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a MARINE REVIEW AND MARINE RECORD. [Mar. 5, BURDENSOME TASK OF GREATER SPEED. {From the Engineer, London.] The admiralty committee on subsidies to mercantile cruisers has just issued its report, which shows, on the authority of our highest experts in naval architecture, the onerous conditions to be fulfilled if any notable increase of speed is to be maintained over a long voyage, taken in the report as about 3,000 miles on the Atlantic passage. But so long as the Germans hold the flag for the fastest vessel, even under the arduous conditions of an extra day to Hamburg or Bremen, the ne plus ultra of steam navigation cannot be said to be reached. As in 18094, when rumors appeared of the new Cunard vessels, materializing in the Campania and Lucania, so now we read of the negotiations be- tween the admiralty and the Cunard company for two new ves- sels, to have a contract sustained sea speed of 25 knots for the Atlantic passage. ‘The plans are under consideration by the ad- miralty and chief constructor at the present time, but all the in- formation relating to size that has leaked out states that the Clyde must be deepened before the vessels can be put in hand or launched, showing that they must run to much larger dimensions than the Campania and Lucania. As a matter of fact they will not be built on the Clyde at all. The report of the admiralty committee is issued in popular language, for the edification of ordinary naval opinion; the theory and calculations are not given on which the conclusions are based; but the tabular statement issued ih the report con- tains sufficient information on which to base some calculations and to reconstruct the theory. The length of the voyage being taken is 3,000 sea miles, the table shows the prime cost and engine power for speeds ranging from 20 to 26 knots, with the annual subsidy based on the present rules of allowance. Speed in . Prime cost. Horse power. Annual subsidy. knots. £ L.° H.-P: & Be Fe i ee GOOG i vin MO00! Sei 0,000 Bi a ee AOOONO <2 eo: ss 22,0002 5 8a vk FQ{HOO: BO cere ie SAT OOOO EG oo enh ies 2B, HOO “5g ee es AO, FOO Bice ie cw TOO e655) ex «890,000 8s es 107,500 BAG Ge So 50 MOO i. 39365940, 000 24 Oe.. 4as5 LLO,800 Be A a. 55:21 OOO 000s ker. Gs 2000 Srie 5 eB 4O, 000 BOs aie) 5 BBO, 000. 515 \s, < 08,000: <6 kj 204,000. An analysis of these figures shows at once that the prime cost has been reckoned on the basis of the horse power at about £19 to £20 per horse power; also that the horse power has been proportioned to the fifth power of the speed, and not to the seventh power, as in Froude’s law of mechanical similitude. This shows that the committee is taking a sanguine. view of pos- sible improvements in the steam engine not yet accomplished, and also that all available space in the swift vessels will be taken up with coal and machinery. he larger vessels are to be run at a higher speed than in accordance with Froude’s law, re- versing the plan adopted with the Oceanic, which has a lower proportionate speed. Limitations of the depth of water at the ports of arrival and departure prevent the naval architect from utilizing to its full extent the most profitable extension of dimension in in- crease of draught in the large vessel; but for the sake of argu- ment we may assume that considerations of seaworthiness will not cause any other material change in similarity of form, and now this similarity, combined with the working assumption of a resistance varying as the wetted surface and square of the speed (pace Mr. Mansel) shows that the committee have made the dis- placement proportional to the cube of the speed, and not to the sixth power, as in Froude’s law; this makes the length of sim- ilar vessels proportional to the speed, so that the 600-ft., 20-knot steamer will stretch to 780 ft. for 26-knot speed. It is difficult to arrive at the displacement tonnage of a mercantile steamer, as a liberal discount is made to arrive at the registered tonnage, which is the basis of taxation and dock dues. But it cannot be far wrong to assume a displacement of 13,000 tons in the 600-ft. steamer at the commencement of the voyage, and this will be raised to 28,500 tons in the 78o-ft. 26-knot vessel. ‘The coal, reckoned at 1.75 Ibs. per horse power hour, is raised from 2,228 tons to 6,131 tons, and the coal per hour from 15 tons to 52 tons. If Froude’s law of mechanical similitude is preserved, it is found that the resistance, reckoned in pounds per ton, in railway fash- 1on or in equivalent incline, is the same for all sizes, and works out to about 20 lbs. per ton, or an incline of 1 in 112 for the 20-knot vessel, taking the formula resistance in pounds per ton = 326 times the horse power divided by the displacement tonnage and the speed in knots. But with the law adopted by the committee the resistance in pounds per ton grows proportionately with the speed up to 26 lbs. per ton for the 26-knot vessel. _ If the pitch of the propeller is 25 ft. in the 20-knot vessel, it will have to make 80 revolutions per minute; and these revo- lutions will have to be maintained throughout if the vessels are fitted with similar propellers. Steam pressure will require to be increased as the square of the speed from, say, 150 lbs. to 254 Ibs. per square inch; on Froude’s law the pressure would increase as the speed. A tabular statement is appended of the calculations, which shows what the committee are confident naval architects and engineers can accomplish, if given a free hand, culminating in a vessel, say, 800 ft. long and 28,500 tons displacement, with coal capacity of over 6,000 tons—sufficient to drive it at 26 knots over a voyage of 3,000 miles. But any re-arrangement which would shorten the voyage, say, 500 miles, by choosing a Canadian and Irish port, would render the condition of speed far less onerous to fulfill. Speed, in knots... 20 21 22 23 24 25 26 Ti f age, Sita. hogs: . 150 143 136 1380 125 120 115-5 Prime cost .. £) 350,000 | 400,000 | 470,000 | 575,000 | 850,000 | 1,000,000 |1,250,000 Horse-power. IHP| 19.000} 22,000} 25.500} 30,000 | 40,000 52,000 | 68,000 Annual subsidy £| 9,000} 19,500} 40500} 67,500 | 110.500} 149,000} 204,000 Length, in ae es 600 630 660 690 720 750 780 Disp] t,ton- nal eo : 13,000} 15,000} 17.300} 19,800) 22,400 25,400 | 28,500 er H.P. hour), ie ; forié pau ae 2,228 | 2,456] 2912] 2,058] 3,900 4,876 6,181 Coal, in tons per 9 Reo See anes. AD Sched adore tale Gast creme mewn inten ges: 5 esistance, in ‘pounds per ton.. 20 21 22 23 24 25 26 Equivalentincline, one INA ee. 112 195 102 198s srs, 90 8&6 Steam pressure,|bs per squareinch.. 150 165 Le ee 216 234 254 Machinery depart-| ment, number a 100; 110 125 150 200 260 340 How is it, then, that the Germans can beat us, handicapped as they are by an extra day’s steam? Do they coal up at South- ampton or Cherbourg? And what is the basis on which the sea speed is reckoned? The actual chronometric hours of the westward passage are subjected to a deduction of four hours and a half, due to longi- tude difference; if this discount is made, the apparent sea speed of the 26-knot vessel is raised to 27 knots. The problems of the Atlantic passage are not the only ones requiring solution; South Africa demands a rapid steamship service, available in time, we hope, for the projected visit of the British Association in 1905. But if an Atlantic steamer is put upon this passage of double length, a reduction in sustained sea speed of over 30 per cent. must be anticipated. At the Dusseldorf exhibition, in the Krupp annex, a very fine piece of steel work was shown in the shafting of one of the two propellers of the North German Lloyd Kaiser Wilhelm II. The shaft was 283 ft. long, weighed 226 tons, and was providéd with six cranks, arranged so as to avoid vibration, on the Schlick system, and actuated by eight cylinders, two steepled. Thus the vessel will be provided with four complete sets of four-cylinder engines. A sleeve in the shaft was shown, to serve -in case the shaft was broken at sea; unfortunately, the fracture takes place too often in an inaccessible part. The Parson turbine has been running with success for the past two years in the Clyde Union steamers King Edward and Queen Alexandra. It is,rumored that an order has been placed for a turbine steamer to make the Newhaven-Dieppe passage of 60 miles in two hours and bring this route to the front as the quickest route to Paris. A similar vessel would knock off only 20 miles from the Dover-Calais passage. But to retain command of the ocean we must bestir ourselves, and shake off the lethargy in which we were discovered in the last century. NEW YORK HARBOR NOTES. Members of the maritime exchange of the metropolis take exception to several bills introduced in congress recently to give American register to certain foreign-built vessels. ‘They suc- ceeded, a few days ago, in passing a resolution against the ad- mission of such vessels, except in strict accordance with fixed law on the subject, no matter what reasons may be advanced in favor of special acts for registry. ‘The resolution declares that the association is opposed to the granting of American registry to any foreign-built vessels whatsoever, except those captured in war, forfeited to the United States for violation of our laws, or wrecked in American waters and repaired in American ship yards at three-quarters of their cost, when repaired. “T‘hat such a resolution did not pass by a unanimous vote,” says a correspon- dent’s note on the subject, “is to be inferred from the fact that there are members of the exchange who are interested in such vessels, and who believe in, and act on the adage that ‘half a loaf is better than no bread.’ And it is to be expected that they will continue to act on this theory by investing their money in such vessels as long as the present United States laws regulating such matters remain in force, and the cost of building ships here ex- ceeds that in foreign countries, as attested by words and acts of members of the exchange.” The fine steam yacht Clermont, under the chaperonage of the Hudson River Day Line, Desbrosses street pier, New York city, is offered for sale or charter the coming season. She goes into conumission in May. Capt. C. B. Howell, formerly commander of the yacht Safa-el-Bahr for Mr. Charles M. Schwab, has just been secured to take charge of the Claremont. She ranks amiong most attractive and desirable yachts offered for charter or sale. Among the charterers of the Claremont during the past three years are Mr. W. B. Leeds, Mr. Henry W. Cannon and the Hon. Wm. C. Whitney, all of whom attest to her comfort, speed and general satisfaction.