256 AUTOMATIC RECORD OF PROPELLER ACTION. 
rheostat of the generator and a dead beat ammeter in the pilot house, and 
the average result of the variable currents shown by records is very close to 
that shown by the curves. 
From the records taken directly from these instruments as shown by the 
curves, other curves have been made showing the variation of speed to power, 
slip, and average revolutions per minute of the two propellers, and also a 
curve showing the relation between the torque and the time required to stop 
the vessel. 
In considering the reversal conditions shown by these tests, the pro- 
peller characteristics as shown by the slip curve should be borne in mind. 
The maximum speed which the vessel is capable of making is 11 miles per 
hour and at this speed the slip is nearly 19 per cent., while at 5 miles per hour 
it is only 9 per cent. ‘This increase of slip at higher speeds indicates that 
the propeller is of insufficient size and this deficiency must tend to diminish 
the value of high torque in reversal. 
The apparatus for these tests was arranged by the author’s assistant, 
Mr. Eskil Berg, and the tests were run by him after carefully experimenting 
with all the parts. 
DISCUSSION. 
THE PRESIDENT Gentlemen, you have heard the paper on ‘“‘Automatic Record 
of Propeller Action in an Electrically Propelled Vessel,” by Mr. W. L. R. Emmet. 
The paper is now open for discussion. 
PROFESSOR Haroip A. EVERETT, Member:—I would like to ask Mr. Emmet 
where he located his log with reference to the hull, the length of boom, where the 
log itself was towed, and the length of the towline. 
Mr. Emmet :—The log was an outrigger near the bow of the boat, and at about 
15 feet from the bow, to one side, so as to clear the bow. 
Mr. EVERET?Y :—How long a line? 
Mr. Emmet :—No line; it was an outrigger. 
Mr. EVERETT :—So as to clear the waves of the bow? 
Mr. EMMeErT:—Yes, entirely. 
