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: : : ; : September, 1909 to be hoped that suitable forms of mechanical trimming and stoking of coal may be brought about, or that the adoption of other fucls or systcm of propel.ing machinery may become prevalent. Water Tube Boilers. Before passing from the important subject of boilers, it would not be fitting to omit some allusion to the water-tube boiler. Notwithstanding the numerous designs which have been put to work on _ warships, torpedo craft, and in some cases merchant vessels, it must be admitted that up to the present this class of boiler has not succeeded, be the reasons what they may. In the warships of all nations, circumstances seem to have forced the adoption of the designs, but that it is unwillingly done is evi- dent from the fact that for the vari- ous craft associated with royal navies outside the fighting line, the Scotch or tank form of boiler is generally adopted, as also in all royal yachts and other pleasure craft. So far as the mercantile marine of the world is: concerned, there. are no more than 250 vessels of all classes of 300 tons and upwards fitted with water-tube boilers, and of these about 50 are passenger and the remainder of the ordinary cargo type. <lhe most recent vessel fitted with water-tube boilers and the first with turbine ma- chinery built in Japan is the Japanese steamship Sakura Maru, which is of the following dimensions :--Length, 335 ft. by 43 ft. by. 31.6 ft, of: 3,200 tons, and a displacement of 3,880 tons on 17 ft. draught, and 8,500 indicated horsepower, with speed of 21 knots per hour; being of the so-called Volunteer fleet, it is not unlikely that the adop- tion of the water-tube boiler Miyabara design has in this case been due to the naval requirements more than to its general suitability for commercial pur- poses. marine Fuel. Coming now to the important ques- tion of the nature of the fuel used, even here it is to be regretted that no great advance has been made; true it is that in certain trades and on steam- ers favorably situated to obtain oil-fuel progress has been made, but up to the present there is no pronounced sign that liquid fuel will genera ly supersede coal. Internal Combustion Engines. Following upon the subject of liquid fuel, there naturally comes the ques- tion of internal-combustion engines, "TAE MARINE REVIEW which are now being widely adopted for smaller craft and also for barges. Numerous designs for different kinds of fuel are now being put to work, and are gradually being made use of in al parts of the globe, but up to the present no ordinary cargo vessel of 1,000 tons or upwards has been so fitted, but, like other branches of marine en- gineering, the striving after greater economy will no doubt bring further developments, Following upon the iiquid fuel in- ternal-combustion engine comes the very important one of using gas gen- erated on board the vessel: of this it is difficult yet to express a decided opinion, as, with the exception of the now well-known -- suction-gas vessel Rattler, but little experience -has been gained and that only on smaller craft; at the same time consideration of the subject .tends to. raise hopes that a gradual introduction of the system may soon come about. That a considerable number of wants for this class of machinery have yet to be ' surmounted cannot be denied; the want of simple and reiable reversing of pro peller, ready provision for working all the numerous auxiliaries, providing heating apparaus and simple working appliances for cargo and such like, pre- sent great but not insuperab'e diffi- culties. One feature connected with all de- scriptions of internal-combustion -- en- gines; which will no doubt to a cer- tain extent militate against them, is that up to the present for marine and practically all other purposes they must be of the piston and reciprocating type, which leaves them. open to the objection that they are commencing where the modern marine steam engine is leaving off. That is to say, the success of the steam-turbine machinery on board ship (as already considered) has practically created an objection to the further use of the crank-shaft and ail its accom- panying parts, so that under present outlook the rotary form of power mo- tion appears to have the most favorab'e chance of general adoption, and itis to be regretted that, so far as can be seen at present, there is but little hope that direct rotary power can be ob- tained by explosive motors in the near future. Direct Electric Drive for Propeller. The fact that the coming power for marine propulsion must be directly ro- tary, coupled with the success of the steam turbine, has brougnt forward an- other system, which, in the author's opinion, will soon be widely adopted, 327 namely, the application of electric power direct to the propeller shafts. In view of the fact that up to date steam still remains the most simple and most use- ful source of power available on board ship, and can, thanks to turbine ma- chinery, be readily and economically put to generate electricity up to yreat power, it will not be out of place to note the advantages likely to ac- crue from the adoption of direct elec- trical shaft drive. In the first instance, reversal of the propeller with ful effective power is attained and readily effected. Second- ly, the design of both the steam and electric plant can be so modified as to enable the naval architect to make better and more profitable arrange- ments for both passenger and cargo space, The application of the electric drive and form of motor have now been so improved as to reduce wear and tear to a minimum, and has also increased the efficiency, so that prompt and _ re- liable starting, reversing and _ stopping are insured. Owing to the fact that the lower boiler pressure can be used by the steam-turbine generator, it is anticipated that the weights of the steam and electric plants together will not exceed that of the present system of reciprocating machinery, and it is also estimated that the first cost will average about the same. Of the advant- ages of this system one which will commend itself to the navigating de- partment is that. the long-looked-for apparatus to control the movements of the propellers direct from the bridge may be obtained. Another advantage is, that electricity like steam is capable of being readily applied to al the other requirements of shipboard, such as steering, wind- lass, and winch-work, combined with the further advantages of more econ- omical distribution and giving a simple and agreeable artificial light throughout -- the vessel. It will no doubt be ad- vanced by some, that if turbine ma- chinery has been the great success claimed for it in the early part of this paper, why is it mecessary to add further complications by introducing electrical drive? To this may be replied, that it is not proposed to use electric drive on fast vessels (naval or mer- canti'e) where the turbine has been so successful, but to apply it to the slower- going cargo tramps, as if the promises now put forward are carried out--and electricians state that they are quite within the range of present practice-- it will present the most simple means of obtaining rotary motion slow enough in speed to apply to the ordinary screw-