For the new navy of the United States Congress has authorized the construction of twenty-five vessels, of which seven will be armored, sixteen unarmored, and two “such floating batteries, rams, or other naval structures for coast defence” as may be determined by the Navy Department. This list embraces five double-turreted Monitors, one armored battle-ship, one armored cruiser, eight partially protected cruisers, one dynamite-gun cruiser, four gun-boats, one despatch-vessel, and two torpedo-boats. Of the twenty vessels already built or ordered but three are in commission. They vary so much in type that the following conventional data may perhaps be of some use (see table on the following page), though it must be remembered that the performances stated are theoretical, except in the cases of theAtlanta,Boston, andDolphin.
The defects found in theAtlantawhen first tested were so easily remedied that the machinery finally developed a maximum horse-power which was only a little less than that required by the contract; while theBostonreached a maximum of 4248.5 horse-power. In his last report to the President the Secretary of the Navy said:
“TheDolphinand theAtlantahaving both been completed, and having had trial trips, it is possible to compare them in their results with similar vessels built contemporaneously elsewhere. TheDolphin, of 1500 tons displacement, can be compared with theAlacrityandSurprise, English despatch-vessels of 1400 tons each, and theMilan, a French despatch-vessel of 1550 tons, all built contemporaneously. TheDolphinwas designed for 2300 indicated horse-power, theAlacrityandSurpriseeach 3000, and theMilan3900. The highest mean horse-power developed upon trial was, in the case of theDolphin, less than 2200; of theAlacrity, 3173; of theSurprise, 3079; of theMilan, 4132. The highest speed of theDolphin, resulting from several trials, was 15.11 knots, running light; of theAlacrity, 17.95 knots; of theSurprise, 17.8 knots; of theMilan, 18.4 knots.
“TheAtlanta, the sister ship to theBoston, can be compared with theEsmeralda, theGiovanni Bausan, and theMersey. All three were built in England: theEsmeraldafor Chili, theGiovanni Bausanfor Italy, and theMerseyfor the English government. TheAtlantais of 3000 tons displacement; theEsmeralda, 2920; theGiovanni Bausan, 3086; and theMersey, 3550. TheAtlantawas designed to attain an indicated horse-power of 3500, theEsmeraldaand theGiovanni Bausaneach 5500, and theMersey6000. The trials had of theAtlantaindicate that her engines will develop less than 3500 horse-power, while theEsmeraldadeveloped 6000, theGiovanni Bausan6680, and theMersey6626. The maximum speed of theAtlantawill be less than 15 knots, while that of theEsmeraldawas 18.28 knots, theGiovanni Bausan17.5 knots, theMersey17.5 knots.”
Thanks to the force of public opinion, liberal appropriations have been made for the navy. Leaving out of consideration the double-turreted Monitors, the additions to the fleet have been the cruisersCharlestonandBaltimore, the No. 1 and 2 gun-boats, the cruiserNewark, the two armored vessels, the torpedo-boat, the dynamite cruiser, the No. 4 and 5 cruisers, the No. 3 and 4 gun-boats of No. 1 type, and the floating batteries. TheStiletto, if accepted, will be bought from the Herreshoff Company; all the rest, except the battle-ship, are to be or have been constructed by contract in private yards. Of the new ones theCharlestonand No. 5 cruiser will be built at San Francisco; gun-boat No. 2 at Baltimore; the dynamite cruiser, gun-boat No. 1, theBaltimore,Newark, and cruiser No. 4, at Philadelphia, and gun-boats Nos. 3 and 4 at New York.
The steel partially protected cruiserCharlestonis, except in details of internal accommodations, a duplicate of theNaniwa-Kan, which was in turn a progressive development of the type-makingEsmeralda, inasmuch as she has greater speed, more powerful armament, and superior protection to stability. The plans of theCharlestonwere bought abroad simply because they could not be made here; and notwithstanding the twopenny-ha’penny criticisms this action evoked, its wisdom has been justified. TheCharlestonhas neither poop nor forecastle, and the unhampered ends give in action perfect freedom of fire for two 10-inch guns, which are mounted in low, thin-plated barbettes, situated on the ship’s middle line, at a distance of sixty feet from the bow and stern respectively. These pieces are without armor protection, except that offered against machine-gun fire by a two-inch segmental shield. Between these heavy guns a high waist stretches amidships, in which six 6-inch breech-loaders are mounted on sponsons or in projecting turrets. The secondary battery includes two 6-pounder rapid-fire guns, eight machineguns, and four above-water torpedo-tubes. The 10-inch guns must always be brought back to the fore-and-aft line for reloading, and their ammunition is passed through steel tubes which extend below the protective deck. The engines are double-compound, situated in separate compartments, and in theNaniwa-Kanthe type developed 7650 horse-power and 18.9 knots.
In the twin-screw cruiserBaltimorea longitudinal water-tight bulkhead joins the double bottom, which runs under the engine and boilers to a protective deck that extends the whole length of the ship, and is three inches thick on the flat top and four inches thick on the sloping sides. The machinery consists of a pair of triple-expansion compound engines which are to develop 18 knots and 7500 horse-power with natural, and 19½ knots and 10,750 horse-power with forced, draft. There are two separate engine-rooms and two boiler-rooms, and the normal coal capacity of 600 tons will be sufficient for 1800 knots. Additional space is provided for 300 tons more, and with this total there ought to be an endurance of 8000 miles at 11 knots, and of 14,000 miles, or 75 days’ steaming, at 8 knots. No sails except storm-sails will be provided. TheBaltimoreis to have a poop and forecastle, on which four 8-inch guns with direct fore-and-aft fire will be mounted. On the main deck six 6-inch guns will be carried in broadside, and the secondary battery and torpedo-tubes are effective and well disposed.
The maximum price fixed at first by Congress for theNewarkwas less than any of the bids received, but at the last session the appropriation was increased to $1,300,000, and the contract was awarded in August of this year. TheNewarkis a bark-rigged, twin-screw cruiser of 4083 tons displacement. A double bottom extends through 129 feet of her length, and a protective deck, which rises fifteen inches above the water-line amidships, runs uninterruptedly fore and aft. Four feet above this the berth-deck is built, the intermediate space being greatly subdivided and utilized for stores. Numerous water-tight frames are worked in the double bottom, and wherever practicable the cellular construction is employed. The engines are to develop 6000 horse-power with natural draft, and 8500 horse-power and a maximum speed of eighteen knots with forced draft. This vessel has a poop and forecastle, and the guns are carried on the upper deck. The main battery consists of twelve 6-inch centre-pivot guns, furnished with segmental shields, and mounted on sponsons so as to obtain the greatest arc of fire; the two guns nearest the bow and stern converge their fire at a point 400 feet distant from the ends of the ship, and those in broadside can be concentratedwithin 100 feet of the ship. In addition to the secondary battery given in the table, there are six above-water torpedo-tubes.
The development of naval construction cannot be proved more conclusively than by comparing the new cruisers with those which were first laid down. In theAtlanta, for example, the builder guaranteed that 664 tons of machinery would produce 3500 indicated horse-power; but theCharlestonmust, before acceptance, develop 7000 horse-power for 710 tons of machinery; that is to say, the energy for weight has been doubled within four years.
The twin-screw gun-boat No. 1 is the prototype of a class that now include three vessels, and a very promising nucleus it is for a fleet to which the defence of the country’s coast must mainly be intrusted. The ship is to be built of steel, with a three and a half inch complete water-tight deck, so arched as to have a spring of about three feet in its greatest width, and a crown that will nearly reach the water-line level. There is no double bottom, but the number of water-tight compartments is very great, and coffer-dams surround the engine and fire-room hatches, and are carried to a height of eighteen inches above the main deck. The complement numbers 150, and the rig is that of a three-masted schooner, with a sail area of 4400 square feet. The machinery is estimated to indicate 2200 horse-power with natural draft, and 3300 with forced draft, and consists of two independent compound engines placed in separate compartments. The speed is given as sixteen knots, but it is probable this rate will be considerably exceeded. The main battery consists of six 6-inch guns, the secondary of two 57-millimetre rapid-fire guns, two 37-millimetre revolving cannons, and one short Gatling. Four of the 6-inch guns are mounted on the poop and forecastle—two forward, two aft—and the other pieces of this calibre are carried on sponsons amidships, so as to have a large arc of fire about the beam. The elevated guns are eighteen feet above the low-water line, the centre ones ten feet, and all are mounted on central pivots and fitted with protective shields. The torpedo armament is of great relative importance; of the eight tubes supplied, the stem and stern ones are fixed and fitted with under-water discharge, while the other six can be trained, and are distributed four forward and two aft. In gun-boat No. 2 the machinery is to develop 900 horse-power with natural, and 1350 with forced, draft; the engines, boilers, and magazines are placed beneath a steel deck three-eighths of an inch thick, which amidships is twenty-seven inches below the water-line at the edge and eight inches above at the crown. The armament consists of four 6-inch sponson-mounted guns, two 47-millimetreguns, two 37-millimetre revolving cannons, and one short Gatling. She is barkentine rigged, with a plain sail area of 4480 square feet, and has a slightly ram-shaped, cast-steel stem. The complement is 100.
The pneumatic-gun cruiser is to be armed with three of Zalinski’s pneumatic dynamite guns of 10½-inch calibre, each of which is to throw a shell containing 200 pounds of high explosives for a distance of one mile, and to be capable of being discharged at least once in two minutes. The guaranteed speed is twenty knots.
Under the law of August 3, 1881, authorizing the construction of two new ships, it was provided that these should be “sea-going, double-bottomed, armored vessels of about 6000 tons displacement, designed for a speed of at least sixteen knots an hour, with engines having all necessary appliances for working under forced draft, to have a complete torpedo outfit, and be armed in the most effective manner.” According to the circular issued by the Navy Department, one of these was to be an armored cruiser, with a maximum draught of twenty-two feet, and the other a battle-ship, with a draught of twenty-three feet; both were to be built of steel, with double bottoms, to have numerous water-tight compartments fitted with powerful pumping apparatus, and to be supplied throughout with perfect drainage and ventilation. A ram bow, twin screws, electric search-lights, torpedo outfit, and a protected steel-armored deck running the whole length of the ship and covering the boilers, engines, and magazines, were essentials; while high power and economy were so equally demanded that, to a maximum maintained speed of seventeen knots when fully equipped, great coal endurance and small fuel consumption were to be added. In each vessel a space sufficient for two hundred and seventy people, for provisions for three months, and for water for one month, was required. The cruiser was to have two-thirds sail-power on two or three masts, each supplied with a military top fitted to mount one or more machine guns. The armament of this ship was to include ten steel breech-loading rifles—four of 10-inch and six of 6-inch calibre—and a secondary battery of four 6-pounders, four 3-pounders, and two 1-pounders, rapid-fire, and four 47-millimetre and four 37-millimetre revolving cannons, all of the Hotchkiss pattern, together with four Gatling guns. There were to be fitted six torpedo-tubes—one bow, one stern, and two on each side, of which at least one on each side forward was to be under water. The heavy guns were to load in not less than two positions, and were to be protected by at least ten and a half inches of steel armor, properly backed; the 6-inch guns were to be fitted with shields, and all the guns were to be arranged so as to obtain the greatest horizontal andvertical fire consistent with other conditions. Any vertical armored protection at the water-line was to be at least eleven inches thick in the heaviest part, and thicker, if practicable.
The armament of the line-of-battle ship was to consist of two 12-inch and six 6-inch guns, and of a secondary battery which included four 6-inch, six 3-pounder, and two 1-pounder rapid-fire guns; of four 47-millimetre and four 37-millimetre revolving cannons, and of four Gatlings. The torpedo outfit was similar to that of the cruiser.
The plans submitted were opened on April 1st of this year, and notwithstanding the difficulties which the displacement imposed upon the other requirements, no less than thirteen designs were received from ten different competitors. The most important of these were offered by the Thames Iron Ship Building Company and the Barrow Ship Building Company, of Great Britain; by A. H. Grandjean, Esq., of France; and by Chief Constructor Wilson, Naval Constructor Pook, and Lieutenant Chambers, all of the United States navy. The designs were submitted to a board, and this finally recommended the Barrow plan as best suited for the armored battle-ship. So far as the armored cruiser was concerned, the Board reported as follows: “The marked differences in the essential features of the designs of armored cruisers of the Barrow Ship Building Company, Lieutenant W. I. Chambers, A. H. Grandjean, and the Thames Iron-Works and Ship Building Company, prevent their classification in the order of merit. Each exhibits features which strongly commend themselves, but the Board does not consider it advisable for the government to build a vessel upon any one of these plans.”
The battle-ship, though designed by one of the most distinguished marine architects in England, has not in its present form received the general approval of experts, for between it and the plan submitted by the Bureau of Construction there seem to be differences of merits which are strongly in favor of the latter. The dimensions of the new ships are as follows:
Barrow Ship.Length between perpendiculars, 290 feet; on load water-line, 300 feet; extreme breadth, 64 feet 1 inch; mean draught, 22 feet 6 inches; displacement, 6300 tons.Navy Department Ship.Length between perpendiculars, 300 feet; on load water-line, 310 feet; extreme breadth, 58 feet; mean draught, 22 feet; displacement, 6600 tons.
Barrow Ship.
Length between perpendiculars, 290 feet; on load water-line, 300 feet; extreme breadth, 64 feet 1 inch; mean draught, 22 feet 6 inches; displacement, 6300 tons.
Navy Department Ship.
Length between perpendiculars, 300 feet; on load water-line, 310 feet; extreme breadth, 58 feet; mean draught, 22 feet; displacement, 6600 tons.
The striking differences between these two ships are found in their relative stability and sea-going qualities. Mr. John, the designer of the Barrow ship, in a paper on “Atlantic Steamers,” read before the Institution of Naval Architects July 29, 1886, made the following statements:
“This question of stability will have to be carefully watched and studied within the next few years, because there is a tendency at present towards a rapid increase in the proportion of beam to length; and as the draught of water in these large ships is limited, we must be careful that in seeking higher speeds with increased beam we do not get too much stability, and so render the vessels heavy rollers and very uncomfortable as passenger-ships. It is possible the future may see vessels of greater beam than any yet afloat in the merchant service; but if so, it is almost inevitable that they will have to be made higher out of water in order to render them easy and comfortable at sea, but even that has its limits. Perhaps it is well to give an extreme case, and here I will make use of our old friendThe Great Eastern.... Now, for the purpose of trading it is quite clear thatThe Great Easterncannot be loaded much deeper than other ships, while her beam is half as great again; and the consequence is, her stability, as compared with our modern passenger-ships, is so excessive that she is bound to be a tremendous roller among the heavy seas in the Atlantic. Her metacentric height, when loaded, was, I believe, stated by the late Mr. Froude to be as much as 8.7 feet, which is from three to four times as much as is thought sufficient for ships in the present day, or consistent with their easy behavior at sea.”
Thus Mr. John himself regards 2.9 feet to 2.2 feet as the proper metacentric height for those steamers, and it is generally considered by modern designers that from 2.5 to 3.2 feet is most suitable for this class of armored ships, and is conducive to easiness of motion in a sea-way. The value of this quality to a ship intended for sea-fighting cannot be overestimated, for upon her steadiness as a gun-platform the aim and efficiency of her guns greatly depend.
It will be noticed that this ship has exceptionally great beam, that of most ships of her class and displacement, varying from 54 to 59 feet, and judging from the sketches which have appeared, her water-line coefficient is about 0.72. From an approximate calculation based on this assumption it is found that her metacentric height will be about six feet. The water-line coefficient may possibly be a little finer than 0.72, and thus reduce the metacentric height, but if this ship is assumed to have a metacentric height of three feet, her water-line coefficient would be 0.6288, which is animpossibility, if her coefficient of fineness of displacement be that given in the published dimensions. Such a water-line and coefficient of fineness for 6300 tons displacement would produce a perfect rectangle for a midship section. So that, unless her dimensions are changed, she will surely be a heavy roller, and aftermuch sea duty she will suffer such severe strains as to require frequent and costly repairs.
The battle-ship designed at the Navy Department has very different qualities, if the dimensions already published be correct. To possess a metacentric height of three feet she would require a water-line coefficient of 0.753, and a midship-section coefficient of 0.89 to 0.90, which is a good proportion for such a vessel. Not only in sea-going qualities does the American design seem to be superior, but her battery is far more powerful and better disposed in every way, while her speed and endurance are equally as great as the plan recommended. Mr. John has adopted theéchelonarrangement of heavy guns, a disposition which both the English and Italian governments have, after long trial, discarded in their latest ships. When the first sketches of a design are made, this arrangement of guns is theoretically perfect, as it is supposed to give quite as much power of fire ahead and astern as on each broadside; but when the design is developed and practically tested, it is found that too much of the ship’s efficiency in other respects is sacrificed, that the powerful end fire is not attained, and that the broadside is greatly weakened, owing to the obstructed arcs of fire.
Besides this, the guns, being placed at some distance from the midship line, have less accurate fire in rolling, and the ship’s propensities to roll are encouraged and are greater than would be the case if the guns were placed on the midship line. It is also found that the blast from the heavy guns is destructive to superstructures and other fittings on the upper deck. The Italians, indeed, have placed stout ventilating shafts on theirItaliaandLepantoto prevent the rearmost pair of heavy guns from being trained within twenty degrees of the fore and aft line. This is done so that the blast from these guns will not prostrate the gunners attending the other pair, notwithstanding the fact that those men are under the armor cover. TheDuilio’sforward smoke-pipe is placed entirely on the port side of the fore and aft line, in order to permit of one pair of turret guns firing ahead. The upper-deck, 6-inch, central-pivot guns of theAndrea Doriaclass are now to be placed wholly within the superstructure, in order to be out of danger from the blast of the heavy guns when the latter are fired near the line of keel, and the same change would have to be made with the upper-deck, 6-inch guns in the Barrow design.
Similar objections exist to the Bureau of Construction design for an armored cruiser. This vessel, although possessing the bad features inherent in theéchelonarrangement of heavy guns, does not have thebest ideas of the Barrow design,i.e., high freeboard, heavy guns mounted high above the water-line, and commodious quarters for officers and men. Both designs besides have the very objectionable and old-fashioned features of requiring the turrets to be revolved to fixed loading positions after being fired. The Bureau cruiser, it may be said, is not saddled with too much metacentric height. She has ten feet less beam, her centre of gravity is about one foot lower, and unless her water-line coefficient is very full, she will have a metacentric height rather less than what is regarded to be the best.
It is not surprising, however, that the Bureau plans are so different in efficiency, for while the better plan, the battle-ship, is original with the Navy Department, the armored cruiser is a copy of, and no substantial improvement over, that of the Brazilian shipRiachuelodesigned several years ago. This ship is considered one of the best of her date, but great improvements in ship design have been made within the past few years, and it is against the tendencies of American inventive genius to take a step backward.
The general plans of cruisers No. 4 and 5 were published in theNew York Heraldof June 1st, together with the following data:
“They are to be twin-screw cruisers, 310 feet long on the water-line, 49 feet 1¾ inches extreme breadth, 18 feet 9 inches mean draught, displacing 4083 tons. They are to have machinery of 10,500 indicated horse-power under forced draft. The maximum speed is 19 knots, rig that of a three-masted schooner, spreading 5400 square feet of sail. They will have a double bottom extending through 129 feet of the length. The framing in this portion is on the bracket system. Before and abaft the double bottom, above the protective deck, Z-bars form the transverse frames. The protective deck, which is nineteen inches above the water-line amidships, is flat across the top, with sides which slope down to a depth of four feet three inches below the water-line. The horizontal portion is two inches thick, the slope being three inches, reduced at both ends to one and a half inches. It extends uninterruptedly forward and aft, and protects the machinery, magazines, and steering-gear, the machinery being further defended by the disposition of the coal-bunkers. The main hatches in this deck are protected by armor-bars, and have coffer-dams extending to the upper deck. The guns are carried on the gun, forecastle, and poop decks.
“Armament.—The main battery, which consists of twelve 6-inch breech-loading rifles, all on centre-pivot mounts, with two-inch segmental steel shields, is arranged on sponsons so as to obtain the greatestpossible arc of fire. The forecastle, the poop, and the bridges have been as much as possible availed of to shelter the guns. The two guns forward and the two guns aft converge their fire a short distance from the ends of the ship, and the broadside can be concentrated within 100 feet of the side. Four above-water torpedo-tubes are provided on the berth-deck, and two direct ahead under-water torpedoes in the bow. The secondary battery is composed of four 47-millimetre revolvers, four 57-millimetre single-shots, two 37-millimetre revolvers, and one short Gatling. The coal capacity is 850 tons. The complement of men 300....
“To appreciate what is required to make nineteen knots an hour at sea, we have only to remember that theUmbriaandEtruriaare 500 feet long, with more than 12,000 tons displacement and 14,500 indicated horse-power, ordinarily making 18½ and on special occasions 19 knots an hour. Now, to increase her speed to 20 knots an hour, theUmbriawould require about 19,500 horse-power, which means 5000 extra horse-power for the extra knot. For a second extra knot would be required about 6000 horse-power more, making about 25,000 horse-power necessary to develop a speed of 21 knots.”
Gun-boats Nos. 3 and 4 are to be copies of gun-boat No. 1. No designs for the floating batteries and the torpedo-boat have been published. TheStilettois one of the famous Herreshoff boats, and is now being tested in consequence of a favorable report made by a board of officers. On July 23, 1886, with a total displacement of twenty-eight tons, she made an average of 22.12 knots as the mean of four runs over the measured mile in a rough sea and fresh wind, and on July 30th she attained an average of 22.89 knots. These were excellent results for a boat ninety feet in length, and promised that the type, with certain modifications, was equal to greater demands. The trial data of this year have not yet been published, though it is unofficially reported that her performance was equally as creditable.