14. Korvin-Kroukovsky, B. V., "Investigation of Ship Motions in Regular Waves", SNAME, 



1955. 



15. Chadwick, Jr., J. H., "On the Stabilization of Roll", SNAME, 1955. 



16. Allan, J. F., "The Stabilization of Ships by Activated Fins", INA, 1945. 



17. Wallace, W., "Experiences in the Stabilization of Ships", NEIES, 1955. 



18. Davidson, K. S. M., and Schiff, L. I., "Turning and Course-Keeping Qualities", SNAME, 



1946. 



19. Mandel, P., "Some Hydrodynamic Aspects of Appendage Design", SNAME, 1953. 



20. Eisenberg, P.: "A Critical Review of Recent Progress in Cavitation Research", Cavita- 



tion in Hydrodynamics (Proc. of Symposium held at National Physical Laboratory). 

 Her Majesty's Stationery Office, London, 1956. 



21. Gawn, R. W. L., "Results to Date of Comparative Cavitation Tests of Propellers", 



SNAME, 1951. 



22. Lewis, F. M., "Propeller Tunnel Notes", SNAME, 1947. 



23. Saunders, H. E., "Hydrodynamics of Ship Design", 2 Volumes, being prepared for pub- 



lication by the Society of Naval Architects and Marine Engineers. 1957. 



24. Froude, W., "On the Rolling of Ships", INA, 1861. 



Abbreviations 



INA Transactions of the Institution of Naval Architects, London, England. 



SNAME Transactions of the Society of Naval Architects and Marine Engineers, New 



York. 

 NEIES North-East Institute of Engineers and Shipbuilders in Scotland. 



DISCUSSION 



H . E. Saunders 



If I may seem a bit critical of some of the author's remarks it is not because 

 we have a different basic thought on these items, but because we look at them a little 

 differently. 



Mr. Niedermair said that certain hydrodynamic barriers which exist for the 

 surface ship vanish in the case of the submarine. This is a pure submarine, entirely 

 submerged. 



He mentioned hydrodynamic noise, which I think all of you can visualize. 

 However, if you think that just going down in a pure submarine, and getting below the 

 surface, eliminates some of these problems, you might try calculating the submergence 

 depth at which separation at some point disappears, if it does disappear. I am talking 

 now of a separation which occurs at some place on the submarine when it is at or near 

 the surface. Just try this for breaking one of the hydrodynamic barriers. 



It is true that in the old days naval architects got along with very little in the 

 way of an analytic approach, relying on practical experience and intuition. That was 

 possible, because if the ship didn't behave the way you wanted it to, well, you just 

 stopped and tried to figure out what to do next. But unfortunately, the airplane designer, 

 or pilot, if he gets up in an airplane, can't quite do that. He has to keep on flying and 

 to figure out, if he can, what is going to happen until he gets back down to earth again. 



Mr. Niedermair made the comment that it was the development and the use 

 of the analytic approach in the aircraft industry, and all of the things that went with it, 

 which stimulated us to do likewise in naval architecture. I would like to think that this 

 is so, but there is a long period of relative inaction between what the airplane people 

 were doing back in the 1910's and what we are doing now in the 1950's. 



What really poked us from behind, to use a frank term, was the realization of 

 the fact that the empirical approach was just no longer adequate. We had problems 

 to be solved which could not be solved by the engineering knowledge then in our posses- 



144 



