PLATE IV. ENGINE OF U. S. S. ERICSSON.
The use of more than one screw for propulsion dates back to 1853. During our Civil War multiple screws figured, to a small extent, in the “tin clads” and larger monitors. The application of twin screws, in the modern era, begins with the British ironclad Penelope of 1868. France, in the years 1884–85, blazed the way for another naval advance of much importance in conducting a series of trials with the launch Carpe, equipped with triple screws. The system, however, although of much value, from engineering and tactical points of view, was not adopted in large, high-powered vessels until the advent of the French armored cruiser Dupuy de Lôme in 1890, and the protected cruisers Columbia and Minneapolis of the United States navy in 1893. It has now won full approval in the navies of continental Europe, and triple-screw ships, aggregating 500,000 tons, are built or building there.
The limits of space forbid more than a passing note of the triumphs of the engineer in torpedo craft, the light cavalry of the sea. With steamers of normal proportions, the speed and power depend largely upon, and increase with, the displacement. As has been stated, the maximum performance of large cruisers is now 23 knots on a tonnage of 4500. These particulars give a faint glimpse of the extraordinary problem which has confronted the torpedo-boat designer in driving hulls of, at present, about 150 tons at a speed which now approximates to 30 knots. With the brilliant record of success in this task, there will be linked always the names of Yarrow and Thornycroft in England, of Schichau in Germany, and of Normand in France. The achievement but recently of a British inventor, the Hon. Charles Algernon Parsons, in giving the Turbinia of 44.5 tons a speed of over 31 knots, has drawn the attention of engineers the world over to the possibilities of the steam turbine on the sea. This performance is phenomenal with such a displacement. The French Forban, of 130 tons, has made 31.2 knots, and a reported speed of 35 knots gives a Schichau boat her temporary laurels as the fastest craft afloat.
A brief glance at the improvements which have made possible these extreme speeds in cruisers and torpedo craft will be of interest. The progress which has been made has been, firstly, in the economy in the use of steam arising from higher pressures and multiple expansion; secondly, in the reduction of weight, per horse power, due to increase in strength of materials and in engine-speed with the employment of forced draft—which was reintroduced by France—and the water-tube boiler; and, finally, in the application of a more efficient propelling instrument. The advances of half a century in propelling machinery are shown, in some respects, by Plates III and IV, which contrast, on the same scale, the side-wheel machinery of the United States war-steamer Powhatan, of 1849, with the engines of the United States torpedo boat Ericsson of to-day. The data of the former vessel are: horse-power, 1172; steam pressure 15 lbs.; weight of machinery per horse-power 972 lbs.; while, for the Ericsson, the figures are: horse-power, 1800; steam pressure, 250 lbs.; weight of machinery per horse-power, 56 lbs. This comparison, however, must be qualified by the statement that the older engine was for a steamer of about 3760 tons, while the torpedo boat is but 120 tons in displacement. The contrast lies, therefore, only in the reduced weight of material per horse-power developed and in the increased steam pressure, which, however, are in themselves most striking.
V. THE GROWTH OF ORDNANCE.
At Trafalgar, the Victory drifted before the wind into action. In her slow advance, at a speed of one and one half knots through but 1200 yards, she was for half an hour under the prolonged fire of 200 guns, and yet she closed, practically unhurt, with her foes, and lived, not only to win the day, but to bring undying glory to the English flag. What a contrast the latest sea-fight of the century presents in the power of modern ordnance as compared with the puny guns of Nelson’s time! Our battleship Oregon, at a range of nearly five miles, with one 1100-pound shell, drove the Colon, an armored cruiser, not only shoreward, but to surrender, stranding, and wreck.
The largest naval guns in the year 1800 were the long 32 and 42-pounders, smooth-bore muzzle-loaders, with a range of about 1200 yards. Carronades—short pieces with a heavy shot but limited range—found favor also, especially with British sailors, eager for that close-quarter fighting in which the “Smasher”—as General Melville called his carronade—would be most effective in shattering timbers and in sending clouds of splinters among the foe. The projectiles were spherical shot, canister, and grape, the diabolical shriek of the shell being yet unheard. Both gun and shot were of cast metal, and the mount was a wooden carriage on low trucks. The training, or horizontal angle of the gun, was effected by rope tackles, and the amount of elevation of its muzzle depended upon the position of a “quoin,” or wooden wedge, thrust beneath the breech. The recoil was limited by rope “breeching,” passing through the cascabel,—a knob behind the breech,—and secured to ring-bolts in the ship’s side. The gun was harnessed, as a horse is, in the shafts.
BATTLE OF TRAFALGAR.