endurance which has long plagued the designer of surface ships and submarines. With 

 the advent of nuclear propulsion, this barrier has been largely circumvented. We have 

 only begun the exploitation of nuclear propulsion in submarines, but just this one de- 

 velopment has given us a type of ship relatively free from hydrodynamic barriers. 



From the foregoing discussion it is apparent that the several barriers to progress 

 in naval architecture are largely interrelated and quite complex. This is true of most 

 scientific work when it once passes the rudimentary stages. It almost seems that 90% 

 of the progress is made in the very first crude step. The man who evolved the formula 



My 

 for the flexural stress in a beam, for example, S = provided a theoretical tool which 



permitted the creation of many structural wonders, and all the modern research of the 

 past 50 years in this field has refined our design approach but little. The parallel with 

 hydrodynamics is obscure because the latter science has proven more complex and less 

 tractable to simplifying assumptions, but it is real nevertheless, and the initial strides 

 in understanding made by Froude, Taylor and others are not likely to be equalled by all 

 our high powered modern techniques. We have only the 10% which they left us to 

 play with. The challenge nevertheless is great and the 10% looms large in the highly 

 competitive world of today. 



As a final thrust for the future I would like to present a few questions which 

 were asked by Admiral E. L. Cochrane in 1954, as a means of emphasizing the prob- 

 lems we face in this matter of barriers and the work that needs to be done. 



What are the forces acting on a ship at sea as compared to those acting upon a 

 model in an experimental towing tank? 



What does happen to a ship's speed in rough weather? 



What happens to a naval vessel's weapons platform or flight deck in a storm? 



What does happen to a ship in a really rough storm? 



These are not new thoughts, in fact they are very old, probably as old as when 

 man first ventured out to sea. Questions similar to these must have been in the mind 

 of Brunei, the designer of the "Great Eastern," when he requested William Froude 

 in 1860 [24], to investigate the probable sea-going characteristics of that ship. 



REFERENCES 



1. Froude, W., "Experiments on Surface Friction", British Association Reports, 1872 and 



1874. 



2. Schoenherr, K. E., "Resistances of Flat Surfaces Moving Through a Fluid", SNAME. 



1932. 



3. Todd, F. H., "Skin Friction Resistance and the Effects of Surface Roughness", SNAME, 



1951. 



4. Telfer, E. V., "Further Ship Resistance Similarity", I.N.A., 1951. 



5. Havelock, T. H., "Wave Resistance Theory and Its Application to Ship Problems", 



SNAME, 1951. 



6. Lunde, J. K., "On the Linearized Theory of Wave Resistance for Displacements Ships 



in Steady and Accelerated Motion", SNAME, 1951. 



7. Guilloton, R., "Potential Theory of Wave Resistance of Ships and Tables for its Cal- 



culation", SNAME, 1951. 



8. Weinblum, G., and St. Denis, M., "On the Motions of Ships at Sea", SNAME, 1950. 



9. Lewis, E. V., "Ship Speeds in Irregular Seas", SNAME, 1955. 



10. Niedermair, J. C, "Ship Motions", INA, 1951. 



11. St. Denis, M. and Pierson, W. I., "On the Motion of Ships in Confused Seas", SNAME, 



1953. 



12. Sims, A. J. and Williams, A. I., "The Pitching and Heaving of Ships", INA, 1955. 



13. St. Denis, M., "On Sustained Speed", SNAME, 1951. 



143 



