Lin, PauUing, and Wehausen 



will, of course, cause an added resistance associated with viscosity which is not 

 taken into account in the expression used for Rf/pgV . Furthermore, if contravenes 

 to some extent the fundamental assumption of streamline flow upon which Michell's 

 integral is based. 



TEST RESULTS 



Figure 7 shows R,./pgV for the symmetric model extrapolated to a 400' ship 

 by using Schoenherr's friction coefficients and a roughness allowance 0.0004. On 

 the same figure is shown the same resistance coefficient for the equivalent ships 

 in Taylor's Standard Series and Series 60 and for the "optimum" ship in Taylor's 

 Standard Series, as explained earlier. The results speak for themselves. The 

 optimum symmetric ship is slightly but insignificantly better than either of the 

 "equivalent" ships near the design speed but is not as good as the optimum 

 Taylor's-Series ship. 



FROM EXPERIMENT 

 TSSeouiv 

 TSSopT 

 SERIES 60 



Fig. 7 - Total resistance coefficients for symmetric model 

 and equivalent models 



Figure 8 shows the residary-resistance coefficient Rj./pgV for the symmetric 

 ship and the equivalent Taylor's-Series ship, and also the Michell wave resist- 

 ance Rj^/pgV . It is evident that the residuary resistance of the model is much 

 greater than its Michell wave resistance in the neighborhood of the design speed, 

 but that the two become more nearly equal both below and above this speed. On 



1056 



