the certain knowledge that if you climb, with that airplane, more than say 500 feet above 

 the earth, it will surely explode. One such climb, to too high an altitude, will mean the 

 end of you and your crew, and of the airplane. 



This is the sort of problem which we still face with the submarine, regardless 

 of the type of propulsion, or the type of fuel, or the type of power. I am sure that the 

 aerodynamicists and aeronautical engineers, if they were faced with a problem like this, 

 would be very much busier than they are today. 



/. F. Allan 



I congratulate Mr. Niedermair on his paper, and particularly on the title, which 

 I found stimulating and speculative. 



There is an old saying that an engineer can solve any problem in the technical 

 sense, provided he is given time, but time, of course, costs money, and that brings us 

 up against the economic aspect of the matter. 



There are two approaches to the situation, one from the service point of view, 

 and the other from the commercial point of view. These two approaches tend to be 

 very different, as from the defense point of view economy is not the first consideration 

 even in times of peace. 



When we come to the commercial approach, at least in my country, the ship 

 owner is not interested in technical developments unless he can see that they are going 

 to lead to a clear commercial benefit in what is a very highly competitive industry. It 

 is against that background that I tend to view this question of hydrodynamic barriers. 

 These barriers may also be looked at from two angles. One is concerned with the 

 improvement of existing techniques, and this is of particular interest to the commercial 

 user of ships, and also, of course, to the service user of ships. The other is the more 

 spectacular and revolutionary approach, where quite new techniques may be proposed, 

 and successfully introduced, and these are of primary importance from the service 

 point of view. In many cases they lead to developments which are of great value from 

 the commercial point of view. 



The author stated that the improvements which had been provided in propulsion 

 of ships by the marine engineer were much more spectacular than those provided by 

 the naval architect. One must agree with that statement, but we should not forget 

 that the naval architect has been responsible for improvements of the order of 30 

 per cent in the last 25 or 30 years, and that is no mean achievement. 



I mention the friction barrier, which is a very important contributor to the total 

 resistance of the ship, and although a great deal has been done in recent years to reach 

 a better understanding and appreciation of the importance of a smooth surface. I think 

 we still have quite a lot to learn, perhaps not so much in producing an initially smooth 

 ship, but in preserving that smoothness over the life of the ship. It may even be pos- 

 sible that spectacular developments will come along to reduce friction much further. 

 We do not fully understand the detailed mechanism of fluid friction. As regards wave- 

 making resistance that, I am afraid, will always be with us on surface ships, and the 

 only thing one can do is either go down below or get up above. 



We have had quite a lot of comments today and yesterday about the remarkable 

 performance of the latest submarine down below, and it may be that there is a future 

 in that direction for cargo carrying, but it would be difficult to persuade passengers to 

 travel in a high speed submarine. The alternative is to lift the vessel above the water 

 on hydrofoils, and considerable success has been achieved in that direction. There 

 may be service applications for such vessels, but I doubt if there will be much big 

 scale commercial application. If you want to lift the boat out of the water, it seems to 

 me the obvious thing to do is to get right up in the air and fly properly. 



As regards sea speed, there may be some very interesting developments in that 

 direction in the next few years. Captain Saunders mentioned several American ships 



146 





