PREFACE 



This Symposium is the fifth in a series each of which has been concerned 

 with various aspects of Naval Hydrodynamics. The first (held in September 

 1956) presented critical surveys of Hydrodynamics that are of significance in 

 naval science. Subsequent meetings were to be devoted to one or more topics 

 selected on the basis of importance and need for research stimulation, or of 

 particular current interest. 



In keeping with this objective, the second symposium (August 1958) had for 

 its subject the areas of hydrodynamic noise and cavity flow; the third (Sep- 

 tember 1960) was concerned with the area of high performance ships; and the 

 fourth (August 1962) emphasized the topics of propulsion and hydroelasticity. 



Still continuing with the original plan, the present symposium selected for 

 its dual theme the areas of ship motions and drag reduction, thus emphasizing, 

 among other things, the interest in the current problems and latest accom- 

 plishments associated with: theoretical and experimental determination of 

 the coefficients of the equations governing the motions of ships in a seaway; 

 the characteristics anddesignof motion stabilizers; the reduction of frictional 

 resistance by the introduction of additives; and the design of bulbous bows to 

 reduce wave drag. 



The international flavor of these meetings continues to be an outstanding 

 feature, and in this case, has been enhanced by virtue of the setting, the par- 

 ticipation, and most particularly by the joint sponsorship by the Skipsmodell- 

 tanken of Trondheim, Norway and the U.S. Office of Naval Research. 



The address of welcome by Dr. Weyl and the speech opening this sym- 

 posium by H.R.H. Crown Prince Harald more than adequately describe the 

 background and objectives of this meeting, thus leaving little more to be said 

 other than to express our gratitude to all those who contributed so much to the 

 success of this symposium. However, taking the liberty of speaking both for 

 the Office of Naval Research as well as the international scientific community 

 of hydrodynamicists, I should like once again to express our deepest appre- 

 ciation to Professor J. K. Lunde, to his associates Dr. H. Aa. Walderhaug 

 and Mr. O. Skjetne, and to the Norwegian Ship Model Experiment Tank, Trond- 

 heim for their outstanding efficiency and care in managing the many varied 

 aspects of this symposium. 



RALPH D. COOPER, Head 

 Fluid Dynamics Branch 



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