ELECTRIC PROPULSION OF A BATTLESHIP. 73 



The following table gives a comparison of steam consumption per effective 

 horse-power between the California as guaranteed, the Florida and Utah which 

 are driven by Parsons turbines, and the Delaware which is driven by reciprocating 

 engines. These figures are taken from the published records of trials. 



POUNDS OF STEAM TO MAIN ENGINES PER HOUR PER E. H. P. 



Prop, speed 

 13 knots 15 knots i^ knots 2 1 knots si knots 



Florida 31.8 24.0 23.0 328 



Utah 28.7 .... 20.3 21.0 323 



Delaware 22.0 .... 18.7 21.0 122 



Cahfornia 17.3 15.2 15.0 16.4 175 



Such a table as this affords the truest basis of comparison of prime movers 

 in ships. 



The estimated weight of the propelling machinery without condensing auxil- 

 iaries is 530 tons, and that of the turbines originally proposed was 653 tons. 



The contract price for the California propelling machinery with auxiliaries 

 given above is $431,000. The estimates made at the New York Navy Yard indi- 

 cate that this equipment will cost $200,000 less than the Parsons turbine equipment 

 previously considered. 



The accompanying cuts show engine-room arrangements with three types of 

 machinery. Plate 37 is the California. This is the arrangement suggested by the 

 General Electric Company's proposal, but a somewhat different arrangement will 

 actually be used. Plate 38 is the Utah, and Plate 39 a geared turbine equipment for 

 a large warship shown in a paper by Sir Charles Parsons. Attention is called to 

 the simplicity of piping, steam and vacuum connections with the electric drive as 

 compared with the other methods. The California has two turbines, the Utah has 

 ten, and the proposed Parsons geared equipment has thirty-two. 



All of the steam passages between turbines in these arrangements involve loss 

 of useful pressure, and many of them involve risk of vacuum loss through air 

 leakage, for it must be remembered that ships are often subject to vibration and 

 that there may be appreciable relative motion of these different parts through ex- 

 pansion strains or working of the ship, or through their own inertia when the ship 

 is vibrating or laboring in a seaway. 



The advantages and simplifications incident to electric drive are greatest in 

 such large warships as are here shown, but they apply in only slightly lesser de- 

 grees to all large high-power vessels. 



