NOTES ON FUEL ECONOMY AS INFLUENCED BY SHIP DESIGN. 



By E. H. RiGG, Esq., Member. 



[Read at the twentieth general meeting of the Society of Naval Architects and Marine Engineers, held in 



New York, November 21 and 22, 1912.] 



In recent years we have witnessed great progress in marine engineering ; 

 new types are striving for first place, each having its advantages and its 

 advocates; geared turbines, oil and gas engines, electric transmission and 

 other schemes, each offering economies of fuel and therefore lesser operating 

 expenses. 



The latest transactions of the technical societies concerned each contain 

 papers bearing on the subject, especially that read before the Northeast 

 Coast Institution last April and that on the geared turbines on the channel 

 steamer Normannia read before the Institution of Naval Architects this year, 

 to say nothing of many important papers read elsewhere. 



These all point out the possibilities of economy from the point of view of 

 machinery savings. It is the object of these notes to point out possible 

 economies due to efficient ship design, because savings are being made by 

 naval architects, as well as by marine engineers. 



Cheapness of operation is one of the necessities for commercial success 

 in a competitive age. The problem of evolving economical ship forms is an 

 intricate one, and a study of the records of this society will show that much 

 time and money have been spent in the pursuit of efficient forms, which is 

 another way of saying economy. 



Experimental tanks have been built in all the leading maritime coun- 

 tries, and commerce is slowly but surely beginning to reap the benefits. Not 

 only has ship form come in for the attention it deserves, but we have lately 

 witnessed renewed efforts to solve propeller problems, so necessary to keep 

 up with the higher speeds of revolution demanded by the new types of pro- 

 pelling machinery. 



It is at once evident that the naval service has reaped the greatest bene- 

 fit of the study devoted to ship propulsion ; perhaps this is only natural, the 

 pioneer experimental tank in our country being the government one at Wash- 

 ington. That this tank pays is evidenced by the difference between the 

 Connecticut trials and those of the Michigan. The average ship of the 

 Coimecticut class required 15,700 indicated horse-power for 18 knots, whereas 

 the later design, of identical displacement and type of machinery, required 



