The evolution of artillery falsified these expectations. With the growing advantage of artillery over the defence, and with the coming of the torpedo, fighting ranges increased and the use of the ram declined. With greater speeds and greater ranges the possibility of ramming became (as might be deduced mathematically) a diminishing ratio; before the end of the century it was sufficiently clear, and was confirmed by actual warfare, that the ram formed but a very secondary factor of a warship’s offensive power. But for some years ramming, and “bows-on” fighting in which ramming was intended to play an important part, influenced to a great extent the designs of warships.
So much for the ram, first fitted in the Warrior. In her sister ship the ram was less pronounced and, before Hampton Roads had drawn attention to its possibilities, it was even in question to renounce it altogether. In the case of the Warrior the heavy figure-head so overhung the ram that many were dubious whether the latter would seriously damage an enemy; and, moreover, the wisdom of driving a fully rigged ship against another vessel, and risking the dismantling of her masts and rigging, was widely doubted. In other respects, except for her armour belt and for the material of which she was built, that vessel was not radically different from her predecessors; the first of iron-built ironclads was a handsome screw frigate not unlike previous British ships of her type, from whom she was lineally descended.
Although on the whole she was a conspicuous success, it was soon apparent that the great length of the Warrior tended to make her difficult to manœuvre: in fact, made her deficient in that very quality—handiness—which was indispensable to her effective use as a ram. And this unhandiness was accentuated in the Minotaur class which was begun in 1861. These ships were given a belt an inch thicker than that of the Warrior, and, partial protection being considered objectionable, especially as leaving exposed the steering gear and a portion of the gun armament, the belt was made continuous over the whole length of the ship. This length, owing to the extra weight of the armour, was 400 feet: 20 feet greater than that of the Warrior and a hundred greater than that of the longest timber-built ships. At first, five masts were fitted, in order to obtain a large sail-area while at the same time keeping the size of each sail within desirable limits; but these were afterwards reduced to three. Sail power and steam machinery were seen to be an imperfect combination in so large a vessel. The Minotaur class proved to be costly, unhandy and vulnerable ships, and signalled a return to smaller dimensions. It was found possible to design ships equally fast and equally well armed and protected, by the use of fuller lines and less length and an increased engine power. “Increased manœuvring power and reduction in prime cost,” wrote the designer of the new type, “more than make amends for the moderate addition to the steam power.”[164]
Here we may briefly note the conversion of the timber-built fleet. In ’57 Captain Moorsom had submitted a scheme of cutting down ships to a short height above the water-line and using the weight thus gained to provide an armour belt. Sir Charles Napier had advocated a similar policy in parliament. As soon as the necessity for armour was accepted this policy was adopted; not only were the resources of the private ship-yards bent to the building of a fleet of new iron warships, but the best of the old navy was metamorphized in the royal dockyards by the process of the razee: the cutting down of two-deckers and their conversion into iron-belted frigates. By these exertions France was soon outstripped in the struggle. For a long time she clung to wooden ships, though in ’62 she adopted iron for upper works; and of such ships, of wooden bottoms but of iron above the water-line, she built a fleet “possessing only one possible merit—uniformity; which the new English construction lacked.” The combination of heavy steam machinery and wooden hulls was the cause of continuous difficulties; the growth of artillery rendered the ships obsolete almost before they were built.
§
By the time the Warrior and her sister ships were afloat the great struggle between armour and artillery was well in progress. It was a struggle which was to lead to unsuspected developments in naval architecture.
For the moment, and in the presence of the new iron-built ironclads, the gun was at its lowest point of effectiveness. But rifling had conferred new powers on it, and the greatest efforts were being put forth to improve its position. As it grew rapidly in size and power, naval experts were faced with a succession of problems of extraordinary difficulty. Two things were in question: both the type and the disposition of gun best suited for a warship’s armament.
With regard to type, the adoption of armour inevitably gave a set-back to the value of the shell gun. Shells, which would rend and set on fire a wooden ship, would not pierce armour or inflame iron plates; of which facts Hampton Roads afforded a demonstration. It seemed clear also from that incident, to experts in this country and in France, that no extension of the Paixhans principle was likely to compete with armour in the future. The system of shell fire of General Paixhans, like the shot system of the inventor of the carronade, had relied on low muzzle velocities and curved trajectories, to effect its purpose. His shells were for lodgment rather than penetration, and did not gain their effect by their kinetic energy; and in view of this their inventor had himself conceived the use of iron armour as the very means whereby they might be countered. Nevertheless the Americans had been strongly attracted by the Paixhans principle, and with their Dahlgrens and Columbiads had extended it in practice to embrace the use of guns of the largest calibres. The action between the Monitor and the Merrimac did nothing to shake their faith in this class of ordnance. Subsequent experiments appeared to confirm the national predilection; and one of their writers, in giving credit to the navy chiefs for adhering to the principle of the large smooth-bore gun, recorded that the small-bore-and-high-velocity theory had received its quietus by the utter demolition of a 6-inch plate by a ball from a 15-inch gun at Washington in February, 1864.[165] In France and England it was held, and held rightly, that high velocities were necessary for the attack of armour.
If shell guns were of small value, what was suitable? Were the old spherical solid shot still capable of beating the defence? A serious effort was made in this country to bring them to do it. The Armstrong rifled breech-loading guns recently adopted had been proving defective and indifferent on service; a return was wisely made to muzzle-loading; and it was in question also to revert to spherical shot and shell. Spherical shot of hardest steel were tried by the Excellent, in the hope that they would penetrate 4½-inch plates. Experimental guns were also made, in 1864, to discharge 100-pound balls with charges of 25 pounds of powder; guns so heavy (6½ tons) that it was doubted at the time whether they could be efficiently worked on the broadside of a rolling ship. Should not increased power be obtained by persevering with rifled guns? The advantages possessed by the rifled gun in ranging power, accuracy, capacity of shell, were admitted; nevertheless the navy as a whole favoured the smooth-bore, with its simplicity, rapidity of fire, strength, and greater initial velocity, and thought that, at close ranges, the 100-pounder 6½-ton smooth-bore gun was the best and most suitable weapon for the service. But the rifled gun was advancing rapidly. “By May, 1864, the 7-inch muzzle-loading rifled shunt gun of 6½ tons had been tried in the Excellent, and had a good deal shaken the position of the smooth-bore. Captain Key reported that it was more than equal to naval requirements.... It was admirably adapted for the naval service.”[166] This fired a projectile 115 pounds in weight. By June of the following year the target of 9-inch plate representing the side of the Hercules had beaten the latest Armstrong achievement, a 12½-ton 300-pounder. And on this pretext, and judging the defensive power of the whole ship by the defensive power of the thickest patch of its armour, a still more powerful gun was demanded for the navy by the inventor and by the press: a 25-ton 600-pounder.
So rapidly the power of ordnance grew. It has been observed that of this feverish evolution of armour and artillery the circumstances were doubly remarkable. Firstly, no foreign pressure existed which called for such overleaping and experimental advances. The Americans still clung to their smooth-bore system; the French, who like us had adopted breech-loading guns, retained the system in their service and suffered for some years from its continuous inefficiency. Secondly, the navy was itself “unwillingly dragged into the cul-de-sac of experimental construction induced by the clamour of public opinion.” The type, the size of the gun which was to be embodied in our latest warships, was decided mainly by forces outside the navy, and changed from year to year. Naval architecture changed with it. The adoption of the succession of increasingly powerful rifled guns set experts at their wit’s ends devising warships suitable for carrying them; entailed continuous alterations both in the armaments of new ships and in the design of the new ships themselves; but also, as it happened, had the effect of giving this country a mastery over naval material which it has never since surrendered.