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24 MARINE REVIEW. [June 5 PROGRESS OF MARINE ENGINEERING. Mr. W. M. McFarland, now with the Westinghouse companies, but who was until a few years ago one of the foremost engineers of the United States navy, has just concluded in the Engineering Magazine a series of very interesting articles on the "Progress of Economy in Marine Engi- neering." Discussing briefly in the final article such subjects as auxiliary machinery, the steam turbine, etc., Mr. McFarland says: . "A point of difference between naval and merchant steamers 1s in the auxiliary machinery. For convenience in handling the main engines, which is of vital importance in a war vessel, all the auxiliaries. of naval vessels are independent, while in all of the smaller merchantmen, and ip some quite large ones, all such auxiliaries as the air pump are worked from the main engine. Most of these independent atxiliaries, for simplicity and 'convenience, have hitherto been operated almost entirely by simple engines using steam with scarcely any expansion, and even where the air pumps have had compound engines the speed is so slow that the economy is very low. At maximum powers the steam and coal expenditure for the auxiliaries is not of so very great importance, but at cruising speeds the percentage of the total coal expenditure due to the auxiliaries rises to a very appreciable figure. Prof. Hollis of Harvard University, in a lecture before the-Naval War College (in 1892), while he was still an officer in the navy, gave some very interesting data on this point with respect to the machinery of the United States steamer Charleston. From these it appears that when.the main engines were working at half power the coal for auxiliaries was 21 per cent. of the total coal used, while at one-eighth power, for ordinary cruising, this percentage had risen to 34, One of the methods proposed for making the auxiliaries more economical is to deliver their exhaust to one of the receivers of the main engine, from which it can be used economically in the other cylinders, and an extension of this prin- ciple is to have the auxiliaries take steam from the first receiver and ex- haust into the second, which would make them in effect a part of the intermediate cylinder of the triple-expansion engine. My attention has been called to saving of some five or six tons of coal per day on one of the large American cruisers, due to turning the exhaust of the auxiliaries into the low-pressure receiver, when the total coal used was some sixty tons per day. Another method of securing economy is to have the exhaust from the auxiliaries pass through a feed-water heater, and this method has been adopted in some of the later ships. "So far as can be seen at present, it would appear that the simplest and most economical method of operating the auxiliaries which. are actually in the engine and fire rooms is by steam, although, as has been noted, in the past these auxiliaries have nearly all been simple engines, and there may be cases where they could be compounded to advantage. For the auxiliaries outside of the machinery compartments, electric driv- ing has been seriously considered, and in some cases has been tried with considerable satisfaction. The experience with electric transmission on shore would indicate that this method of driving the outside auxiliaries ought to give great satisfaction, both on the score of economy of opera- tion and the avoidance of long leads of steam and exhaust pipes through living quarters and other places where they are undesirable. Thus far the electric machinery installed on board ship has been exclusively of the direct-current type, as the electric experts in the navy have been remark- ably conservative. The present practice on shore for power plants is al- most entirely to use the alternating current with induction motors, and these seem peculiarly adapted to the conditions on board ship. When some. . navy shall have been sufficiently progressive to use these motors and give them a thorough test, it seems probable that it will lead to their general introduction. The remarkable simplicity of induction motors and their ability to withstand rough usage and neglect make them particularly adapted for use in situations where their manipulation would fall into the hands of people who are not trained mechanics, as is the case with the deck force on board ship. "A subject which is of great interest to all who study marine economy is the use of liquid fuel, and it is appropriate in these articles to discuss this subject briefly. It is well known that crude petroleum is not adapted to use on board ship on account of its containing volatile constituents, which at moderate temperatures are given off, and which involve serious danger because some of them form explosive compounds. Under special circumstances the use of crude petroleum might be permitted, but cer- tainly on naval vessels it is entirely inadmissible. The refuse which re- mains after the distillation of the crude petroleum is, however, perfectly safe, and it resembles in appearance and some properties the oil used for cylinder lubrication. This refuse has a high calorific value, giving about 21,000 thermal units per pound, which is about one and a half times the calorific value of the best steam coal. Notwithstanding the lower density | of the oil, the fact that there is absolutely no waste in stowage enables about the same weight of oil to be stowed in a given space as of coal. To burn this refuse successfully it has to be sprayed, or atomized, either by a jet of steam or by the use of compressed air, and under moderate rates of combustion it gives highly satisfactory results, as the combustion is com- plete and there is neither refuse nor smoke. The reduced personnel re- quired to handle boilers with fuel oil, and the ease and cleanliness with which it can be taken on board, all tend to commend it very highly. Under existing conditions there are, of course, the objections to the use of liquid fuel that it can be obtained in only a few places, and that any attempt to | use it on a large scale would probably raise the price to such a degree as to make its use very much more expensive than that of coal. Some years ago one of the great American railroads was considering the use of liquid fuel for trains running through thickly populated districts. Experiments showed that, as far as manipulative considerations were concerned, it was a great success; but when the question of the amount to be used came up it was found that if this road had attempted to use petroleum refuse alone, it would have taken up nearly the entire amount available in the United States at that time. Notwithstanding these considerations, the obvious advantages of liquid fuel have made it seem peculiarly adapted to use on torpedo boats, and during the last few years Admiral Melville has been Carrying out experiments to decide the question and to find by actual tice just what advantages would accrue. It may not be amiss in*this ark that, on the whole, the simplest ,methodiof «spraying of steam, and that this is entirely practicable in spite quired, 'The Italian experiments of about 1892 opinion that sea-geing vessels couldnot afford to. demonstrated that the steam required for spraying is less than 2 per cent. of the amount evaporated in the boilers,so that evaporators to make up the necessary amount of fresh water would weigh less than the air-compress- ing machinery which would be necessary tf air were used for spraying. The-preliminary experiments on the torpedo boat Stiletto, at moderate powers, were very promising and enabled an excellent form of atomizer to be thoroughly tested. After the close of the Spanish war the experiments were resumed upon a small sea-going torpedo boat called the Talbot, but when the effort was made to get as good results as had been obtained with coal, a difficulty was encountered which had developed in previous experi- ments with liquid fuel, namely, that, as far as experience has gone, it seems impossible to get as great a power out of a given boiler'plant with oil fuel as can be obtained with coal. Admiral Melville states in his report for 1900 that the highest power obtainable on the Talbot was only about three-fourths of that obtained with coal, and this last for only a short time. There was also another serious objection which had not been antici- pated, namely, that at this power there was a great deal of smoke. It thus appears that, in spite of its many promising features, liquid fuel is not likely to play any large part in marine engineering. It has long been used on the steamers of the Caspian sea, which are near the Baku oil fields, and it is quite likely that steamers which operate near the newly- developed oil fields in Texas may also use it, but it does not seem possible that it can play any large part. : "Any series of articles treating of marine machinery would be incom- plete which did not make some mention of the new motor which is attract- ing so much attention, and which at last has been applied to a commercial vessel, namely, the steam turbine. This invention of the Hon. C. A, Parsons of England has been developed by that gentleman from a light but extremely wasteful engine to one which compares in economy very favorably with all but the most economical engines of the ordinary type. For marine purposes it was first used in a little vessel of the torpedo boat class, called the Turbinia, in 1897, and the results there obtained in the way of enormous speed for such a small hull and great pe m light weight were so phenomenal that two larger vessels--the: : afterwards built to give it a further test. The T tons displacement, and there weré thrée shafts di each of the shafts carrying three propellers 7 trons. were 2,100 per minute, and the herse power developed 1,576. The Viper and Cobra had four shafts with two lers"on each, and the aggregate. horse power developed was abet 11. The steam pressure was Ibs. and the revolutions about 1,050 per minute. There were two sets of compound steam turbines for driving the vesselahead, and special smaller turbines were provided for @ the vessel astern. The speed obtained by these vesselseaw 0 tons displacement, was about 37 knots, which is comsnde 'than the maximum speed attained by any vessel drivem by It is, of course, somewhat difficult to get exactly the: of these engines, as the ordinary indicator cannot be usedeamedtie horse power has to be estimated from the known results in simtlar vessels driven by ordimary engines. In America the Westinghouse Machine « wbines for driving electric 'os generators 'been mad me turbines of more than 400 owed a steam consumption of 18.8 lbs per kilowatt k allowing for the known efficiency of the genera- tors and f@ efficiency .of good engines of the ordinary type, would be eqttvalent to 14 lbs. per indicated horse power in an ordinary engine. These results are for full-poy vomditions. At half power the steam consumption had only. imeme © 20.7 Ibs. per kilowatt hour, or, as already explained, 1:4 "indicated-horse-power hour. ee "The firm of William, Denny & Bros. of Dumbarton, Scotland, who are well-known for their great:progressiveness, have recently built a vessel called the King Edward, which is an excursion steamer for plying on the Firth of Clyde, and which is the first commeréial vessel to be fitted with turbines. While no reports of specific tests of the performance of the. King Edward have been published, the comparative statement given below of the performance of the Duchess of Hamilton and of the King Edward gives a good idea of the economy of the turbine: 3 COMPARATIVE STATEMENT OF SPEED, MILEAGE AND COAL CONSUMP- TION OF THE PADDLE STEAMER DUCHESS OF HAMILTON AND THE . STEAMER KING EDWARD. hcdel : : ag : Duchess of Hamilton. King Edward. Total 6a ee) 3: 1758 tons 13 ewt. 1429 tons 16 cwt. ~ Miles rin is 48 ". ~ 15,604 : 12,116 Miles per ton s5,'h4% 8.87 © o> 84 Number of days running; © ~ EEE ie Daily average consumption 15 tons 17 ewt. 18 tons 2 ewt. Average speed s. . eo. ccd about 16%4 knots. about 18% knots. "The Duchess of Hamilton is one of the crack boats on the Clyde, so that her performance may be considered as representative of excellent economy for machinery of the ordinary type. We have not the data of the dimensions of the. two vessels at hand, but if they were of about the same - displacement the increased speed of the King Edward would justify an 'increased expenditure of 40 per cent. in coal. As a matter of fact, the increased coal expenditure is only about 14 per cent., thus showing a de- cided economy for the steam turbine. The performance of the King Ed- ward has been so satisfactory that it has been decided to build another boat of the same type, although somewhat larger, her length being 20 ft. greater and her speed 21 knots. The Parsons Marine Steam Turbine Co. has also.on hand at the present time turbine machinery for three high-speed yachts, the largest of which is for Mr. A. L. Barber of New York, and is to be of about 1,400 tons, yacht measurement. The turbines will de- velop 3,500 horse power. It is most unfortunate that-both the Viper and the Cobra were lost at sea before there had been time to gain experience with their machinery under the conditions of regular service, but it is interesting to note that the Parsons company are building another de- stroyer whith will have about the same speed asthe Viper, but which is designed to have a superior performance to hers in regard to coal con- sumption at cruising as well as at higher speed. "The advantages of the turbine are the reduced weight of machinery ~ due to thevery high rotational speeds, the reduction of vibration, the . smaller amount of space ired, and the.relatiy, attention needed i tfor. aust men, 1 HR advantage is the com un ity from any danger, due to priming, or-carrying over 0 the 'boilers,