I05.0 



25-0 



1-5 



176 AN EIvECTRICALLY PROPELLED 



LIST OF MACHINERY. 



Weight 



Eight water-tube boilers: — ^ in tons. 



Grate surface, 44 sq. ft. each 352 sq. ft. total ' 



Heating surface, 1,635 sq. ft. each. . . 13,080 sq. ft. total 



Pressure 250 lbs. 



Main generating units : — 



Two 3-phase, 6o-cycle, 1,500 K. W. maximum 24-hour rat- 

 ing, 35° C. rise, 3,600 R. P. M., 2,200 volts, 80 per 



cent power factor 57.5 



Three i ,000-horse-power induction motors, 24 pole, 300 



R. P. M 33 5 



Three sets of switches and controllers 20.5 



Two condensers, 3,000 sq. ft. cooling surface each 

 Two combination turbine-driven centrifugal pumps 



Two independent exciter sets 3.0 



Two turbine-driven centrifugal feed pumps, 200 gallons 



each 2.0 



Two bilge and fire pumps, 150 gallons 1 



Two tank pumps, 50 gallons J 



Two air compressors for 10 lbs. pressure 4.0 



Steam and other piping 5.0 



Two open heaters, 50,000 lbs. per hour 2.0 



Three propeller shafts 11. 5 



Three propellers 3.0 



Steel foundation for supporting machinery 25.0 



Total weight of machinery 298 . 5 



All auxiliary machinery is in duplicate and, as far as possible, turbine- 

 driven units are used. 



The total weight of the machinery, including propellers, shafting, 

 auxiliaries, switchboard, boilers, piping and water in boilers and condensers 

 will probably not exceed 300 tons. This figure includes the steel seatings 

 for the generating units and motors. Considering an equivalent of over 

 3,000 indicated horse-power in the motors, the weight of machinery is 

 approximately . i ton per indicated horse-power. 



Reference has already been made to the saving in deck space, about 

 4,000 square feet, by the substitution of screw propulsion for paddle-wheels. 

 The saving in weight over the vertical beam engine type with return tubular 

 boilers is much more marked, as the average of a number of these boats 



