252 HEAVY-OIL ENGINES FOR MARINE PROPULSION. 
years, it is only within the past four or five years that any serious attempt has been 
made to use it for marine purposes. ‘This mere fact, however, does not appear to 
affect the merits of the engine itself. The engine, with a capacity of 2,000 horse- 
power per cylinder, was built within the past year in Nuremburg, Bavaria, by the 
Maschinenfabrik Augsburg-Nitirnberg. 
It is true that the pressure of 500 pounds per square fact present certain diffi- 
culties. These difficulties have fortunately been overcome. 
In reply to the question as to where we may look for trouble. A complete 
answer to this question would be difficult. In general the troubles may be divided 
into two classes. First, those which are purely mechanical and which would be 
found in any engine, namely, hot bearings, loose connections, etc. For this class the 
troubles in a Diesel engine are no more, nor no less, than in a steam engine. The 
factors of safety used are about the same in both types. Troubles peculiar to Diesel 
engines are in connection with air compressors, valve springs, auxiliary pumps, etc., 
which are more than offset by the troubles in a steam plant exterior to the engine 
itself. 
Undoubtedly Diesel engines suffer at the present time due to lack of experience 
of operatives. This is an evil which will cure itself with time. 
In reply to Mr. Robinson. 
Flexibility of engine. It has been found in practice that the engines when 
installed in a ship can be run at one-third the maximum speed. While this paper 
was being discussed the writer was engaged in the trials of a vessel fitted with Diesel 
engines. The maximum speed obtained was 380 revolutions per minute. The 
engine ran smoothly at 150 revolutions per minute, and no effort was made to run 
at a lower speed. So far as flexibility is concerned, the lowest speeds finally reduce 
to the question of fly-wheel effect. If forany reason it should be desired to runat a 
very low speed, with corresponding reduced power, a number of cylinders could be 
cut out, and the remaining ones used at reduced power. A moderate sized fly-wheel 
will accomplish this result. 
After the engine mentioned had once been warmed up, no trouble was found 
with ignition at low speeds even when the compression pressure was less than 
originally designed. 
In conclusion, the writer wishes to thank the gentlemen who discussed this 
paper for the questions raised, and for the additional information furnished. 
THE PRESIDENT:—I am sure the thanks of the Society are due to Mr. Davison 
for his very interesting paper. 
We will now take up the paper entitled, ‘‘ Automatic Record of Propeller Action 
in an Electrically Propelled Vessel,” by Mr. W. L. R. Emmet, Member. 
Mr. Emmet:—This paper is simply a record taken automatically on an 
electrically propelled boat, and as the text is short, I will read the paper in full. 
