36 





m 













•i- = 0.50 





\ 



















ie 





12 3 4 



V 

 1 1° 1 1 



Figure 22 - Wave-Resistance 

 Coefficients c T = R „ 



w p/2 U z S 

 Referred to the Wetted Area 

 S for the Pour TMB Models 

 I-IV, f/L =0.50 



Figure 21 - Wave -Resistance 

 Coefficients c tr = — ,-JBL — 



w p/2 U*S 

 Referred to the Wetted Area 

 S for the Four TMB Models 

 I-IV, f/L =0.25 



and Froude numbers can be estimated for a comparatively wide span of prismatic 

 coefficient O.71 > <t> > O.59. Attention is drawn to the changes in the mutual 

 relations between the curves in Figures 20 to 22. These changes are dependent 

 upon f/L and upon the obvious shift of the peaks towards smaller Froude numbers 

 as compared with Figures l6 to 18, because of the factor U 2 in the denomina- 

 tor of c, . 

 w 



Considerations of wave resistance may play a significant role when 



fixing the optimum elongation ratio D/L as long as free-surface conditions 



are important. Assuming both ¥ and <f> to be constant, the surface S and there- 



3 / — - — 

 fore the viscous drag vary only with V L/D while the wave resistance varies 



