Redoubtable was a central battery and barbette ship of the French Navy. She was the first warship in the world to use steel as the principal building material.
Compared to iron, steel allowed for greater structural strength for a lower weight. France was the first country to manufacture steel in large quantities, using the Siemens process. At that time, steel plates still had some defects, and the outer bottom plating of the ship was made of wrought iron.
All-steel warships were later built by the Royal Navy, with the dispatch vessels Iris and Mercury, laid down in 1875-1876.
The thread of ironclad development did not continue immediately after the Devastation class, and the so-called dark ages of the Royal Navy could be said to have commenced with the resignations of Reed and Robinson from the Admiralty. No new mastless turret ironclads would be laid down by the Royal Navy for another decade, and nearly full-sail rigs actually reappeared on the world’s ironclads. Technologically, even the British began to slip somewhat, a reflection of the rising scientific and industrial power of Germany. German guns came to surpass those of the Royal Navy by the 1870s, and British naval constructors had to go to France for suitable material when the time came for the transition to steel warship building. Surprisingly, even in numbers, the Royal Navy, unprecedentedly, fell to something like qualitative and quantitative inferiority with the French from the mid-1870s to the early 1880s. Admittedly, the French designs were, like the Union monitors, another dead end in naval architecture. With exaggerated ram bows and unprotected hulls, and their emphasis on sponsoned ahead-fire, they are difficult to take seriously today. Nonetheless, the genius of Royal Navy ironclad design seems to have gone on hiatus for about 15 years with the departure of Reed and Robinson.
In all fairness, it should be pointed out that battleship designers worked under severe, politically imposed constraints on dimensions and tonnage. Even the admirable RN Admiral class was cut to dimensions little greater than those of Warrior. In something of a reaction to the Captain catastrophe, ironclad construction reverted to earlier forms, and masts and sails reappeared, with all the troublesome and basically unsatisfactory design expedients that this ancient form of propulsion imposed on any warship. Yet it should have been perfectly obvious that the loss of HMS Captain was in large measure due to its towering sail rig and top hamper, as well as its heavy iron tripod masts, adding weight topside and thus undermining stability-excellent arguments against sailing ironclads.
Presumably, in some spirit of compromise, HMS Inflexible, the Royal Navy’s last first-class sailing capital ship (completed in 1881), carried a brig training rig that could be jettisoned in wartime. Even with the return of turrets, instead of Devastation’s fore-and-aft turret arrangement, Inflexible and other contemporary ironclads sited turrets en échélon (off-center) amidships. This arrangement would, in theory, give some fore-and-aft fire. Inflexible’s two 750-ton turrets housed four great 16-inch muzzle-loading guns that were too long to load inside the turrets; consequently, the shells had to be inserted through an awkward arrangement using a deck hatch in front of each muzzle. In reality, had the guns been fired repeatedly in a combat situation, this turret arrangement would have imposed severe hull stresses and topside damage. Yet it could be argued that no one needed to worry much about such strains for, in the best of conditions, Inflexible’s guns could fire only every 2.5 minutes. This freak ironclad is also notable for carrying the thickest armor plate of any British battleship ever built; later, improved armor gave the same protection with less thickness. Armor also seemed to go to extremes; Devastation’s armor (maximum 14 inches on the turrets) shielded everything above the waterline except the light upperworks. HMS Inflexible’s unmatched 2 feet of armor shielded only a central citadel, consisting of the turrets and their handling and turning works, plus an underwater deck, and all subsequent ironclads followed this example until around 1900. Nonetheless, for all its faults, Inflexible would have made short work of its French contemporary, Admiral Duperré, which was very vulnerable above the waterline.
Even when the Royal Navy finally again constructed mastless turret ironclads, and introduced breech-loading guns, steel construction, and armor in the Inflexible diminutives, Colossus and Edinburgh (completed in 1886 and 1887, respectively), the turrets were arranged again in the hull-straining echelon arrangement to give ahead-fire for ramming. When the Admiralty finally went over to Devastation-pattern fore-and-aft turrets with Hero and Conqueror (completed in 1886 and 1888, respectively), they were mounted on dwarf ironclads, still designed primarily for ramming and counterramming, as were the Victoria and Sans Pareil (completed in 1890 and 1891, respectively).
Steel construction resulted in a hull lighter by some 35 percent. (The all-iron hull of Warrior absorbed some 52 percent of its entire weight.) Steel was considerably more expensive than iron, but improved production methods made steel cost-competitive by the 1870s. Here again, the French took the technological lead, laying down the first capital ship constructed completely of steel, Rédoubtable. (By contrast, wrought iron was far more long-lasting than steel, which undoubtedly accounts for the remarkable preservation of the surviving nineteenth-century ironclads more than 100 years after their completion.)
The increasing cost, size, and complexity of nineteenth-century ironclad capital ships led many naval theorists of the time to claim that the torpedo had doomed the large warship. If one small, cheap torpedo could sink a large, expensive warship, the need was for the former, not the latter. In fact, in 1886, it was announced in Parliament that, in light of the rapid developments in torpedoes and torpedo warships, the newly authorized Nile and Trafalgar would probably be the Royal Navy’s last battleships. Actually, no new capital ships were laid down in Great Britain for three years after 1886. Yet Nile and Trafalgar, with their breech-loading turret guns arranged fore and aft, were in the line of future development of capital ships, although they were hindered by their low freeboard, designed keep the heavy weights of the turrets as low as possible in the interests of stability.
It has also been argued that this erratic ironclad development and even retrogression after 1870 was more the result of severe budgetary restrictions in this time of widespread European peace after the German Wars of Unification, rather than simple-minded resistance to change. In fairness to Reed’s successor, Nathaniel Barnaby, it should be noted that much of the inadequacies of the ironclads of the dark ages of the Royal Navy were indeed due to the cost-cutting economics followed by both Liberal and Conservative governments of the time. Such economizing led to ironclad dimensions far too small for adequate armor and ordnance, which Barnaby did protest on occasion. True enough, but the argument weakens somewhat in light of the enormous sums spent uselessly on sailing tackle during those same decades. For example, in 1876, the Admiralty spent £113,000 on coal and £123,000 on raw hemp, canvas, and the like. And these figures do not count the cost of the many extra seamen needed to man sailing rigs. HMS Bellerophon, for example, required 200 of its 556-man crew for work aloft. (Sailing was also somehow supposed to build character.) Armor also seemed to go to extremes; in all, Devastation led the way until the close of the century.
Emphasis on coastal defense and on the ram inhibited tactical thought, and throughout the nineteenth century only one tactics textbook was published by a British officer. The lonely author, G. H. Noel, in the spirit of the times, argued “that the ram is fast supplanting the gun in import” (Peter Padfield, The Battleship, Edinburgh: 2000, p. 69). In fact, complex evolutions, the type that led to the Victoria ramming disaster, took the place of any serious study of battle tactics. (Still, it could be argued that in the absence of wireless, the complex maneuverings of ironclads in a fleet action would have to be worked out ahead of time and rigidly adhered to in time of battle.)