bee. 
HEAVY-OIL ENGINES FOR MARINE PROPULSION. 251 
In regard to the character of labor required to look after the engine, that does 
not seem to be anything out of the way. We took some of the parts toa shop in 
Montreal, and nearly scared the life out of the machinists there, when they found 
in one case they had to work to a clearance of 4;%;> of an inch—they got quite a 
little bit upset about this—but these are troubles which can easily be overcome, and 
I am positive the Diesel engine has not only to be reckoned with, but reckoned with 
right now; I further think a great deal of trouble would be obviated if the Diesel 
engine builders, in every case, would do just as this gentleman has done—speak 
frankly about the details, the points where trouble may be expected. It would be 
very much better if they would let out the information they have about the troubles 
encountered, and show the people where they occur, and how to cure them. 
Mr. Davison (Communicated) :—In reply to the questions raised by Mr. 
Monteagle. 
First. The supply of fuel oil. The present production of fuel oil amounts to 
about 1,500,000,000 gallons per annum. From 30 per cent. to 50 per cent. of the 
crude oil taken from the wells is available for fuel oil, and except for road making 
has very little other use. For every gallon of gasoline produced there is about five 
gallons of fuel oil. The present supply of fuel oil on the eastern coast of the 
United States is sufficient to have warranted its use to the exclusion of coal on our 
latest torpedo boat destroyers. It has been stated that the Navy Department 
proposes to fit the latest Dreadnoughts to burn fuel oil only under their boilers. 
As a gallon of oil in a Diesel engine will do from three to four times the work that is 
now being obtained from its use in steam plants, it seems apparent that the supply 
is sufficient to warrant its use in engines of large power. The writer of this paper 
does not mean to give the impression that internal combustion engines will entirely 
displace steam turbines and reciprocating engines. 
Second. In regard to using a compression of 500 pounds per square inch. This 
limit has not been arbitrarily fixed, but has been arrived at as a result of experience. 
A higher pressure would be objectionable on account of the additional strength of 
parts required. Too low a pressure is objectionable for the reason that ignition, 
combustion, and efficiency are interfered with. The lowest pressure successfully 
used is about 400 pounds. 
Third. A piston speed of-1,000 feet per minute is used only on the lighter high 
speed types of engines, and a number of engines now running do not seem to have 
met with any serious difficulty. In ordinary heavy type engines the piston speed 
varies from 600 to 800 feet per minute. 
Fourth. The figures for annual cost of repairs for a steam plant were arrived 
at by consulting the records of certain torpedo boats and destroyers. The figures 
for the oil engine were estimated based on reports from users of Diesel engines. 
In reply to questions raised by Mr. Crane. 
While it is true that the Diesel-engine has been known for more than fifteen 
