of significant progress in a field. The second symposium, in 1958, was marked 

 by original contributions in fully cavitating flows, when Marshal Tulin showed 

 the possibility of obtaining good lift-drag properties from specially designed 

 sections, and A. J. Tachmindji and W. B. Morgan applied the idea to the design 

 of fully -cavitating propellers for high-speed craft, with a reduction of blade 

 erosion and possibly beneficial effects on noise emission. 



The third symposium, in 1960, introduced a new feature, that of holding alter- 

 nate meetings in countries outside the United States, which has been continued up 

 to the present time and culminates in our presence here in Rome today. The 

 third symposium was co-sponsored by ONR and the Netherlands Ship Model 

 Basin, and had as its theme High-Performance Ships. It was dedicated to Sir 

 Thomas Havelock, a world-famous figure in ship hydrodynamics, the dedication 

 speech being made by Theodore von Karman. This present occasion is an addi- 

 tional opportunity to pay tribute to Havelock, who died a few weeks ago at the age 

 of 91 after a long life dedicated very largely to the subject of these symposia. 



The papers at the third symposium coveredalltypesof craft— hydrofoil boats, 

 hovercraft, deep-diving submarines, and submarine cargo ships and tankers. 

 Mister Tulin underlined the severe problems which the designer faces in hydro- 

 foil craft, including power plants, power transmission, structural strength, and 

 propeller design, pointing out that the wing loadings are much higher than in air- 

 craft and that such craft operate in a very hostile environment. 



High-speed submarines introduced many critical control problems, and this 

 symposium was marked by the description of new experimental techniques for 

 carrying out research on models and new methods of analysis. A planar-motion 

 mechanism, devised by Morton Gertler and Alex Goodman at the Taylor Model 

 Basin, was described by Mister Goodman. That development enables coefficients 

 to be measured which can then be applied in mathematical models to explore dif- 

 ferent maneuvers and arrangements of control surfaces. Replicas of this instru- 

 ment are now in use in a number of towing tanks in Europe as well as in the 

 United States. 



In Washington in 1962 the themes were Propulsion, covering new theories of 

 propeller design and fundamental differences in the method of operation of non- 

 cavitating and fully cavitating propellers, and Hydroelasticity, dealing withforces 

 on hydrofoils and control surfaces in fully cavitating and ventilated flow. 



The fifth symposium, co-sponsored by ONR and the Norwegian Model Basin in 

 Bergen, in 1964, was dedicated to a study of Ship Motions and Drag Reduction. 

 Important papers dealt with the prediction of ship motions in waves, the applica- 

 tion of seakeeping research results to design, and a new "force-pulse" testing 

 technique for ship models in waves which made possible a great reduction in 

 model testing time. Some of the problems of hydrofoil ships and hovercraft in 

 waves were also discussed. Other papers described the results of original re- 

 search in methods of reducing ship resistance by the use of additives to the water, 

 by boundary layer suction, and by designing the hull form to ensure low wave- 

 making resistance. 



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