xxxvi INTRODUCTORY PROCEEDINGS. 



We note, also, that in cargo vessels, improved methods of construction intended to give 

 maximum strength and capacity with minimum of material are being employed. 



With respect to machinery, it may be remarked that the increased use of the Diesel en- 

 gine has not been so rapid as its enthusiastic admirers anticipated. It was, of course, obvious 

 to all naval architects and marine engineers that the general use of the Diesel engine de- 

 pends on the ability to construct single cylinders of large power. Although we still hear of 

 experiments with cylinders of 1,000 and of 2,000 horse-power, and even rumors of vessels 

 that are to have engines with such cylinders, I think I am correct in saying that up to date 

 the largest cylinders which have been used in successful installations are of about 300 

 horse-power. As a consequence of this, an equipment of several thousand horse-power 

 means a multiplicity of cylinders, with all the numerous parts requiring care and attention. 



In this progressive age it would be exceedingly unwise to say that any problem in me- 

 chanics (which does not absolutely defy natural law) is impossible, but all who have studied 

 the problem of the Diesel engine will realize that the construction of cylinders for large 

 powers is an exceedingly difficult one. If a metal could be discovered with all the good qual- 

 ities of cast iron and about four or five times its thermal conductivity, the problem would be 

 much simplified. 



There is another aspect of the Diesel engine which is not often referred to; namely, that 

 not all kinds of fuel oil are adapted to its use. This is not surprising when it is remembered 

 that some of the oils have a large percentage of silt and other impurities, and it would hardly 

 need to be mentioned but for the fact that, in the early days, it was claimed that any kind 

 of fuel, including powdered coal, was entirely suitable. 



The most serious commercial drawback to the Diesel engine has been the recent in- 

 creased price of oil. When crude oil could be obtained for two cents a gallon or there- 

 abouts, there was no question of the fuel economy as measured in dollars. Speaking roughly, 

 the Diesel engine has about double the efficiency of the steam engine; and also speaking 

 roughly, when burned under a steam boiler, average coal and average oil are of the same 

 thermal value, as measured in money, when the price of the coal per ton in dollars is twice 

 the price of the oil per gallon in cents; or, in other words, two-cent oil is equal to four-dollar 

 coal. It thus appears that when the relative engine efficiencies are taken into account, the Die- 

 sel engine with two-cent oil would be equal to the steam engine and boiler with coal ^t two 

 dollars a ton. When the price of oil is doubled, however, this advantage is lost; and from 

 the figures given it is easy to see that, speaking roughly. When the price of oil is above four 

 cents a gallon, a good steam-engine and boiler will produce power at a less money cost for 

 fuel per imit than the Diesel engine. 



I may remind you that our Vice-President, Admiral Cone, while Engineer-in-Chief of 

 the Navy, arranged for the building of a Diesel engine for one of the navy fuel ships, and 

 this work is now under way at the New York Navy Yard. When this engine is finished, 

 the Navy Department will imdoubtedly conduct extended experiments which will give 

 a great deal of valuable information. 



The limitation as to the quality of oil mentioned above does not seem to hold where it is 

 a question of using oil as fuel under steam boilers. Well-designed burners give good results 

 even with Mexican oil and all its impurities. 



The many advantages of oil fuel, where its price is not prohibitive, commend it very 

 highly, and its use on steam vessels is steadily increasing. 



