which he considered have remarkable sea-going performances, but he admitted that 

 nobody understood why these ships were outstanding. 



Roll stabilization has been successfully achieved in the United Kingdom, and 

 the system is now being applied to American ships. Pitch stabilization is more difficult, 

 but a useful degree of pitch damping is possible. With these things accomplished it 

 will probably be reasonable and economic to drive at full speed in bad weather 

 conditions. 



I mention again the point I made yesterday, that if a ship is being driven hard 

 in such conditions, it is of the very greatest importance that the control mechanism on 

 roll and pitch stabilization does not fail, otherwise the ship could be in serious difficulty. 



May I conclude by recalling a speech which was made at a dinner here five 

 years ago in connection with the International Towing Tank Conference. The then 

 Secretary of the Navy cited the remarkable developments in aircraft, and rather threw 

 down the gauntlet in regard to ships. At the time, the proposals he was putting forward 

 seemed to me rather fantastic, but it may be that in the course of time we will get some 

 way towards achieving them. 



F. H. Todd 



Mr. Niedermair has given us an excellent review of some of the problems facing 

 the naval architect today. 



As many of you here today are working in other fields than ship design, I 

 would like to focus your thoughts on the ship problem by considering the design of a 

 large passenger vessel. The civil engineer has to face many problems in the design of 

 modern bridges, the architect and the civil engineer have to combine their skills in 

 the erection of many modern buildings, whilst the mechanical engineer is concerned 

 with all forms of power plants and other machinery. In the design of a large passenger 

 vessel, the naval architect is faced with all these problems at once, and generally in a 

 more acute form. The ship hull is a much more complicated structure than a bridge 

 because of the variation which is necessary along its length to accommodate various 

 machinery, boiler and other spaces, the accommodation has to include all the amenities 

 of a first-class hotel whilst circumscribed between the sides of the ship's hull, and the 

 machinery plant has to have power equivalent to that necessary to supply a small city 

 with electricity. Add to these the fact that this whole structure has to cross rough and 

 stormy seas at a speed of 30 knots or more, safely, economically and to time table, 

 and you begin to get a picture of the problems which the naval architect has to face 

 and, indeed, has overcome with considerable success in the past. 



At one place in his paper, Mr. Niedermair refers to Ship Hydrodynamics as 

 being "a plaything for the theoretical minded." When asked what I do, my wife is 

 prone to reply "research" and when asked to describe this, she describes it as "organized 

 play for adults." As a player in this game, I would like to comment on a few of the 

 points which Mr. Niedermair has raised and on which research work is presently 

 being carried out. 



The author has drawn attention to the great effect which frictional resistance 

 has on a ship's performance. For a great number of years now, much effort has been 

 devoted to obtaining surfaces with as low a resistance as possible. It would seem that 

 as long as a surface is very smooth and hard, its exact nature has little, if any, effect 

 upon the resistance. With a hard, smooth paint of this kind, most of the excess fric- 

 tional resistance on a new, clean ship has in the past been due to seams, laps and 

 rivet points. With the advent of welding, this "structural roughness" resistance has 

 been greatly reduced, particularly where care has been taken to grind off the welds 

 and make them as smooth as possible. On clean, new ships with this type of surface, 

 the additional structural roughness resistance appears to be very small and the resistance 

 approaches that of a smooth plane surface. Two things can spoil this effect. Anti- 

 fouling paints if carelessly applied can increase the resistance materially, as noted by 



147 



