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274 lies in economy of propulsion. As to the cost of wages, subsistence, econ- omy in handling of fuel (per ton), has little advantage over the oil- en, ing steamship, while the quality of oil required is more expensive. But in the direct cost of power production, the economy of the internal combustion principle, as compared with the con- version of heat into steam, now ap- proaches demonstration. Cost of power is to a ship what cost of food and clothes is to a family—not only the largest, but the most vital item of operating expense. Hence, other conditions being equal, the power which costs least will determine the type. To this is due the rapid advance of the motorship. Improvements Must Be Made The progress made up to the present can not be considered as conclusive in regard to the permanence of existing mechanisms. Even owners who are now running motorships with success, as well as engineers who are converts to the principle involved, express the opinion that present types have defects and weaknesses which must be over- come before the motorship can really relegate the steamship to second place in ocean traffic. But that such handi- caps can be eliminated, or even that they are now in process of elimination is not doubted by those who have keenly watched recent developments. Since the admitted advantages of the internal combustion engine have been. widely shown, it is pertinent to glance at current criticisms of that engine in its present -stage of development: In a matter so highly technical, only the opinions of trained engineers are of real value; but it certainly does no harm for the average shipping man to consider what such criticisms are, and how suggestive they may be to him in planning the future. Sir Owen Phillips, a large English owner of successful motorships, has expressed the opinion that, if the oil engine is eventually to hold the field, its weight must be greatly reduced and its power much increased. In ad- dition to this several vital items are to be considered. ‘ The excessive cost of installation, as compared with the steam engine is a matter of vital import. An addition of 60 to 70 per cent in cost of engine, constitutes a constant factor in over- head, which Paust always act as a deterrent, but» “Sespecially in periods when high price levels make overhead so grevious a burden upon owners. This high cost is due to many causes; among the chief of which the follow-. ing may be named: The high pressure ‘required by pres-_ MARINE REVIEW This according to compe- tent observers, requires too great a weight of metal, as well as abnormal cylinder dimensions and capacity. While the actual pressure normally experienced is from 500 to 700 pounds per square inch, the strength required to with- stand emergency pressures, to provide resistance in narrow clearances, and to take care of back fires and unconsumed charges may, it is claimed, run as high as 3000 pounds. High Temperatures. Resistance of a heat up to 2700 degrees Fahr., is said to be necessary, and the generation of such temperatures is most trying to cylinders and piston heads. This not only adds greatly to the weight and expense of engines, but abnormally increases the risk of mishap, and consequent delay. ent types. Other suggestions are the difficulty of obtaining complete combustion in turbulating fuel in narrow clearances; and in preparing it for proper gasifica- tion, which latter necessitates the re- sort to lighter and more expensive oils in order to complete combustion during the stroke. Another suggestion is the hazard in operating at low speeds, due to rapid cooling under low frequency; and the extreme accuracy and fine ad- justment required in the parts. Is Operators Problem How far such objections are justi- fied is not to be decided except by technicians. But it would be obvious to the layman, even had experience not proved it, that the operation of such mechanisms will require specialists, highly trained in the care and opera- tion of this particular type. This problem comes squarely up to _ the operator. It is inadequately met—in fact tan not be met—by a surplus of trained steam engineers who have been thrown out of employment by the present depressed conditions of deep sea traffic. A marine engine at best is a complex machine; but new types, involving problems of operation, care and management peculiar to them- selves, must obviously require special engineers. The lack of such is sure to prove a ‘serious handicap in the long run—resulting in delay to the ship while the proper staff is being assembled, or incidental vacancies filled. In case delay is avoided, the owner. may run into an_ inefficiency which is likely to be far more costly. A triple expansion steam engine is not exactly fool proof, and when incompe- tently managed may %.cause_ great trouble. But an_ internal: ‘combustion engine in charge of an engineer, un- trained in its care and Management, is simply hopeless. However, such ‘handi¢aps as’ these are common to all comparatively new July, 1922 equipment, which seeks to displace types long used and widely established. In the same category may be placed the natural difficulty of finding suitable repair shops, or obtaining replacement parts at outports. In this respect, the motorship must long remain at a dis- advantage. But this, too, will gradu- ally disappear with .the increased use of the motorship and consequent ex- pansion of repair facilities. Under such conditions any compara- tive novelty, however efficient, is heavily handicapped by an initial cost which greatly exceeds that to which owners have become accustomed. It may, therefore, be confidently pre- dicted that engineering talent will eag- erly seek such improvements in present types as will greatly reduce the cost of installation. Hence the engineering problems of marine propulsion appears to be in a transitional stage. If the oil engine can be so modified as to more closely approximate the first cost of its steam competitor; elimi- nate the complexities which threaten continuous and economical operation; and maintain the thermal efficiency al- ready achieved, the steamer is now on the way to the relative position oc- cupied for many years by the sailing vessel; and for similar reasons. Ex- cessive cost, high pressures and tem- peratures, and complexities and delica- cies of mechanism, are factors which today cause owners to. hold off in adoption of this new type of ship. These are but a few suggestions as to the lines along which engineers are thinking and workimg. Which of the criticisms are well founded, and which are debatable are matters in which they will no doubt disagree among themselves. But in such a_ discussion a layman has no place. Arguments Are Established The main contention of oil engine advocates seems to be fairly estab- lished. Such contention is briefly this —that any given unit of power may be more effectively and economically ap- plied by the direct action of inflam- mable vapor, mixed with air than by any known method of producing steam and applying its expansive power for the same ‘purpose. As to per ton-mile expense of pro- pulsion, this contention is becoming more and more generally admitted. In the release of .capacity for revenue- producing purposes, which steamers must devote to fuel, the case is equally clear. As to breakdowns at sea, these are common to all types of machinery, as every operator of any experience knows only too well; and these are particularly to be expected in mechan-