Page:The New International Encyclopædia 1st ed. v. 02.djvu/62

ARMOR PLATE. in all its features, the protective deck of thirty years later. In September, 1854, the French Government began the construction of several of the armored floating batteries fitted with weak auxiliary steam-power, for which designs had been prepared some years before. Three of them took part — the principal part — in the attack upon the Russian batteries at Kinburn, October 17, 1855. While practically uninjured themselves, they were able to lie so close to the enemy's works, 800 yards away only, that they dismounted nearly half his guns and compelled him to surrender after four hours' firing, though these batteries had held at bay the combined wooden fleets of France and England for months. The plans of these armored vessels were sent to England by the French Emperor. After considerable opposition and delay the Admiralty began the construction of similar vessels, but they were completed too late to join in the attack on the Kinburn forts, as they did not reach the Crimea until October 24, seven days afterwards. The success of the French armor-clads was followed at once by renewed and widespread interest in the armoring of ships. The French Conseil des Travaux de la Marine then determined to construct some sea-going armor-clads. Before elaborating a design, further experiments were made with armor plates, which resulted in the adoption of armor five inches thick. The thickness of plating and the general features of the design having been decided upon, plans were invited. Those of constructor Audenet were accepted, and were carried into effect by the building of the Couronne. In the meantime. M. Dupuy de Lôme had been studying the results of the recent armor trials. In November, 1857, he laid his plans and proposals before the Government, and in March, 1858, was begun the conversion of the 1.3-knot, 5000-ton wooden line-of-battle ship Napoléon into an armor-clad. The armor was applied very liberally, extending from well below water to the deck above the battery: the water-line belt being 4.75 inches thick, backed by 26 inches of oak, and the armor of the battery 4.5 inches thick with 24 inches of backing.

With the armor trials for the plating of the batteries used at Kinburn, in which the superiority of the solid plate was shown, the steady development of armor commenced. Before the application of armor to sea-going ships, which began with the Couroane and Gloire, the investigation of its qualities naturally lacked impetus, but henceforward its improvement was steadily sought, and its manufacture soon became a separate industry. The quality of the early plates was very poor, showing lack of facilities for manufacture and experience in producing pure and homogeneous metal and in working it. This condition of affairs was speedily altered; heavy hammers and rolls were rapidly brought into use, and by 1802 the manufacture of homogeneous wrought-plate was brought to the highest state of perfection, both in England and France. In the meantime gun and projectile makers had not been idle. The 32-pounderand 68-pounder smooth-bores using solid cast-iron projectiles were the standards for armor testing: the 8-inch, 9-inch, and 10-inch shell guns were brought out long before the application of armor to sea-going ships, but shells from these guns were too light, and the shot of too low velocity, to render them superior to the longer pieces mentioned. Rifled guns began to be used commonly about 1860; France, Prussia, and Russia adopted them in 1858, the two latter deciding upon the breech-loader. France retained the muzzle-loading system until 1864; the Gloire was armed with a battery of muzzle-loading rifles in 1859, though her designed armament consisted of smooth-bores. In I855 Armstrong brought out a breech-loading piece of small calibre, and Whitworth submitted to the Government in 1856 designs for breech-loading and muzzle-loading guns of all calibres. The Armstrong system was adopted for use in the British Navy, but repeated accidents led to an outcry against the breech-loading system, and in 1863 the Committee on Designs for Artillery conducted experiments with muzzle-loading guns which led to the adoption of the Woolwich type of muzzle-loader. 15ut whether breech-loading or muzzle-loading, the guns were all rifles, and the increased penetrative power rendered all armor so far produced easily vulnerable. The armor makers endeavored to meet the new situation in various ways. The thickness of the plate was increased; steel plates of various kinds were tried, as were plates made up of layers of steel and iron. The steel plates resisted perforation better than wrought iron, but were so easily cracked and destroyed that they failed to gain favor. Whitworth, always in the van in the development of ordnance, made and used forged steel projectiles in 1862, but their value was not generally realized, because the soft iron armor then in vogue was equally penetrable by the cast-iron shot. As the thickness of the wrought-iron plate increased, the difficulties of its manufacture grew rapidly. Neither rolls nor hammer could successfully handle the thickness demanded by ship designers. Resort was had to welding, but this was not satisfactory; first, because it could not be effectively done except by machining the faces to be joined, which added greatly to the expense; and secondly, because even then the weld was usually imperfect. The next step was to 'sandwich' several plates with a layer of wood between them. The result was found to be inferior to that obtained from a single plate, but the plan was for a time accepted as the best available one. In 1866. Gruson in Germany and Palliser in England brought out cast-iron shell with hard, chilled points. These further increased the penetrative power of the gun.

The question of the backing of armor received attention from time to time, and the results obtained are interesting even now. With the low velocities in use up to 1880, wood-backing played a very important part, but its importance has diminished in recent years; all thick armor is still backed with wood, but its thickness is about a quarter of that considered desirable in the days of wrought-iron plate. The backing of the Warrior's 4.5-inch armor was of teak, 20 inches thick, in two layers of 10 inches each. A less thickness of backing and 5 inches of armor gave inferior resistance to penetration. As projectiles improved in quality and acquired greater velocity, the advantage of thick backing was less apparent: indeed, except for the purpose of reducing the shock to a ship's framing it is now regarded as disadvantageous, for the same weight added to the plate to increase its thickness will give greater resistance to penetration.

Notwithstanding the confessed weakness of