However we may have deserved the eulogy of the French writer in respect of developing the paddlewheel war steamer, the development of screw propulsion in the next decade was marked by a succession of failures and a large outlay of money on useless conversions and on new construction of poor fighting value, most of which could have been avoided. Had our methods been less tentative and more truly scientific the gain would have been undoubtedly very great; we should have laid our plans on a firmer basis and arrived at our end, full screw power, by a far less circuitous route than that actually taken. In this respect France had the advantage of us.
Although a decision had been made to maintain the full sail power of our ships and install screw machinery only as an auxiliary motive power, attempts were naturally made to augment so far as possible the power exerted by the screw; and within a short time new ships were being fitted with machinery of high power, in an endeavour to make the screw a primary means of propulsion. The results were disappointing. As the power increased difficulties thickened. The weight of the machinery grew to be excessive, the economy of the comparatively fast-running and short-stroke engines proved to be low, and the propulsive efficiency of the screws themselves grew unaccountably smaller and smaller. So poor were the results obtained, indeed, that in the case of a certain ship it was demonstrated that, by taking out the high-power machinery and substituting smaller engines an actual gain in speed was obtained, with the reduced displacement. The first screw ship in which an attempt was made to obtain full power with the screw was the Dauntless, of 1846. Although a frigate of beautiful lines she was considered a comparative failure. It was agreed that, equipped with paddlewheels and armed with guns of larger calibre, she would have constituted a faster and more powerful warship than, with her 580-horse-power engines, her 10 knots of speed, and her 32-pounder guns, she actually was.
Part of the trouble was due to the unsuitability of our ships’ lines for screw propulsion. It has already been noted that, owing to the carriage of heavy weights at their extremities, war vessels were always given very full bows and sterns. In the case of the Rattler, whose records served as a criterion for later designs of screw ships, the lines of the stern were unusually fine: partly, no doubt, in imitation of the Archimedes. Also, since it had been necessary to allow space enough for a long screw to be carried (a screw of a complete convolution was thought possible) the Rattler’s short screw as finally adopted worked at some distance aft of the deadwood, and thus suffered no retarding influence from it when under way. But in the case of later ships these advantages did not obtain. They were built with the usual “square tuck,” a bluff form of stern which prevented a free flow of water into the space ahead of the propeller and thus detracted from its efficiency. It was not appreciated at this time that, for efficient action, the screw propeller demands to be supplied with a body of unbroken, non-eddying water for it to act upon, which with the square-cut stern is not obtained. At low speeds, and in the ship to which the screw was fitted as an auxiliary, the effect of the square tuck was not marked. But as power and speed increased its effect became more and more evident; the increase in power gave no proportionate increase in speed; and many, ignorant of the cause, surmised that there was a limit to the power which could be transmitted by a screw and that this limit had already been reached. The inefficiency of the square tuck was exposed by trials carried out in H.M.S. Dwarf at Chatham. As a result of these, future new and converted ships were given as fine a stern as possible.
For several years, however, the policy of the Admiralty remained the same: the screw was regarded solely as an auxiliary. The French, on the other hand, took a less compromising line of action. After waiting for some time and watching our long series of experiments, they convened in 1849 a grand Enquête Parliamentaire: a commission which, primed with the latest information as to British naval material, was to decide on what basis of size, number, armament and means of propulsion future French warships should be built. For two years the commission sat sifting evidence. And then it recommended screw propulsion of the highest power for all new ships, as well as the conversion of some existing classes to auxiliary screw power. England had fitted her ships with screws capable of giving them small speed; France must fit hers with screws of greater power. Speed, said the commission, is an element of power. Superior speed is the only means by which the English can be fought with a good chance of success. Sails must be secondary, therefore, and full reliance must be placed on the screw. The recommendations of the commission were duly realized. In the following years a powerful force of fast screw battleships, frigates, transports, and despatch boats was constructed which by ’58 had brought the aggregate of the horse-power of the French fleet almost to a level with that of England.
When the Crimean War brought the two navies together as allies in ’54 the full effect of the new policy of the French had not yet been made apparent. Some apprehension existed in this country as to the adequacy and efficiency of our navy, when compared directly with that of France. But from then onwards this country became aware of the increasing hostility of the French public and government; speeches were made, and letters appeared in the press of both countries, which tended to fan the flames of fear and suspicion.[159] It was not till ’58, however, that general attention was drawn to the great strides which the French navy had made in recent years, and to the skilful way in which its position, relative to that of its great rival, had been improved. An article entitled “The Navies of England and France” appeared in the Conversations Lexicon of Leipsic, and caused a great sensation. Reprinted in book form, with a long analysis and with a mass of information about the French, English and other navies and arsenals,[160] this notorious article brought apprehension to a head. Though written by no friendly critic, it was in most respects an accurate presentment of the respective navies and of their condition. The analysis of Hans Busk, while ostensibly exposing its bias and its inaccuracies, in effect confirmed the main contentions of the German article; in addition his book gave in spectacular columns a summary of the units of the rival navies, which gave food for thought. The article itself professed to show how much France had benefited by the bold and scientific manner in which she had handled the problem of naval construction since the coming of steam. Other factors were discussed, the forms of ships, the Paixhans system of armament, problems of manning and of education; but the factor which had caused the greatest accession of strength to France, by her wise divergence from the English policy, was (according to the critic) steam propulsion. In the case of paddlewheel steamers England, by her unscientific and ruinous experiments, had squandered millions of money and produced a series of crank and inefficient war vessels. In the case of screw ships England’s waste of exertions and money was even more surprising; the building of new ships and the conversion of others was carried out at an enormous cost with many galling disappointments. The French, on the other hand, took longer to consider the principle of the screw, but then, when their more scientific constructors had completed their investigations and analysed the new power, they acted thoroughly and without delay. From all of which the German critic inferred that England had good reason to watch with anxious eye the significant development of strength on the part of her neighbours across the Channel. “We must pronounce,” he concluded, “that with a nearly equal amount of matériel, the French navy surpasses the English in capacity and in command of men. France need feel no hesitation in placing herself in comparison with England.... Never was the policy of England so yielding and considerate towards France as at the present day. And then, with respect to the vexed question of the invasion, it is certain that Napoleon III has the means of effecting it with greater ease and far greater chance of success than his uncle.”
The means was steam power. But the much-talked-of invasion was never to be attempted. Other events intervened, other developments took place, which reduced the tension between the two great naval powers and removed for an indefinite time the danger, which the Leipsic article disinterestedly pointed out, of war under novel and unprecedentedly terrible conditions: with shell guns and wooden unarmoured steam warships.
CHAPTER X
THE IRONCLAD
The year 1860 marks the most dramatic, swift, and far-reaching change which has ever befallen war material: the supersession of the wooden ship-of-the-line by the modern battleship in its earliest form. What were the causes, suddenly realized or acknowledged, which impelled this revolutionary change, and what were the circumstances which moulded the new form of naval construction? This final chapter will attempt to show. Before descending to a detailed examination of this evolution, however, let us trace out the most striking features of the transition; their measure of accuracy can be estimated by the light of the subsequent narration of progress.
In the first place, then, we remark that, potentially, from the time when shell-throwing ordnance was introduced into the French, and then as a counter-measure into our own fleet, unarmoured wooden ships were doomed. Strange it seems that so long a time elapsed before this fact was realized; though it is true that with spherical shells and small explosive charges the destructive effects of shell fire were not greatly superior to those of solid shot, that fuzes were unreliable, that trials of artillery against material were rarely resorted to, and that, moreover, no opportunity occurred between 1822 and the outbreak of the Crimean War to demonstrate in actual sea-fighting such superiority as actually existed. Implicit trust was placed in our fine sailing ships. So long as solid shot were used, indeed, these timber-built ships were admirably suited for the line of battle; as size and strength increased and as our methods of construction improved the ship gained an increasing advantage over the gun, defence increasingly mastered attack, to such a degree that by the end of the long wars with France the ship-of-the-line had become almost unsinkable by gun-fire. But so soon as shell guns were established—even with spherical shells fired from smooth-bore ordnance—wooden ships loomed easy targets for destruction. For a long time this disquieting conclusion was ignored or boldly denied; expert opinion with sagacity turned a blind eye to the portentous evidence presented to it of the power of shell. War came, but even then the full possibilities of shell fire were not developed. Enough proof was given, however, to show that in the special circumstances of that war unarmoured ships were of small value against shell fire. Armour was accordingly requisitioned, and, some few years after the war, was applied to seagoing warships.