Yamazaki 



DISCUSSION 



William B. Morgan 



Naval Ship Research and Development Center 



Washington, D.C. 



This paper is very interesting and ambitious. We at the Naval Ship Research 

 and Development Center have followed the work of Prof. Yamazaki with interest 

 for many years. Studies at the Naval Ship Research and Development Center in- 

 dicate that the influence of the propeller on the hull is mainly potential in origin 

 and the influence of the hull on the propeller is mainly viscous in origin. These 

 conclusions are based on theoretical work confirmed by tests in the Naval Ship 

 Research and Development Center. The influence of the propeller on the sep?ra- 

 tion point, especially on single- screw ships, is very important, and I wonder if 

 Prof. Yamazaki has plans to include the viscous effects in a more rational man- 

 ner. It seems to me that the vorticity in the wake of the ship must be considered 

 to make the solution practical. 



DISCUSSION 



V. F. Bavin 



Kryloff Ship Research Institute 



Leningrad, U.S.S.R. 



I wish to compliment the author on the considerable amount of work he has 

 done in formulating the problem of the hull- propeller- rudder interaction in its 

 most general aspect. Being also involved in this field I agree with the author 

 that the rigorous solution of this problem is a very difficult task. 



Therefore it seems to be quite reasonable first to investigate each aspect 

 of the problem separately. The evaluation of the effect of blade width and skew 

 on the amplitudes of bearing forces made by the author is very valuable. I was 

 a little surprised to find the theoretically predicted influence of the blade area 

 ratio to be rather small. This conclusion is not consistent with the results ob- 

 tained by Krohn and Miller. 



It would be very interesting to compare in the future the magnitude of the 

 surface and bearing forces for some typical hull forms and to evaluate the in- 

 fluence of the afterbody configuration on the magnitude of the surface forces. 



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