BATTLESHIPS. EXPERIENCE GAINED ON THE JUPITER. 201 



turbine, or, for that matter, you can make no concessions as to the speed of the propeller, 

 without sacrificing the electrical losses. 



In the study I made of the Pennsylvania, the Bureau of Steam Engineering made a 

 study of propeller possibilities on that ship for our company, in order that I might look into 

 the possibilities of the case. They showed that the efficiency with four propeller shafts on 

 the Pennsylvania, operating at 160 revolutions per minute, which, I proposed, was about 8 

 per cent better than operating at 222 revolutions per minute, which is to be used on the tur- 

 bine-driven Pennsylvania. The turbines which are going into the Pennsylvania have an 

 efficiency of about 61 per cent, I should judge, at full speed, and the turbines that I am put- 

 ting into the California have an efficiency of about 75 per cent, and the difference of propeller 

 efficiency in our favor would compensate for the electrical losses. 



Mr. John F. Wentworth^ Visitor: — I did not come prepared to do any speaking on 

 any but my own line, but in connection with this subject I hope the fight will be carried, and 

 am interested in having it carried, into the enemy's camp. I would like to point out one or 

 two facts here. For instance, we read that the fuel consumption per steam horse-power 

 varied from 1.66 to 2.50 pounds of coal per hour, but from what goes above, I take it that is 

 on the turbine; in other words, the efficiency of the turbine is around 11 per cent. That 

 means that you are using 1 1 pounds of coal and throwing away 89 pounds of coal. 



As far as comparing different ships goes, it reminds me a good deal of an experience 

 I had in Washington one time. I ran up against a man whom I tried to get to back me. 

 He had some mining machinery of some kind on the Potomac River, and had some stamps 

 up there. He had an idea about the efficiency to be obtained by using water as a fuel. He 

 said that these stamps were using the full capacity of the boilers, and he had to do some- 

 thing, so he was going to put water under the boilers in connection with his fuel, put in 

 more stamps, and show clearly that he obtained energy from decomposition of the water, 

 and subsequently reunition again of the hydrogen and oxygen. The joke was this man actu- 

 ally claimed to have demonstrated by results the saving from "burning water." It seems to 

 me in an engineering proposition the whole thing should be gotten down to the factor of the 

 coal pile or the oil tank, so that we know where we stand. To state that a turbine is 75 per 

 cent efficient, it seems to me, is misleading. I do not quite understand what that means, but 

 it is a fact when you shovel your coal under the fire and take your load off the shaft, you only 

 have 1 1 per cent. 



I would like to ask a few questions. Why not investigate the possibilities of the in- 

 ternal-combustion engine as it can be developed when considered as a thermodynamic prob- 

 lem? Cannot the oil engine be built in low-pressure type without a sacrifice of efficiency? 

 Cannot this type be built in cylinder sizes of 60-inch to 72-inch bore? Cannot this type 

 of oil engine run at all the piston speeds now used in reciprocating steam engines ? Cannot 

 this type of plant show a greater efficiency at partial load than any known plant ? I believe 

 all this to be possible. 



Is it not a fact that in the proposed electric plant in order to produce 1,000 horse-power 

 in the motor it is necessary to have over 1,050 horse-power in the generator, 1,100 horse- 

 power in the turbine, and boilers large enough to drive these turbines? Does this not mean 

 3,150 horse-power in the machinery to produce 1,000 horse-power on the shaft, besides the 

 boiler ? 



