590 



HYDRODYNAMICS IN SHIP DESIGN 



Sec. 70.5 



PROPELLER FOR DOUBLE-ENDED TERRYBOAT 



Exponded-Areo Ratio ° 0.42 



Me on- Width Ratio 



(Width Qt 0.9R)/(MeonWidtl^ 



/j= 1.99 Ib-sec^/ft^ 

 ^ Kt ,- Ka 



n is m rps 

 N is in rpm 



H.EN0RD5TROMJ947 

 Number of Blodes Z" 3 



Pitch Ratio P/D-- 0.960 

 Blode-Thickness Fraction^ 0.045 

 Hub-Diometer Ratio d/D'0.16 



Ro><e Angle = 



Zero 



Sl<ew- Bock : None 



LOGARITHMIC 

 PROPELLER DIAGRAM 



Blode Sections Symmetricol 



Wash Back: 



Diameter of Model Propeller 



Units for Mixed Form are in: 



ton s, feet, Horses, knots 

 jo6''"'af>' 'yid ' '7o" 



Fig. 70.A Logarithmic Chart of C. W. Prohaska for a Single Screw Propeller 



