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with reciprocating engines. Dr. Elgar suggested as an effective means of ac- quiring additional knowledge _ the building of a special launch by which screws up to three feet in diameter could be experimented with, believ- ing that a research on these' lines would bring within reach of practical solution the important problem' of propeller efficiency. At the present moment the greatest interest centered in the form which-propelling machin- ery was likely to take in the imme- diate future. The progress of the steam turbine had been remarkable, but up to the present time compara- tively few ocean steamers had been fitted with this type of machinery, the. chief reason being the doubt which existed as to coal consumption. The Cunard company was making a cru- cial experiment upon the largest scale now possible. But the result was to some extent uncertain, and the imme- diate future of the turbine in fast liners depended greatly upon the is- sue. It was probable that the marine turbine would ultimately be so im- proved as to beat the best reciprocat- ing engines in economy of consump- tion in ocean liners, but no proof was forthcoming that it could yet do it. TURBINE PROBLEMS, The problem was to secure a com- bination of turbine and propeller such as would give an efficient speed of turbine without reducing unduly the diameter of propeller, and experience with regard to this was much needed. | The smaller propellers of turbine en- gines doubtless gained in efficiency on service by being immersed more deeply, and being thus less affected by the rising and falling of the sea at the stern. This was especially the case with some of the cross-Channel boats, in which the propellers had to be so large relatively to the shallow draught of vessels with reciprocating engines, even when these were run at the greatest possible number of revo- lutions per minute, that they were sen- sibly affected by the least disturbance of water-level. The difference in pro- peller efficiency soon became very marked as the weather got bad. In the Newhaven and Dieppe service, for instance, it was found that whereas the turbine boat Brightom only gained an average of three minutes upon the time of the reciprocating-engine boat Arundel in "fine weather, she gained 15 minutes in anything like bad weather. The difference in favor of the turbine on account of extra immersion of pro- peller was not likely to be so great as that in ocean liners, because in them the immersion of propeller was not relatively so unfavorable with re- "TAE Marine. REVIEW ciprocating engines, but it would doubtless be of appreciable value. There appeared to be some other cause, however, which operated unfa- vorably in bad weather at sea, espe- cially when running against a strong head wind, to turbine wessels with comparatively small propellers. In such circumstances they fell off in speed more than reciprocating-engine boats with their large propellers would do; and, altogether, notwithstanding the greater depth of immersion, the efficiency of. the propellers appeared to diminish more rapidly as they are reduced in diameter when driving the vessel against a head wind and sea. NEW MAIL BOATS, "It might be interesting,' contin- ued Dr. Elgar, "to give some particu- lars of two fast turbine steamers that are being built by the Fairfield company for the Egyptian Mail Steamship Co. to run between Mar- seilles and Alexandria. These ves- sels will go upon their station at the beginning of next winter season. They are 525 ft. in length, and their speed on service is to be 18% knots. The turbines are to run at about 340 revolutions per minute, a rate which necessitates as small a diameter. of propeller as prudence would allow. Everything that appears possible has been done to favor the efficiency of the turbine and reduce the weight of machinery. The boiler power is in- creased 6 per cent above what would be allowed for reciprocating machin- ery of equal power, but the gross weight of engines, boilers, and auxil- iaries work out about 400 tons light- er for the. turbines. The space occu- pied by the boilers and machinery is practically the same. A greater con- sumption of coal and a correspond- ing increase of bunker capacity has been allowed for, and it remains to be seen how the consumption will work out. SPEED COMPARISONS. "IT am enabled, by the kindness of the general' manager of the London, Brighton \& South Coast Railway, to give some further particulars of the speed and consumption of their two boats, the Arundel and Brighton, the former fitted with ordinary recipro- cating engines, and the other with turbines. These vessels are approxi- mately similar in dimensions, dis- placement, and form. The figures given are the averages of more than a years running, during which a to- tal distance of about 20,000 miles was covered in each case. The average speed of the Arundel was 19.29 knots, with an average consumption 15 of coal per trip of 16.16 tons. 'The corresponding figures for the Bright- on are an average speed of 19.59 knots; with 17.18 tons of coal 1 the figures for consumption be cor- rected so as to give the comparison at equal speeds, it will be seen that there is nothing to choose between the two boats in economy of fuel." INTERNAL COMBUSTION ENGINE, Nothing fresh had transpired with regard to the application of the in- ternal combustion: engine to marine work since Mr. Milton had laid down the conditions to be satisfied in this respect. Such an engine must be reversible, capable of being quick- ly stopped and. started, of being promptly speeded to any _ desired number of revolutions, must be ca- pable of running continuously for long distances, and of working un- der all conditions met with at sea. In addition, the engine must be eco- nomical in fuel at the ordinary work- ing speed, must be compact, light im weight, and well balanced, must not involve the formation of an_ explo- sive mixture in the ship, and must be capable of using a fuel the supply of which at moderate price was un- limited and which could be obtained in any part of the world. Gas and oil machinery for large battleships at present existed only in imagina- tion. Great practical advances had been made in the application of oil fuel for marine boilers, and a con- sumption as low as 9 lb. per I. H. P. per hour had been regularly realized 'in mercantile vessels. COMFORT ON SHIPBOARD. "The securing of all the comfort that is possible for passengers on board ship is a modern idea. For- merly it was thought sufficient to take them safely, and without much regard even to time, to their destina- tion, and very little attention was paid to comfort. Now it is the chief object of the best shipping compa- nies to leave and arrive in port on fixed days and even at fixed hours, and to make the life of passengers on board ship as comfortable and luxurious as on_ shore. pioneer in this cause of convenience and comfort to passengers was the late Mr. Thomas Ismay, the head of the White Star Line. He always held that the best ship for passen- gers was not necessarily the very fastest, but that comfort and regular arrivals in port were even more im- portant. The traveling public seems to be coming to Mr. Ismay's way of thinking. It is not now so much the highest possible speed across the Atlantic that is in demand by pas- The great. pa RS