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[September 12, PROGRESS IN MARINE ENGINEERING. GREAT STRIDES HAVE BEEN MADE DURING THE PAST TEN YEARS--FOWER REQUIRED A FEW YEARS AGO COMPARED WITH + WHAT IS NOW NECESSARY. -A. brief reference has already been made in the Review to Mr. James McKechnie's address upon the "Progress of Marine Engineering During the last Ten Years. We are now enabled to give the summary of his conclusions, together with his reference to the latest development in marine engineering--the steam turbine. The most notable progress during the past ten years has been in the direction of speed. In 1891 there Fug. #2. Arrangement of Turbine Machinery "for proposed Steamer of 7,000 1.H.P. (Shown on larger scale Figs 43 and a4) cr suzy 7 At + fgnadiee fesdeeers fh tas ae 4 COMPARISON EETWEEN THE PARSONS TURBINE (Fig.42) AND = RECIFROCATING ENSINES OF 7000 HP. 'were only eight vessels whose speed exceeded 20 knots. Now there are fifty-eight. The vessels between 19 and 1914 knots' speed have doubled numbering now thirty-four. Great Britain holds a high position relatively Owing to its number of swift channel steamers. The highest speea 'attained ten years.ago was 25 knots, recorded for a British-built Braziliaz torpedo boat, the fastest British navy torpedo boat being 2214 knots, The record for speed sow is held by the Viper, lately destroyed, with a maxi- 'mum of 37.113 knots and a mean for one hour of 36.581 knots. The highest ocean speed ten years ago was 20.7 knots by the Paris and New 'York, Today th 'Deutschland, which has maintained an average of 23.51 knots, while the best speed got with channel steamers is 23.62 knots. _ It is interesting also to compare the weights of machinery with those of ten and twenty years ago. In 1881 the average for merchant ships was recorded:as 4.66 I.H.P. per ton, while in 1891 the average. for cargo boats was 4.8 and-is now about the same. For the fastest liner the weight ten years ago was also about the same as it is now, 6.7 I.H.P. per ton, but -generally there is now more boiler power and additional weight, in the -machinety, In naval practice there has been a marked diminution in uweight, the rate in 1881 being 6% I.H.P. re - 189 16 I..H. P. per ton, and now 12 I. H. oe ee ton of machiner . all for natural draft. 'without 4 reference to the possibilities of propulsion by steam turbines. 'In electricelight work the steam turbine has become a most : efficient: _motor, and exhaustive trials have demonstrated its economy'in steam 'con: -sumption, the actual rate of a 1,000 kilowatt set having been 9.19 'kilo- | "grammes per kilowatt-hour, which may be accepted as equalling about i A Ibs. per HP. hour. In the case of a long-distance sea voyage at a -uniform speed--and this is the condition prevailing in 99 per cent. of mer- & Saeed: e highest speed on an ocean run has. been attained by the. 'chant stéamers--thete can be no doubt of the economy of the turbine" Pf San ge ac aioe oa eer i eae a a ok MARINE REVIEW. | PRO. vy Any: review of marine engineering progress would be incomplete >>| am - aa) ; hes ees =Y. iraad a = : : conte Meet bak oe fond ' erg pee st thon si --e ay 'oot + u ie De t ey ts Sees j sot f : : ? MV . ? 0 1 " Hi -- ' . i \\ 4 + Ke a Sena) ss ER SOR ea ' WN 4i TN ae} t " E Nf r oe nee ed eo ; ie a =e 1 In such case it can be designed for the maximum load, which would be the average working load. For naval work, where the speed is variable, the same advantage may not accrue, because the steam losses are prac- tically constant irrespective of the power being developed. Where weight is a primary factor, even this need not militate against its adoption, and thus it would seem as if the future would see a great development in this direction. Fig. 42 illustrates the design for a Parsons turbine-driven steamer of 7,000.H.P. with three shafts, two of which are driven by low- pressure turbines, while the center shaft motor is of the high-pressure type. The turbines for driving the ship astern are incorporated with the low-pressure system, being fitted in the exhaust casings with a valve to pass the steam direct from the boiler to the astern turbines, in which case the low-pressure ahead turbines on the same shaft rotate in a vacuum. At the same time, the steam is cut off from the high-pressure turbine, which also runs idle in a vacuum. It will thus be seen that for driving ahead the steam passes through the high-pressure turbine, thence through self-closing valves to the. two. low-pressure turbines, and finally to the condenser; but should the order be given to reverse the engines, the main admission valve is closed, and the steam is then.passed through other valves to the two astern turbines, which, being of large area, develop con- siderable power and speed sternwards. The self-closine valves prevent the steam passing to the high-pressure motor. The change is easily made, as all the valves are actuated from the same platform; and the arrange- ment is such that either or thé side propetfers may be driven ahead 'or astern separately. As to the relative space occupied, the sections (Figs. 43 and 44), show the difference at a glance, and the weight and space occupied for turbine machinery and reciprocating engines of 7,000 I. H. P. are as follow: Reciprocating Turbine engines. machinery. Weight in engine-rooms and tunnel complete.. 270 tons. 190. tons. Floor space in engine-room............-- ewe 911 sq: tt 911 sq.ft. Cubic capacity required by engines............. 14,430 cu. ft. 10,500 cu.ft. The success of the Parsons turbine has brought several others into the field, and although experiments have been made at Barrow-in-Furness with several of these, they:are not sufficiently advanced or conclusive to enable results to be given here. The season's work of the turbine-driven ene King Edward, built on the Clyde, will also yield most important ata. : In-conelusion, the author summarizes the results attained during the ten years. -Steam pressures. have been increased'in the merchant marine from 158 lbs. to 197 lbs. per square inch, the maximum attained being 267 Ibs. per square inch, and 300 lbs. in the naval service. The piston speed of mercantile machinery has gone up from 529 to 654 ft. per minute, the .. hound, is the reduction in the coal consumption. maximum in merchant practice being about 900 ft., and in naval practice 960 ft. for large engines, and 1,300 ft. in torpedo boat destroyers. Boilers also yield a greater power for a given surface, and thus the average power per ton of machinery has gone up from an average of 6 to about 7 I.H.P. per ton of machinery. The net results in respect of speed are that while ten years ago the highest sustained ocean speed was 20.7 knots, it is now 23.51 knots; the highest speed for large warships was 22 knots, and is * now 23 knots on a trial of double the duration of those of ten years ago; the maximum speed attained by any craft was 25 knots, as compared with 36.581 knots now; while the number. of ships of over. 20. knots was eight in 1891, and is fifty-eight now. But probably the result otf most import- ance, because affecting every type of ship from the tramp to the erey- Ten years ago the rate for ocean voyages was 1.75 Ibs. per H.P. per hour; today, in the most -modern ships, it is about 1.5 lbs. Ten years ago 1 ton of cargo was car- ried 100 miles for 10 lbs. of fuel; whereas now, with the great in- crease in the size of ships and other mechanical improvements, the same work is done for about 4 lbs. of coal--a result which means a very great saving when applied to the immense fleet of over-sea carriers throughout "the world. Ge fh The new steamship La 'Savoie, of the Compagnie Generale Transatlan- ~ tique arrived in New York on her maiden trip this week. She is a sister ship of La Lorraine, which entered the service this year. She is 580 ft. long, 60 ft. 214 in. wide-and 39 ft. 4 in. deep. She has a displacement of 15,300 -tons and. 22,000 H..P.. La,Savoie has six decks with six steam transverse _ and nine longitudinal water-tight bui!-heads, two sets of triple expansion engines and nickel steel shafts. * Hér dnterior furnishings are elaborate. She is equipped to carry 400 saloon, 125 second-class and 1,000 steerage: "passerigerse 9. 88! nhs 4