to reduce pitching motion by means of fins or other devices located towards the ends 

 of the ship introduces much more severe problems than the reduction of rolling 

 because of the much greater forces and leverages involved. It is interesting to note 

 that despite these problems serious consideration is now being given to the fitting of 

 such fins, and we have carried out experiments at the Model Basin which indicate 

 that reductions in pitching can be achieved by such means and that the forces acting 

 on the fins, while large, can still probably be handled. Of course, the achievement of 

 substantial reductions in pitch by such fins will contribute not only to greater comfort 

 on the ship but will also minimize the reduction of speed, the damage due to slam- 

 ming, and if the shipping of green seas can be avoided, then damage to superstructures 

 should also be greatly reduced. 



The recent emphasis on rough water performance has demonstrated that 

 reduction in speed is normally dictated by the necessity of avoiding excessive ship 

 motion rather than by lack of power. The choice of a ship's lines should no longer 

 be made solely on the basis of good smooth water performance. It may well be that 

 some of the latter will have to be sacrificed in order to achieve the best performance 

 under average sea conditions. In the relatively slow speed cargo ship, for example, 

 the best smooth water performance can generally be achieved using full bow lines with 

 a very fine stern. If this tendency is overdone, however, the ship may give disappoint- 

 ing results at sea and lose speed quite rapidly. Research into the seakeeping qualities 

 of ships has been greatly handicapped through the lack of proper test facilities but 

 fortunately this is now being remedied. 



Although Mr. Niedermair's paper is concerned with hydrodynamic barriers of 

 ship design, I think that the overcoming of such barriers is partly dependent on over- 

 coming some economic barriers. Mr. Niedermair comments on the rapid strides made 

 by aeronautical engineers and this is in large measure due to the immense sums of 

 money that have been spent in research and development in the field of aeronautics. 

 In comparison, the money devoted to research in hydrodynamics is almost negligible. 

 In the matter of experimental craft, too, the naval architect has been much too con- 

 servative in the past. The aircraft industry thinks nothing of building experimental 

 craft at great cost to try out new ideas, but most new ships, whether of naval or 

 merchant type, are usually expected to pay their way when completed. In recent 

 years, the value of a ship designed primarily as an experimental craft has been well 

 shown by the success achieved with the submarine ALBACORE. It is to be hoped 

 that in the future more experimental ships will be built in order that the naval architect 

 may have opportunities similar to those of his aeronautical colleague to try out new 

 ideas without the burden of having to make the ship pay its way in the military or 

 commercial sense. 



H. de Luce 



As Mr. Niedermair brings out in his paper, we Naval Architects actively 

 engaged in designing ships have relied almost entirely on full scale experience and on 

 empirical research. On this basis, over the years, we have succeeded reasonably well in 

 producing war ships and merchant vessels of increasing size, speed, and fitness for 

 their intended services. 



I have no doubt but that empiricism will continue to provide the solutions to 

 our problems for some time in the future. On the other hand, the interpretation and 

 evaluation of empirical data and experience may certainly be misleading without theory 

 to establish the significant parameters and their relationships. And, looking to the 

 future, it seems to me to be only reasonable to expect that the configuration of ships 

 will undergo as radical a change as has occurred in aircraft with the advent of super- 

 sonic speed. In developing this ship of the future, we are certainly going to need all 

 the guidance we can get from fundamental theory and basic research. 



I think all of us interested in the design of ships can feel great satisfaction in 



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