, propelled by air highly compressed, which can be regulated to give a high speed for a short distance or a greater range at a lower rate. By mechanical contrivances the torpedo could be set to run any required distance, and then come to the surface or sink. The firing arrangement was not operative until it had proceeded some way on its course, but for exercise it was necessary that this should be in a condition of safety when the run was finished. As may be imagined, all this required a long period of anxious thought and a series of experiments, but eventually Mr Whitehead brought to the notice of the world what had not often been seen before, an entirely new invention perfect in every detail. Its efficiency was demonstrated on trial, and the weapon adopted by nearly every maritime state. What limited its usefulness was the comparatively low speed, which at first was about 8 knots. Hence, if discharged at a vessel half a mile off, it took a considerable time to traverse the distance, so that any little inaccuracy in its course, currents, or alteration of direction in the vessel aimed at would result in a miss. A great advance was therefore made when the speed was increased to 18 knots by the use of Mr Brotherhood's well-known three-cylinder air engine, a model of compactness, simplicity, and efficiency. When gun cotton was used a less amount of explosive was required for the same result with gunpowder, and hence a smaller torpedo could be employed. The improved weapon was 14 ft. long, with a diameter in its largest part of 14 in. Complete it weighed about 500 lbs. Plant for the manufacture of these torpedoes having been established at Woolwich, a healthy competition arose between our officers and Mr Whitehead's staff, for having started a factory at Fiume in Austria he was now supplying other Governments with torpedoes. Succeeding improvements brought the speed up to 27 knots an hour for a distance of 600 yards. This was the range selected as that at which the torpedo should be discharged at a ship, a maximum distance beyond which the chances of hitting rapidly diminished, while at closer ranges they were increased. In the earlier patterns the head of the torpedo had been made exceedingly sharp, under the idea that this form would give increased speed. But the late Mr Froude's experiments with submerged bodies showed this to be erroneous, and that a better result can be obtained with a bluff head. A further advantage of such a form is that a considerable increase of explosive can be carried without adding to the length of the torpedo. With this modification the later patterns have a charge of 60 lbs. of gun cotton, equivalent, it may be considered approximately, to 200 lbs. of gunpowder. Exploded in contact with the bottom of a ship, the effect must be either to sink or disable, according to the precise locality struck.
This new weapon, directed at the most vulnerable part of a ship, had to be met, and it led to the extension of the double-bottom system. There was an idea that the torpedo might expend its energy on the outer skin, leaving the inner hull intact, and thus save the ship from fatal injury. But as Sir Nathaniel Barnaby truly remarked fifteen years ago: 'I say it is idle to attempt to form the bottom of a ship strong enough to resist a fair blow from a powerful torpedo. The utmost that can be done is to keep the disabled ship afloat after she has received such a blow. It would be possible to protect the bottoms of ships with armour to withstand the present charges of the Whitehead torpedoes. When this was done, it would only be necessary to increase the charges of the torpedoes and the armour we had applied would become vulnerable.' No more accurate forecast could have been made. The latest development of the Whitehead is a torpedo 18 in. in diameter, with a speed of 30 knots, and carrying 200 lbs. of gun cotton. No modification in construction could render the explosion of such a mass beneath a ship other than irresistible. Should it be otherwise, an addition of 2 in. to the diameter of the torpedo would probably allow the charge to be increased to 500 lbs., and I am quite unable to see how this could be counteracted.
In the successful application of the Whitehead torpedo much depends on the method by which it is launched from the ship or boat. It is now usually discharged, like a projectile from a gun, by means of a small charge of gunpowder, or compressed air, from a tube which it accurately fits. In most cases the tube is a few feet above the water line, and the torpedo is launched at any given moment. But it has always been considered that if it could be projected under water from a ship the apparatus would not be exposed to an enemy's fire, and the torpedo would start under more advantageous circumstances. The preliminary plunge from above water has always been trying to the mechanism contained in the interior. The difficulty under water is to get the torpedo clear of the ship when the latter is proceeding at high speed. An elongated body thrust out of a hole into water rushing past at a rate of 18 knots is naturally subjected to severe strains. It must be supported until the tail is outside, and then the propellers take it onward. After years of research and experiment this has been accomplished, and large ships are now fitted to discharge their torpedoes under water.
When the Whitehead torpedo was introduced it was at once seen that for boat attack it had enormous advantages over the old method of carrying a tin of explosive at the end of a pole. The ship need not be approached within 600 yards, and thus the operation was not one of such great hazard. But any chance of success and escape afterwards would be much increased if it were possible to command in the boat very high speed, so as to reduce the time during which the boat would be under fire in its approach or retreat. Such a consideration led to the development of the high speed torpedo boats which we now see in the hands of nearly every nation. At first it was thought a boat about 80 ft long would answer all requirements, and Russia in 1877 constructed a hundred boats 75 ft. long and 10 ft. beam. The size was such that they could be transported from the Baltic to the Black Sea by rail. Mr Yarrow, the eminent torpedo boat builder on the Thames, supplied some sets of machinery and drawings from which other sets could be made in Russia. The first of these boats tried on the Neva had a speed of 18 knots. This was a great advance in a boat of such dimensions.
In the meantime Messrs Thornycroft, at Chiswick, had constructed for us the first torpedo boat, which was about 15 ft. longer than the Russian type, and her speed, 19 knots, was considered so remarkable that we 
First Class torpedo boat, built for the Argentine Government by Messrs. Yarrow & Co.
Having thus a boat of high speed, the equipment was completed by placing a tube in the bow from which a Whitehead torpedo could be ejected. In our boats the tube revolved so as to point on either side as well as ahead. Thus, in attacking a ship the boat could run rapidly past her, and without checking speed discharge the torpedo when in the most convenient position. Other nations fixed the tube in the stem of the boat, so that the torpedo can only be discharged when the bow of the boat is pointed directly to the object. This method is the simplest, as the torpedo is not deflected as on the broadside, for which a special calculation is required. But the disadvantage is that the boat is approaching the enemy, and will continue to do so after discharging her missile until she can turn and retreat. She is thus under fire longer. These boats are from 80 to 90 ft. in length, and in moderate weather are capable of operating a short distance from the coast. Then it was considered they might perform a more ambitious function in keeping the sea independently, or working with a squadron. For this a larger structure was required, and Mr Yarrow provided for Russia a boat l00 ft. long, which steamed out to the Black Sea by herself. This craft was followed by others, for different countries. Some of these, 110 ft. long, crossed the Atlantic under sail temporarily provided.
As demands came for higher speed, so did the length of the boat increase. We ordered a further batch, 125 ft. long, to carry five torpedo tubes, one in the stem and two on each broadside. Then Messrs Thornycroft built two boats for the Spanish and one for the French Government, which, with a length of 147 ft, gave a speed of 26 knots on the measured mile. These boats carry two torpedo tubes fixed in the stem.
Notwithstanding this notable increase of size, it has not been found that these boats can keep the sea for any length of time. The continual motion is so wearing to the crews that in rough weather their physical energy becomes exhausted, and inability to sleep is one of the most trying conditions of such an existence. When attached to a squadron, their presence at sea is a constant source of anxiety, and hence I think it must be recognised that for a craft able to keep the sea much larger dimensions are necessary. The proper function of torpedo boats is to operate from fixed bases on land, to guard the coast, and harass the squadrons or single ships of an enemy that may venture on aggressive action. A blockading fleet would have to be continually on the alert against night attacks by these wasps of the sea.
It has been sometimes asserted that blockade has been rendered impossible by the introduction of steam and the torpedo boat. I am unable to agree to this. There never was a time when blockades were not broken through over and over again. Steam will now enable vessels to remain in positions which dependence on wind in former times prevented them from keeping with certainty. The torpedo boat is a new danger to blockading squadrons, but it can be met by a line of other small craft whose special mission it would be to paralyse the attack before the boats could reach the main body. It has been shown recently that a special vessel of 600 or 800 tons, suitably armed with numerous light guns, forms the most efficient protection to a battle ship, grappling and subduing the small assailants before they can effectually launch their torpedoes. A striking feature of the fleet of 1900 will probably be the great increase in the number of its satellites, as this view receives further confirmation.
Although by adding to the length and displacement of torpedo boats better seagoing qualities have been secured, they have thereby become more conspicuous objects by night or day, whereas formerly, being small, they were not easily seen or hit. The difficulty of getting within range without detection has once more led people to seek a solution in submarine navigation. The idea of travelling under water in an hermetically sealed boat has engaged the attention of many enthusiasts, but hitherto without much practical success. When a submarine boat is in such a state of equilibrium as to freely rise or sink when its buoyancy is increased or diminished, this equilibrium is easily disturbed, and the tendency is then rather to go to the bottom than rise to the surface. At least this appears to have been the habit with most submarine boats since the first tried by Drebbel, in the reign of James I., up to the present time. In France and Spain boats capable of acting under water are now under experiment, but in my opinion the chief advantage of a submarine boat is to travel on the surface partially submerged, so that, while the crew can see, the boat itself is almost invisible.
The best protection against torpedoes was at first thought to be in subdividing the ship into numerous small compartments. But it was soon evident that this was not sufficient, and then the system of surrounding a ship with wire netting was devised in order to stop the torpedo before it could come in contact with the hull. The nets are suspended from long booms projecting from the ship's side, and, with the vessel stationary, hang vertically in the water. At sea, or when moving, the nets do not retain this position, and are an awkward appendage not favourably regarded by sailors, who strongly object to anything that may foul the screw. Moreover, torpedoes are now provided with an apparatus in the nose which enables them to cut their way through the netting, and travel on uninjured to the vessel now unguarded. It is probable, therefore, that in the immediate future nets secured to the ships will be discarded, and the torpedo frustrated in some other manner.
Another branch of defence against this attack at night is a powerful light thrown on the advancing 
First class torpedo boat, Ariete, built for the Spanish Government by Messrs. Thornycroft & Co
On a small scale this has been done before, and I believe a search light produced by a voltaic battery and a parabolic reflector was used in the Crimean War. This was little more than a toy, but the dynamo-electric machine, since introduced and perfected, has enabled great advances to be made, while the spherical reflecting mirror, devised by Colonel Mangin, is no less important in utilising the light thus produced. This reflector is of glass, ground so that the circumference is thicker than the central portion. This mirror collects and concentrates all the rays which impinge on it from the carbons in front, and then projects them forward in an intense beam of light. In clear weather small objects can be clearly discerned at upwards of a mile, when the ray is thrown on them, but in fog or mist the light has no penetrative power. There appears to be a deficiency of red rays, which are not absorbed by aqueous vapour to the same extent as the rays of other colour in white light. As also, when these lights are used from a ship, the rest of the horizon is made to seem darker than before, the opinion as to their value is conflicting. They are most efficient when external to the point sought to be protected, and placed so as to illuminate the space that must be traversed before the ships can be reached. I can conceive that, as it is desirable to have special ships to destroy torpedo boats when discovered, other craft might be equally advantageously fitted with powerful lights for this special duty, while the main force remained in darkness.
The electric light detects one colour much better than another. White is most easily distinguished, while a black boat can approach much nearer without being discovered. Steam escaping shows up at a great distance. Torpedo boats, whose period of action is during the hours of darkness, should show as little white as possible.
The want of success which has attended the efforts of those who hoped that torpedo boats could keep the sea led to the demand for a type which is now being largely constructed. This is a vessel of from 400 to 800 tons, which can accompany a squadron and during a naval action dart in under cover of smoke and launch torpedoes at the enemy when he exhibits signs of confusion. The French were the first to carry this idea into practical execution by building the 'Bombe' class, of about 340 tons. They are useful little vessels in some respects, but too small for efficient service in rough weather. We followed with the 'Rattlesnake,' of 550 tons, which has proved an excellent sea boat. But our latest development in this type is a number of vessels of 735 tons. Their armament consists of one 4.7-inch gun at each end and several torpedo tubes. They thus combine a gun and torpedo vessel, which does not appear to me advantageous. A gun of this weight may be useful in the stern if a bigger vessel is pursuing; in the bow it probably reduces her steaming capability against a moderate sea. In the chapter on foreign navies will be found a brief account of what is being done elsewhere in this direction.
It now only remains to consider what the torpedo has done, and whether it is likely to influence still further the course of naval architecture. So far it cannot boast a large score of successes. But when complaint is made that torpedoes do not run straight, and sometimes disappear, it is forgotten how many projectiles lie at the bottom of the sea that never went near the mark aimed at, or how many were fired before such a puny antagonist as the 'Huascar' could be brought to submission. The number of shot and shell fired at Lissa would, if placed against the damage done, afford an instructive lesson. Too much is expected of the torpedo, still only in its infancy. At the same time I would not claim for it equal rank with the gun. We may say, however, that if successfully applied it has the power of doing infinitely greater mischief. An instance of this is to be found in the sinking of the 'Blanco Encalada' in Chili from injuries inflicted by a torpedo, of which the following is a brief account.
When the revolution against the authority of President Balmaceda broke out, the whole of the fleet present joined the insurgents. The latter thus had a free hand on the sea until the arrival at Valparaiso of two swift torpedo vessels, the 'Almirante Lynch' and ’Almirante Condell.' They were built in England, by Messrs Laird, for the Chilian Government, and are of the sharpshooter class. Their dimensions are, length 240 ft., displacement 750 tons, speed 20 knots. The armament consists of two 14-pounder and two 3-poundcr quick-firing guns and four torpedo tubes. Having given their adherence to the President, the officers and crew of the two ships were ready for any service against the other side. They were accordingly despatched to attack the enemy’s squadron, then lying at Caldera, about 500 miles north of Valparaiso. They arrived off this port just before dawn on April 23d, and observing the 'Blanco Encalada' at anchor, determined to attack at once. The ironclad was taken apparently completely by surprise. If those on board knew of the arrival of the torpedo vessels in Chilian waters, they had not counted on such speedy offensive operations. The ship seems to have been without any net protection. No guard boats patrolled outside the harbour, a portion of the crew was on shore; and it would be impossible to imagine a condition of affairs more favourable to a torpedo attack. It was made with a courage and determination which has always signalised the fterce struggles in this part of the world. Met by a confused and ineffective fire from such guns as could be got into action, the two assailants approached within about 300 yards uninjured, and each discharged two torpedoes, none of which struck the ship. The 'Lynch' then turned, and again passing the 'Encalada' within about 50 yards, discharged a torpedo, which struck the ironclad abreast the engine-room. A tremendous shock was felt on board her. A great many men were killed in the engine-room by fragments of machinery flying in all directions, others on the deck above were thrown down and injured by the concussion. The ship heeled over on being struck, then rolled back, and the water pouring into the interior by the large gap made in her double bottom, she sank in about five minutes. Some of the crew plunged into the sea and escaped to the shore, but a considerable number went down with the vessel. On board the 'Lynch' and 'Condell' the casualties were not numerous or serious. The former vessel suffered most when she passed so close to the 'Encalada,' but both were able to retreat when a large ship was observed approaching the harbour, which was supposed to be the 'Esmeralda,' a cruiser of the enemy, but turned out to be our flagship the 'Warspite.'
It may be observed that the torpedo used on this occasion was one of the latest pattern, of small size, and carrying a charge of about 60 lbs. of gun cotton. From the effect produced some idea may be formed of what 200 lbs. could accomplish. The blow would be resistless in that portion of a ship containing the machinery. The opponent of torpedoes may lay stress on the fact that five had to be fired at close range before one took effect; but the fact remains that a vessel of 3500 tons was sunk in less than half-an-hour by two craft of 750 tons each, and that both were intact after the operation. We have no parallel to this in past naval warfare. It was not possible when the gun alone decided all combats, but now, while we have gone on adding to the dimensions, cost, and power of resisting artillery in our ships of war above the water line, the addition of a few pounds of explosive renders them liable below to the same fate as overtook the 'Blanco Encalada' in Caldera Bay.