“La Gloire” (France) 1857.
Side Armor Iron 4½ in. Solid.
“Warrior” (England) 1859.
Side Armor Iron 4½ in. Solid.
U.S. Monitor “Passaic” 1862.
Side Armor Iron 3 to 5 in. Laminated.
Turret Armor Iron 11 in. Laminated.
“Inflexible” (England) 1876.
Belt & Citadel Armor Iron Sandwiched.
“Duilio” (Italy) 1876.
Belt Armor Steel Solid.
U.S. Battleship Oregon.
Belt Armor Harveyed Nickel Steel Solid.
13 in. Turret Armor Harveyed Nickel Steel Solid.
PLATE VIII. THE GROWTH OF ARMOR.
At the outbreak of the Civil War in the United States, the government appointed a special naval committee to report upon types of ironclads. The conclusions of this board are of interest, in showing the state of armor development at that period. They required rolled armor of solid iron, whose minimum thickness was 4½ inches. Ericsson’s Monitor, however, carried laminated plating from 3 to 5 inches thick on her low sides, and 11 layers, each one inch thick, on her turret. This construction, which the difficulties in the manufacture of solid plate necessitated, made the record of endurance of this type far from good. The defect lay mainly with fastening bolts, which broke frequently, thus loosening or detaching the side armor, and the heads or nuts of which, flying off with violence when the armor was struck by shot, became sometimes fatal missiles against those within the turrets. In contrast with this, the behavior of the New Ironsides, clothed with solid armor, was most excellent. She was a casemated ironclad frigate with unarmored ends, her plating was 4½ inches thick, and inclined throughout the citadel, at an angle of 30° from the perpendicular. For two years she was subjected to the most severe test that a war-vessel must meet, the tossing and straining of blockade duty and the fiery ordeal of close action with fortifications. In one engagement, she sustained alone a fight against the combined fire of the forts in Charleston harbor, and, although struck on her side-armor sixty times, came out of the struggle unhurt. The record of this ship is one which does honor to the flag.
The achievement of the Confederacy during this war, in the matter of armor, was remarkable. With iron worth almost its weight in gold, and with most limited facilities for manufacturing, they yet succeeded in constructing some of the most formidable ironclads of their day. The Merrimac, for instance—with 3-inch armor, in two layers of narrow bars, at an angle of 30° with the horizontal—sustained no material damage to her plating from the fire of the Monitor; although had the full charge of 30 lbs. of powder been used in the 11-inch smooth-bores of the latter, the story would have been different. Every fair blow would have smashed a hole completely through the armor, and driven a shower of splinters about the battery-deck. Again, the armor of the Atlanta and the Tennessee—both casemated ships, with the sides of the citadel inclined at a sharp angle to the horizontal—was sufficiently strong, with the former vessel, to withstand, at 500 yards, the 11-inch projectile fired with a 20-lbs. charge, and, with the latter, the same shot practically at the muzzle, although the 15-inch projectile broke through completely in both cases.
It is unnecessary to follow in detail, through its many tests in peace, the advance of iron armor. Its growth in strength, as the power of the gun developed, came almost solely from increase in thickness, the latter reaching its maximum with the British Inflexible, completed in 1876, which carries from 16 to 24 inches of iron on her belt and citadel. This plating, however, is divided and “sandwiched” with wood, there being, exterior to the skin, 6 inches of teak, then 12 inches iron, 11 inches teak, and an outer 12-inch plate. As armor, iron received its death-blow in the famous tests at Spezia, Italy, during the autumn of 1876, when the 100-ton gun, with a full charge, at a range of 100 yards, attacked solid and “sandwich” targets of iron and solid targets of steel—the single or aggregate thickness of metal in each case being 22 inches. These trials were undertaken through Italy’s desire to build, in the Duilio and Dandolo, the most formidable vessels afloat. Steel won the day, and the roar of that mighty gun, thundering from the Spezia firing ground, sounded the knell of iron armor, deprived the as yet unlaunched Inflexible of her crown of invulnerability, and demanded, with success, a revolution in the armor manufacture of Europe.
As a compromise, compound armor, i.e., iron faced with steel, became popular for a time. As with steel, its beginnings were old, dating back at least to the year 1857. The first perfected compound plate, made by Cammel & Co., of England, was tested at Shoeburyness in 1877. It was composed of 5 inches of iron with a 4-inch face of steel; the iron being raised to a welding heat and the molten steel poured on its top. The great heat partially fused the contact face, the two metals were united, and the combination was assured by immediate rolling. Compound plates sprang in 1877 from obscurity to popularity; by 1879 iron armor had become obsolete with progressive naval powers, and, in 1880, both compound and steel plates had reached such development that they were close rivals, the leading competitors being Cammel in England and Schneider in France. Steel, however, slowly forged ahead during the next decade; and, at its close, compound armor was practically out of the race. In steel’s victory, its alloy with nickel, in minute proportions, has materially aided; the combination imparting hardness without decreasing the toughness of the plate. This material gave superior results from the beginning. Its first plate, tested in 1889, was 9⅓ inches thick; it was pierced by a Holtzer shell, whose body did not pass wholly through and whose energy was 1.6 times that just necessary to perforate a wrought-iron plate of the same thickness. To the increased strength given by nickel there has been added a further gain through the application of face-hardening processes—such as that of the American, Harvey—which produce superficial carbonization, transforming the surface into a high grade of very hard steel, without the pronounced plane of demarcation between the two qualities of metal, as in the weld of the compound plate. A 10¼-inch nickel steel Harveyized plate, tested at the Indian Head Proving Grounds in 1892, showed a strength which previously had never been equaled in the history of armor, and established beyond question the value of the face-hardening process, which, by various methods, is applied to the nickel-steel plating of to-day. The distribution of armor in the development of battleship construction is shown by the shaded sections on Plates VI and VII, and its relative thicknesses, on various vessels during this progress, by [Plate VIII].
VII. THE RAM AND THE TORPEDO.
For two thousand years the ram—the razor-edged “beak” of the swift galley—was the chief naval weapon. With the advent of sail-power and the employment of gunpowder, it vanished from the seas; but to reappear when the coming of steam gave again controllable propulsion. In 1859 there was built into the French frigate Magenta a sharp spur,—the first modern ram. British construction of the modern era, from the Warrior down, has also recognized this weapon, and it is to-day a factor, although a minor one, in the design of all vessels of high speed.
The ram has, however, but a scant record of service in action, while in accidental collision it has wrought more than once appalling disaster. The ironclad Merrimac rammed and sank in Hampton Roads, in March, 1862, the United States sailing sloop-of-war Cumberland, which, under the gallant Morris, went down with guns thundering and ensign flying. On July 20, 1866, during the action off the island of Lissa, in the Adriatic, the Austrian flagship Ferdinand Maximilian rammed the Italian armorclad Re d’ Italia, which, with many of her 800 men, sank with a swiftness that chilled the blood of those who watched. Like this, in its sudden tragedy, was the destruction of the British battleship Victoria by her consort, the Camperdown, off Tripoli, Syria, in the summer sunlight of a June day in 1893. The ram of the latter vessel cut a deep and fatal gash in the Victoria, which within ten minutes turned bottom upward and went down, bow first, bearing with her 321 officers and men, whose unfaltering discipline gave a heroic splendor to their end. Despite these occasional instances of its deadly power, the ram holds a secondary place among naval weapons. To strike a modern vessel at high speed will require more than the skill of the swordsman.