Mori 3 Inui and Kajitani 



DISCUSSION 



Louis Landweber 



University of Iowa 

 Iowa City, Iowa* U.S.A. 



The intensity of a ship's centerplane source distribution is 

 related to the ship -side wave profile by an integral equation of the 

 first kind. Since the strength of the source distribution is assumed to 

 be independent of the depth coordinate, which is not true in general, 

 the solution of the integral equation can yield only an approximation 

 which matches well the ship- side wave profile, but not necessarily 

 the far -field wave pattern, and hence the amplitude -distribution funct- 

 ion and the wave resistance. 



The assumption of thin-ship theory in the derivation of the 

 integral equation seems unnecessary. It would be more accurate to 

 apply the expression for the ship-side wave profile at the actual later- 

 al coordinate of the hull than at the centerplane, as can equally well 

 be done. 



In their reply to Brard's discussion, the authors have shown 

 that the agreement between the wave amplitude function from a lon- 

 gitudinal cut and from the ship -side wave profile is greatly improved 

 by including the contribution from a line integral of singularities 

 around the contour of the intersection of the hull with the free surface. 

 Since the discussor has shown in his paper for the 40th Anniversary 

 NSMB Symposium that this line integral can be transformed into an 

 integral over the surface of the hull in such a way that the resulting 

 system of singularities consists only of a source distribution on the 

 hull surface, it would be interesting to know more precisely what sin- 

 gularities were assumed along the contour and how their strengths 

 were obtained. 



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