Part 8
Closely allied with mechanism in this evolution, has been the transformation of the structural material of the hull, which has passed from the hands of the shipwright in wood to the engineer who works with steel. The reasons for this are not far to seek. They lie, firstly, in the greater strength of the metal construction to withstand the vibration of swift and heavy machinery, and the strains arising from the unequal distribution of massive weights in a hull which pitches or rolls with the waves. With wooden ships, the present proportions would have been unattainable. Again, there is a marked saving in the weight of the hull proper of the steel vessel, which is not only stronger but lighter. This weight in the days of timber averaged fully one half of the displacement; while in the Oregon, whose tonnage, at normal draught, is 10,288, the hull percentage is 44.06, leaving a gain over the wooden vessel of 611 tons to be applied to armor, armament, or equipment. Finally, the durability of the metal vessel, with adequate care, greatly exceeds that of the wooden war steamer, whose average life was but 13 years.
The creation of the steam machinery of navies has been the achievement of the engineers of practically but three great nations. The daring of France, the inventive genius of America, and the wide experience and sound judgment of Great Britain, have united in this work. Our country has led time and again in the march of improvement; although our progress has been fitful, since, more than a generation ago, we turned from the sea to the development of the internal resources of this continent. Limits of space permit but brief review of a history which has had its full share of triumphs, not only in battle, but over wave and wind.
[Illustration: THE U. S. S. OREGON.]
A contemporary authority states that, when British Admiral Sir John Borlase Warren ascended the Potomac River, during the war of 1812, his expedition was reconnoitred by an American steamer. This appears to be the first record of the use of such craft for military purposes. In 1814 the United States built the first steam war-vessel in the world’s history. She was called the Demologos, later the Fulton, and her completion marked truly, as her commissioners said, “an era in warfare and the arts.” She was a double-ended, twin-hulled floating battery of 2475 tons, carrying twenty 32-pdr. guns, protected by 4 ft. 10 in. of solid timber. She was driven by a single central paddle-wheel; her speed was 5½ miles per hour; and she was both handy and seaworthy. France, in 1820, sent a commission to America to report upon steam vessels of war; and in 1830 the French had nine armed steamers afloat and nine building. In 1821, the Comet, a small side-wheeler, was commissioned as the first steam war-ship in the British navy, and in 1840, at the bombardment of Acre, steam vessels fought their first battle.
[Illustration: ACTION BETWEEN MONITOR AND MERRIMAC.]
The growth of steam in navies had been retarded by its application solely to paddle craft, whose wheels and machinery were incapable of protection in action. During the years 1842–43, however, the United States built the sloop-of-war Princeton, of 954 tons. This vessel was the product of the genius of John Ericsson, the ablest marine engineer the world has ever seen. She was the first screw-propelled steam warship ever built, and, in other respects, foreshadowed the advances which were to come. Thus, her machinery was the first to be placed wholly below the water-line beyond the reach of hostile shot; her engine was the first to be coupled directly to the screw shaft, and blowers, for forced draft, were with her first used in naval practice. She was virtually the herald of the modern era.
The Princeton was followed closely by the Rattler, the first screw vessel of the British fleet, and in 1843–44 the French 44-gun frigate Pomone was fitted with propellers. In 1843, also, the English Penelope was the first man-of-war to be equipped with tubular boilers, and the year 1845 was notable for the building of the ill-fated Birkenhead, the first iron vessel of the British fleet. In 1850, when the French constructed the screw line-of-battle ship Napoleon, the English became alarmed, and began with vigor the renovation of their navy with regard to screw propulsion.
France, in 1854, laid the keels of four armored batteries, three of which, forming the first ironclad squadron in history, went into action a year later under the forts of Kinburn in the Crimea. They were of 1600 tons’ displacement, carried 4⅓ inch armor and sixteen 68-pdr. guns, and had a speed of four knots. In 1862, Ericsson launched the famous Monitor, the first sea-going ironclad with a revolving turret, and an “engineers’ ship” from keel to turret top.
[Illustration: THE TURBINIA.]
The Civil War found us with a sailing navy, and left us one of steam. Passing over its victories, in which steamers played always the chief part on sea and river, we come to that most notable triumph of Chief Engineer Isherwood, the cruiser Wampanoag of 4200 tons’ displacement. This vessel, phenomenal in her day, steamed in February, 1868, from Barnegat to Savannah, over a stormy sea, in 38 hours. Her average was 16.6 knots for the run, and 17 knots during a period of six consecutive hours—a speed which for 11 years thereafter was unapproached by liner or by warship. In 1879, the British despatch vessel Mercury, of 3730 tons and 18.87 knots, wrested the palm from America; but, in 1893, it was won again for the United States by the triple-screw fliers Columbia and Minneapolis of 7475 tons, with speeds respectively of 22.8 and 23.073 knots. The laurels rest now with the Buenos Ayres, which, though built in England in 1895, flies the flag of Argentina. She has a tonnage of 4500 and a speed of 23.202 knots.
[Illustration: ENGINE OF U.S.S.POWHATAN. A.D. 1849.
PLATE III.]
The British ironclad Pallas, completed in 1866, was remarkable for having the first successful naval engines on the compound principle, in which the steam is admitted at high pressure to a small cylinder, and passes thence to a larger one which it fills by its expansion. To Great Britain the world owes also the development of triple expansion, i. e., the use of steam successively in three cylinders. This system was inaugurated in naval engines by the British, in 1885–86, and is now universally employed. Prior to 1879, the boilers of all modern war-vessels had been those of the Scotch type, in which the flame passes through tubes fixed in a cylindrical shell containing water. In that year, however, France began a revolution in the steam generators of navies by equipping a dispatch-vessel with the Belleville tubulous boiler, in which the water to be evaporated is contained within tubes surrounded by flame confined in an outer casing. The water-tube principle, also, bids fair to become of universal application. It has had its most noteworthy naval installation in the British cruisers Powerful and Terrible, of 14,200 tons and 25,886 horse-power, completed in 1895.
[Illustration: 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.
[Illustration: BATTLE OF TRAFALGAR.]
Aiming was largely a perfunctory process, since the gun had no sights and the shot had excessive “windage,” its calibre being from one fifth to one third inch less than the bore, making its outward passage a series of rebounds and its final direction a matter of chance. “Windage,” however, was essential to facilitate muzzle-loading and to provide for the expanded diameter of red-hot shot. It is true that in 1801 a proposition to use sights was made to Lord Nelson. He, however, rejected it with the words:—
“I hope we shall be able, as usual, to get so close to our enemies that our shot cannot miss the object.”
His blind courage in this cost his countrymen dearly when, in 1812–14, their shot flew wild, while their ships were hulled and their gallant tars fell before the then sighted guns of the United States.
To ignite the charge the slow-match was still used, as is shown by the sharp words of a sailor of that time. Hailed in the darkness by a British ship and ordered to send a boat, his quick answer was:—
“This is the United States frigate Constitution, Edward Preble, commodore, commanding, and I’ll be d—d if I send a boat!”
Then to his men, silent and eager by the shrouded battle-lanterns:—
“Blow your matches, boys!”
A full crew for a 32-pounder consisted of 14 men. An old rule as to this was one man to every 500-lbs. weight of the gun, which would give the Oregon 1100 men to handle the four 13-inch rifles of her main battery, or more than twice her whole crew. Steam and mechanism have wrought a magic change in this.
The slow-match remained in use until well into the nineteenth century, although, until 1842, the flint lock was generally employed in the British navy, having replaced the priming horn and match in 1780. In 1807 there was discovered a composition which could be ignited by friction or concussion, and in 1839 the French had adopted the percussion lock, which exploded the cap and retracted, uncovering the vent before the backward rush of the gas could strike it. Later, a similar composition was used with “friction-primers,” or tubes filled with mealed powder and capped with composition, the tube forming a train leading to the charge, and the composition being fired by the friction of a rough wire drawn briskly through it. Percussion and friction have been in turn largely displaced by the electric primer, which consists essentially of a fine wire, or “bridge,” passing through a highly inflammable mixture. The bridge offers a resistance to the electric current, is heated thereby, ignites the composition, and fires the gun.
The older type of the cast-iron smooth-bore gun for solid shot reached its ultimate development in the 68-pounder, which endured until the advent of armor. In 1819 the system of firing shells loaded with gunpowder from smooth-bore guns was suggested by General Paixhans, of France. In 1824, it was introduced into the French navy, and about 1840 into that of the United States. At Sinope, in 1853, the terrible effect of shell fire upon wooden ships startled the world, when a Russian fleet destroyed absolutely 11 Turkish vessels, with their force of 4000 men. The Paixhans gun was modified and its form improved by Admiral Dahlgren, U. S. N., and in the late 50’s the armament—designed by him—of United States vessels was superior to that of any other in the world. The 9, 11, and 15-inch Dahlgrens formed the bulk of our guns afloat during the Civil War, the remainder being almost wholly rifles of the Parrott type.
[Illustration: _The Growth of Ordnance_
_32pdr 6m Smooth-bore, Muzzle-loader Weight 3600 lbs. Muzzle Energy, 642 Foot-tons_
_U S (Dahlgren) 440pdr 15m Smooth-bore, Muzzle-loader Weight 42000 lbs. Muzzle Energy, 7273 Foot-tons_
_Italian (Armstrong) 2000pdr 17in Rifle, Breech-loader Weight 101.5 tons, Muzzle Energy, 51930 Foot-tons_
_U S Naval 1100pdr 13in Rifle, Breech-loader Weight 60 tons, Muzzle Energy, 33627 Foot-tons_
PLATE V.]
The resistance which spherical projectiles met from the air, their deviation in flight, owing to the frequent lack of coincidence of the centres of gravity and form, their excessive “windage,” and their light weight relatively to calibre, led to the adoption of the rifled gun and the cylindrical projectile. The principle of the former—making the shot act as a screw-bolt and the bore as a screw-thread—is very old, there being at Woolwich a barrel of this type bearing date of 1547. The objects aimed at in rifling are to give a pointed cylindrical shot rotation on its axis that it may keep steady during flight, and secondly, to obtain increased weight in the projectile from its elongated form. As to the latter consideration, it may be noted that the old 32-pounder smooth-bore was of 6-inch calibre, while the United States 6-inch rifle of to-day throws a shot of 100 lbs. weight.
France, during the Crimean War, brought out the first heavy rifled gun. In 1860–61, Armstrong rifles were introduced in the British navy. The labors of Krupp met such success that at Paris, in 1867, he exhibited a rifle weighing 50 tons with a projectile of 1080 pounds. The Parrott rifle was brought out about 1856 in the United States, and was so developed that in 1862 it was the most powerful gun, for its weight and size, in existence. The adoption of rifling was the first great step on the road which engineering had laid toward the growth in power of modern ordnance.
Having thus secured a projectile of great weight and moderate calibre which would bore through the air a true path to the distant mark, there remained to seek but four chief elements in the magnificent advance made within a generation by the naval artillery of our day. These factors were: 1st. Increased strength in the material of the gun. 2d. A method of construction which would not only permit enormous pressures in the powder-chamber, but would make possible the continuous acceleration of the projectile during its passage through the bore. 3d. An explosive which would satisfy the objects of the method of construction; and, 4th. A system of loading which would enable guns of great length to be charged with ease. The mounting of ordnance of any weight, its control, and its rapid and facile handling were but minor matters of engineering.
In a paper such as this, of limited length and addressed to laymen, it is possible to give but a glance at the progress in the various elements of gun-construction which have been noted. Of material, little need be said. The rifle of Crimean days was a cast-iron piece; Parrott ordnance was of cast and wrought iron; and the first Armstrong gun was built of wrought iron and steel. Cast and compound materials, however, have vanished with the past. Steel—hardened and toughened to the last degree by every refinement of manufacture—forms the “reeking tube” for the “iron shard” of the century’s close.
The method of construction is the “built-up” process, shown by the partial section on Plate V., the barrel being reinforced by tubes which are shrunk on—like the tire of a wagon-wheel—so as to produce initial compression. The explosion in the powder chamber strains and expands temporarily the barrel, and the application of the shrinkage principle enables a portion of the strength of the tubes to be employed in preliminary internal pressure. The barrel thus supported can be strained by the charge, not only to its own limit of safety, but to an additional amount equal to this initial compression. The all-steel, built-up gun has a possible rival in wire-wound ordnance, a system which replaces the tubes, to a greater or less extent, by layers of wire, wound while in tension around the barrel.
Powder is the soul of the gun; it transforms the huge inert mass into a flaming engine of death. The great development of explosives began but a generation since. The researches of Robins and Rumford in the last century, and of Hutton in the dawn of this, formed the world’s knowledge of the gun’s internal ballistics until the year 1870. To the genius of Noble and Abel is due the stimulus to growth since then. The powders have kept pace with gun-construction in its advance. The increased strength of the chamber has been met by heavier and slow-burning charges—cocoa, brown prismatic, and the like—which have given not only greater initial velocity, but a continuous acceleration through bores whose maximum length has exceeded 47 feet. Indeed, to the production of this lingering combustion is due the great linear dimension and power of modern guns. Initial pressure had its limit; advance lay only in the subsequent acceleration given by late ignition of a portion of the charge.
Gunpowder, however, after a reign of more than five hundred years, has been dethroned. The “villainous saltpetre” of the monk, with its allies, charcoal and sulphur, yields now to nitro compounds, which produce not only far greater energy, but are as well smokeless. The sea-fights of our war with Spain saw the last contending fleets to be wrapped in a cloud, lingering and baffling, of their own making. Cordite, one of these compounds in use abroad, is prepared in long “cords” from di-nitro-cellulose and nitro-glycerine. The new smokeless “powder” of the United States navy is made from nitro-cellulose dissolved in ether alcohol. France was the first in employing explosives such as these, which, in their offensive and tactical advantages, form one of the signal triumphs of the century’s last years.
The long gun of modern days is of necessity breech-loading. The development of other elements gave, as a resultant, great length; and this, in turn, required a system of charging which would permit protection for the men while loading, and would obviate the intolerable inconvenience of ramming home powder and shot in a long muzzle-loader—an operation which was, in fact, impossible beyond a certain limit of length. The advocates of the older construction, especially in England, urged long and earnestly its simplicity and the superior strength of a solid breech; but the logic of events was against them, and the breech-loader won a complete triumph. It is worthy of note that it, like rifling and the principle of building up, was but a revival. From the warship Mary Rose, sunk in 1545 in action off Spithead, there were recovered in 1836 a number of guns, some of which are of wrought iron, built-up and breech-loading. There are in use two methods of closing the breech when the gun is loaded from the rear. In French, English, and American ordnance an axial screw-plug is inserted; in the Krupp system a cylindro-prismatic breech-block slides in a horizontal opening cut across the bore. The former, or interrupted screw mechanism, was first set forth in the United States’ patent of 1849 to Chambers.