REDUCTION GEARS FOR SHIP PROPULSION. 



19 



Table I. 



Reciprocating 



Turbine 



Die 



Electric drive 



Speed of ship, knots 



Diameter of propellers 



Revolutions per minute 



S. H. P. (or 250 sea miles per day 



S. H. P. maximum 



Weight of machinery and vpater-tons 



Weight of machinery in lbs. per max. S. H. P.. 



Space occupied by machinery, cubic feet 



Total vfeight of hull and machinery, tons 



Net carrying capacity of ship bunkered for 20 

 days' steaming and 8 days' reserve fuel, tons. 



Comparative cost of machinery 



Fuel consumption per day, 250 sea miles, tons . 



Estimated cost of operating per day* 



Crew 



Repairs 



Stores 



Provisions 



Depreciation 



Insurance 



General 



Fuel oil 



Total 



Per deadweight ton 



11.5 



17' 6" 



76 



4,135 



4,600 



1,060 



517 



171, 826 



9,350 



18, 775 



100 



60 



13.33 

 11.34 



4.82 



3.97 



27.10 



17.60 



1.42 



20.42 



11.5 



15' 8" 



105 



4,350 



5,800 



914 



353 



171, 826 



9,200 



19, 220 

 98.3 



48 



18.33 



11.34 



4.82 



3.97 



27.00 



17.53 



1.42 



16.34 



100.00 

 100 



95.74 

 90.7 



11.5 



15' 8" 



105 



4,350 



5,000 



1,267 



567 



192, 251 



9,700 



19, 482 



123.5 



24 



14.46 



11.34 



7.89 



4.26 



29.83 



19.40 



1.42 



8.18 



96.38 

 93.2 



11.5 



15' 8" 



105 



4,350 



5,800 



981 



379 



171, 826 



9,267 



19, 153 

 128.3 



48 



13.33 



11.34 



4.82 



3.97 



30.10 



19.67 



1.42 



16.34 



100.99 

 99.3 



* Based on total of 100 for reciprocating machinery. 



The reciprocating engines are triple expansion 



25" X 41" X 68" 

 48" 



and there are three cylin- 



drical boilers 17 feet 6 inches diameter by 12 feet long, operated at 190 pounds per square 

 inch and 20 degrees superheat, oil fired and with heated air forced draft. 



The turbine machinery is cross compound with single reduction gears, turbine revolutions 

 1,930 per minute to 105 at the propellers. The boilers are the same size as for the recipro- 

 cating set and arranged for 220 pounds per square inch working pressure and 200° F. super- 

 heat. The water rate for the turbines will be 9.6 pounds per shaft horse-power per hour. 



The Diesel machinery consists of two engines, each with six cylinders 25 >4 inches di- 



