SHIPS OF WAR, BUDGETS, AND PERSONNEL.
AUSTRIA. VESSELS BUILDING.
The Brazilian Government has placed orders for two battleships with Sir W. Armstrong, Whitworth & Co., who have sublet the building of one of them to Vickers, Sons & Maxim; also for two cruisers, to be built by Armstrong's and engined by Vickers. The battleships are to cost about £1,800,000 each, and the cruisers about £330,000 each. The main battery of the battleships is said to consist of four 13.5-inch guns.
Launched April 9, 1906
“ Aug. 31, 1905
“ Sept. 21, 1907
PROGRAMME FOR 1908.—The French naval programme for 1908 has been published. It is merely a continuation of the programme of 1906, and although the vessels in the list number III, only 98 will really be in hand next year. The expenditure upon new constructions will be 104,267,606 francs, of which 90,173,000 francs are for hulls, armor, and torpedoes, and 14,094,606 francs for gunnery armaments. The vessels included in the programme are battleships, armored cruisers, destroyers, and submarines, protected cruisers having disappeared. Of the 98 vessels on the list six battle ships belong to the programme of 1906, and four armored cruisers, the Ernest Renan, Jules Michelet, Edgard Quinet, and Waldeck-Rousseau, to that of 1900. In addition to these are 32 destroyers, of which seven at Rochefort and Toulon and 25 in private yards, and the list closes with 61 submarines or submersibles. In 1908 two armored cruisers, 12 destroyers, and 16 submarines are to be completed; 6 battleships, 2 armored cruisers, 10 destroyers, and 35 submarines to be continued, and To destroyers and 5 submarines to be put in hand. Four of the latter are of special types, designed by MM. Hutter, Radiguer, Bourdelle, and Maurice. They vary in displacement from 577 tons to 355 tons. Four of them are to have a maximum speed of 15 knots, and one of 15.8 knots. The larger vessels will have seven torpedo tubes, and all except the smallest will carry three officers and from 22 to 25 men.—Army and Navy Gazette.
PROGRAMME FOR 1909.—In view of the limited expenditure upon new vessels in the coming year, it was anticipated that the Minister of the Marine, by restricting his efforts to the six battleships of 18, 350 tons now tieing built under last year's programme, was preparing for a much bigger development in the early future. The necessity for clearing of far rears and carrying out reforms in the arsenals and shipyards appeared sufficient to justify the small number of units which is to be put on the stocks during 1908, but a still more important factor in determining the Minister to postpone the final preparation of his programme is the uncertainty that has existed concerning the armament that should be carried on future battleships. While submarines, submersibles, and torpedo boats will continue to form an important part of the French Navy, it is obvious that so far as heavy units are concerned the Conseil Superieur de la Marine intends to follow the lead of other nations by equipping the fleet with as many powerful battleships as possible. It is doubtful whether many, if any, armored cruisers will be included in the list of constructions for 1909, which seems likely to be almost entirely comprised of battleships of 20,000 10 21,000 tons. Fitted with turbine machinery, they are expected to have a speed of 20 knots. Before deciding upon the dimensions to be given to these new heavy units, the Conseil Superieur de la Marine is now holding frequent sittings with a view to discussing the armament that will be carried. It appears that the Conseil has five proposals under consideration. The first is to equip the future battleship with 12 guns of 305 mm. bore; the second, to increase the number of these guns to 14; the third, to employ 16 guns of274mm.bore; the fourth, to have 20 guns of 240 mm. bore; and the fifth to adopt a compromise with 8 guns of 305 mm. and 8 of 240 mm.bore. There is apparently a strong feeling in favor of the third of these proposals—that is to say, adopting a numerous armament of 274 mm. guns—because it is argued that this type of ordnance is capable of proving very effective at a distance of 7000 m., which is regarded as the extreme fighting range. It is claimed that at a distance of 7000 m. the gun of 274 mm. bore will pierce armor 330 mm. thick under an incidence of 20 degrees. The advantage of having 16 guns of the same caliber is that a greater quantity of shells can be carried than would be the case if there were 305 mm. guns on board, while the number would permit of a concentrated firing which might prove very deadly at the maximum fighting range. All this depends, however, upon whether tile future developments in the protection of battleships will not nullify the effect of shells from 274 mm. guns at the extreme fighting range. As it is expected that the Conseil Superieur de la Marine will very shortly come to a final decision upon this question of armament, it will be interesting to see whether it has more faith in the guns or in defensive armor.—Engineer.
The estimated dates of the entry into service of French ships now building for the Danton and Mirabeau, December, 1910, and for the other four of that class April, 1911. The Edgard Quinet and Waldeck-Rousseau are to be finished in 1910.
THE NEW BATTLESHIPS.—The Superior Council has fixed the following chief characteristics for the new battleships:
The main battery will be identical with that of the Danton class (four 12-inch and twelve 9.44-inch) and with the same arrangement, but a greater number, of rounds per gun will be carried. The secondary battery will consist of eighteen 10-cm. and eight 47-mm. guns, and there will be four torpedo tubes. The main hull and turret protection will be the same as for the Danton, but there will be To-cm. armor on the six casemates in which the 10-cm. guns are placed, and the smoke stacks, uptakes, and ventilators will be covered with 6-cm. armor as high as the upper deck. The torpedo protection of the Danton class will be suppressed, and Bullivant nets be relied upon instead. There will be the same coal supply as on the Danton, but the speed will be increased to 20 knots (instead of 19.25). These changes will increase the displacement to 21,000 tons (instead of 18,400) and make the price 60,000,000 francs.
THE EDGARD QUINET.—The armored cruiser Edgard Quinet was launched at Brest on September 21. She is 515 feet long, of 70 feet beam, and 14,000 tons (French) displacement. She will have 36,000 horsepower, giving at least 23 knots speed. Her armor consists of a 634-inch belt extending from 2.3 meters above to 1.4 meters below the water line, and of reduced thickness, but rising 5.2 meters above the water line forward. She has two armored decks, the upper from 9.8 inch to 1.3 inches thick and the lower from 2.6 inches to 1.8 inches thick, forming, with the belt, a caisson. Her guns are fourteen 7.7-inch,of which four are in two axial turrets, four in casemates and six in single turrets (the same arrangement as on the Democratic.); eighteen 65-mm. and eight 47-mm.guns. She will have six smokestacks and two masts, and will carry six 750-mm. searchlights. Her crew will consist of 750 men and 30 officers.—Le Yacht.
OIL FUEL FOR DESTROYERS.—One of the three new torpedo-boat destroyers of 450 tons and 28 knots speed has been ordered from the Forges et Chan- tiers de la Mediterranee at Havre, and another from the Chantier de St. Nazaireet Penho Et. They will carry six 9-pounder quick-firing guns, and three 18-inch torpedo tubes, and will be the first French destroyers to be fitted with oil fuel.—Engineer.
TRIALS OF FRENCH BATTLESHIPS DEMOCRATIE AND JUSTICE.—These two battleships, which have recently finished their official trials, are the third and fourth of the 1900 programme, being sisters of the Republique and Patrie, described in our August number, and of the Liberte and Verite, which are nearly completed. The ships have a load waterline length of 439 feet, an extreme beam of 79 feet 7 inches, and a draft.of 27 feet 5 inches. The displacement is 14,867 tons, with a block coefficient of 0.543. An armor belt, with a maximum width of 18 feet 5 inches, has an extreme thickness of 11 inches, tapering to 3 inches at the ends. There are two protective decks.
The battery, which is a powerful one, consists in the first two of the type of four 12-inch guns mounted in pairs in two turrets, and eighteen 6.4-inch rapid-fire guns, of which twelve are in pairs in turrets and six are in casemates. The secondary battery includes twenty-seven 3-pounder and 1-pounder guns, and five torpedo tubes, two of which are submerged. A considerable difference exists in the battery of the last four ships of the type, through the substitution of ten 7.6-inch guns and eight 3.9-inch guns for the eighteen 6.4-inch guns on the first two vessels. This change makes for increased strength of broad side, particularly at long ranges. The 7.6-inch guns are located, six each in a single turret and four in casemates.
Each of the ships is propelled by three screws operated by triple expansion four-cylinder engines in separate watertight compartments. The cylinder diameters are 35, 49, and 55 inches, with a stroke of 4 1/2 inches. Steam is supplied by 24 water tube boilers, located in three boiler rooms, each with its own funnel. The total grate surface is 128 square meters (1378 square feet), with a heating surface of about 46,000 square feet, making a ratio of 33.4 tor. The boiler pressure is 251 pounds per square inch. The normal coal supply of 900 tons gives an estimated steaming radius at To knots of 4200 nautical miles. With the full coal supply of 185o tons, the estimated radius is increased to 8500 miles.
It must be pointed out that for the first time since the days of the old sailing fleet France possesses a homogeneous squadron of six vessels of high power, it having until recently been the French naval policy to construct contemporaneous vessels on the divergent designs of various naval architects, resulting in the acquisition of a fleet which was described by one of the French admirals as a "museum."
The first two ships of this type were compared in our August number with the battleship Virginia, of the United States Navy. The last four ships have a more powerful battery than the first two, but even with this advantage they could scarcely be expected to compete successfully with the ships of the Virginia class under ordinary conditions.
The results of the trials of the Democratie and Justice are given in the table. The Democratic, is fitted with Belleville boilers, while the Justice has Niclausse generators. The poor propulsive efficiency at low speeds is more than offset by the magnificent results at 17 to 18 knots, while the figures for full speed are extremely good. It will be noted that, in passing from the intermediate to the highest speed, the index is in the expression H1:H2::V1n: V2 n is very high, indicating a limit in highest propulsive efficiency at about 18 knots. This index, which is often assumed as 3, becomes 4.58 for the Democratic and 5.98 for the Justice.
6-hour trial at low power.
Boilers at work.
Grate surface, square feet.
Consumption of coal in pounds.
Per square foot of grate.
Mean speed in knots.
Normal steaming radius.
24-hour trial at low power.
Boilers at work.
Grate surface, square feet.
Consumption of coal in pounds.
Per square foot of grate.
Normal steaming radius.
Full power 3-hour trial.
Boilers at work.
Consumption of coal in pounds.
Per square foot of grate.
Average speed in knots.
Normal steaming radius.
- Nautical Gazette.
NEW SUBMERSIBLES.—An order has been placed for 10 more submersibles of the Pluviose type; they will be designated, for the moment, as 99-0 to 99-9, and will be built, two at Cherbourg, three at Rochefort, and five at Toulon. This order is proof that this type, the first of which have but recently begun their trials, is regarded as a satisfactory one.
BUILDING PROGRAMME—The battleships which are to follow the four 19,000-ton ships now building will be the Ersatz Oldenburg and Ersatz Siegfried, to be begun in 1908, and the Ersatz Beowulf and Ersatz Frithjof, to be begun in 1909. The Ersatz Kaiserin-Augusta, Ersatz Hertha and Ersatz Victoria-Luise are to follow, being begun in 1910, 1911, and 1912, respectively.
Of the six armored cruisers voted in 1906,the four remaining are to be begun in 1909, 1910, 1911, and 1912, respectively. Cruisers E and F are the two first of the six.—Le Yacht.
ADDITIONS TO THE FLEET.—On October 1 the Pommern replaced the Kaiser Frederick William, the Hanover replaced the Brandenburg, and the Kaiser Barbaross are placed the Kaiser Frederick III in the fleet. The Pommern attained a maximum speed of 19.26 knots, with 20,348 horsepower, on her trials, a record ahead of that of any other German battleship, and nearly equal to that of the French Liberte; her coal consumption, however, is said to have been very much higher than that of the Liberte.
The Kaiser Barbarossa has undergone the work of reconstruction, which is to be applied to all the battleships of that class. This consists of removing portions of the superstructures as well as the four 6-inch guns of the lower casemates, leaving them armed with four 9.5-inch guns and fourteen 6-inch guns, and raising their armor belts somewhat.
ARMORED CRUISER F.—The new large German cruiser F, the contract for which has been placed with the Hamburg firm of Blohm & Voss, will cost over it,800,00o, and will be fitted with Parsons turbines, which are to be constructed by the same firm. The cruiser E, which was laid down in the navy yard at Kiel a year ago, will have a displacement of about 15,000 tons, but, as the cost already shows, the new cruiser is designed to be considerably larger. The gradual conversion of the German naval authorities to the turbine system of engines is further shown by the fact that the two small cruisers which are to be laid down by the Schichau and Vulcan cornpanies this year are also to be fitted with this type of engine. The small cruiser Stettin, the newest of her class afloat, which is also propelled by turbines, developed a speed of 25.8 knots on her trials a few days ago…It is believed that for the present tactical considerations forbid the adoption of the system for battleships, but according to various statements in the Press, it is not unlikely that before long efforts will be made to create a homogeneous squadron fitted with these engines.—Army and Navy Gazette.
Cruiser F, which is the first real continental reply to the British Inflexible class, has just been definitely ordered from Messrs. Blohm and Voss, of Hamburg, who have recently completed a splendid new machine shop fore the construction of marine turbines. This vessel is to be completed within two years from now. Her designed displacement is practically 20,000 tons, and her speed of 24 1/2 knots will require about 44,000 indicated horsepower, which will be provided by turbines of the Parsons type. Exceptional care is being taken to keep the details of construction confidential; the main dimensions, however, appear to be as follows: Length on water line, 560 feet; beam, 85 feet; draft, 27 feet.
Two small cruisers of 4300 tons have also been ordered from the Vulcan yard at Stettin and from Messrs. Schichau, at Danzig. The former will be fitted with a modified form of Curtis turbine supplied by the Allgemeine Elektrizitits Gesellschaft, and the latter with turbines of the type introduced by Melms and Pfenniger. The latter turbine is a modified Parsons, embracing many features of the Westinghouse combination system. The Krupp Germania works are also reported to have the order for a similar vessel which is to be fitted with Zoelly turbines. The speed in the case of these small cruisers is to be 25.5 knots.—Engineer.
The German Navy League does not appear to be so satisfied with its Admiralty as is the British one. It is just conducting a strong agitation in favor of ships of 22,000 tons and 12-inch guns instead of 11-inch. Recent report has had it that the Ersatz Sachsen class are to carry two 12-inch per turret, instead of the original three 11-inch. The Navy League agitation suggests that the matter is still undetermined—a thing that should be useful powder to those of our contemporaries which expend so much energy in proving that the new German battleships do not yet exist.— Engineer.
The Lokal Anzeiger says that the new naval programme will include a proposition to decrease the nominal lifetime of battleships from 25 to 20 years of active service; this project, if carried, will lead to the construction of five 19,000-ton battleships instead of only four.
TURBINE CRUISER DRESDEN.—The Ersatz Komet, now named Dresden, was launched at Hamburg on October 5. She is a sister ship to the Ersatz Pfeil, is of 3800 tons displacement; 118 meters by 13.5 meters by 4.8 meters draft; armed with ten 4-inch and eight 2-inch guns, and two torpedo tubes; and is designed for 13,700 horsepower, giving a speed of 24.5 knots.—Moniteur de la Flotte.
THE STETTIN.—The Stettin, sister ship to the Nurnberg and Stuttgart, but equipped with the Parsons turbine, attained a mean speed of 25.8 knots for six hours on 3200 tons displacement. From this it is judged that she will make at least 25 knots on her contract displacement of 3400 tons. —Moniteur de la Flotte.
PERSONNEL—Vice-Admiral Fischel, commanding the second squadron, has been made admiral; he is one of the best-known leaders in the German Navy, and is likely to soon be given command of the sea-going fleet.
Vice-Admiral Schmidt has been called to the general direction of the Navy Department; Vice-Admiral Breusing to the command of the arsenal of Wilhelmshaven; hitherto these places have been held by rear-admirals. An important change, which will perhaps have considerable results, is the relief of Vice-Admiral Eickstedt, by Rear-Admiral Rollman as director of the Department of Naval Construction. The former has filled this office for more than eight years, ever since the death of Chief Constructor Dietrich since which time there has been no chief constructor in the German Navy.
There are now 4 admirals, 10 vice-admirals, and 22 rear-admirals in the German Navy, of whom the senior, Admiral Tirpitz, entered the service in 1865.—Moniteur de la Flotte.
SMALL CRUISERS.—The Koenigsberg, which replaced the Medusa in the German fleet, on September 15, is the connecting link between the seven small cruisers of the Bremen class, of 3250 tons, and the three cruisers of the Nurnberg class (Stuttgart, Stettin, and Nurnberg), of 3450 tons: though she is much nearer the latter than the former class, having attained 24.1 knots speed on her trials. The distinction between these ships is, however, but slight, the Nurnbergs and Bremens having practically the same outline, the main battery of all being ten 4-inch guns, and the speed in each case the highest attainable at the date of laying down. Still, as we shall see, while keeping the same armament and practically the same profile, the eight types of small cruiser which have succeeded one another from 1897, when the Gazelle was begun at Kid, to the present time when the Ersatz Greif and Ersatz Jagd, of the 1907-1908 programme, are building, have almost doubled in displacement. The Gazelle was of 2645 tons, the Ersatz Greif will exceed 4000 tons. To some small extent this increase has profited the armament; since the Ersatz Pfeil and Ersatz Komet will have, besides the ten 4-inch guns of 50 calibers, eight 2-inch guns, instead of the ten 37-mm. guns of the preceding types, but the protection remains unchanged, consisting of a deck from 50 mm. to 20 mm. thick and a conning-tower from 76 to mo mm. thick. In the main the increased displacement has been used to increase speed and radius of action.
The speed of the Gazelle was 19.5 knots; that of the Frauenlob (1900) was 21.5 knots; of the Bremen (19o2), 23.2 knots; it exceeded 24 knots with the Koenigsberg (1904); and should be 24.5 knots with the Ersatz Pfeil (1906) and over 25 knots with the Ersatz Greif (1907). If now we examine the linear dimensions, we find that length and beam alone have increased. The draft of the Gazelle, which was 4.85 meters, is found unchanged on the latest types, though it is true that the Frauenlobs and Bremens were exceptions in drawing 5 meters.
The radius of action of the Gazelle is 4000 miles, with 560 tons of coal; 700 tons give 4500 miles to the Frauenlob; the Bremens carry 800 tons and can steam 5000 miles, and the Koenigsberg is the same; the Nurnbergs, with 850 tons, should have 5500 miles radius; and the latest types will probably do still better.
That the increase of displacement comes from increase of length and beam, the following figures show: The Gazelle is 100 meters long and of 11.8 meters beam; the Frauenlobs are too meters by 12.3 meters; the Bremens 104 meters by 13.2 meters; the Nurnbergs ][08 meters by 13.4 meters; and, finally, with the Ersatz Pfeil we come to 118 meters length, 13.5 meters beam, and 4.8 meters draft.
These small cruisers are not only excellent scouts, but well suited for foreign service—more powerful and seaworthy than the English scouts, they have no equivalent in any other navy.
GERMAN TORPEDO BOAT CONSTRUCTION.—The steady addition of torpedo craft of large size to the Imperial German Navy continues unchecked, and their value for war purposes is somewhat disguised by the official system of frequently describing them as torpedo boats, instead of classing them, as would be the case in England, as "destroyers." In general, their torpedo equipment is greater than that of British vessels of corresponding date, while their guns are fewer and less powerful; their hulls are of relatively heavier scantlings, and the vessels themselves have proved to be excellent sea boats, though slightly inferior in trial-trip speed to those of other nations.
No less than 22 boats of about 420 tons service displacement—G110 to G113, and S114 to S131—were constructed by Messrs. Krupp, at the Germania Works, and by Schichau, at Elbing, between 1902 and 1905. Differing only slightly in detail, they are all about 205 feet long by 23 feet beam, and have bunker capacity for 100 tons of coal; at 15 knots the service radius of action is about 1400 miles. Their trials were run at displacements varying from 380 to 415 tons, and speeds between 27 and 28 knots were obtained with about 6000 to 6500 indicated horsepower. S12.5 of the latter division, built by Schichau, was the first vessel in the German Navy fitted with Parsons' turbines. On her official trials she attained 26.7 knots at 440 tons, the increase in displacement being due to the greater amount of coal on board compared with her sister ships. The armament consists of three 4-pounder quick-firing guns, two machine guns, and three 450-mm. torpedo tubes. Comparing these with British practice, we find that during the same period 35 River class destroyers of 570 tons were added to the Royal Navy, each carrying one 12-pounder and five 6-pounder quick-firing guns, but only two tubes. Their average full speed was barely 26.0 knots, but on their greater dimensions-225 feet in length by 23 feet 6 inches beam—they carry 125 tons of coal, and their radius at 15 knots is nearly 1800 miles.
The next batch of German boats—G132-G136—was ordered in 1905, and consisted of 460-ton boats of 28 knots speed, carrying, as usual, three torpedo tubes, as well as four 5-pounder quick-firing guns and two machine guns. All these vessels were launched in 1906, and are now either in service or being completed at the Germania Works. They are almost identical with the previous destroyers, and, being built by only two firms, present fewer divergencies of appearance than is the case with the various British boats—Laird's and Palmer's, for example.
Since the commencement of 1907 several 30-knot boats, ordered in 1906, have been launched or have run their trials. G137 really belongs to this class, though she was ordered in December, 1905; the others consist of the Schichau division, 5138-5149. These vessels all carry one 15-pounder, three 5-pounders, two machine guns, and three torpedo tubes. The designed displacement was 570 tons in the case of G137, and 530 for the other boats; the indicated horsepower was to be 10,000. Four Schulz boilers are fitted, as against three in the earlier boats, the pressure being 230 pounds per square inch. In point of size they closely approach the dimensions of the River class, but are about 10 feet longer and r foot wider. About eight of the S class have run their trials, and, at a reduced displacement, have only attained 29.6 knots, though the horsepowers ran up to nearly 11,000. Considerable difficulty was involved in reaching even this speed, and numerous propellers were tried without success. The remainder of this batch is now approaching completion.
The latest destroyer division to be built for the German Navy was ordered early this year from the Vulkan Company, which was entrusted with torpedo-boat work for the first time, and consists of twelve 580-ton boats V150 to V161. Like G137 they are 235 feet long by 24.10 beam, and carry the same armament. As in most of the German destroyers, the engines are placed in two compartments, one abaft the other, and the coal bunkers, of 115 tons capacity, are extended at the sides of the engine-room for purposes of protection. The designed speed is 30 knots, and in view of the performance of G137, it will be interesting to see how these vessels compare with her. At present they are approaching the launching stage.
G137 is fitted with marine turbines of the Parsons type, and on her recent official trials on the German Admiralty mile at Neukrug, attained a maximum speed of nearly 34 knots, and a mean speed for four hours of 33.1 knots, the vessel being run at full load. This performance makes her, for the time being, the fastest vessel afloat, and, following on the failure of the sister ships of the S138 class to attain their designed speed, has created considerable interest in German naval circles where the turbine has hitherto been greatly disparaged. The main turbines consist of one high-pressure and two low-pressure cylinders of the usual type, arranged on three shafts, and revolve at about 850 revolutions per minute. Running astern, a speed of over 16 knots was obtained. The coal consumption averaged about 12 tons per hour at full speed.
No vessels corresponding to the large British destroyers of the Cossack type are as yet under construction, though it is possible that they may figure in the next naval estimates. For such speeds and displacements- 33 knots and 780 tons—it is probable that oil fuel will be found essential, and this has not yet been applied to German torpedo craft.—Engineer.
The Ministry of Marine have given orders that a third destroyer, one of the group V150-V161, under construction at the Vulcan yard, Stettin, is to be fitted with turbine engines on the Curtis system. The first boat to be fitted with turbines was S125, one of a group built in 5904, by the Schichau firm at Elbing, which had a displacement of 470 tons, and a speed of 28.5 knots, her turbines were on the Parsons system. The second, also fitted with Parsons turbines, is G137, built at the Germania yard, Kiel; she has a displacement of 570 tons, and at her recent official trials attained a speed of over 32 knots, or more than two knots over the contract speed. She will probably form the model for a division of similar vessels—United Service Institution.
Launched July 27, 1907.
“ Aug. 24, 1907.
“ Nov. 7, 1907.
Launched June 6, 1906.
“ Sept. 20, 1906.
“ Apr. 27, 1907.
“ Apr. 13, 1907.
“ June 26, 1907.
“ Mar. 16, 1907.
NEW BATTLESHIPS.—The battleships of the improved Dreadnought type about to be laid down at Portsmouth and Devonport dockyards, and a third by private contract, are officially to be known as the St. Vincent class. The particulars sent out by the Admiralty state that their length between perpendiculars will be 500 feet, the beam 84 feet, and the displacement 19,250 tons. It is added that the primary armament will be 12-inch guns, but the number is not stated. Compared with the Bellerophon, Temeraire, and Superb, the new ships will be to feet longer and of 650 tons more displacement.—United Service Gazette.
The new battleship of the 1907-8 programme, being built at Portsmouth, will be named St. Vincent; the one at Devonport, the Collingwood. The third battleship to be built by contract will, it is rumored, be called Rodney—at any rate, one of the class will.
The battleships that may follow are provisionally intended to be of the same class, and the names Benbow, Camperdown, Anson, and Howe are gradually to be used up for them.—Engineer.
The report that the St. Vincents were to have 13.5-inch guns seems to be without warrant, and it is almost certain that they are to be armed with ten 12-inch guns in five turrets, all probably on the middle line. It is now said that the 13.5-inch guns are really intended for the two Brazilian battleships building in England.
The Superb, launched at Elswick, on Nov. 7, was laid down on February 6 last, and will be completed for service by the spring of 1009.
The Superb—like the Bellerophon and the Temeraire—is a little larger than the Dreadnought. Her dimensions are: Length, 493 feet; beam, 82 feet; draft, 27 feet; displacement, 18,600 tons. She is thus of the same length and beam as the Dreadnought (and will have the same speed, 21 knots), but has 700 tons more displacement and 6 inches greater draft.
The armament will consist of ten 12-inch guns, together with a number of 4-inch quick-firers for use in resisting attacks by torpedo craft. The main armor belt has a maximum thickness of 11 inches, tapering to 6 inches at the forward and 4 inches at the after extremity of the vessel. Special attention has been given to safeguarding the ship from destruction by under-water explosion.—Page's Weekly.
H. M. S. GHURKA.—The torpedo-boat destroyer Ghurka has recently been completed by Messrs. Hawthorn, Leslie & Co., Limited, of Hebburn-on-Tyne, and will shortly undergo her official trials. The Ghurka is 255 feet in length by 25 feet 6 inches in width, and 16 feet 6 inches in depth amidships. She is fitted with turbine engines, built under Messrs. Parsons' patent, arranged on three shafts and developing between 14,000 and 15,000 horsepower in the aggregate. There is one high-pressure turbine on the center shaft exhausting into two low-pressure turbines on the wing shafts, the astern turbines being incorporated with the latter. Ahead of the low-pressure turbines on the wing shafts is a high-pressure and low-pressure cruising turbine, each turbine driving a shaft with one propeller. Steam is supplied by five water-tube boilers of the latest Yarrow type, working at a pressure of 220 pounds per square inch, and fired with oil fuel. The only coal carried on the vessel is that for heating and cooking purposes. The whole of the machinery, which is arranged for forced lubrication, is interchangeable with the sister vessels, the contracts for the construction of which we replaced by the Admiralty with Thornycroft & Co.; White & Co.; Cammell, Laird & Co., and Armstrong, Whitworth & Co. The Ghurka is armed with three 12-pounder quick-firing guns, two being placed on the forecastle and one aft, whilst she will also have two deck torpedo tubes.
In preliminary trials the vessel attained the speed of over 33 knots, and after certain minor modifications are carried out it is believed that this speed will be substantially increased.
The Laird-built destroyer Cossack is completing her official trials on the clyde. On her full speed trial she averaged 33.141 knots, and, like all of her class, was displacing considerably more than was originally intended.— Engineer.
SEA-GOING TORPEDO-BOATS.—The Eden is one of 34 sister vessels launched for the British government between 1903 and 1905. As a class, they are from 220 to 225 feet in length, 23 1/2 feet beam, and draw 10 feet of water. There are slight variations among the 34 vessels as to dimensions and general particulars, the Eden being 220 feet long, 23 feet beam, and 8 ¾ feet draft. She is driven by Parsons turbines, operating six propellers, and with 7000 horsepower her mean speed is 25 1/2 knots an hour. She carries one 12-pounder gun forward and five 6-pounders aft and in broadside. She has two torpedo tubes, a coal capacity of 130 tons, and a complement of 70 officers and men.
Now in the Eden class of boats, the high speed of the preceding class of seventy 30-knot boats, built between 1896 and 1902 for the British Navy, has been sacrificed in favor of seaworthiness, comfort, and coal capacity. The 30-knot boats were about 10 feet shorter, of from 2 to 3 feet less beam, and about 4 feet less draft, and their displacement was 300 tons as compared with the 550 tons displacement of the Eden class. The Eden carries a high forecastle deck, which extends aft to the conning-tower, and it is upon this deck that the 12-pounder gun is mounted. She has a rather lofty bridge, a single signal mast, and two low funnels of large diameter. The other vessels of the class are generally similar in design, the main difference being that 15 of the boats are provided with four funnels instead of two.
In the later ships, authorized from 1905 to 1906, the tendency to increase the displacement is even more marked, but at the same time there is a return to the high speed of the boats of the 1896 to 5902 period. Under this programme there are now being built five ocean-going turbine-driven torpedo-boats of 600 tons displacement and 33 knots speed, and one turbine-driven ocean-going torpedo-boat of 800 tons displacement, 30,000 horsepower, and 36 knots speed.—Scientific American.
The Agamemnon has finished her steam trials. She made 18.75 knots at full power, with 17,285 horsepower and 130 revolutions; the coal consumption being 2.11 pounds per horsepower per hour.
The cruiser Blenheim, which was launched 15 years ago, has been transformed into a sea-going depot ship for torpedo craft. Equipped originally with two 9.2 and ten 6-inch breech-loading guns, her armament is now reduced to four 6-inch guns, and her auxiliary armament of 16 quick-firing guns has been reduced to 10 small quick-firing guns. Extensive alterations have been made in the Blenheim to enable her to carry, in addition to her own complement of 670 tons of coal, 9400 cwt. of coal in i cwt. sacks for the use of destroyers. She will serve with the active service flotillas in the North Sea.—United Service Gazette.
H. M. S. Dreadnought, which is having new steering gear fitted at Portsmouth, is shortly to be placed in dock to have her propeller blades changed. —Page's Weekly.
It is reported that the Dreadnought's new propellor blades are 12 inches longer and 7 inches wider than her old ones.
MECHANICAL STOKING.-A series of interesting experiments is being carried out on board the gunboat Sharpshooter at Devonport, with the object of proving the possibility of the application of mechanical stoking to marine boilers. On land it has been demonstrated that the employment of a revolving grate with automatic feed, supplies all that is needed in the systematic and careful stoking of water-tube boilers. Want of space in the smaller vessels such as torpedo-boats, however, has precluded the adoption of this appliance on ships. The device, which is now under trial, comprises a set of hoppers with mechanism for regulating the supply and depth of fuel, and a small engine geared to an eccentric and piston which keeps the fire bars in continual motion. The movement of the bars is from front to rear and return, the travel being about 18 inches each way.— United Service Gazette.
A YEAR'S CASUALTIES TO WARSHIPS.—A return of casualties to ships on the Navy List during the year ended December 31, 1906, has been issued as a parliamentary paper. The casualties include all cases of collision or grounding, and casualties to machinery, and the return shows the date, the name, and class of the ship damaged, the nature of the accident, time under repair, and the result of any inquiry that may have been held into the circumstances, specifying if a court-martial was held. The number of casualties, including those which happened to destroyers, submarines, special service vessels, and other small craft was 74, and the casualties to machinery nine. Of the above casualties 14 happened to battleships, 15 to cruisers, 23 to destroyers, 14 to torpedo-boats, and the remainder to other classes of vessels.
The mishaps to the battleships include such as the flooding of an engine- room owing to a valve being left open, which happened in the Cornwallis, several collisions, the mishap to the Dreadnought, which struck the sill when being put into dock, and the loss of the Montagu. Only in the last-named case was there a court-martial. In several of the cases no blame was attributable to the officers, and in others those responsible and held to blame were punished. In respect of the cruisers the nature of the casualty varies very widely, and only one court-martial was held, in the case of the Donegal, while in the majority of cases it was reported after inquiry that no blame was attributable to the officers in charge of the ship.
Only one other court-martial was held, in the case of the loss of a torpedo-boat, while in tow of the Arrogant. Very many of the mishaps were of a trivial character, and even such an accident as the capsizing of the pinnace of the Hindustan is included in the list. The longest time during which a vessel was under repair occurred in the case of the destroyer Thrasher, which, after grounding at Bantry, was 21 1/2 weeks in the dockyard hands, during which time she was given a general refit. None of the casualties to machinery were of a serious nature.—United Service Gazette.
HEALTH OF THE NAVY FOR 1905.—The returns for the total force for the year 1905 may be considered as very satisfactory. As compared with the averages of the last eight years, there are decreases in the ratios of cases, invalidings and deaths, and this year's case and death ratios are the lowest recorded since 1856.
There have been considerable changes in several of the stations, hence comparisons with the returns of former years from these stations would be misleading.
A comparison with the average for the last eight years is instituted when possible.
The ratio of cases per 1000 of force shows a reduction of 119.29 as compared with the last eight years' ratio.
The invaliding ratio, viz., 23.89 per 1000, shows a decrease of 4.98 in comparison with the average for the last eight years.
As regards the death rate, the ratio per 1000 was 3.9,showing a decrease of 1.42 when compared with the last eight years' ratio.
The Mediterranean station shows the highest invaliding ratio, the East Indies the highest death rate.
No cases of yellow fever or plague, and only two cases of small-pox are returned.
Venereal diseases show a small decline as compared with the last eight years' ratio.
One man was invalided out of the Service for wounds in action sustained in 1904.
The total force, corrected for time, in the year 1905, was 111,020, and the total number of cases of disease and injury entered on the sick list was 81,568, which is in the ratio of 734.71 uper 1000, being a decrease of 119.29 per 1000 as compared with the average ratio of the last eight years.
The average number of men sick daily was 3,365.53, giving a ratio of 30.31 per 1000, and showing a decrease of 5.44 in comparison with the last eight years average. The total days' sickness on board ship and in hospital was 1,228,419, which represents an average loss of service from disease and injury of 11.06 days for each person, which is a decrease of 1.99 in comparison with the average of the last eight years.
The total number of persons invalided was 2653, which is in the ratio of 23.89 per 1000, and shows a decrease of 4.98 in comparison with the average of the last eight years. Of the above total 1719 persons were finally invalided from the Service (121 of these refused surgical operation), giving a ratio of 15.48 per 1000 for the whole force, or 64.79 per cent of the number invalided, thus showing a decrease of .4 per 1000 when contrasted with 1904.
Including the marines invalided at headquarters, the total number invalided out of the Service was 1941. It should be noted that the invalids from marine headquarters appear for the first time in this table.
Deaths number 433, a ratio of 3.9 per 1000—showing a decrease of 1.42 per 1000 as compared with the ratio for last eight years.
The average number of entries on the sick list for disease and injury per man was: On the Home station, .68; Channel, .65; Atlantic, .78; Mediterranean, .71; North America and West Indies with particular service squadron, .89; China, .85; East Indies, .83; Australia, .7; Cape of Good Hope, .93, and the Irregular Force, .92. In the total force the average per man was .73, a decrease of .02 in comparison with 1904.
The total number of persons invalided was 2653, of whom 2445 were invalided for disease and 208 for injury. The ratio of invaliding for disease alone was 22.02, and for injury 1.87, per 1000.
The total number 9f deaths was 443, of which 305 were from disease and 128 from injuries. The death rate due to disease alone was 2.74 and that due to injuries was 1.15 per 1000.—United Service Institution.
Gov’t Yard, Spezia.
Launched Apr. 21, 1907
“ “ Naples.
“ Sept. 10, 1905
“ “ Castellamare.
“ Oct. 1, 1904
Gov’t Yard, Castellamare.
“ “ “
Launched, Sept. 15, 1907
THE SAN GIORGIO CLASS.—The Pisa was launched at Leghorn, on September 15. She is a sister ship to the San Giorgio, San. Marco, Amalfi, and a fifth ship (B) also building at Leghorn. These ships are of 10,200 tons displacement, and carry four to-inch and eight 7.5-inch guns, in double turrets, together with sixteen 3-inch guns and three torpedo tubes (450 m.), two broadside and one stern. Special chrome steel was largely
used in the hull construction of the Pisa. She is to have a speed of 23 knots, and is to carry 1600 tons of coal, giving a radius of action of 10,000 knots. She has a complete armor belt, of Krupp armor, 8 inches thick at the center and tapering to 4 inches at bow and stern.
The Moniteur de la Flotte states that the Italian Government has purchased the Pisa and Amalfi.
According to Le Yacht, the Superior Council has approved the expenditure of 200 million francs for four battleships of great displacement.
Launched Nov., 15, 1906
“ Apr. 15, 1907
Launched Nov. 21, 1907
“ Oct. 21, 1907
THE KURAMA.—On October21 the Kurama was launched at Yokosuka. She and the lbuki are like their predecessors, the Tsukuba and Ikoma, except that they are said to be slightly larger. The London Times gives the displacement of the Kurama at 14,800 tons and her battery as four 12-inch, eight 8-inch, and twelve 6-inch guns, besides a number of small R.F. guns. Her anticipated speed is 22 knots.
AN 1100-TON DESTROYER.—Japan is building the biggest and fastest torpedo-boat destroyer in the world. The craft will have a tonnage of 1100 and a speed of 35 knots. The armament will be one 5-inch and eight 4- inch guns, and she will have four torpedo tubes. It is intended that she shall be able to accompany battleships in any weather.—Nautical Gazette.
Le Yacht states that the 1100-ton destroyer above referred to has been laid down at Maitzuru, but gives her battery as one 4-inch and several 3-inch guns, with four torpedo tubes.
The Iwami, ex Orel, which is being reconstructed in Japan, has had her secondary armament altered—six 8-inch being substituted for the twelve 6-inch that she formerly carried. The reason of the change is that the Japanese—like some others—have found these double turrets quite unsatisfactory. The rate of fire of a pair of 6-inch is very little more than for a single 6-inch gun. Several of the turrets being badly damaged had to be replaced. Advantage was taken of this to make a clean sweep of the old secondary armament.—Engineer.
The personnel of the Japanese Navy has just been returned at 40,044.
WARSHIP BUILDING IN JAPAN.—During the past decade or SO Japan has made great progress in the building of warships. The naval shipbuilding yards at Yokosuka and Kure are now able to construct battleships and armored cruisers of the latest type, such as the Satsuma, Aki, Tsukuba, Ikoma, Kurama, and Ibuki, with tonnage between 13,000 and 20,000 tons. Of these, the third—namely, the Tsukubo—is the finest ship ever built in Japan, being furnished with excellent machinery and everything necessary for the highest efficiency. She is at present on a voyage round the world, and she has been very successful in every respect. The plans of two new sister-ships, each of 20,000 tons, are said to have been completed, and it is expected that before long their keels will be laid at Yokosuka and Kure. An ample supply of good steel can now be obtained in Japan, and only a few of the materials which cannot yet be made in Japan have to be ordered from abroad. Since 1875, when the gunboat Seiki was launched at Yokosuka, the number of warships built in Japan totals 38 (destroyers and torpedo craft excluded), their tonnage aggregating 184,588 tons.—Engineering
Le Yacht gives the following particulars regarding Japanese ships: “The Aki has a battery of four 12-inch, twelve 10-inch, and twelve 4.7- inch guns, on a displacement of 19,250 tons. The four battleships proposed to be begun next year are to be of 21,000 tons and to carry twelve 12-inch and ten 6-inch guns each. The speed of all these ships is to be 20 knots."
Emperor Paul I.
Launched Sept., 1907
“ Oct. 20, 1905
“ Oct., 1906
“ May 13, 1906
Launched Aug. 15, 1907
“ Nov. 10, 1906
THE EMPEROR PAUL I.—The launch has just taken place at St. Petersburg of the Russian ironclad Imperator Pavel-Perroy. The vessel has a displacement of 16,900 tons, and she is 460 feet long by 81 feet 4 inches beam. Her engines work up to 17,600 horsepower; they drive two screws, and are expected to give her a speed of 18 knots per hour. She will carry 3000 tons of coal, which will enable her to steam 6000 miles at 12 knots. She will carry 62 guns and 8 Maxim mitrailleuses; she will also be fitted with six lance torpedo tubes. The Imperator Pavel-Perrvy resembles the Czarevitch, built in France by the Forges et Chantier de la Mediterranee, but she is a larger ship.—Engineering.
NEW SHIPS.—The two battleships to be begun this year will be given to the new Admiralty Works and the Baltic Works, respectively. They will be of 19,900 tons, carry ten 12-inch guns, and have 21 knots speed with turbine machinery. Their armor and armament will be made in Russia.
Two 4500-ton cruisers, of the Variag type, but with a light armor belt, have been ordered from the Newski Works; they are to be finished in three years.
% of Completion
Nov. 1, 1907
Wm. Cramp & Sons.
Wm. Cramp & Sons.
New York Shipbl’g Co.
Wm. Cramp & Sons.
New York Shipbl’g Co.
Bath Iron Works.
Fore River Shipb’g Co.
Fore River Shipb’g Co.
THE PROGRESS OF THE SUBMARINE BOAT.(A review of the results of the tests recently carried out by the United States Navy Department).—The recent announcement that an order had been placed by the United States Navy Department for seven submarine boats of the Octopus type recalls the elaborate and searching tests made in the early summer of the present year to determine the best available type of submarine boat for the proposed extension of this arm of the navy. Three designs were submitted to the board: the Octopus of the well-known Holland type, a boat of 273 tons displacement, launched in 1906 by the Electric Boat Company of New York and embodying the latest conceptions of this design of boat, the Lake, and a small model of the sub-surface type. The report submitted to the Navy Department shows the unanimous opinion of the board to have been in favor of the adoption of the Octopus type. The results of the tests as given in the report are summarized in an editorial review in a recent number of Engineering, which also contains some interesting details of the progress of the submarine boat in other navies.
"The Octopus ,like the great majority of submarine craft, is driven on the surface by internal-combustion engines, and the consumption is such as to insure that, with a fuel storage supply of 4000 gallons, the radius of action will be 700 miles. Electric motors are used for propulsion when submerged. The surprisingly good speed of 10.03 knots was realized as a mean of three measured-mile runs with the conning-tower of the vessel to feet under the surface. This is a splendid performance. On the surface the maximum speed was 11.57 knots, and the mean 11.02 knots. As regards diving, the vessel went down at an angle of 8 degrees to a depth of 26 feet within 40 seconds; she immediately returned to the surface, remained there under observation for five seconds, and dived once more. The complete evolution was carried out in about a minute and a half. This facility of disappearance is of the greatest importance from the point of view of fighting efficiency, and the result is, therefore, most interesting. Again, the time taken to disconnect the gasoline engines and to couple the electric motors was only 12 seconds, five seconds for the former, and seven seconds for the latter operation. As to maneuvering, the vessel, when awash, made a complete circle in 3 minutes 40 seconds, the diameter of the circle being about 200 yards. Running on the surface, with only one screw, she made a half circle to starboard in 1 minute 35 seconds, and a half circle to port in 2 minutes 40 seconds; in the latter instance the screw propeller was working against the rudder. Going full speed ahead when awash, the vessel was able to reverse her direction of propulsion in 52 seconds. As to endurance, the boat was required to remain 24 hours submerged at a depth of 200 feet, and it was computed that only 1-45th of the total air supply was exhausted, which suggests a long radius of action under water.
"The Lake boat also did well in remaining under water for this lengthy period, but in the other tests the Octopus proved superior. The Holland boats are fitted with an automatic device for blowing out the tanks when submerged, in order that the vessel may rise to the surface from any predetermined depth, for which the apparatus is set to come into action. The mechanism was set to be effective at 40 feet, and when this depth was reached 30 tons of water were blown out of the ship in 18 seconds, the total time taken for the test, including the immersion of the boat, being 48 seconds. Another important trial was made in connection with submarine bell signals from the mother ship, and by this means it was possible for the commander of the fleet to communicate to the various vessels when submerged. It was also found that wireless telegraphy could be used on the Octopus when on the surface and awash. The masts were 30 feet high, and the antenna, 50 feet long, consisted of four strands of wire. Under these conditions it is anticipated that the range of communication will be 40 miles.
"These facts, which were evolved by the Government tests, again prove the practicability of submarine navigation, which has frequently been demonstrated, although actual data have been withheld. The data further establish the efficiency of the Holland type of submarine boat, and ‘that she is equal to the best boat now owned by the United States or under contract. The results suggest that a larger boat than the vessel referred to, which is of 273 tons displacement, would be a superior weapon. As to the Lake type of boat, the Commission report:—‘1. That the type of sub- marine boat as represented by the Lake is, in the opinion of the board, inferior to the type as represented by the Octopus. 2. The closed super-structure of the Lake, with the large flat deck which is fitted to carry water ballast, and to contain fuel tanks and air flasks, which is an essential feature of the Lake boat presented to us for trial, is inferior to the arrangement on board the Octopus for the same purposes, and also, in the opinion of the board, is detrimental to the proper control of the boat. 3. The hydroplanes, also an essential feature of the Lake boat presented to us for trial, were incapable of submerging the boat on an even keel. They are, therefore, regarded as an objectionable incumbrance.
"As regards the design known as the sub-surface type of boat, the Commission very properly reported that it could not be compared with submarine boats, being of an entirely different type. In this class of boat the machinery, magazines, and habitable quarters are enclosed in a submerged hull, from which there is communication to a surface hull through conning-towers or armored-tubes, the two hulls being joined, pretty much like the booms of a girder, by web plating or cellular structure. The surface hull is used only for the accommodation of the guns and the gear for controlling propulsion and navigation. In other words what would be considered the upper deck of an ordinary ship is separated from the sub-structure with the exception of tubes for communication, so that in action damage to the upper part would not affect or endanger the lower hull with the machinery and magazines. The system is ingenious, but is, as the Navy Board point out, analogous to the torpedo-boat or torpedo-boat destroyer. The sub-surface boat does not afford that advantage of invisibility which is the great desideratum met by submarine craft, and therefore its potentiality for damage is not so great. There was only submitted to the board a quarter-size model, and consequently it was impossible to make a satisfactory comparison, even with the performance of torpedo- boats and torpedo-boat destroyers. The Commission, however, point out that so far as their observation went there was no reason to doubt that the guarantee made as to speed, etc., would not be carried out. The subsurface boat is less vulnerable than the torpedo-boat, requires fewer men, and has a larger steaming radius, but she has less speed and greater draft. The president of the commission, Captain Adolph Manx, took exception to the general pronouncement that the tests of the sub-surface model 'did not develop that boats of this type, built of a size suitable to render their qualities available, are equal to the best torpedo-boats now owned by the Government. In the opinion of the captain, the smallest size of sub-surface boat fitted with a regular torpedo-tube, and built to give a speed of 15 knots, would be a weapon of great value, additional to any now owned by the Government, and that this value could be enhanced by the rapidity with which they could be constructed, and the ease with which they could be transported.
"The board were not called upon to pronounce as to the strategical or tactical advantages of the submarine boat. This was scarcely necessary in view of the general consensus of opinion in all Admiralties in favor of the type, and the large number now being built by the various Powers. In the recent Dilke return it was shown that there are already in existence 117 vessels of a submarine type, and that there are building 86; while the programmes of many Powers, in addition to the United States, anticipate very considerable additions. We, in Britain, have 37 completed and 11 on order, and the size has steadily advanced from 122 tons displacement to 400 tons, the power of the machinery having increased in the same period from 160 to 800 horsepower on the surface, while the power of electric motors for propulsion under the surface has increased from 70 brake horsepower to well over zoo brake horsepower. These vessels, as we have already indicated, have been evolved from the Holland type, and long experimental research has been carried out, with the result that no dubiety exists as to the efficiency of the type, while at the same time there is achieved that homogeneity which is so important in the training of the personnel to secure a sufficient supply of men during action, and to maintain the highest efficiency, which is dependent on thorough experience in these vessels more than in any other. France has 40 boats completed, and 59 are in course of construction. Here there is great diversity of opinion as to the best type of vessel, and the boats vary in size from 21 to560 tons displacement. The tendency, however, is all in favor of vessels of large size, most of the boats under construction being of about 400 tons displacement. Russia has 20 vessels completed, and has on order 8. Germany has moved more slowly in this matter, but she has completed her first vessel and has two building; the estimates for the next three years provide about 350,000 for submarine construction. Italy has four vessels building, and two in course of construction. Japan has seven built, while the United States have in commission eight vessels, and four in course of completion, all of the Holland type." As noted above, seven additional boats of this type have been ordered for the United States Navy since this review of the trials was written.—Engineering Magazine.
ORDNANCE AND GUNNERY, TORPEDOES.
BRITISH GUNNERY ITEMS.—Modifications in the battle practice of the fleet have been approved to be carried out in the coming new year. The firing will, in future, be made from both sides of the vessel, half the authorized number of rounds being apportioned to each ship. A towing target is to be used if available, and a scheme of points will be arranged by which increasing values will be given to hits made by the more important guns. The order of merit of each ship will be determined by the ratio of the points obtained by her to the possible maximum of her armament.
The targets resembling torpedo-boat destroyers which are used by the Revenge for night firing, consist of obsolete torpedo-boats from which the engines and fittings have been removed, the interior being completely fitted up with cork so as to render the boats unsinkable. Canvas stretched on battens represents the funnels, masts, and superstructure, the whole being painted black. The targets are towed by destroyers at a speed of about 23 knots, and form good representations of torpedo craft.
"BACK-FLASH" FROM MODERN SMOKELESS POWDERS.—The recent terrible disaster on board of the Japanese battleship Kashima, in which over 40 officers and men were killed and injured owing to charges of modified cordite, while waiting to be loaded into a 10-inch gun, being ignited by the "back-flash" from the previous charge just fired, once more directs serious attention to an ever-present danger which threatens our own navy. Both nations use practically the same pattern of gun and absolutely identically the same "powder"—or, to be more precise, the same propellant—namely, modified cordite. The tale of these accidents is mounting up; the United States has to deplore the loss of many of her sailors from exactly the same cause, though the propellant used in the United States Navy is of a somewhat different type.
Briefly narrated, what happens is this: When a charge of modern smokeless propellant is fired, the shot issues from the muzzle, but inside the bore of the gun there is left a large quantity of various mixed gases at a high temperature. Owing to their nature, however, they themselves are not sufficiently rich in oxygen to cause a visible flame. When the breech is opened there is an access of fresh oxygen from the atmosphere, and the hot gases then burst into flame.* If there is a draft down the bore of the gun from the muzzle to the breech, this flame is blown backwards a considerable distance to the rear of the gun, scorching and burning anything in its way. Should a charge of fresh propellant be ready behind the gun, waiting to be loaded after the shot is rammed home, it is not difficult to understand how there is certainty of terrible devastation, accentuated as it is by the small enclosed space in a turret, barbette, or Fasemate, and the further possible danger of the flame spreading to charges in the ammunition hoists and thence down to the magazines.
As the velocity of the projectile is increased in each succeeding type of gun, the charges of propellant rendered necessary are greater, and thus the danger from back-flash is intensified, owing to the larger quantity of residual gases being left in the bore.
It was appreciated some time ago in our navy that precautions must be taken to guard against such accidents as these, and the method since adopted is to expel the residual gases by an air-blast before the breech is Opened; but this is at best a makeshift, and must unduly delay the service of the gun. Moreover, in the hurry of an action, sufficient time may not be given to the operation; nor if the ship is steaming to windward, or the guns pointing to windward, can it be safely depended upon to clear out all the gases.
The Germans seem to have solved the problem in a much more scientific and satisfactory manner by adopting for their navy in 1936 a propellant powder which gives no back-flash, even in their largest guns. This has replaced in their navy the modified cordite which is used at present in the British Navy. This final rejection, owing to the serious back-flash defect, in favor of the flameless powder, known by the designation C/06, is a consequence of searching trials, extending over four years since 1902, the "/06” denoting the year in which it was adopted.
The exact composition of this powder is kept secret, but it consists of a mixture of nitro-glycerine and nitro-cellulose and vaseline, in which, so far, it closely resembles the composition of our modified cordite; but there is, in addition, a small quantity of some chemical which has the effect of Preventing back-flash at the breech, and in smaller ordnance no flame is apparent at the muzzle. This latter is a considerable advantage during night-firing, as the gun-layer of the quick-firing weapon is not blinded by the intense brilliancy of the flame usual with our cordite, whereby the speed of firing is reduced, and the accuracy of shooting impaired. It appears that the new German powder gives excellent shooting results.
So far as keeping qualities are concerned, the German powder is even better than our own cordite. This also is an important factor in view of the cordite explosions which have taken place from time to time in the magazines of British war vessels, fortunately, so far, without loss of life or of a ship; but similar good fortune may not continue. The report on these explosions has been kept extremely quiet, so that it is difficult to speak more fully of them; but on one occasion it was mere luck that a battleship was not sunk with all hands. Owing to this immunity from disaster, the public have not had their faith in the safety of ships in our fleet shaken in the same way as France quite lately was rudely awakened from her confidence in the excellence of the propellant powder used in her navy by the terribled is astern on the Jena. Apart, however, from the question of instability of a powder, which can be met to a large extent by the installation of refrigerating machinery for the magazines, there remains the equally important question of doing away with back-flash. So far no mechanical means have been devised to entirely obviate the danger there-from, and recourse must therefore be had to the chemist's art.
* It is thought that a spark of some sort is necessary to ignite the mixture. No part of the gun get shot enough to do this.—P.R.A.
Germany has always been renowned for her progress in chemistry, and in no branch has she shown herself more progressive than in matters connected with explosives. There is no single authenticated case of which we know of where an explosion has occurred on a German vessel of war, and the reason for this seems to lie in an intelligent anticipation of possible sources of danger and in the steps taken to prevent them. For example, as soon as nitro-smokeless powders replaced the smoke powders it was a once realized that the dictum of former days "keep your powder dry" must be changed to "keep your powder cool." All ships in the German
Navy were fitted with apparatus to keep the magazines cool, but our Admiralty only seem to have appreciated the importance of this during the past year, when the matter was forced on the attention of the Government by the accident which occurred on H. M. S. Fox, though several years previously a similar accident had occurred on H. M. S. Revenge. In both cases, by a simple chance, the loss of the ships and their crews, fortunately, did not occur.
Now, again, it would appear that we shall have to follow the lead given by Germany and adopt a powder which will obviate the danger of back flash in a proper and scientific manner.—Engineering.
EROSION OF GUNS.—With regard to the investigations of erosion of guns and mortars, an effort has been made to separate the effect of erosion of the bore due to the action of highly heated powder gases from the simple wear of the bore due to friction of the rotating band of the projectile and at the same time to arrive at some conclusion as to the grade of steel most suitable for the manufacture of gun tubes. The results of both the erosion and friction tests lead to the conclusion that the metal used at present in the manufacture of gun tubes is as satisfactory as any that can be obtained.
Causes of Erosion.—The most reasonable explanation advanced for the erosion of guns appears to be that the effects are due to the softening and washing away of a thin skin of metal at the surface, subjected to the highest temperature and pressure, at each round, by the extremely hot gases in contact with it. This explanation covers all the points which have been raised.—Report of Chief of Ordnance, U. S. A.
The report of the special committee appointed by the French Senate to enquire into the causes of the explosion which led to the destruction of the battleship Jena has been issued. It is in three parts, the first giving the views expressed by the committee, accompanied by plans of the vessel and the conclusions of the reporter, M. Monis. The reporter urges the necessity of more strict surveillance over the manufacture of the powders employed, in order to secure greater homogeneity and stability, both from the stand point of safety and from that of their ballistic qualities. He proposes the use of freezing apparatus to keep the temperature of the powder magazines under 77 degrees Fahr. The reporter further dwells upon the necessity of greater precautions in the handling of the different powders, suggesting that the black powder should, if possible, be excluded from the ships. If that be found impracticable, then it should be kept isolated and removed from the B powders, which, according to the committee of the Senate, were the cause of the disaster.—Army and Navy Gazette.
It has been decided to only repair the Jena sufficiently to enable her to be used as a target for gunfire.—Le Yacht.
BATTERY PLANS OF RECENT SHIPS.—The following diagrams, from the Mitteilungen aus dem Gebiete des Seewesens, show the battery plans supposed to have been adopted in certain recent designs.
The St. Vincent class are said to differ from the preceding English ships
by having all five of their 12-inch gun turrets on the middle line, as are those of the Delaware and North Dakota.
It is by no means certain that three-gun turrets will actually be installed on the Ersatz Sachsen class. The many inconveniences, difficulties, and disadvantages of this system are now apparently being recognized. The armored cruiser F is to differ from E merely by having twelve instead of ten 11-inch guns.
The French battleships which follow the Danton class are (as at present decided) to carry four 12-inch, twelve 9.44-inch, and eighteen 3.94-inch guns.
SAFETY LOADING ARRANGEMENTS FOR HEAVY GUNS.—The finding of the court which investigated the accident that occurred in the 8-inch turret of the Georgia, resulting in the death of 10 officers and sailors and the injury of others, appears to show that air-blast, as at present arranged in the U. S. Navy, for clearing the bore of the gun from after-gases, is not entirely satisfactory. What ever else may be considered as uncertain, and the witnesses who could throw any real light on the cause of the accident were comparatively few, it appears to have been clearly established that what the Americans call "flare-back," but what is more commonly called "back-flame" in the British naval service, was the actual cause of the regrettable disaster.
There is, however, one question open to doubt apparently, and that is whether the air-blast was actually used at the gun at which the accident occurred before the charge which caused the explosion was ignited. On this point the court itself found that "All firing rules were observed and all safety precautions adopted, except it appears that after the firing of the right gun immediately preceding the accident, the air-blast was shut off (the italics are ours), and the ammunition car consequently brought above the turret floor before the bore was clear of the dangerous gases." Experts will best realize the importance of this pregnant sentence, for if this finding is in accord with the facts, the effectiveness of the air-blast in clearing the bore of dangerous gases after firing, is not impeached, as the blast had not apparently been used. It would simply have been an omission on the part of certain numbers at the gun, having taken risks, and suffered for them, in their keenness for rapidity of fire. Most of our recent gun accidents have occurred from similar causes, and in competitive firings the temptation to "scamp" is always present in a more or less degree, especially when the spirit of emulation is fully kindled and familiarity most readily breeds contempt.
Whether, however, this was the actual cause of the accident is left in doubt, as an expert examination of the evidence taken by the court, led the examiners to the conclusion that "After the accident the left gun was found loaded and the breech partially closed, the gun depressed about two or three degrees, and the ammunition car at the foot of the hoist on the buffers, with only the shell in, the powder having been removed when burning powder grains fell into the handing-room at the time of the accident. At the right gun (the weapon whose charge was actually ignited) the gun was found to be depressed two or three degrees, breech open, loading tray in the breech, air-blast turned on, and blowing 112 pounds' pressure gauge in the turret, the ammunition car at the top of the hoist with the controller off."
It will be seen by the italicised sentences above that the court and the experts who examined the evidence appear to have arrived at diametrically opposite opinions as to whether the air-blast was turned on or off. To gunnery men this will rob the report of much of its value, as the British service is adopting, after exhaustive experiments, the air-blast system of purging the bores of our large guns of "back-flame" after each round has been fired. At present a water-jet from a wash-out arrangement only is used in our own fleet. If the air-blast was used at the right gun in the Georgia turret, and a "flare-back" followed its withdrawal, strong enough in force to rush out of the breech of the gun and envelop one of the gun- loaders and the charge he was handling, and to set fire to the material of which the cartridge bag was composed, then air-blast arrangements, as used in the Georgia on this particular occasion at least, were ineffective. If this had been proved to be the case, it would behoove our own authorities to see that a more effective plan is adopted for our own guns. Since the point is left in doubt, and our own experiments have been exhaustive and severe, we probably need have little doubt as to the safety of the system we are adopting in some of our latest warships.
A great deal depends on the force of the air-blast used, as to whether this method of driving dangerous gases out of the muzzle is, or is not, effective and safe. If the experts' opinion is correct that the "air blast Was turned on and blowing 112 pounds' pressure gauge" after the accident, this, if used, should have been ample to have cleared the bore of gases, even against a strong wind blowing "down range," which is the most dangerous time, as then the draft from muzzle to breech is at its maximum.
There is another point of importance brought out in the report which goes to show that the Americans take hazards with their8-inch guns which wear every careful to avoid with our own large turret guns. Mention is made in the evidence of the fact that one of the loading numbers stood with one of the charges in his hand when the bag containing the powder is believed to have been set on fire. With the 8-inch gun it is, of course, possible to "man-handle" the charges of the guns as our own 9.2-inch charges are handled; but with our larger turret guns the charges are kept covered in a metal cover until they are tumbled into a loading position in rear of the gun, and so are less exposed to what the Americans call "flare-back." This appears to be the safer plan, and should be possible of adoption, as their charges appear to have been served to the breech of the 8-inch gun of the Georgia in much the same fashion as our 12-inch charges are served in our oldest ships, viz., direct from the handing-room to the breech of the gun.
In our later ships a safeguard is introduced in the ammunition supply by a break in the service about half-way up from the magazines—in the case of the larger guns. This entirely removes all danger of burning grains falling from above to the waiting gun-charges below. Had it not been for the great presence of mind, the coolness and courage of some of the officers and men of the Georgia after the first explosion, there would doubtless have been a much worse accident, for the burning grains might have penetrated to the magazines through the handling-rooms below. This danger is, as pointed out above, averted in the later British warships by halving the service, and thus preventing direct communication between the breech of the gun and the magazines where their charges are stowed. This undoubtedly establishes a better arrangement, and since the service is so arranged that rapidity is not lost, the British method is undoubtedly superior, and affords the men and the ship more security should "back- flame" ever manage to light one of our large turret gun-charges.
The danger of this "flare-back" is, of course, peculiar to breech-loading guns, and although not responsible for so many accidents as the burning cartridge bag residue that smoldered in the old muzzle-loading guns, yet it has cost many lives since the introduction of B.L. guns, especially since slow-burning powders have been used, and our own navy has suffered with the rest of the fleets. Sponging with a saturated kind of mop-head was the method of removing the danger occasioned in the muzzle-loader by burning cartridge bag residue, and ejecting the flame from the bore by means of an air-blast at great pressure is the means of overcoming the "flare-back" of the modern breech-loading ordnance. Both of these agencies depend on careful manipulation by man for their effectiveness, and, unfortunately, man has ever erred since the fall, and when naval men enter gunnery competition the statement that it is human to err is only too often realized, even when the death penalty is the sure and certain result. The danger which besets our sailors from the cause to which the accident on the Georgia is clearly traceable, increases with every foot of the length of our guns, and we have advanced in this direction at a very lively pace during the last decade. Ten years ago a 40-caliber gun was considered a very long weapon; to-day our naval guns have leaped up to a length of 50 calibers, which in a 6-inch gun adds approximately five feet to its muzzle. To eject the flame, therefore, the air-blast will have to be increased with every caliber of length added to the gun if we are to keep the same margin of safety as exists to-day, after thoroughly exhaustive experiments. As, however, it is believed that the maximum of length has now been reached in guns built on our present models, extra air pressure may not be required to eject the "back-flame," which naturally takes longer to escape from a long gun than from a short one.
Taken as a whole, our safety arrangements in our loading and ammunition supply can be said to be in advance of other countries, and have more than once been admired by foreigners; while our cordite is proving to be more stable than most high explosives, even though it is sometimes necessary to promptly "jettison" an old "lot” that has been kept in a magazine close to the boilers in certain classes of our ships. Without being boastful, therefore, it is permissible to be grateful, and to acknowledge the great care that our Admiralty and constructors bestow upon the task of winning the confidence of naval men in their weapons and munitions, by introducing every possible safeguard into the designs of our men-of-war.—United Service Gazette.
EXPLOSIVES AND THEIR PROPERTIES.-As a result of the terrible explosion on board the French battleship Jena, there has since been a thorough overhauling of the explosives stored in the various arsenals and magazines in the United Kingdom, and large quantities of them have been condemned, a considerable amount being now in process of destruction in the neighborhood of Bull Point, Devonport. Similar measures were taken quite recently in India, as a result of a visit paid to that country by Lieutenant-Colonel Sir F. L. Nathan, superintendent of the Royal Gunpowder Factory, Waltham Abbey, but this visit had no connection with the Jena disaster, being prompted rather by the deterioration of much of the cordite and other explosives that had been stored in the Indian arsenals and ordnance stores, resulting in several serious explosions and outbreaks of fire.
The chemical reactions by which explosive substances are converted into gases vary very greatly in nature and rapidity, the latter fact determining the character of the explosive. Thus, when reaction through the mass of the explosive is slow, ordinary combustion is produced; when comparatively very rapid, the action is called" explosion"; and when practically instantaneous it is termed detonation. The pressure developed by an explosive in any given space depends upon the volume and temperature of the gases produced. The amount of work is proportional to the heat produced by the chemical actions involved in the decomposition of the substances. The force developed by a given explosive depends theoretically upon (1) its chemical structure and constitution, and the products of its decomposition; (2) the heat produced in the decomposition; (3) the nature and volume of the produced gases; and (4) the rapidity of the chemical action. Where combustion is complete it is possible to determine the products of decomposition and their amount with considerable accuracy, but when the explosive is not sufficiently rich in oxygen to ensure perfect combustion, these products will vary with the conditions of their production. The pressure of the resulting gases can be approximately measured by the ordinary laws connecting gaseous volumes and pressures, while the heat produced can be estimated from the chemical equations representing the various reactions involved.
Explosives may be divided into two divisions: (1) Those used to propel a projectile, and to open the shrapnel shell, and release the bullets; and (2) those used to explode common shell, generally styled high explosives." Under the first heading we have gunpowder and cordite, while as "high explosives" are ranked lyddite, melenite, dualine, dynamite, Atlas powder, tonite, rackarock, rendrock, and giant powder. Other explosives that are employed in the services for demolitions, and elsewhere for mining and similar purposes, are guncotton, cotton powder, blasting gelatine, and the Japanese shimose powder. Of all these, blasting gelatine contains the largest percentage of nitro-glycerine, viz.: 82 parts, with eight of gun- cotton; then dualine,8o parts of nitro-glycerine and 20 of nitro-cellulose or guncotton; dynamite, 75 parts of nitro-glycerine and 25 of infusorial earth; Atlas powder,75 parts of nitro-glycerine, 21 of wood-fiber, five of carbonate of magnesia, and two of nitrate of soda; tonite, 52% parts of guncotton,47/12 of nitrate of baryta; rack a rock, 77.7 Parts of chlorate of potash and 22.3 of nitrobenzol; rendrock is a composition of 40 parts nitro-glycerine, 40 of nitrate of potash or soda, 13 of cellulose, and 7 of paraffin; and giant powder, 36 parts nitro-glycerine, 49 nitrate of potash or soda, 8 of sulphur, and 8 of resin or charcoal.
Lyddite, freed from all technical description, is merely a form of picric acid brought into a dense condition by fusion. Picric acid is obtained by the action of nitric acid on phenol, or carbolic acid. Lyddite itself is a yellowish compound of the consistency of tallow. It is one of the most violent explosives known, and has the peculiar virtue of being totally unaffected by damp. It is somewhat difficult to detonate, and can be safely carried about in unfused shell. Its chief disadvantage is that special primers and fuses have to be employed with it in consequence of the difficulty of detonating it. There is rather a curious story attrached to its discovery, or rather rediscovery, for it was first discovered in 1771, and for a century and a quarter served a peaceful but very useful purpose as a dye for silk and woollen materials, without its explosive powers being dreamt of. Then, some years ago, a warehouse fire occurred in Manchester, and the flames spread to a shed in which picric acid was stored. There was a terrible explosion, and an investigation took place, with the result that lyddite was born. Meleniteis employed by the French, and is very much akin to lyddite, but it is said to contain chlorate of potash, which, while making it easier to detonate, renders it highly dangerous to handle.
High explosives all require to be detonated, that is to say, they must simultaneously receive a shock and the application of flame to explode. This is generally applied by detonators of fulminate of mercury or chlorate of potash. When merely lit, they flame away in much the same manner as cordite.
The advantages obtained by the use of cordite are due almost wholly to the fact that the powder is practically completely converted into gas. The experiments of Noble and Abel show that the gases evolved by charcoal powders amount to only 43 percent of the weight of the powder, and part of the energy of this quantity of gas is expended in expelling the residue from the bore. A smaller quantity of smokeless powder will therefore produce an equal weight of gas, and with smaller charges the projectile may be given equal or higher velocities. The smokelessness of the powder and the absence of fouling in the bore are also due to the complete conversion of the powder into gas. Cordite itself consists of 58 parts of nitro-glycerine, 37 of finely-divided gun cotton, and five of mineral jelly. It is made in various sizes, and is broken up into very short lengths for use with revolvers. The ordinary sizes are designated by the size of the sticks in hundredths of an inch, and by their length. Thus size 50/16 signifies that each stick has a diameter of 5o hundredths of an inch, and a length of 16 inches. In addition to being smokeless and leaving little fouling in its use, it is unaffected by damp, and being a more powerful explosive than gunpowder, a smaller charge produces the same effect. It is, however, affected by heat, which destroys it by melting out the nitro-glycerine of which it is composed. For this reason it is found necessary in tropical climates to store it in cool chambers, as is done in our battleships.—United Service Gazette.
PROTECTION AGAINST TORPEDOES.—The new French battleships of 18,000 tons will be provided, over almost their whole length, with an armored inner hull intended to safeguard them against torpedo explosion. This
measure seems judicious, and the presence of this supplementary armor may result in reducing the importance of leaks caused by an under water explosion. But it is also possible that it may be of no use; certainly no one can affirm the efficacy of the system. Ever since the 1901 experiments against the Henri IV caisson, it has been well known that the special kind of protection aimed at in that vessel was illusory, and yet the method was nearly the same. As a matter of fact, we are too little informed as to the mode of propagation of the explosive effects to know how to arrest them; and it may well be that subdivision is the only effective means at our disposal whereby leakage can be localized and the ship's stability assured.
But there is a surer way of arming oneself against torpedoes, at least in certain cases, and those, too, the most frequent ones; it consists in causing them to explode at a respectful distance from the ship by means of the metal nets invented by Bullivant. It is known that we used these nets for several years; then did away with them on account of their weight and the difficulty of handling them. At the time of their suppression, we were almost alone in having torpedo-boats, and submarines did not exist; we counted a great deal on our own torpedoes, but had nothing to fear from those of our adversaries. To-day, torpedo-boats and submarines have been developed everywhere, if not as much as in France, at least to a considerable extent, and we must expect to be attacked by them. Consequently there is reason to consider which of us has been right, we who have given up, or other navies which have kept torpedo nets.
They have even perfected these nets, and England is at her third model in ten years. These changes have been necessitated by the invention of “net cutters," whose object is sufficiently explained by the name, and which are placed at the front of the torpedo to cut the links so as to make an opening in the net through which the torpedo can pass, and thus reach
the ship's hull. But for each kind of net, a different net cutter is needed, and, moreover, no one of these devices is absolutely sure to function. Besides, the net cutter retards the torpedo, may swerve it from its path, and, when the torpedo reaches its mark, causes it to explode: further from the hull than it otherwise would, thus decreasing its explosive effect as well as reducing its chance of hitting.
The old French net (Fig. 1) was formed of round links of is cm. diameter, side by side, and tied together by iron rings. The links were made of iron wires twisted together.
The links of the German net (Fig. 2) are rectangular and of greater size, 20 cm. by 12 CM.
In the Russian net (Fig.3) the links are round and arranged in diagonal lines; they are of 12 cm. diameter.
The English at first had a model like ours; in 1898 they replaced it by another much more complicated (Fig. 4) with to cm. links, evidently designed to meet the net cutters of that time; and quite recently they have adopted a new system (Fig: 5), quite different, which might better be called a casing than a net; it is made of flat steel rings, only 6 cm. in diameter, one passing through another without any connecting rings. This veritable "coat of mail" serves as the outer covering of the new battleships of Dreadnought type. It seems, at first sight, particularly difficult to pierce.
The weight of these nets is naturally very different for the different models; it varies from 3 kilos per square meter for the German net, which is the lightest, to about 25 kilos per square meter for the latest English net. But the importance of the resulting extra weight on a battleship should not be exaggerated; if we suppose a net 6 meters high, completely surrounding a ship 180 meters long, and weighing 25 kilos per square meter, the total weight is 54 tons; that is very little, out of a displacement of 18,000 tons, even if 20 tons are added for the booms and the rigging. If this weight were taken out of the coal supply, it would reduce the radius of action at 20 knots from 1000 to 940 miles.
Admitting the principle of net protection, there is, however, no great object in economizing on the weight per square meter; if increasing it obliges us to also increase a little the power of the winches by which it is worked, on the other hand, the net will behave better when the ship is moving. Our old nets, which weighed only 5 kilos per square meter, lifted at 5 knots speed, and, dragging along the surface, no longer gave any protection. The last two English models, on the contrary, remain immersed and nearly up and down when the ship carrying them is moving at 10 knots speed. Under these conditions, nets permit a blockading force to approach nearer the shore and their role is no longer limited to protecting ships at anchor.
As to the difficulties of maneuver, they are real—and that is the true reason of our giving up the use of nets; but they are not insurmountable. The English put out their nets of latest pattern, which are particularly flexible, in two or three minutes, and take them in, stowing them properly along the sides in the same time. What they have done, there is no apparent reason why we should not attain to doing.
The cost of a complete outfit for a large battleship is 100,000 francs (that is what the Admiralty pays to the Bullivant Company, which has kept the monopoly of the manufacture).
It seems to us that, if the necessity of supplying our new ships with this supplementary system of protection is not evident, it would be well at least to carefully consider the matter. The question could be submitted to the
Counseil Superieur de la Marine, for whose information there should be communicated an exact estimate of weight and cost as well as data concerning the performance of nets in the Russo-Japanese war; for both sides used nets, and it was due to them that the injuries caused by torpedoes were generally so slight. We should remember the numberless attack of the Japanese torpedo-boats, from February to June, 1904, before Port Arthur, and still better the end of the Sevastopol, moored off the harbor, having disembarked her rapid fire guns for shore use, and having on board only a few men armed with rifles, and withstanding during five nights the furious assaults of the hostile torpedo-boats, her nets stopping nearly boo torpedoes. A system of protection capable of such resistance is not to be despised, and its advantages are perhaps such as to outweigh its inconvenience.—Henry Bernay, in Le Yacht. (Translated by P. R. A.)
MARINE TURBINES AND GAS ENGINES.
The recent overhaul of the cruiser Amethyst has been extremely satisfactory as far as the turbines are concerned, the work involved being extremely small compared with that required by her sister ships fitted with piston engines.
POWER ESTIMATING FOR TURBINE STEAMERS.—There is one great feature about the adoption of marine turbines, which is that they have made naval architects and marine engineers think on new lines. Empirical methods of design, and a discreet copying of the last similar job, sufficed for the vast majority of work done for the mercantile marine when the comparatively slow running engine and propeller were adopted. In their case the margins were large in all directions the propeller was—generally—nowhere near its breaking-down point, the link motion enabled a greater mean pressure to be used if the required power was more than the estimate, analyses of component losses were almost invariably ignored, and, with one or two exceptions, shipbuilders were content to trust the indicator, and base everything thereon. Consequently vital variables remained undisturbed for want of investigation that the turbine has since enforced, and lest anyone should be unduly assisted by the work of his predecessors, providence seems to have carefully arranged that this casual satisfaction with indicated horsepower and speed should also extend to the stokehold, and that the coal consumption should be measured while the water evaporated—and hence boiler efficiency as well—should be left undetermined. Consequently there arose a term—pounds of coal per indicated horsepower hour—that, while based on a good experience with innumerable vessels, was absolutely useless for scientific comparison of results. For the moment we are not so much concerned with the boiler end of estimating as with the term indicated horsepower. For up-to-date fast steamers it is as useless as nominal horsepower, as Kirk's analysis or Rankin's augmented surface method—excellent as they may have been in their day. Times change, and what we have to face now is the problem of foretelling the effective thrust needed to propel a hull of given dimensions at a given speed. The term that marine engineers will not only have to get into the way of using, but also of estimating, will be effective horsepower, and not indicated horsepower. Now, the horsepower actually required to propel a given hull has to overcome the (1) frictional resistance of the hull; (2) the wave making resistance; (3) the eddy resistance. The first of these can be calculated with considerable accuracy, though it is customary, by taking a higher value for the coefficient of friction than that originally found by Froude, to include eddy resistance with it, owing to the impossibility of separately determining the resistance due to this cause. Wave making resistance is hard to determine without a tank, though some empirical coefficients do exist that give a close approximation for certain types of vessel, and careful analytical estimates from similar ships help us to determine the percentage of the total that it represents. In the case of tanks, when the resistance of the naked model has been determined, the effective horsepower is first calculated and the probable indicated horse- power arrived at by means of propulsive coefficients made up as follows: About 5 per cent is added to the E. H. P. of the naked hull for resistance due to appendages—rudder, bossing, shaft brackets, etc.—and the figure thus found is multiplied by about 1/.85 for engine efficiency, and about 1/.65 for propeller efficiency, and by a very small corrective for hull efficiency— that is, for the difference between wake gain and thrust augmentation due to the action of the screw. The net result is that the ratio of EHP/IHP is about 50 percent, but varies very considerably. For most vessels the value is between 48 per cent and 56 per cent at full speed, but instances of greater and lesser values could easily be quoted. It is an interesting question as to how accurate tank horsepower is. Models of the same ship trid in different tanks give amazingly variable results, but with care and experience the resistance can be determined very closely.
Consider for the moment the analysis of power from the engine end. The indicated horsepower as given by the indicator is considerably in excess of that delivered to the propeller boss on account of friction in the moving parts. Until the genesis of the torsion-meter about four years ago it was very difficult to say what this loss was, as the testing of large marine engines against a brake was prohibitively costly. It was generally assumed—largely on the basis of trials of land engines against brakes or generators—to vary from 10 to 16 per cent, and it came as a considerable surprise to many when the Vulcan Company proved the mechanical efficiency of the main engines of the Kaiser Wilhelm II to be as high as 94 per cent in service. Even assuming the accuracy of tank trials, it was therefore impossible to determine propeller efficiency correctly owing to the uncertainty as to the power actually delivered to the screw. Now that this can be done with comparative accuracy, it is so far only attempted on turbine steamers, and we find ourselves in the position of gradually commencing to accumulate isolated facts on the subject, but without any means of comparing them with reciprocating practice, as torsion meters are very rarely applied to piston engines. When, therefore, it becomes necessary to estimate the power required for a turbine steamer, and consequently revolutions of shafts, weight of turbines, etc., there is no guide established yet by past practice enabling us to decide exactly what brake horsepower is required. If a tank is available, or rather if a store of tank data is at hand to estimate from, the matter is simplified at once. If not, the procedure is guesswork. An Admiralty coefficient for indicated horsepower is taken as if piston engines were to be used, and an equally approximate propulsive coefficient is assumed in order to arrive at the E.H.P. Consequently we find some cases of large margins, and others cut very fine indeed.
With the improvement in steamship performance the value of the coefficient should be rising in ships of all types; but as far as Channel steamers are concerned, there is now no indicated horsepower, and hence no trustworthy coefficient. The solution seems to be to substitute E.H.P. for I.H.P. wherever it can be done. It applies equally to both types of engine, and obviates the inclusion of undetermined losses in important estimates. The known propulsive efficiencies can be used, but the absolute values will change. Instead of taking, say, 240 as a suitable Channel steamer coefficient whose propulsive efficiency is known to be 54 per cent, our value in future will be 444. Unless some step like this is taken, and a new series of values compiled for a most useful formula, we are afraid that for all fast steamers its use and value for power estimating will rapidly wane. The same arguments apply equally well to proportions of boilers, to fuel consumption or relative weights; but at the present time we are in a transitory state on this question, and it is by no means easy to change over from the old-established symbols.—Engineer.
ELECTRIC MOTORS FOR SHIP PROPULSION.—Some time ago we described an interesting method of propelling ships, proposed by a Russian. Several vessels, constructed according to his ideas, were tried. The results of these tests have been reported rather briefly, but it may be said that they, at least, were promising. The idea of this system was to utilize the internal-combustion engine, with its high thermal efficiency. But to adopt this engine to propulsion, a transmission gear was necessary. That proposed was a generator coupled to the engine, thus supplying power to one or more motors driving an equal number of propellers. The electrical transmission gear was not only efficient, but made it possible for the engine to run at its most efficient speed, while the speed of the propellers was that best suited to them. An incidental advantage of the system was the bringing of the control of the propelling motors directly under the hand of the pilot.
Now, a somewhat similar plan is suggested for steamships, by the Engineering Times, to overcome the difficulties which have been met in applying the steam turbine to this work. This prime mover is at its best at high speeds, while the propellers, for efficient working, should be driven at much lower speeds. Therefore, in order to drive directly, not only must the turbine itself be run at a speed lower than is best, and hence be large and expensive, but the propellers must also compromise and run at higher speeds than is desirable. These disadvantages are removed by interposing an electrical link. By using a high-speed turbine directly connected to a generator, the former may be designed for that speed which best suits it. Since there is no fixed relation between the speed of the generators and the speed of the motors, the latter may be built so as to suit the propellers. Hence, each mechanisms works at its most efficient speed. Moreover, the system not only gives the pilot complete control of his propelling machinery, so that he can regulate the speed at will, but it makes reversing possible. With the ordinary steam turbine equipment, a reversing turbine must be introduced. With the electric drive this turbine is eliminated. Further, on naval vessels, where most of the cruising is done at low speeds, but which must be capable of sustained high speeds when occasion demands, it has become customary to introduce a second set of turbines simply for cruising purposes. With the electrical system this unit is also eliminated. By these savings, and taking into consideration the smaller size of the high-speed turbine, as compared with the low-speed direct-current turbine, it is estimated that the introduction of the electrical link will not increase the weight of the equipment, nor its cost, and will, besides, give the advantages which have been enumerated.
At the present time we are not aware of any attempt to apply such a system to boat propulsion. A some what similar system has, however, been tried for self-propelling vehicles, although the prime mover in this case
has generally been a gasoline engine. If, however, this arrangement proves satisfactory for railway purposes, there seems to be no reason why the electrical steamer should not also be successful.—Electrical Review.
THE INDICATED POWER AND MECHANICAL EFFICIENCY OF THE GAS EN- GINE. (Abstract of a paper by Professor B. Hopkinson, read before the Institution of Mechanical Engineers.)—In the report of the Committee of the Institution of Civil Engineers on the Efficiency of Internal Combustion Engines, the following remark occurs:
"It would be desirable but for one circumstance to calculate the relative efficiency only from the indicator horsepower. But it appears 19 the case of gas engines, and especially gas engines governed by hit-or-miss governors, the indicator diagrams do not give as accurate results as is generally supposed. The diagrams vary much more than those of a steam engine with a steady load, and the mean indicator horsepower, from the diagrams taken in a trial, may, it appears, differ a good deal from the real mean power."
The opinion of the committee quoted above is obviously important, and may be expected to have a wide-spread effect in gas-engine testing. It throws doubt upon many of the efficiency tests of gas engines which have hitherto been made and published. Moreover, the method which the committee themselves adopted for getting the indicated power from the brake-power seems to require further investigation before it can be accepted as accurate. It may no doubt be assumed on the evidence of steam engine tests that under given conditions of lubrication the friction is practically independent of the pressure in the engine. But whereas in the steam engine the whole of the mechanical losses are to be ascribed to friction, that is not the case in the gas engine, in which a considerable amount of power is wasted in pumping and is usually included in the mechanical losses. Moreover, with a given supply of oil, lubrication conditions in the steam-engine are practically constant, but in the gas engine that is by no means the case. Great changes can take place in the temperatures of the cylinder walls in a comparatively short time, and this will affect the viscocity of the oil and therefore the work spent in friction. The author therefore determined to undertake an investigation with the object of finding whether the indicator power of the gas engine does, in fact, vary so much and is so difficult of determination as the report of the committee referred to suggests. If it were found that the indicated power could be accurately determined directly, it was further desired to test, by direct comparison of brake and indicated power, the validity of the committee's method of getting the mechanical efficiency. Briefly, the conclusions reached are:
Conclusions of the Research.—(1) If precautions are taken to keep the pressure of the gas-supply constant, the diagrams given by the engine are remarkably regular, and whether the engine be missing ignitions or not, it is possible, by the use of a sufficiently accurate indicator, to obtain the indicated power from diagrams within 1 or 2 per cent. It seems probable that the difficulty experienced by the committee was due either to the essential defects, for this purpose, of the ordinary form of indicator, or to casual variations in the gas supply per suction due perhaps to variation in the gas pressure at the engine.
(2) The difference between I.H.P. and B.H.P. is rather less than the H.P. at no load under the same conditions of lubrication, mainly because of the difference in the power absorbed in pumping. In the particular engine tested by the author the error from this cause in obtaining the indicated power would amount to about 5 per cent. The friction is substantially constant from no load to full load, provided that the temperature of the cylinder walls is kept the same, but the influence of temperature is very great.
The engine used in the tests was intended to give a maximum output of 40 H.P. on the brake, and the following are the particulars of it: Cylinder, 11 1/2 inches diameter by 21 inches stroke; speed, 180 revolutions per minute; compression space, .407 cubic inches; compression ratio, 6.37; compression pressure, 175 pounds per square inch absolute.
When exploding every time, the indicated horsepower at 180 revolutions per minute is 0.495 times the mean effective pressure.
The engine works the ordinary "Otto" cycle, governed by hit-and-miss. The ignition is by magneto. The engine was loaded by belting it to a dynamo, which also served to motor it round when required. The fuel used was Cambridge coal-gas. When an accurate measurement of brake-power was desired all-round rope-brakes were used, one on each flywheel, and as the measurements were such that the brake-tests only lasted a few minutes it was not necessary to use any water cooling. The engine was fitted with an exhaust gas calorimeter of the spray type.
For measuring the gas supply a standard holder by Messrs. Parkinson and Cowan, having a capacity of 10 cubic feet, was placed between the main gas supply and the engine, and as close as possible to the latter. In the ordinary running of the engine the holder stood at a constant level, the flow of gas into it just balancing the flow out, and under these conditions it served as a gas-bag, coming down by about 1-10th of a cubic foot at each suction of the engine. In a measurement of gas consumption the supply to the holder was cut off, so that the engine took gas only from the holder, and the quantity taken in a definite number of suctions (usually about 50) was noted. The indicator diagrams were photographed at the same time as this measurement was made. After the completion of the measurement the inlet pipe to the bolder was opened, and the counter-weights adjusted so that the holder slowly rose to nearly its highest position, when the measurement could, if necessary, be repeated. It was possible M this way to read off the gas consumption correct to one part in 500, and, allowing for possible inaccuracies in the gas-holder divisions, small changes in temperature and pressure, etc., it may be taken as certain that he gas consumption given is within one-half percent of the truth. This method of gas measurement is, of course, especially adapted for cases like the present, in which the actual gas used in a particular cycle or series of cycles is desired, but it may be noted that it is almost equally suitable for the measurement of gas consumption for a long period. It was found that it made no perceptible difference to the power given by the engine whether the inlet-pipe to the holder was open or closed, and it may be assumed therefore that the gas consumption remains the same under these two conditions. The rate of consumption determined by the holder may therefore be assumed to hold during the intervals when the holder is filling or is standing at a constant level. This method of measurement, which is much superior in accuracy to any meter, and is very convenient, might easily be applied to much larger engines, since all that is required is a holder of capacity sufficient to run the engine for about one minute.
The New Optical Indicator.—The first requirement for the investigation proposed was an accurate indicator. In order to get at all satisfactory results it was necessary to construct an instrument which could be relied Upon absolutely to give the indicated power within 2 per cent. Further it was necessary that the instrument should be capable of working for long periods without breaking down, so that large numbers of diagrams could be taken under given conditions. The author's experience of indicating gas engines has convinced him that it is quite impossible to fulfill the first of these conditions, to say nothing of the second, with any form of pencil indicator. It is unnecessary to discuss here the various sources of error in the pencil indicator, but it may be noted that two of them, namely the inertia of the piston and looseness in the joints, are of especial importance in the gas engine.
The combined effect of this and of back lash is to increase the mean height of the diagram by an amount which, from the nature of the case, is quite uncertain, but which may easily reach 1-30th inch even with a new indicator in perfect adjustment. This error is in most instruments counter balanced to some extent, and in many overbalanced, by that due to motion of the pencil at right angles to the piston bore.
To overcome both these defects of inertia and back lash it is necessary to reduce very much the motion of the moving parts of the indicator and to use optical means for magnifying that motion. The diaphragm manograph first proposed by Perry and now in use to some extent as a commercial instrument in the form of the Hospitallier-Carpentier Manograph, is unsuited for accurate quantitative work for a number of reasons; the chief of which are that the displacement is not proportional to the pressure, so that the diagrams cannot be integrated by a planimeter, and that it is in convenient to calibrate. The author therefore determined to get a new design of indicator of the piston and spring type with optical magnifying mechanism. In the form finally adopted, after a considerable amount of experimenting, the spring consists of a straight piece of steel strip held as an encastred beam in a steel frame. A piston slides in a bore communicating with the engine, the axis of this bore being at right angles to the spring and passing through its center. The pressure on the piston deflects the spring and so tilts a small mirror about an axis at right angles to the bore, the pivots of this mirror being carried on a steel frame. To give the other motion to the mirror, the whole apparatus (straight spring and mirror with its pivots) is positively connected to an eccentric on the crank axle by which it is rocked about the axis of the bore, thus giving the piston motion of the diagram without the possibility of any lost motion. This instrument is practically indestructible, and it has been left open to the engine for considerable periods without giving it any attention. The vertical deflection is accurately proportional to the pressure, so that the diagrams can be integrated with a planimeter. Finally, the period of oscillation is only about 1-700th of a second with such strengths of spring as were used in the mechanical efficiency tests. The indicator is very easily calibrated by dead weights. The diagrams used in these measurements were photographed, but for many purposes it has been found sufficient to observe them direct by means of a telescopic arrangement by which they are projected as a bright light on to a transparent screen with vertical and horizontal scales. It is easy to plot the diagram on to a piece of squared paper, and its area can thus be obtained within 5 per cent without the trouble of photography.—Page's Weekly.
TRANSATLANTIC WIRELESS TELEGRAPHY ESTABLISHED.-AS had been promised by Mr. William Marconi, on Thursday, October 17, wireless service across the Atlantic was opened. This transmission takes place between Glace Bay, Nova Scotia, and Clifden, Ireland. During the first day, it is said, ten thousand words were transmitted altogether, in both directions. These included a number of enthusiastic congratulatory messages in recognition of the important event, and prophesying the benefits to humanity which must follow from the developing and putting into actual service of the new system of communication. Judging from the reported success of the first day's public trial, there is no reason to expect anything but continued good working, so that the date on which this service was inaugurated is an important epoch, not only in the history of wireless telegraphy alone, but in that of all systems of communication. It is true, of course, that for some time past Mr. Marconi and others have said that they had maintained excellent communication across the Atlantic, but when a system is put into service, as now has been done, it must be considered as having passed out of the experimental state and entered into one of actual use. Moreover, since the announced rates for transmission are very much lower than those of the cable companies, in spite of the fact that the latter system has been in service for about 40 years, the new system can certainly expect to secure as much business as it can handle. Just what proportion of the whole this will be remains to be seen. It must be remembered that at the present time at least, these two stations can send but a single message at a time, and the rate of transmission is not high.
No one can tell now what place the wireless, or rather the radio-telegraphic system will take. The expense of the apparatus is trifling compared with that of the cable, and it will not be subject to breakdowns, or failures, in parts a mile or more under water. On the other hand, the problem of preventing interference between stations has not yet been completely solved, so that the application of the system must yet remain somewhat limited. Nevertheless, the possibilities are very great. There seems to be no reason now why communication with the Antipodes may not be established, provided, of course, sufficient power can be radiated. But if everyone else must be silent while one of us is talking to Australia, the system is, in one sense, handicapped.
Whatever may be the outcome of this telegraphic development, certainly Mr. Marconi must be given all credit, not only for the truly wonderful work he has done, but also for his faith in the system and his persistency in carrying it from good to better. Today he is applauded by all the world for his magnificent achievement, and his work is greeted by the wondering praise of people grown accustomed to modern wonders, but who, tomorrow, when "little men, of little souls, rise up to buy and sell again," will turn to some new feat, forgetting the real importance to civilization of the system which Marconi has put into service.—Electrical Review.
CULMINATION OF WIRELESS TELEGRAPH IMPULSES ATTHE ANTIPODES OF THE SENDING STATION.—The letter from Mr. Ernest F. Smith in our correspondence columns this week on the subject of the intensity of wireless telegraph signals at great distances from the sending station affords an opportunity for interesting speculation. Mr. Smith points out, although the same suggestion has been published before, that a wave which spreads at uniform speed and with uniform attenuation in all directions from a sending station on a sphere, should continually weaken in local intensity until it reached the equator of the globe with respect to that station. Beyond that distance the wave front tends to shorten and not to lengthen, until at the antipodes of the ending station it should tend to collect into a Point with a splash or culmination. This would depend, of course, upon whether the rate of absorptive attenuation fell below a certain critical value. If, for instance, the absorption were so great as to make the wave inappreciably faint at a distance of say 100 miles, then it is clear that there would be no use looking for an antipodal splash 12,000 miles away. On the other hand, if the wave could be safely detected up to the equator from the sending station, or up to the ring 6000 miles off, so as to start fairly on its narrowing career, it would be reasonable to hope for a distinct culmination at the antipodes. Thus far we believe that there is no authentic or reliable information as to the reception of signals over 6000 miles away from their base, though there have been certain newspaper reports. There is, of course, no reason why they should not be found at such distances, if they are sufficiently strong at the start. All wireless telegraphists scattered about the ocean world should be encouraged to keep watch for and record of, faint signals from afar, in order to transfer antipodal wireless telegraphy from the class of interesting speculation into the class of determined fact.—Electrical World.
RECENT CONTRIBUTIONS TO ELECTRIC WAVE TELEGRAPHY.—Professor J. A. Fleming, in a recent Friday evening lecture at the Royal Institution, took as his subject the recent advances in wireless telegraphy. In commencing his address, Professor Fleming said that, though hardly more than ten years old, the system of wireless telegraphy by electric waves had developed immensely in its practical applications.
Every important navy had adopted the system in some form or other. With respect to the British, he was informed that it had been decided to fit it to every vessel larger than a torpedo-boat. At the same time over a hundred commercial vessels had been fitted with the Marconi apparatus. Concurrently with this practical development of the method there had been a corresponding advance on the scientific side. As in other cases, a stage was reached in which exact measurement was necessary to indicate the lines along which further progress was possible. In the case of wireless telegraphy, the things to be measured would be best comprehended by considering the nature of the phenomena involved. At each electric wire station there was an antenna which, in the case of a small station, might be a simple vertical wire, whilst in the case of a large one it might consist of 20 to 30 miles of such wires upheld by lattice towers. At the sending station this antenna was the seat of electric oscillations which gave rise to waves in the surrounding space. These waves fell on the antenna at the receiving station, and reproduced in it electrical oscillations which could be detected by suitable means. The state of the antenna and the space around it, previous to the passage of a spark, could be represented diagrammatically as in Fig. 1, lines of electric strain extending from the wire to the ground. When the spark passed these lines of strain were released; but in virtue of inertia the released electrons rushed to and fro along the wire in a series of oscillations. In so doing they set up a magnetic field around the wire, the direction of which was reversed at each oscillation. The point of reversal of this field spread out through space with the speed of light, and was accompanied by loops of electric strain, having their feet resting on the ground. The distance between the maximum values of successive loops was known as half a wave-length. The power which the waves possessed of passing round obstacles depended upon this wave length.
Electric wave telegraphy formed a portion of the great science of radiation, which included optics and spectrum analysis, the fundamental laws of which were the same as for wireless telegraphy. In all cases of wave motion the relation V=n? held, where V denoted the speed of propagation, n the frequency, and ? the wave-length. Hence, if the periodic time of the vibration could be determined, the wave-length was also known, as V was, in the case under consideration, the velocity of light. The plan followed was, therefore, to bring near the emitting circuit, which had both capacity and inductance, another circuit having a variable inductance and capacity. These were altered till the two circuits were in tune, and it then followed that the product of the inductance and capacity was the same for both circuits, in which case the periodic time was given by the relation
where C and L were respectively the known capacity and inductance of the secondary circuit. An instrument devised by him for the above purpose he had named a "cymometer." The inductance was provided by a long wire wound spirally, and the capacity by two tubes separated by ebonite, one of which could slide over the other. As a means of detecting when the two circuits were in tune, he used a vacuum tube filled with neon, which was connected to the terminals of the cymometer and glowed brightly when resonance was obtained between the two circuits, the indication being very sharp. These instruments were now made to measure wave-lengths ranging from 200 feet to 20,000 feet.
The cymometer might also be used to measure the decrement or damping of the waves. The waves emitted by an antenna fitted with a spark-gap died away gradually, each successive wave having less amplitude than its predecessor of the same group. The ratio of the amplitudes was the same for each successive pair of waves, and was called the "decrement." If this were known, the total effective duration of the group could be calculated; that was to say, the time in which the amplitude had diminished to 1 percent of its initial value. Waves might die out rapidly or slowly, and it was also possible to produce undamped or persistent waves. In using the cymometer to determine the decrement, a very sensitive amperemeter, formed by a thermopile, was introduced into the cymometer circuit. This done, it was easy to plot out a curve, showing the relation between the natural frequency of the cymometer circuit, as its inductance was varied, and the strength of the current observed. After adding a small resistance to the circuit a second curve of the same kind could be determined, and from the two it was possible, as shown by Bjerknes and Drude, to determine the damping factor for the primary circuit. The amplitude could also be obtained, so that by means of the cymometer the wave-length, the number in the train, and the damping factor could be found.
Various kinds of transmitting circuits had been used in wireless telegraphy. In general the aerial was charged by inductance, and then it might be either "closely" or "loosely" coupled with the primary, and, as a result, the oscillations emitted might be strongly or feebly damped. In the latter alternative each train consisted of many oscillations, and thus it was easier to get resonance in the case of the receiving circuit. Several methods had been proposed for getting an undamped train of waves. Thus a small alternator had been used by Mr. S. G. Brown. This ran at 6000 revolutions per minute, and gave waves with a frequency of 12,000 per second. The total power of the machine was, however, only so watts. It was, however, necessary in wireless telegraphy to have either a high frequency or a large power. With a frequency of 10,000 per second the waves would be 100,000 feet in length, and very expensive antenna, absorbing large power, would be required. Tesla, Elihu Thomson, Duddell, and Fessenden had all experimented along this line; but he believed that the highest frequency yet obtained from an alternator was 50,000 per second, and the power put into the circuit was small. The next method he would con- sider was the electric arc as a source of undamped waves. As in many other cases, this application had been foreshadowed by a sort of twilight before the dawn. Thus Elihu Thomson, in 1892, had, as represented in Fig. 2, shunted a spark-gap with a condenser, and observed that a high-frequency current was obtained in the condenser circuit.
In 1899 or 1900 Duddell had shown that if an arc lamp was shunted by a condenser and inductance, as in Fig: 3, a high-frequency current was again obtained round the condenser circuit. In 1903 Mr. Poulsen had made a further advance by making the arc between a carbon and a copper rod, the latter being cooled by water, and the whole arc surrounded by an atmosphere of hydrogen. At the same time a strong magnetic field was
established across the arc, as indicated in Fig. 4. In this way a much higher frequency was obtained. This method of producing undamped trains of waves was highly interesting and very important. It had been the subject of much investigation in the speaker's laboratory, where, at his (Dr. Fleming's) suggestion, Mr. Hudson, one of his research students, had determined the relation between current and potential for a carbon-metal arc. This had already been done for the carbon-carbon arc, and it was found that the potential fell as the current increased, a fact which was sometimes expressed by stating that the arc had a negative resistance; but he himself preferred to say that it had a falling characteristic curve. In the case of the metal-carbon arc this droop in the characteristic was much more marked, as would be seen on reference to Fig. 5.
He had a Poulsen arc on the table. The arc was enclosed in a brass box kept filled with coal-gas. The capacity in the circuit was small—merely 1/300 microfarad, or that of a large Leyden jar, whilst the inductance was large. As antenna he would use a long wire helix which had a natural periodic time equal to 5/200,000 second. The impulses from the arc must be supplied at exactly this rate, and when this was done, strong electric brushes appeared at the terminals of the helix, whilst all around it was an intense alternating magnetic field. The waves emitted in this case were about a mile in length. With this apparatus Dr. Fleming showed many beautiful experiments. Every kind of vacuum tube glowed highly when brought near the helix, especially fine results being obtained with those containing neon, which gave quite a brilliant light. It was, however, an uneconomical method of lighting, as the apparatus took about 3 horsepower to work it. Tubes containing rarefied air also lit up, and soon became very hot, as the quantity of electricity oscillating to and fro in them was very considerable.
With the neon tube several important points could be established. In the first place, the great accuracy of tuning required; as a change of an inch or two in the position of the slider constituting the variable inductance in the primary circuit caused the glow to vanish, and a similar result followed when the lecturer brought his open hand near the helix, and thus slightly increased its capacity. By mounting a neon tube on a rotating axis he further demonstrated that the Poulsen vibrations were not quite continuous, as dark bands then became visible in the glowing mass formed by the rotating tube, showing that at certain points the light vanished. He had been trying to find a reason for this lack of continuity in the Poulsen oscillations, and it was, perhaps, partly due to a lack of uniformity in the speed with which the carbon member of the arc was rotated. This was done by an electromotor, and had to be effected with great smoothness. The brushes visible at the end of the helix he showed were actual flames capable of lighting a piece of paper.
The question might arise as to how the large currents in evidence were produced in the helix. This was effected in much the same way that a theater manager managed to represent on the stage a large army by marching to and fro a party of fifty supers. Similarly, the large currents in question arose from the passage to and fro of a small quantity of electricity. A 50-volt lamp connected to the terminals of the helix glowed brightly. Placing a coil of thirty turns of copper wire near the helix, Professor Fleming next showed that the currents induced in this could be transformed down. This was accomplished by bringing a coil consisting of a single turn of stout copper, short-circuited by a piece of fine iron wire, near this thirty-turn coil, when their on first glowed red, and finally melted.
As to the theory of the musical arc, it had, he said, been likened to that of the organ pipe, in which the passage of air, through the opening, set up and maintained a set of stationary waves in the rest of the pipe. In the same way, when a condenser was put across an arc it first robbed the latter of current. This caused the potential difference across the arc to rise and more current to flow into the condenser. The latter next began to discharge back across the arc, and as the current increased across the latter the potential difference fell, causing a further flow from the condenser. When this was discharged the current fell off in the arc, and the cycle of operations was repeated. A carbon arc in air appeared to require a large capacity, and hence there was a limit to the frequency produced.
With the carbon-copper arc in coal-gas, the characteristic, as shown in Fig. 5, was much steeper, and then much less capacity was needed. In the apparatus on the table the potential difference across the arc was zoo volts, but 1200 to 1500 volts were reached in the condenser, and some 60 to 70 per cent of the total energy involved was obtained in the form of the alternating current, which might have a frequency of one million per second.
As regarded the application of the system to wireless telegraphy, its announcement had been hailed as the death-knell of the spark-gap; but it was always a risky proceeding to issue an obituary notice of an invention prior to its actual decease. The Poulsen system was not free from drawbacks. It was much more complicated, and involved the use of coal-gas, means of keeping the carbon in rotation, and of preserving its exact distance from the copper electrode. Skilled attention was required, and it was very difficult to maintain it in continuous work for more than a quarter of an hour. Further, it was difficult to work it with either a small or a large amount of power. An ordinary 10-inch coil, with which spark-telegraphy could be effected up to a distance of 100 miles, took but one-fifth of a horsepower, whilst the Poulsen arc could not be well worked with less than 1 ½ horsepower. Again, 100 horsepower could be applied to the working of spark-telegraphy, whilst this could only be done on the Poulsen system by arranging a number of arcs in series, which presented great difficulties. Mr. Marconi had, however, recently devised a purely mechanical method by which the energy from a continuous-current dynamo could be transformed into high-frequency alternations. Owing to pending foreign patents, he could not, he regretted to say, describe the system in detail that evening, but he hoped that Mr. Marconi would do so himself ere long.
Professor Fleming next proceeded to consider several types of detector for electric oscillations, taking first the electrolytic detector of Fessenden. This consisted, he stated, of a very fine platinum point dipping for about
1 millimeter into an electrolyte of weak sulphuric acid, and acting as one electrode of an electrolytic cell. The other electrode was a plate of silver, see Fig. 6, and the apparatus when employed as a detector was arranged as indicated in Fig.7. The platinum electrode became polarized by means of oxygen, but if an electric oscillation was induced in the circuit, this polarization was dispersed and the current through the cell momentarily increased, thus causing a sound in the telephone. The detector, it should be noted, acted not merely qualitatively, but quantitatively, and it had therefore been possible to apply it to wireless telephony. The apparatus for this was, he continued, represented in Fig. 8, and consisted of a Poulsen arc coupled up with an antenna, the transformer of which was short-circuited by a microphone, as indicated. The latter, when spoken into, varied the strength of the waves, but not their length, and hence a current of varying intensity was passed through the electrolytic detector, coupled to the receiving antenna. Speech had with the apparatus been maintained over a distance of 16 miles, and it would be quite possible to speak across the Channel.
Another form of detector which also had the property of being a quantitative instrument had, Professor Fleming said, been introduced by himself some years ago. It consisted, as indicated in Fig. 9, of a glow-lamp, the filament of which was surrounded by a cylinder of nickel. When the filament was hot, negative electricity could pass from the filament to the nickel cylinder, but not in the reverse direction, and the instrument therefore acted as an oscillation valve. When submitted to the action of electric waves the current between the filament and the cylinder was rectified; as all oscillations in one direction were filtered out, this unidirectional current would deflect a galvanometer. The sensitiveness of the device had nothing to do with the size, of the filament, and he had himself used in some cases 12-volt lamps and in others 4-volt ones.
Hitherto the antennea used had been upright wires, which corresponded to Hertzian oscillators half buried in the ground; but, as Fitzgerald had shown, a closed circuit, if the frequency were very high, also acted as an oscillator. This Professor Fleming demonstrated by using two square coils, in one of which a high-frequency current was set up, whilst the
other was connected to a galvanometer through one of the oscillation valves just described. The coils being in tune, this galvanometer showed a deflection which, it was stated, was not due to Faradaic induction, but to electric waves. Here, then, he continued, was a new system of wireless telegraphy based upon the Fitzgerald oscillator, as Marconi's was on that of Hertz; and this new system was, he thought, capable of considerable development. If the oscillation valve was not fitted, the galvanometer showed no deflection, since it was affected by continuous currents only. The efficiency of this oscillation valve depended much on the intensity of the incandescence of the filament.
The objection had been raised to wireless telegraphy, he said, that there was no privacy in the matter, as the waves spread out in all directions, affecting all instruments within range. A little progress had, however, been made lately in giving the waves a definite direction. About a year or so ago Mr. Marconi found that if the antenna was bent horizontally, as indicated in Fig. 10,the waves were more intense in the direction opposed to that of the horizontal limb, and that a receiver similarly bent was most sensitive to waves reaching it from the corresponding direction. Such an antenna radiated better on one side than the other, but there was still a considerable radiation in every direction. By bending down the antenna, as represented in Fig. 11, the proportion of radiation in the one direction could be increased; and by using three wires arranged so that the waves produced interfered with each other in certain directions, Professor Braun, of Strassburg, had succeeded in keeping the radiation almost wholly on one side of the transmitter. Mr. Marconi had shown that these bent antenna could be used for the purpose of locating a ship. A number of these were arranged round a receiver, and by coupling this to each in turn the direction of the ship would be given by the antenna, which showed the strongest indications on the detector. By means of two such stations some miles apart the distance of the vessel could also be approximately determined.
In conclusion, Professor Fleming pointed out that, although much work had been done, large districts of research were still incompletely explored. The variable transparency of the atmosphere to these waves was, for instance, not yet fully explained. Very long transmissions were dependent, not only on special skill in devising the apparatus used, but also on the condition of the atmosphere. Sunlight, for instance, had been found prejudicial to the transmission of these waves. It was now known that there were numerous positive and negative ions in the atmosphere. These, when a wave passed, were moved by it, absorbing energy, so that an atmosphere charged with ions corresponded to a slightly turbid medium.
The lecture was illustrated by a large number of brilliant experiments. — Engineering.
WIRELESS TELEPHONY FOR THE U. S. NAVY.—Wireless telephony, as also wireless telegraphy, depends upon the production of electric waves that Pass through the atmosphere, and also solid substances, with a velocity equaling that of light—186,000 miles per second.
In order to transmit either telegraphic signals or vibrations corresponding to those of the voice, it is necessary to interrupt or vary these waves at intervals depending on the signals or character of the sound. The production and transmission of the waves is essentially the same in wireless telephony as in wireless telegraphy, but their interruption is an entirely different matter. The vibrations corresponding to the human voice have an average rate of about 500 per second, for a man's voice, extending up to 20,00 per second for the overtones, while in wireless telegraphy, manually operated, it is possible to work at a rate of about five interruptions per second, the telegraph signals of course corresponding to the familiar Morse alphabet. In wireless telegraphy the receiving of the waves is accomplished by any one of a number of devices, such as the coherer, the magnetic detector, electrolytic responder, etc., but in wireless telephony there is need of a specially sensitive device, and this is realized in the Audion, which, devised by Dr. De Forest and adapted for both space telegraphy and telephony, has been found a specially valuable element in the latter. This instrument appears at first glance to be simply a small incandescent lamp, but there will be noticed a plate and a grid of platinum sealed into the bulb and connected with the exterior by platinum wires. The filament is of tantalum or other metal and is made to glow by a current from a small storage battery. At the transmitting instrument current is supplied at 220 volts from the ships lighting mains. This direct current flows through choke coils which prevent the high-frequency alternating current from Passing, and then goes to the oscillator, which consists of an arc maintained in the flame of a small alcohol lamp. The production of high-frequency alternations from an arc was first discovered by Duddell in England and has been investigated by several physicists and experimenters, so that it was comparatively easy for Dr. De Forest to adapt the principle to his transmitting apparatus, although the actual application and the construction of a practical device required most elaborate and careful experiment. These currents with a frequency of about 40,000 per second pass through the primary of the transformer as indicated, a condenser being interposed in the circuit. The secondary of the transformer is connected with the antenna or aerial wire of the usual type used in wireless telegraphy, and to the ground through the microphone of an ordinary telephone transmitter. By adjusting properly the two circuits it is possible to pro duce in the aerial wire.oscillations that will cause waves of the desired frequency to be sent out in to the air. Now the vibrations of the voice acting on the microphone cause the resistance of the carbon granules to vary, consequently the resistance of the aerial wire circuit varies, and this correspondingly affects the amplitude or intensity of the waves emitted from the antenna, not cutting them off absolutely as in wireless telegraphy. Examining now the diagram for the receiving instrument, a similar aerial wire will be seen connected to the earth through one coil of a transformer,
while the circuit of the secondary includes two condensers, the audion with its storage battery, and the telephone with its cells. The electric waves impinging on the aerial wire set up a series of oscillations, which in turn are reproduced in the corresponding circuit of the transformer and affect the audion, causing the resistance of the gas ionized by the heat of the glowing filament to vary in proportion to the amplitude of the oscillations in the aerial wire, and the diaphragm of an ordinary telephone receiver is made to vibrate in the usual manner, reproducing the sound spoken into the transmitter.—Scientific American.
THE LUSITANIA.—The new Cunarders Lusitania and her sister-ship, the Mauretania, being intended to act as auxiliary cruisers in time of war, the following details taken from The Times may be of interest. The dimensions of the Lusitania are as follows:
Length over all 785 feet.
Length between perpendiculars 760 feet.
Beam, moulded 88 feet.
Depth, moulded 60 feet 4 1/2 inches.
Gross tonnage 32,500 tons.
Draft 33 feet 6 inches.
Displacement 38,000 tons
Type of engine Parsons turbine.
Number and type of boilers Twenty-five cylindrical.
Number of furnaces 192
Steam pressure 195 lbs.
Total heating surface 158,350 square feet.
Total grate area 4,048 square feet.
Total I.H.P. (designed) 68,000.
Speed (designed) 25 knots.
One important feature dealt with in fixing the designs had reference to the use of the ships as cruisers or scouts in time of war, and the machinery-which is almost entirely under the water-line—has been so disposed in separate compartments, and with coal protection along each side, as to Counteract, as far as possible, the effect of the enemy's fire at the water-line. For purposes of attack, the Lusitania will be provided with an armament as satisfactory as the armored cruisers of the County class, because on one of the topmost decks there will be carried, within the shelter of the heavy shell-plating, four 6-inch quick-firing guns, while on the. promenade deck on each side there will be four more guns on central pivot mountings, also able to penetrate 4 3/4-inch armor at 5000 yards range, and 6-inch armor at 3000 yards range. With the great speed, which can be maintained for three or four times the period that any modern cruiser can steam even at only 21 knots, and with the careful sub-division for protection and their satisfactory offensive power, the Lusitania and her consort may be regarded as most effective additions to any fighting squadron. Their advent is, therefore, a great advantage from the point of view of British sea-power.
The rudder and steering gear are all placed well below the water-line. This is a most important point in respect of protection, should these vessels be ever impressed into the national service. The stern has been suit- ably shaped in the Lusitania to enable this object to be accomplished satisfactorily.—Royal United Service Institution.
THE HAGUE CONFERENCE.—Among the new rules of war adopted at the final sitting of the Peace Conference recently are three affecting the navies of the world, to which the various Powers concerned will be required to signify their adherence or otherwise before June 30, 1908. The first en- acts that military hospital ships and hospital ships privately equipped, the names of which shall have been communicated at the opening or in the course of hostilities before being employed, cannot be captured during hostilities. Military hospital ships will be painted white, with a horizontal green band of about a yard and a half in width, while private hospital ships are to be painted white, with a horizontal red band of the like width.
The second new rule was obviously suggested.by the progress that has lately taken place in the evolution of dirigible airships. It provides that the contracting Powers shall agree, for a period extending to the end of the third Peace Conference, to the prohibition to hurl projectiles and explosives by dropping them from balloons or by new methods of a similar character. The declaration will cease to be binding when, in a war between contracting Powers, a non-contracting Power should join one of the belligerents. Should one of the contracting Powers denounce this declaration, the denunciation shall only come into force one year after written notification to that effect has been made by the denouncing Power to the government of the Netherlands, which will immediately communicate the denunciation to all the other contracting Powers.
The third rule, bearing on naval affairs, deals with the opening of hostilities, and enjoins that the contracting Powers recognize that hostilities between them shall not begin without previous unequivocal warning, which shall take the form either of a declaration of war with reasons assigned, or of an ultimatum accompanied by a conditional declaration of war. It is significant of Germany's attitude towards this last measure that Baron Marschall declared at the Conference in substance what amounted to a notification that Germany will be no party to any international compact that would limit, in the faintest degree, her freedom to make a sudden attack upon any nation with which she may have a difference of opinion. —United Service Gazette.
BATTLESHIP STRENGTH AND RELATIVE VALUE.-With October comes the intersessional political oratory, and this year we are promised a more than usually vigorous campaign. Two questions of interest to all connected with industry will be brought to the front: the one connected with trades-union organization and legislation, the other associated with naval strength and Admiralty administration. The former topic can only be considered when the demands of the labor socialist have been formulated. As regards the latter subject, the facts are indisputably in favor of the Admiralty policy during the past three years or so. We shall, as ever, be confronted with lists which state that Great Britain possesses so many battleships, that France, Germany, the United States of America, etc., possess so many; and starting from this hypothesis, articles will be written to prove that either now, or at some date in the comparatively near future, the first-named Power will be overtaken and passed, and that the sea supremacy, which none deny to her in the present, will then be dangerously jeopardized. But the writers and speakers who merely count units—units which are described as battleships—do not always analyze, and lay before the public which they address, the data concerning the vessels mentioned in these lists.
If a comparison is to be of any value, it must take into account not only the number of ships, but also their fighting capacity. As an example let us see in what way the Channel fleet, under the command of Lord Charles Beresford, will be constituted in the immediate future. It will consist of eight ships of the King Edward VII type, and six of the formidable type, fourteen battleships, forming the most powerful and also the most homogeneous force, which is an all-important matter, in the whole world. Of the first type mentioned, the oldest was launched in 1903, the youngest—the Hibernia—in 1905. These eight ships each carry four 12-inch, four 9.2-inch, and ten 6-inch guns, as well as small guns and five submerged torpedo tubes; their armor is 9-inch Krupp amidships, tapering to 6-inch and 2-inch; their horsepower is 18,000, and their speed nearly 19 knots, their tonnage being 16,350 tons. The Formidables are older, November, 1898, being the date of the oldest of the class, and their size is smaller, being 15,000 tons, carrying four 12-inch, twelve 6-inch, besides small guns and four submerged tubes; the horsepower is 15,000, and speed 18 knots. These details are given in order that comparisons may be instituted be- tween this, the principal British fleet, and the ships of foreign Powers; showing the relative strength of the units which go to make up their fleets, as well as our own. The home fleet, which contains the Dreadnought, and the Atlantic fleet are purposely left on one side in order to avoid confusion.
The Navy of the United States of America has, of late years, outstripped that of France and taken second place, next to our own. Undoubtedly, however, the Dreadnought took the Americans by surprise, and since her trials and the demonstration that this new departure was a success, they have been at tempting to make up their leeway. If we go back to 1898, the date of the oldest of the Formidables, we shall find that the United States built in that year the Kearsarge and Kentucky, of 11,500 tons, carrying four 13-inch, four 8-inch, and fourteen 6-inch guns, with a 16, A-inch Harvey-nickel armor belt amidships; the horsepower is to 500, and speed 16 knots. In the same year were built the practically identical ships Alabama, Illinois, and Wisconsin—as tar as tonnage was concerned—but the armament of which differs considerably from that of the Kearsarge and Kentucky, as, instead of four 8-inch, they carry fourteen 6-inch guns. It will be observed that the Formidables are superior in nearly every respect, and have the enormous advantage of homogeneity. In 190x the United States built the Maine class of three ships, of a tonnage of 12,500, carrying as their main armament four 12-inch and sixteen 6-inch guns; horsepower, 16,000, and speed, 18 knots. In 1904 came the New Jersey class of five ships, of 14,948 tons, with four 12-inch, eight 8-inch, and twelve 6-inch guns; horsepower, 19,000, and speed, 19 knots. In the same year came the Louisiana and Connecticut, of 16,00o tons, with practically the same armament; and in 1905 came a reversion to a smaller type—the Idaho and Mississippi, of 13,000 tons, with eight 7-inch guns, instead of twelve 6-inch. The Kansas class, of 16,000 tons, also date from 1905, and carry the same guns, except that they have twelve instead of eight 7-inch guns, and that with a horsepower of 16,500 their speed is 18 knots. In 1906 the first of the South Carolina class was laid down; and in this ship, and her sister, the Michigan, comes a foreshadowing of the future, as with a displacement of 16,000 tons their armament is eight 12-inch guns, the speed and horsepower remaining the same as in the case of the Kansas class. But the Dreadnought had seized upon the American imagination, ever prone to indulge itself, both by sea and land, with the biggest thing going, and two ships, forming the Delaware class, are to be laid down during the present year; their displacement is reckoned at 20,000 tons, and their armament will be ten 12-inch guns. In considering the available battleships of the United States, we shall see that, supposing them all to be in commission and ready for sea—which they are not—they could oppose 21 to the 14 of our Channel fleet (which are ready and in commission), that five of these are vessels of 11,500 tons, and that homogeneity would be far to seek. Of personnel it may be stated in passing that the United States Navy is short some thousands of men; and although the officers responsible say that this deficit could easily be filled, it cannot be considered that the navy is an efficient service until this is done; and, in spite of official optimism, the supply of free-born white Americans who seek to gain a living on the sea is by no means on the increase.
The importance of the French Navy has been always reckoned as one of the most potent factors in keeping the balance of European armaments; but it cannot be said that of late years the great Republic has kept up her ancient fame in this respect. This is no place to deal with the political aspect of affairs, but the man who has followed with intelligent interest the doings in the French Navy, and the French arsenals, for the last five or six years, would be blind and deaf to patent facts did he not recognize the enormous mischief wrought, both in the disciplined service and in the great industrial undertakings with which its upkeep is maintained, at the hands of a socialistic Minister of Marine. Dearly is M. Gaston Thomson paying for the policy of his predecessor, M. Camille Pelletan, the Socialist, and dearly are the country and the government paying in bad discipline and slackness among its employees, as well as in the more vulgar and tangible asset of hard cash. Thus it is that in relation to the French fleet of the present day one finds some difficulty when it comes to comparison of battleship strength, as no battleships were laid down for more than three years, and the last of the 1900 programme has only just left Saint-Nazaire for Brest, to begin her trials. Not only was in calculable mischief done to discipline and the morale of the fleet and dockyards—witness the strike of the Inscrits Maritimes at Toulon three summers ago, and the antics of that most militant union, the "Syndicat Rouge," in the dock yards; but also the Minister considered that, in addition to anything else, it behoved him personally to advise as to the class of vessel upon which the naval credits voted were to be spent. M. Pelletan decided against battleships, and perpetuated the error of Gabriel Charmes and the "jeune marine" of the early eighties, who declared that the day of the "capital ship" had come to an end as soon as the automobile torpedo became a practical and accomplished fact. Gabriel Charmes and his school pinned their faith upon torpedo-boats of great speed, but the sea soon demonstrated that such craft were of small value in heavy weather. The submarine, in like manner, became the obsession of M. Pelletan, and on the submarine and the "petite marine," or small craft, has all the money been spent of late years. At last, however, saner counsels have prevailed, and France has started to make up all the leeway that she has lost.
It is impossible in the present day to consider that the Charlemagne class, of three ships which date from 1895, are of very much fighting value. They are, however, still on the active strength of the navy; they are 11,200 tons, and carry four 12-inch and ten 5.5-inch guns. The Jena, dating 1898, was, as all the world knows, blown up at Toulon in March of the present year. The Suffteen, 1899, is 12,750 tons, and carries four 12-inch and ten 6.4-inch guns; horsepower, 16,200; speed, 18 knots. The list closes with the Republique (1902) and Patrie (1903), of 14,865 tons, carrying four 12- inch and eighteen 64-inch guns; and the Liberte class, of four ships, of 14,900 tons, with four 12-inch and ten 7.6-inch guns; horsepower, 18,000; speed, 18 knots. But "mastodonte," as the French aptly call the craze for big ships, has seized also upon the Republic. At last common sense has regained her sway, and with it recognition of the fact that to be strong on the sea you must possess ships capable of lying in the line-of-battle. Therefore there have been laid down six ships—the Danton class, of 18,400 tons, to carry four 12-inch and twelve 9.4-inch guns. Further than this, it has been recognized that the worst of all economies is to keep ships too long upon the stocks, and in consequence, instead of seven years, it is designed that the Danton and her five sister ships shall pass into the active service four years from the date upon which their keel-plates were laid.
Their fleet, both war and mercantile, is among those things of which the Germans are the most proud—and with reason. The Kaiser on a memorable occasion declared that "the future of Germany is on the sea," and to do him justice, he has never ceased, in season and out of season, to do his best to ensure that that future shall be prosperous. Germany, like every other nation, piles ship upon ship and gun upon gun, protesting loudly all the while that nothing is further from her thoughts than war; this, of course, is all part of the game, and nobody minds, because we all do and say the same thing. But it may be permissible to doubt whether Germany does not view the development of "mastodonte" in warships with greater dismay than any other nation. The Fatherland was really getting along very nicely in the naval way until the arrival of the Dreadnought put all her plans astray. There is one thing that neither King, Kaiser, nor Republican President can alter, and that is the physical configuration of the land in which they dwell, and Nature has ensconced Germany behind one of the most intricate and tortuous labyrinths of sandbanks which exist in the world. Very useful are such natural defences against a potential maritime enemy, but when a nation wishes to develop into a great maritime Power, they embarrass it almost as much as they would do its foe. As at present constituted, the German Navy possesses no battleship of over 13,200 tons, and has a float no gun of a greater caliber than 11 inches. There are five of the Braunschweig class, dating 1902-3,and five of the Deutschland class, dating 1904-6, of this tonnage, carrying four inch and fourteen 6.7-inch guns; horsepower, 16,000; speed, 18 knots. There are also five Wittelsbachs, of 11,830 tons, and five of the Kaiser class, of 11,150 tons, carrying four 9.4-inch and eighteen 6-inch guns, 15,000 and 14,000 horsepower and speed 18 knots. The Brandenberg class, of four ships, date from 1891, and are of 10,060 tons.
If we compare these ships, of which the German high sea fleet is composed, with the Channel fleet alone, we need not, at all events, fear the comparison. But Germany has further ambitions and the "mastodons" which she has projected are the Sachsen, Baiern, Baden, and Wurtemberg. They are to have a tonnage, it is reported, of 17,710 tons, possibly 19,000 tons—but apparently nothing definite has been settled—and are to carry sixteen 11-inch guns.
The most modern battleships possessed by Japan are the Kashinta and Katori, dating 1905; they are 16,400 tons, carry four 12-inch, four 10-inch, and twelve 6-inch guns, have a 9-inch Krupp belt amidships, horsepower 17,000, and speed 18.5knots. Our allies, however, are, perhaps, further advanced than any other nation except ourselves along the road of big-ship building, as the Satsuma, of 18,800 tons, is already in the water, and her sister ship is advancing towards completion. There a re also one ship, as yet un-named, building, and one projected of 20,750 tons.
Of Russia there is but small need to speak at present, as her navy is in anembryonic stage. Even when it is completed, it will not rank very high in the estimation of the world unless its methods of training are vastly different from those which obtained before the Russo-Japanese war.
Italy projects to lay down three or four ships of 16,000 tons; but those remarkably able men, the Italian constructors, have always held that for their country moderate tonnage would suffice, and to-day 16,000 tons represent moderation.
Austria is more modest still, as 14,500 tons is the limit, as far as is known, to which she will goat present in big-ship construction. There are other countries also which possess warships; but, as far as battleships are concerned, they may at present be left on one side.
The conclusion of the whole matter would appear to be that, for the present, England is in as at is factory position. But the pace is being forced all along the line, and our rivals are striving to overtake and to surpass us. If this fact is kept in mind by our politicians, we need not fear for our supremacy, for we can build faster than any other nation, and certainly quite as well. The danger is that we may presume on our abilities, and defer our preparations too long. Fortunately, all parties are agreed that the British Navy must always remain supreme on the seas—Engineering.
THE DEVELOPMENT OF THE MOTOR BOAT.—The rapid development of the motor boat during the past few years has been one of the direct results of the enormous growth of the automobile industry. Motor-boat building can as yet scarcely be called a separate industry, but that it is rapidly attaining that position is evidenced by the large number of firms who are interesting themselves in its development and by the attention which is being paid by engineers to the problems connected with the application of the internal-combustion engine to marine propulsion. An interesting sketch of the development and present status of the motorboat was recently given by W. Kaemmerer before the Verein Deutscher Ingenteure, of which the following is an abstract.
When one considers the share of the various countries in the development of the motor boat, the industry is seen to be a direct result of the development of the automobile, for France has taken first place in motorboat building also. This applies, of course, less to boats for commercial and general use than to racing craft, in which department French builders have been unusually successful. That racing trials, for which such boats were primarily built, have an important technical value aside from their sporting interest is easily seen from the progress of French motor-boat building, which certainly would not have attained its present status if the stimulus of the racing fever had been lacking. One of the most important results which must be attributed directly to the prevalence of the sport in France was the gradual lessening of the weight of the motor. Some of the results obtained in this direction were quite wonderful, the Societe Antoinette, for instance, producing a motor which had the almost incredibly small weight of 1 to 1.5 kilograms per horsepower and was, at the same time, an efficient and safe machine. To the influence of racing must also be attributed a great deal of the development of the motor boat in Italy, where it has attained a high degree of perfection. All the principal firms connected with the industry produce the boat complete and on that account have attained excellent construction. In England, Germany and the United States motor-boat building seems to have been taken up more on the practical and commercial side, and, although some firms in each country make a specialty of racing craft, by far the larger number of boats built are designed for commercial and general service. The United States leads in the number of firms which produce motor boats as a part of their regular output and many of them are attempting to build up a large export trade by the establishment of branch houses in Europe.
The applications which may be made of the motor boat are very numerous, but, aside from pleasure craft, the greatest interest has been paid to its applications in the navy and its associated interests. The Italian Navy has been especially active in this regard. That the motorboat has not had a more rapid and general development is due to the peculiarities of the internal-combustion engine in its present condition. Of these, high speed and low efficiency of screws and the difficulties of reversing and speed regulation have been the most important factors in retarding development. The difficulty of speed regulation is a great drawback in heavy weather: to maintain a high speed in a small boat on a heavy sea results in filling the boat so full of water that it must either capsize or sink. The question of fuel is still unsettled. The use of benzine is attended with great risk of fire unless great caution is used. Recently the effort has been made to substitute petroleum or other heavy oils for the commonly used benzine. The general introduction of these oils would greatly reduce the risk of explosions and also operating costs, but would necessitate alterations in the design of motors.
The British Navy seems to have in view the application of internal-combustion motors to larger vessels, which, unlike the auxiliary boats of the larger ships of the squadrons, are designed to constitute a distinct fighting unit. These are what are known as motor torpedo boats. The first representative of this class was brought out by Yarrow & Co. in 1936. The vessel is 18.28 meters long and 2.74 meters beam and the draft is from 0.3 to 1 meter. Tried without load it reached a speed of 25.5 knots, and, with a 3-ton load, 24 knots. The boat was propelled by three benzine motors of a total of 300 horsepower, working three shafts at a speed of moo revolutions per minute. The outer machines have eight cylinders, and the middle motor, four. The former can be used only forgoing ahead, but by means of a reversing gear the boat can be run astern on the middle motor.
The general introduction of this type of torpedo boat would get back to the original design in the introduction of the torpedo arm into naval service. This was to put in service large fleets of small but very swift boats, offering the smallest possible target area and armed only with torpedoes, which were to attack hostile ships in great numbers. But the size of torpedo-boats has steadily increased until now they resemble small cruisers and are rarely under 50 meters long and of a displacement of 500 tons.
The great advantage of the motor torpedo-boat is its small weight of only eight tons. It is therefore possible to transport it by rail, an advantage which might be of the utmost importance in time of war in providing a harbor, attacked from the sea, with new and important means of defense.
In 1905 ten motor torpedo-boats were built in America for the Russian Navy, after designs by Mr. Lewis Nixon. These were somewhat larger than the Yarrow model, but still light enough enough for transportation by rail. On the other hand their speed, of 20 knots, was considerably smaller than that of the former model. These boats are 27.43 meters long,
3.35 meters wide, and draw 1.2 meters of water with a load of 34 tons. The weight of motors and fuel amounts to 15.5 tons, and with this amount of fuel they have a sphere of action at full speed of 400 knots. The small American torpedo-boats built for similar speed have a displacement of 51 tons and a sphere of action of from 100 to 160 knots. The Nixon boats are propelled by two six-cylinder benzine motors working on two shafts and reversed by means of compressed air. The armament consists of a deck torpedo tube for torpedoes of 450 millimeters diameter, a 4.7-centi- meter quick-firing gun, and several machine guns. These boats are very seaworthy, as was shown by a voyage made by one of them under its own power from New York to the Black Sea during fairly rough weather.
A boat similar in construction to the Yarrow model but somewhat smaller has been built by Fiat-Muggiano for the Italian Navy. It was designed as a torpedo-armed auxiliary for warships, but may be applied to similar service as the British boat, though its speed is only 15 knots. This vessel is 13 meters long and 3 meters wide. It is propelled by two benzine motors of a combined power of 200 horsepower, working on the same shaft and started and reversed by compressed air. The total weight of the vessel, including machinery, is 7 tons. Fuel for an 180-knot voyage can be carried in tanks arranged forward and at the sides. The armament consists of two 356-millimeter torpedo tubes, a 47-centimeter quick-firing gun and two machine guns. A later boat built by the same firm was 11 meters long and had a displacement of 5 tons. It was driven by two 60-horsepower motors on the same shaft and reached a speed of 17 knots. For tenders the Italian Navy uses motor boats almost exclusively. The vessels built for this purpose by Fiat-Muggiano are 8.5 meters long, 2.35 meters wide and 0.58 meters draft. The displacement with a crew of 16 men and 200 kilogrammes of fuel is 3.2 tons. For the service for which these boats are designed an average speed of 8.5 knots is sufficient and this can be maintained by a 20-horsepower motor. At this speed enough fuel for a 24-hour run can be carried.
Although the German Navy has as yet built no motor torpedo-boats, several vessels propelled by internal-combustion engines have been placed in various services and the question of their general introduction is being considered. In 1903 the Daimler Company built a small vessel for general service in the torpedo department of the Kiel navy yard. This boat was propelled by an 8-horsepower petroleum motor which was the first motor using this fuel to have electric ignition and to be started by benzine. Since that time many other boats have been built for use in the navy, nearly all of them using petroleum as fuel owing to the much higher price of benzine.
Probably the most important motor boat employed in the German Navy was built by the Daimler Company for torpedo testing at Kiel and is used also for short voyages by the higher officers of the fleet. This boat is 17.7 meters long and 2.40 meters beam, and the immersion of the screw with 7 tons displacement is r meter. The metacentric height with 600 kilograms of fuel and a crew of six men is 450 millimeters. The boat is propelled by a 300-horsepower,6-cylinder motor which is located amidships. To the rear of the engine room is placed a fuel tank with a capacity of 750 liters. This amount of fuel is sufficient for a 6-hour.voyage, but for longer trips other tanks can be carried easily. The fuel is ordinary lamp oil and the consumption is roughly 0.32 kilogram per horsepower hour. The speed of the mator is from 800 to 900 revolutions per minute. In spite of the high power of the motor it is reversed by a hand-operated reversing clutch. The starting is also by hand, the fuel being drawn through the carbureter into the cylinder by a small hand pump. The average speed attained is 19 knots.—Engineering Magazine.
PRACTICAL STEAM ENGINEERING.
TWENTY-ONE DAYS IN THE ENGINE ROOM.
Compiled by LIEUTENANT PAUL FOLEY, U. S. Navy.
During the summer practice cruise of 1907, on board the U.S.S. Arkansas, there was evolved a course in practical steam engineering, which produced such happy results that the author feels encouraged to present it in the pages of the PROCEEDINGS, in the hope that it may be of some assistance to those still wrestling with the problem of acquiring that knowledge of, and familiarity with details, that alone distinguishes the practical engineer officer from his theoretical brother.
The course herein outlined is by no means complete in itself. At some future time it is hoped to make it more exhaustive, but it is confidently believed that a very cursory examination will convince anyone that this system as a system of instruction is immeasurably superior to the note book and lecture system of old, and that even as it stands it will carry a beginner very far along the road that ends in practical information.
CYLINDER ATTACHMENTS AND FITTINGS.
Read Barton,* pages 131 and 142.
(a) From what point is the jacket steam taken?
(b) What pressure is carried in each jacket?
(c) How is the reduction of pressure in the intermediate, and low pressure jackets obtained?
(d) How is the excess of pressure in each jacket provided against?
(e) To what place do the jacket drains discharge, and how?
(a) To what point on cylinders are they led?
(b) How are they operated?
(c) To what point do they discharge?
(d) Note the use, and location of then on-return valve in the bilge discharge.
(e) Note position of dial thermometer.
Cylinder Relief Valves.
(a) How are they fitted, how are they loaded, and to what point do they discharge?
(a) How is the stroke of the engine reduced for indicator use?
(b) How many valves are there on the indicator stand pipe, and what are they used for?
THE STEVENSON LINK.
Read Barton, pages 94, 95, and 98 to 102 bottom.
In the examination of this link motion, turn steam on the reversing engine, and move links back and forth until you are thoroughly familiar with the gear.
Note carefully the following points:
(a) The point of suspension.
(b) The method of securing the eccentric rods to the link.
(c) The method of securing the suspension rods to the link.
(d) The reference marks on the side of the independent cut-off blocks, and their meaning.
*Barton's Naval Engines and Machinery, published by the U. S. Naval Institute.
(e) How links are always in full gear when going astern.
(f) Note how the twin valve stems of the intermediate cylinder are controlled by one link.
(g) Note the difference in shape between the forked end of the go-ahead and backing eccentrics.
(h) Note how linking up reduces the travel of the valve.
WATER SERVICE, MAIN ENGINES.
(a) How supply may be obtained by gravity.
(b) How it may be augmented by pump.
(c) How circulating water is sent to slides, main bearings, and thrust Read Barton, page 508, Navy Regulations, in regard to use of water on bearings (3 requirements).
OIL SERVICE, MAIN ENGINES.
1. The various parts of a marine engine to which oil must be supplied may be divided into three classes:
(a) Stationary parts.
(b) Parts moving in a straight line, as slippers, and wrist pins.
(c) Rotating parts, as cranks and eccentrics.
2. Start at top of engine and work down, noting the following:
(d) Arrangement of reservoirs, and pipes leading there from.
(e) Arrangement of wicks: How rigged, material of which made, and disposition of same when engines are idle.
(f) Follow lead of oil pipes to:
Down connecting rods to cranks.
(g) Note the position, and rigo foil cups, the hair used in them, and the wires preventing egress.
(h) Follow the lead of oil pipes to eccentrics: This arrangement being what is known as telescopic oil gear.
3. Having finished with the above, look at stationary oil cups for main bearings,and cups for links.
4. Look over oiling system of circulating pumps.
5. Read Barton, pages 507, 508, Navy Regulations, Art. 1606, par. 6, 7; Art. 1609, par. 5.
FOURTH DAY. STEAM REVERSING ENGINE.
1. Read Barton, pages 102, 103, and 104.
2. Turn steam on reversing engine, and find the two instantaneous centers for this vessel.
3. Note the two lines by which steam may be sent to the reversing engine.
4. Note carefully how the oil hand pump is connected to the oil cushion cylinder.
5. Go carefully over the details of reversing by hand, noting that in any case it is necessary to move reversing lever to proper position.
6. Throttle valve: Page 45, Barton, Fig. 7. Examine carefully the spindle "G" in that figure. This spindle, fitted on this ship, is known as the "choke," or "gag."
7. Bleeder valves: Position with reference to separator: Use in warming up main engines to drain the main steam line. How many valves on bleeder line.
8. By-passes to receivers: Location; use in starting; use for admitting live steam to receivers under way.
9. Spring loaded valve auxiliary condenser:
SPRING LOADED VALVE, AUXILIARY CONDENSER.
The purpose of this valve is to regulate the pressure in the auxiliary exhaust line.
If there were no valve, the auxiliary exhaust line would of course be under the same vacuum shown by the auxiliary condenser.
In order to make the feed water heaters, which take their steam from the auxiliary exhaust line function, it is necessary that there be a pressure above atmosphere in the auxiliary exhaust line.
This back pressure may be obtained by means of this spring loaded valve. When the pressure in the line exceeds that for which the spring is set, the valve lifts, and the pressure is relieved into the condenser.
When the main engines are running, and the auxiliary condenser shut down, back pressure in the auxiliary exhaust line can be obtained by turning this exhaust into the low pressure receiver of the main engines, the pressure in this receiver being ordinarily about 3 or 4 pounds above atmosphere. The entire auxiliary exhaust line will then be under whatever pressure there is in the low pressure receiver.
This method is not as reliable as the first, on account of the fluctuations of pressure. It gives a back pressure, but not a steady pressure.
The introduction of back pressure above atmosphere in this line interferes somewhat with the running of the dynamo engines, when they exhaust into the same line. A small pressure makes little difference, but it should not be carried above 6 pounds, when the dynamos exhaust into the same line.
It is essential that it be clearly understood how it is possible to have a line under pressure above atmosphere delivering into a condenser under pressure below atmosphere, without impairing this vacuum.
U. S. S. ARKANSAS, ENGINEER DIVISION. MAIN CONDENSERS. Connections.
(a) Main exhaust pipe. Is there a valve between the low pressure cylinder and the condenser? If not, what is done with this inlet when the condenser is tested under pressure?
(b) Auxiliary exhaust connection. Is there a valve?
(c) Bleeder pipe connection.
(d) Cylinder and evaporator drains. Are heater drains connected?
(e) Boiling out connection.
(f) Connection of balance piston, low pressure cylinders.
(a) Vacuum gage. Why is it graduated in inches?
(b) Mercurial gage. Location and purpose.
(c) Air cock.
(d) Spring safety valve.
(e) Drain cocks.
(f) Location of soda tank, and detailed method of injecting soda or kerosene into each condenser.
(g) What is the atmospheric exhaust, and when is it used?
(h) Read Barton, page 508, Art. 1608, Navy Regulations, par. 1, 2.
(k) How and where is make-up feed introduced into the system?
At various points throughout the department dial thermometers are fitted. These thermometers are constructed upon the difference of coefficient of expansion of two metals, usually copper and tin. They are unreliable.
U. S. S. ARKANSAS, ENGINEER DIVISION.
MAIN AIR PUMPS.
Read Barton, page 179, carefully.
(a) Position of pump with reference to condenser. When possible, the air pump should be so placed that the foot valves are below the level of the bottom of the condenser.
(b) Note construction of rocker driving arm.
(c) Note how the oscillating motion of this driving arm is transferred to the straight line motion of the plunger rod by means of connecting links.
(d) Thermometer on top of pump. What is it for?
(e) Note drains for head plate and bucket.
(f) Are these air pumps single or double acting?
(g) Of what material are the following parts made:
Barrel. Plunger rod. Bucket. Valves.
(h) What is a regurgitating valve, and what is it used for?
(k) Read Barton, page 508, Navy Regulations, Art. 1608, par. 4, 6.
CHANNEL WAY PUMP.
The function of this pump is simply to relieve the air pump suction of entrained water, and at the same time to maintain a low vacuum when the main condensers are in use, with the main engines stopped.
U. S. S. ARKANSAS, JULY 5, 1907. MAIN CIRCULATING PUMPS.
Read Barton, pages 187, 188, 189.
(a) Location of main injection valve.
(b) Location of adjacent suctions to main drain, and bilge, with inter-locking device.
(c) Note steam pipe, leading from auxiliary steam line to injection pipe, outside of valve. What is it used for?
(d) Why is a by-pass fitted between the main injection, and discharge pipes, and when is it used?
(e) Does injection water enter at upper or lower half of condenser?
(f) Is there any other pump in this engine room that could be used to flush the condenser in case the main circulating pump is disabled?
(g) Will one circulating pump flush both condensers?
(h) Is the engine driving circulating pumps a compound engine? If not, what is it?
(k) How and where do you obtain the temperature of circulating and discharge water on this ship?
(l) What is the side injection, and when is it used?
FEED AND FILTER TANKS.
Read Barton, page 185.
(a) Point to which the delivery of the main air and channel way pumps isled. Is there a valve near tank?
(b) Is there a vapor pipe? What is it used for?
(c) Where is the overflow pipe? Where does it lead? Note that it is located so as to be visible from the working platform.
(d) Note the spring-loaded relief valve.
(e) Location of gage glasses.
(f) How and where is the temperature of feed water obtained?
(g) The various feed pump suctions are severally tapped either into the feed tank proper, or more frequently, as in this ship, are tapped into a cross-connecting pipe between the two feed tanks. This pipe is fitted at each tank with a valve operated by a copper float. When the water level in the feed tank falls below float, the valve closes, and prevents air being sucked by pumps. The levers by which these floats are controlled are visible from the outside.
(h) Are there any valves in cross-connecting pipe?
(k) Note the connections for drainage from separators, main and auxiliary steam pipes.
(l) Where is the inlet placed with reference to the ordinary working level?
(m) Does this connection lead to feed tank proper, or to filter tank?
(n) Why are the cylinder, evaporator, and heater drains led to the condenser, while those from the steam pipes, jackets, and separators are led to the feed tanks?
(o) What filtering material is used in this vessel?
(p) Observe that the bottom of the feed tank is above the water end of all the feed pumps.
PREPARATIONS FOR GETTING UNDER-WAY.
In connection with the blue print of the piping system in the log room, and supposing that boiler C is in use for auxiliary purposes, find out:
(a) What valves on the main steam line are open, and what valves are closed. Every valve must be accounted for, 13 in all.
(b) Assuming that fires are to be lighted in boilers A, B, and D, and that the main engines are to be warmed up with these boilers, what changes will be made in what valves, and how many turns will be given to the spindle of each valve?
(c) Disconnect jacking gear. How is it done?
(d) Open main injection and discharge valves. See that by-pass is closed.
(e) Start main circulating pumps. Locate drains, steam, and exhaust valves.
(f) Drain main steam line. Locate two drains in evaporator room on each side, and one in engine room on each side. Open separator drains.
(g) Steam on the reversing engine, using steam from the auxiliary line.
(h) Open cylinder drains.
(k) Open valve to jacket line. Open jacket drains.
(l) Water on water service pipe, where? When put water on slides thrust and main bearings?
(m) Slack stern gland. Where, and how much, and why?
Read Barton, pages 457, 458, and 459.
There are two separate and distinct methods of warming up the main engines and the main steam line, and it is essential that they should not be confused. The two methods are the ordinary and the emergency.
The ordinary method is to warm up the engines and the main steam line by means of the boilers in which steam is being raised. In this method the boiler stops of the new boilers are cracked as soon as fires are lighted, and every other valve on the main steam line and jacket line opened wide, allowing the hot air, and subsequently steam, to flow through. When the steam is up to the working pressure, the auxiliary boilers that have been in
use all the time are connected up to the new boilers.
The emergency method is to warm the steam line and main engines by means of the boilers already in use. The stops of the new boilers are kept closed, and as the pressure comes up, each in turn is connected to those already on, until finally the whole system is connected up.
U. S. S. ARKANSAS, JULY 7, 1907.
FEED WATER HEATERS.
Read Barton, page 344.
The economy and increased efficiency of boiler plant resulting from the use of feed water heaters is very great. The following facts in connection with them should be well digested.
(a) That the saving is obtained by causing the latent heat of the auxiliary exhaust steam to heat the feed water, instead of allowing the circulating water of the condenser to take the heat away.
(b) That the temperature of feed that can be obtained with any given heater depends solely upon the pressure in the auxiliary exhaust line, and varies with that pressure. The temperature of feed water obtained must necessarily be somewhat less than the temperature of the steam used to heat it.
(c) An efficient heater will give a temperature within 10 degrees of the temperature of the steam.
(d) In connection with the subject of the temperature corresponding to pressure, see Barton, Steam Tables, page 520. For example, note that the temperature of an auxiliary exhaust line attached to a condenser showing 16 inches vacuum, or 7 pounds back pressure (absolute) would be 177 degrees. Also that the boiling point of water under 225 pounds pressure, 240 absolute, would be about 400 degrees. In dealing with ships' plants, it is necessary to get away from the 212 degree idea in connection with the boiling point of water.
(e) A pressure of about 5 pounds above atmosphere, 20 pounds absolute, will give a feed temperature of about 220 degrees.
(g) Temperatures above 212 degrees can only be recorded by dial, or some form of attached thermometer. When the feed line is tapped, the maximum temperature that will be recorded will be 212 degrees.
(h) Heaters may be either suction or pressure heaters, and both may, be either vertical or horizontal.
(k) The preferred type is the closed, vertical, pressure heater, similar to that installed on this vessel.
(l) In this type the feed water goes through the tubes, and the exhaust steam outside the tubes. In the heaters installed in this vessel there are about 200 tubes in each heater, of similar size, and material to condenser tubes, and inserted in tube sheets in a similar manner.
(m) To secure the highest temperature the heater must be so arranged that the hottest water strikes the hottest steam—that is that the steam should enter the heater at the top, and be made to flow across the tubes by means of horizontal baffles.
(n) The water should enter at the bottom, and discharge at the top to ensure heater always being full.
(o) Both main and auxiliary feed lines are connected to heater by suitable by-passes.
(p) Heater drains are led direct to the condenser or feed tanks. In this vessel there is a trap.
(q) Note gage glass and steam gage.
(r) Note that there are two heaters, one on each side.
MAIN FEED PUMPS.
Read Barton, page 338.
Main feed pumps have fresh water connections only. They draw from the feed tanks and reserve feed tanks, and discharge to the main feed line, through the heater, or by the heater as desired; and to the reserve feed tanks, the delivery pipe to the reserve feed tanks being a branch of the main feed pipe with a valve in it.
(a) The number, location, and make of the main feed pumps of this vessel.
(b) Locate the maker's name plate on pump, and read it carefully. This data is sufficient to identify pump, and secure new parts.
(c) Locate steam and exhaust pipes of steam end, and cylinder drains.
(d) Locate pressure gage for steam end.
(a) Is it a single or double acting pump?
(b) Locate suction from feed tanks and suction from reserve feed tanks.
(c) Are there any valves on suctions other than those at the pump?
(d) Locate discharge to the main feed line direct, and discharge through heater.
(e) Locate discharge to the reserve feed tanks.
(f) Locate spring relief valves. Where do they discharge to?
(g) How many air chambers are there, and where are they placed?
(h) Are the air chambers fitted with cocks at the top, and if so, what are they used for?
(k) Locate pressure gage for discharge end of pump.
(l) What is the pet cock on the top of water chamber for?
(m) How are the head valves of the water chamber drained?
(n) Is there a blank flange connection, and if so, why?
(o) Why are pump gages graduated to record pressures considerably in excess of the designed working pressure of the boiler?
(p) When a pump is not in operation, the cylinder drains should be kept closed, why?
Read Barton, page 509, Art. Government Navy, 1608, par. 7.
MAIN FEED LINE.
Read Barton, pages 194, 195.
(a) Follow the lead of each main feed pump to the boilers on its own side.
(b) Are the two main feed pipes cross-connected, and if so, where?
(c) How many valves are there on each boiler between the steam drum and feed pipe, and what is each called? (See Bieg, pages 105 and 106.
(d) Why is a stop valve placed between the boiler and the check?
(e) Note carefully how the flange of the feed stop is made fast to the steam drum.
(f) When steaming with all boilers in use on this vessel, from what point is the feed for each boiler controlled, and what is the condition of the two valves at the steam drum?
(g) Will one feed pump feed four boilers?
(h) Are there any other pumps in the ship connected to the main feed line?
(k) Note that all feed pipes are as far as possible carried above the floor plates.
(l) Cut-out valves in feed lines are in most cases gate valves, to give a clear run and reduce friction.
(m) All copper pipes intended to convey salt water are coated on the inside with some form of water proof varnish, applied hot.
AUXILIARY FEED PUMPS; AUXILIARY FEED LINE.
Auxiliary feed pumps differ from main feed pumps in two ways: (1) in capacity;(2) in that they have both fresh and salt water connections, as follows:
Fresh Water Connections.
1. From cross-connecting pipe of feed tanks.
2. From bottom blows of the boilers in the same compartment, or on the same side of the ship.
1. To boilers through the auxiliary feed line only.
Observe that the auxiliary feed pumps are not connected to the reserve feed tanks, in order to avoid the danger of salting that water.
1. Sea Salt Water Connections.
2. Auxiliary drain manifolds.
3. Main drain.
4. Engine and fire room bilges.
5. Hose nozzle for attaching suction hose.
1. To boilers, through the auxiliary feed line. (Salt feed to boilers).
2. Fire main.
3. Distiller circulating pipes and flushing main.
5. Hose nozzle at pump.
The practice of fitting auxiliary feed pumps with both salt and fresh water connections is one of necessity rather than of choice.
The multiplicity of salt water connections for each pump is obtained by connecting each pump to a manifold, all the connections of the manifold becoming connections of the pump. While the connections may appear complicated at first sight, careful study of those of one pump, will make the principles of the piping system perfectly clear.
Find out the following:
(a) Location of manifolds and all connections outlined on preceding page, with valves controlling each.
(b) Open Macomb strainer, and find out how the basket is fitted.
Note: About one-half the Midshipmen, on final examination, get the basket upside down.
AUXILIARY FEED LINE.
The connections from the auxiliary feed pumps merge into the auxiliary feed line on the forward engine room bulkhead. From this point the auxiliary feed line is carried forward on the center line of the ship. The connections to each boiler in the fire room are very simple.
EVAPORATORS AND DISTILLERS.
Read Barton, pages 347 to 352, inclusive.
Locate the following attachments:
(a) Safety valve, one for shell and one for coil.
(b) Steam gage for coil.
(c) Combined steam and vacuum gage for shell. A gage recording pressures above and below atmosphere is called a compound gage.
(d) Reducing valve for coil.
(e) Salinometer pot.
(f) Feed check valve.
(g) Discharge to vapor pipe.
(h) Bottom blow.
In the case of the evaporators installed on this vessel, the primary steam is taken from one place only:
(a) The auxiliary steam line, a proper reducing valve being fitted. The water of condensation is trapped to the condensers, there being a connection to the trap to send steam to the distiller fresh water pump.
(Not in this vessel.)
The sources of supply of secondary steam are as follows:
(a) As salt water from sea direct, by means of the evaporator feed pump.
(b) By gravity from the distiller circulating water discharge. (Usual practice, warmer water being obtained this way). Note: This feed may be urged by evaporator feed pump.
The brine accumulating at the bottom of the evaporator may be disposed of in two ways:
(a) By blowing down to the bilge in this vessel—more generally to a pipe leading overboard.
(b) By pumping down by means of a brine pump, in which case the brine is discharged to the distiller circulating water discharge, well beyond the point from which feed is taken, and sometimes to the sea direct. Brine pumps are not generally used.
The vapor formed by the evaporation of the salt water is discharged through the vapor pipe to:
(a) Auxiliary exhaust line. (Bad practice.)
(b) Feed tanks. (Good practice.)
(c) Reserve feed tanks.
(d) Ship's fresh drinking water tanks.
Discharges (a) and (b) are direct; (c) and (d) indirect.
In the case of the port evaporator only, the vapor may also be delivered as:
(e) Primary steam to the starboard, evaporator, to permit working the evaporators in double effect.
The vapor of evaporation, secondary steam, is almost always discharged through the distillers, where it is condensed and cooled by the salt water circulating through it.
Distiller Circulating Pump.
The distiller circulating water is a loop from the flushing main. Any pump on the flushing system may be used to circulate water through the distillers. The circulating water enters at the bottom, and discharges at the top.
The evaporator feed is a loop on the discharge side of the distiller loop, as given in the following line sketch:
The fresh water condensed in the distiller accumulates in a reservoir tank below, the reservoir being fitted with filtering material and a gage glass.
From this reservoir it is pumped by means of the distiller fresh water pump, to any one of the following places:
(a) Bilge. (For use when the water is salt.)
(b) Fresh water tanks.
(c) Reserve feed tanks. (By gravity on this vessel.)
The distiller fresh water pump takes its steam.
(a) From auxiliary steam line.
(b) From trap of primary steam,—this to prevent evaporators from becoming air bound.
When discharged into the fresh water tanks, the water is still not potable until it has been aerated. Aeration is accomplished by means of air pipes fitted to the tanks. A more efficient way is to fit a connection at the bottom of the reservoir tank as given in the line sketch below.
Read Barton, page 509, Art. 1608, par. 8, 9, 10.
EVAPORATORS AND DISTILLERS.
In starting up the evaporators through the distillers, the following procedure will be observed:
(a) Open distiller circulating water supply and discharge valves.
(b) Open evaporator feed and fill evaporator to about one-half glass, level of the third row of tubes.
(c) Open steam to steam coils.
(d) Open coil drain connections to steam traps.
(e) Allow pressure on coils to conic up to about 20 pounds per gage.
(f) When steam pressure in shell is to pounds, crack vapor valve to distiller and gradually open it so as to keep about 5 pounds pressure on the shell.
(g) Regulate the feed check to keep the water at a constant level.
(k) Open discharge from distiller reservoir to bilge until water is known to be fresh.
(l) Start distiller fresh water pump.
(m) Open distiller discharge to point desired.
In stintting down the following procedure will be followed:
(a) Open bottom blow and blow down well.
(b) Close evaporator feed.
(c) Shut off primary steam.
(d) Close down the distiller fresh water pump.
(e) Shut off distiller circulating water.
Midshipmen in charge of watches will not initial this sheet as completed until each member of their respective watches has done each of the operations outlined below. The starboard evaporator will be used for this purpose, and the sheet will be worked through during the first port watch.
Start evaporator on:
(a) Ship's tanks.
(b) Reserve feed tanks.
(c) Discharge without distiller to feed tanks.
Owing to the damaged condition of the port evaporator it is impracticable to operate the evaporators in double effect.
The boilers installed on this vessel are of the type known as the Schulz-Thornycroft. The type as installed in this vessel is now exclusively installed in all vesses of the Imperial German Navy.
Read Bieg, pages 252, 253, and 265.
When sketching any of the small tube boilers, it is helpful to remember:
(a) That they are practically equilateral triangles.
(b) That the grate level is either at the center or at the bottom of the wing drums.
Find out on these boilers the following:
(a) Location of safety valves. Star duplex safety valves used here. See Bieg, pages 118, 121, and 123.
(b) Where do safety valves discharge?
(c) Arrangement of safety valve easing gear. Bieg, page 124. In this vessel the spindle is vertical.
(d) Sentinel valves. Location and area; where discharge? See Bieg, page 125.
(e) Foster stop valve. See Bieg, page 165.
(f) Why is escape pipe fitted with a bell mouth.
(g) Position of steam gage and connections to the boiler; syphon at the bottom. See Bieg, page 165. Syphons must be so arranged that:
(a) They contain water enough to fill both springs when under pressure.
(b) So fitted that the water seal will not be drawn out of syphon when the pressure is off.
(c) A cock between syphon, and gage.
(h) Dynamo stop. See Bieg, page 134.
(k) Position of surface blow valve. Where does it lead and where discharge? See Bieg, page 134.
(l) Bottom blow from each drum. How open the circulation to the auxiliary feed pumps in the engine room?
(m) How are the bottom blows of the four boilers connected? See Bieg, page 135.
(n) Position of air cock.
(o) Location of gage glasses. See Bieg, page 111.
(p) Location and use of salinometer pots. See Bieg, page 139.
(q) Position of gage cocks: where do they discharge, and how?
(r) Fitting of manhole plates. See Bieg, page 142.
(s) Air pressure gages. See Bieg, page 71.
(t) How is gage graduated?
(u) To what points is each of the legs connected?
(v) Fire extinguishers to bunkers. What line are these pipes on?
(w) How get soda into these boilers, and where?
(x) Furnace door frames. See Bieg, page 19. Why is the axis inclined to the vertical? How is the door kept open when the ship is rolling? Of what material are furnace door liners made? How is air admitted above the grate?
CARE AND OPERATION OF BOILERS—PRESERVATION.
(1) Read Barton, pages 452 to 457; 459 to 466, and 473 to 477, covering the following sub-heads:
(a) Raising steam.
(b) Control of steam.
(c) Standing by.
(d) Banked fires.
(e) Management of fires underway.
(f) Firing a furnace.
(g) Cleaning fires.
(h) Sweeping of blowing tubes.
(k) Routine of watch at sea.
(l) Starting an additional boiler.
(m) Disconnecting a boiler.
(n) Preparations for port.
(o) Surplus feed water.
(p) Loss of feed water.
(q) Renewing grate bars.
(r) Burst gage glass. Find out by inspection of gage glasses in storeroom why a 5/8-inch glass is actually stronger than a 3/4-inch glass.
(s) Low water.
(t) Feed pump inoperative.
Read Barton, pages 508, and following: U.S. Naval Regulations in regard to the following:
(1) Reports on condition. Art. 1609, par. 1.
(2) Periodical examinations. Art. 1614.
(3) Drill tests. Art. 1612, par. 5; Art. 1615.
(4) Hydraulic test. Art. 1612.
(5) Record of tests. Art. 1613.
(6) Distribution of work. Art. 1609, par. 31.
(7) Services of deck force as coal passers, and fire men. Art. 1197.
(8) Increasing speed. (Does not apply to water tube boilers). Art. 1609, par. 27.
(9) Changes in temperature. Art. 1609, par. 17.
(10) Coal in fire rooms. Art. 1609, par. 33.
(11) Connection doors. Art. 1609, par. 18.
(12) Record of time fires are lighted. Art. 1609, par.20.
(13) Banked fires. Art. 1611, par. 20.
(14) Hauling fires after steaming. Art. 1609, par. 21.
(15) Dry pipes and drains. Art. 1609, par. 6.
(16) Priming furnaces. Art. 1609, par. 10.
(17) Lifting safety valves. Art. 1609, par. 12.
(18) Securing valves. Art. 1609, par. 11.
(19) Care of exterior. Art. 1609, par. 16.
(20) Care of up takes. Art. 1609, par. 19.
(21) Air space in up take. Art. 1609, par. 30.
(22) Ashes in fire-room. Art. 1609, par. 32.
(23) Care of forced draft ducts. Art. 1609, par. 34.
(24) Boiler interiors, not in use. Art. 1609, par. 7, 8.
(25) Forced draft. Art. 1603; Art. 1609, par. 26.
(26) Blowers to assist draft. Art. 1609, par. 28.
(27) Tallow or vegetable oil. Art. 1609, par. 5.
(28) Changing water. Art. 1609, par. 14.
(29) Use as tanks. Washing out. Art. 160, par. 8, 15.
(30) Acidity of water. Art. 1610, par. 10.
(31) Litmus test. Art. 1610, par. 2.
(32) Level of water line. Art. 1609, par.9.
(a) What are crank trams, and for what purpose are they used?
(b) What are valve trams, and for what purpose are they used?
(c) Where are the reference marks for crank trams and for valve trams?
(d) What are smothering valves and for what purpose are they used?
How many valves are there on each line?
(e) What are air locks, and for what purpose are they used?
(f) How are the coal bunkers ventilated. See Bieg, page 61.
(g) What are the air escapes from the double bottom reserve feed tanks?
Where are they placed, and are there any valves on each pipe?
(h) What and where are the sounding pipes to the double bottom reserve feed tanks.
(k) How is the quantity of water in the double bottom reserve feed tanks measured? See Barton, page 509, Art. 1608, par. 3.
(l) How is fresh water conveyed from a water barge to the reserve feed tanks of this vessel? What pumps may be used for this purpose?
(m) Where are zinc protectors placed on all copper suction and discharge pipes intended to convey saltwater? See Barton, page 195. Examine one of these boxes on this ship.
(n) Do the armor bars extend across the interior of the smoke pipe?
(o) Each watch will take the saturation of the water in the auxiliary boiler, using the salinometer pot.
AUXILIARY STEAM AND EXHAUST PIPING.
The auxiliary steam pipe extends throughout the length of the boiler and engine room compartments, with branches leading forward and aft. It is the only one of the main arteries of the ship that has a return lead.
In the latest practice, as in this ship, the auxiliary steam pipe takes steam from the nozzle at the cross-connection between the main steam pipes in the engine room, there being a reducing valve between the auxiliary stop, and the line stop of the main steam line on each side.
The auxiliary steam pipe is made of lap-welded mild steel. The auxiliary exhaust pipe is made of seamless drawn copper.
Auxiliary Steam Pipe.
(a) It is so arranged that steam condensing into it is drained back into the separator.
(b) Wherever pockets occur, the pipe is drained and trapped.
(c) All branches from the main pipe to pumps on a lower level have a stop valve close to the main line, to prevent water condensing in the vertical pipes.
(d) All branches to auxiliary machinery outside of the machinery spaces have stop valves in the engine or fire rooms.
(e) All branches leading to crank engines, such as the main circulating pumps, anchor engine, or steering engine are led from the top or side, never from the bottom of the pipe.
(f) All branches leading to direct driven pumps are led from the bottom of the pipe.
Auxiliary Exhaust Pipe.
(a) It is fitted with valves to direct the exhaust into any one of the following places:
(1) Either main condenser.
(2) The auxiliary condenser.
(3) Either low pressure receiver.
(4) Into either feed water heater.
(5) Into atmosphere through the escape pipe.
(b) At each connection with the condensers and the escape pipe,the pipe is fitted with two stop valves to minimize the chances of an air leak.
(c) All branches leading to machinery on a lower level are fitted with stops close to the main pipe.
(d) Connection with the escape pipe will be made below the armored deck.
(e) All exhaust pipes from engines above the armored deck are fitted with valves below the armored deck.
(f) The dynamo engines exhaust are so led that one engine cannot exhaust into another; or an engine not in use flooded. This is accomplished by means of swing check valves close to the valve chests of each engine.
The following connections are made to the auxiliary steam pipe. (a) Anchor engine.
(b) Whistle, siren.
(c) Steam to shower baths.
(e) Crews head.
(f) Deck winches.
(g) Steering engine.
(h) Main and auxiliary condensers for boiling out.
(k) A one-inch steam pipe to each sea suction, out board of the valve.
Used for freeing the strainer of marine growth after the vessel has been in warm waters.
(l) Steam for galley coppers is taken through a separate pipe, fitted with reducing valve, relief valve, and gage.
ADJUSTMENT OF LINKS.
Much of the unnecessary mystery that surrounds the subject of link adjustment can be cleared up by a little careful thought and attention directed upon the following points.
Links may be adjusted with either of two objects in view:
(a) Smooth running.
(b) Equalization of power.
Theoretically, the adjustment for equal power in the cylinders ought also to be the adjustment for smooth running of the engines, but practically such is not the case. The adjustment of the links for smooth running varies with the condition of the cross-head, and crank pin brasses, with live steam in either receiver, with any number of mechanical conditions which not only change the adjustment for each particular vessel, but may even change it also for each particular engine.
The one fact upon which adjustment for smooth running is based is this: Linking-in reduces the travel of the valve.
It is quite possible for the adjustment of a link for smooth running to be diametrically opposite to the adjustment of the same link for equal power. For example:
Suppose the drag links of the intermediate valve gear to be out of adjustment, and producing excessive vibrations throughout the entire reversing shaft; linking-in would stop the vibration, because it would reduce the travel of the valve, but that same linking-in would increase the work done in that cylinder.
Therefore: No intelligent adjustment of links can be made until it is first decided what the adjustment is for. Answered that question, the rest is easy.
It is simply necessary to move the links in or out until the conditions of smoothest running are obtained.
Equalization of Power.
The practical problem is this:
(a) With any given steam pressure and vacuum, what must be the gage reading on the intermediate and low pressure receiver gages in order to produce equal power in the cylinders?
(b) Having determined what the gage readings should be, how get them by altering the cutoffs.
The desired reading of the first and second receiver gages for equal power is obtained by analysis. If each cylinder is to do an equal share of work, the drop in pressure in that cylinder, multiplied by its ratio to the, high pressure cylinder should be nearly equal. For example, take the case where the cylinder ratios are 1:2 1/3:6.
With, for example, 200 pounds pressure at the throttle, and 24 inches of vacuum, the total range of pressure is from 200 pounds to 12 pounds, or 212 pounds.
Dividing this in the inverse ratio of the cylinders, we have 212/ 9 1/3= 22.8 pounds.
The drop in the high pressure cylinder is: 22.8 x 6 = 137 pounds.
The drop in the intermediate cylinder is: 22.8 x 2 1/3 = 53 "
The drop in the low pressure cylinder is: 22.8 x 1 = 23 "
Total drop …………………………………………………………………213 “
That is, for the cylinders of this vessel, the power in the cylinders will be equal, for 200 pounds' pressure, when the gage readings are respectively 200, 63, and to above atmosphere.
On account of initial condensation, an extra allowance should be given the high pressure. Make the gage readings 200, 60, and to above atmosphere.
Construct a table for desired gage readings for varying steam pressures for any particular engine, using the above method, and for that engine the first part of the problem is completed.
The second part, how to get gage readings when they are not, is equally simple. The intermediate, and the low pressure are the only links concerned.
Linking in on either of these links increases the gage reading of its own cylinder.
Linking out on either of these links decreases the gage reading of its own cylinder.
The popular superstition that equalization of power can only be obtained by taking, and working out a set of indicator cards is only a myth. By the above method it is practicable to adjust any engine for equal power at any time, without reference to any indicator cards.
For an explanation of how linking in equalizes the power, see Barton, page 117.
High Pressure Cut-off.
The high pressure cut-off has nothing whatever to do with the distribution of work. It may, and often does, have something to do with smooth running. The function of the high pressure cut-off is solely to secure economy of running by increasing the number of expansions. (See Barton, pages 117 and 118.)
To get the greatest power with the greatest economy, the high pressure cut-off should be run in as far as possible, while at the same time using all the steam made by the boilers.
The high pressure cut-off, and not the throttle, should regulate the steam, for this reason:
By keeping a high pressure in the steam pipe, and throttling, the initial pressure is greatly reduced at the point of cut-off, the steam line of the indicator card falls, and the gain in economy due to high pressure is to a great extent lost.
By regulating with the cut-off, the initial pressure is kept up to the point of cut-off, and the steam line of the diagram becomes more nearly horizontal, as it should be.
Throttling should be resorted to only when the steam pressure in the high pressure cylinder continues to fall with the cut-off all the way in.
THE SLIDE VALVE, THE INDICATOR CARD, AND THE ZEUNER VALVE DIAGRAM.
1. There can be no thorough understanding of the action of valve gears until the intimate and interchangeable relation which exists between the slide valve, the indicator card, and the Zeuner valve diagram, is thoroughly impressed upon the mind.
2. It being assumed that pages 51 to 55, 58 to 66, and 213 of Barton have been carefully studied, the following digest of facts may be made:
Of the Slide Valve.
3. An eccentric is simply a small crank which drives a slide valve. In all the Herreshoff vessels the eccentrics are replaced by small cranks.
4. A slide valve makes one complete stroke with each stroke of the piston, and only one, but the slide valve, and the piston start each from different points. The piston starts from the top of the cylinder, the slide valve starts, not from the top of the valve chest, but from the middle of the valve chest, plus a distance equal to the lead plus the lap.
5. The only difference between an inside and an outside valve of the same dimensions is, that the outside valve would start to move in the same direction as the piston, while the inside valve would start to move in the opposite direction. Once started each returns to the starting point once for each stroke, twice for each revolution.
Of the Zeuner Valve Diagram.
6. As the horizontal was the forerunner of the vertical engine, the line of stroke of the Zeuner Valve Diagram, AA', page 64, Barton, is horizontal. The Zeuner can best be studied and understood for vertical engines, by holding page 64 horizontal, and making the point A the top center. The crank and eccentric are then before the eye as they appear in the engine MOM.
Of the Indicator Card.
7. Indicator cards must be regarded as a series of points,—admission, cut-off, release, and compression, connected by a series of lines, admission line, steam line, expansion line, exhaust line, and compression line. The shape of the card is determined by the relative position of the points. Errors in the position of the points make errors in the lines connecting them. The points are the cause, the lines the effect.
8. The indicator cards, A and B, Fig. 1, are graphic representations of the work done by the slide valve, C, Fig. 11.
9. In the following discussion, it is assumed that C is an outside valve, and that the card, A, the left hand card is the top card,—that is the card traced by the hatched end of the valve, C, while the black card is the bottom card, traced by the black end of the valve, C.
10. The left hand card of a two-card diagram is not necessarily the "top" card. It depends solely upon whether the indicator drum is on the right, or the left side of the tracing pencil, see indicators illustrated on pages 206 and 207, Barton. In the one case the left card will be the top card, and
in the other the right card will be the top. The “top" card is determined practically by taking one card with the bottom indicator cock closed, and noting whether the admission line is to the right or left for that indicator on that cylinder.
11. The dotted card of Fig. I, reproduced in Fig. III, is a series of lines drawn about the four points thereon indicated, and marked,—(1) admission, (2) cut-off, (3) release, and (4) compression.
12. Of these four points two, (1) admission, and (2) cut-off, are traced, Fig. IV, when the hatched edge (steam edge), of the valve, intersects the hatched face (steam face) of the port,—(1) admission when the valve is going down, (2) cut-off when the valve is going up. Two, (3) release, and (4) compression, are traced when the black edge (exhaust edge), of the valve intersects the black face (exhaust face), of the black port,—(3) release when the valve is going up, and (4) compression, when the valve is going down a second time.
13. In the Zeuner Valve diagram, Fig: V, the points (1) and (2) are given by the intersection of the dotted circle, top steam lap, with the top steam valve circle, and points (3) and (4) by the intersection of the black circle, top exhaust lap, with the top exhaust valve circle.
14. The bottom card, the black card of Fig. I, reproduced in Fig. VI, is a series of lines connecting the four points thereon indicated, and marked, (1) admission, (2) cut-off, (3) release, and (4) compression.
15. Of these four points two, (1) admission, and (2) cut-off are traced, Fig. VII, when the black edge (steam edge), of the valve intersects the black face (steam face), of the port,—(1) when the valve is going up, and (2) when going down. Two, (3) release, and (4) compression are traced when the hatched edge (exhaust edge), intersects the hatched face (exhaust face), of the port. (3) When the valve is going down, and (4) when going up a second time.
16. In the Zeuner diagram, Fig. VIII, points (1) and (2) are given by the intersection of the black circle (bottom steam lap), with the bottom steam valve circle, and points (3) and (4) by the intersection of dotted circle, bottom exhaust lap, with the bottom exhaust valve circle.
17. If C, Fig. 11, is an inside valve, the points of the top card, reproduced in Fig. IX, as follows: The valve starts to move up ward, when the piston starts downward. Points (1) and (2) are traced by the intersection of
the hatched edge (steam edge), of valve, Fig. X, with hatched edge of port (steam edge). (1) When the valve is going up, and (2) when the valve is going down. Points (3) and (4) are traced by the intersection of the
black edge (exhaust edge), of valve with the black face of port (exhaust face). (3) When the valve is going down, and (4) when it is going up a second time.
18. The Zeuner for this condition is exactly the same as Fig. V.
19. It will thus be seen that for an inside valve, the steam, and exhaust edges. of the valve interchange, and the steam and exhaust faces of the port interchange; but the indicator card, and the Zeuner valve diagram do not change.
20. From the foregoing it follows that the effect of any abnormal condition in valve gear, such as excessive angle of advance, etc., upon the indicator card can be determined graphically by the Zeuner valve diagram. After a little practice, it is not even necessary to draw the Zeuner. It can be pictured mentally, and again it is necessary to repeat that the Zeuner, and the indicator card are identical for inside and outside valves, for piston valves and for slide valves, for single ported and for double ported valves.
21. For any abnormal condition, it is necessary to answer two questions:
(a) Does it affect both cards?
(b) Does it affect the four points of one or both cards? If not, how many points does it affect?
22. Both are answered by the Zeuner, as the following illustrations will show:
Excessive Angular Advance.
(a) Affects both cards.
(b) Affects four points of each card alike.
Valve Stem Too Long.
(a) Affects both cards.
(b) Affects four points of each card. Two in one way, and two in another.
For the top card, outside valve, the condition is equivalent to decreasing the lead, and,—since the angle of advance remains unchanged, the lead can
only be decreased by increasing the steam lap. See Zeuner. It follows also that there will be too little exhaust lap.
The bottom card will show decreased steam lap, and increased exhaust lap.
Excessive Top Steam Lap.
(a) Affects one card only.
(b) Affects two points of one card only.