Mot-ion and Resistance of a Low-Waterplane Catamaran 



REPLY TO DISCUSSION 



Choung M. Lee 



Naval Ship Research and Development Center 

 Bethesda 3 Maryland, U.S.A. 



Dr. Murthy's suggestion of using three-dimensional singu- 

 larity distribution is well understood. In principle we can always use 

 the method of singularity distribution to obtain the solution of a linear 

 boundary- value problem in the three-dimensional space. The only 

 difficulty is in the evaluation of the hydrodynamic quantities, which 

 takes much more time than the two-dimensional solution does. This 

 is the main reason why we have relied on the strip theory. Owing to 

 the short time at my disposal I did not explain too well, but when I 

 said that the presence of body did not disturb the incoming wave this 

 was applicable only to the case of obtaining relative motion. In obtai- 

 ning ship motion the wave diffraction effect due to the presence of 

 body is incorporated in the wave-exciting term by use of the Haskind 

 relation. 



545 



