PREFACE 
The Ninth Symposium on Naval Hydrodynamics continues in all aspects the 
precedent, established by previous symposia in this series, of providing an inter- 
national forum for the presentation and exchange of the most recent research re- 
sults in selected fields of naval hydrodynamics. The Symposium was held in Paris, 
France on 20-25 August 1972 under the joint sponsorship of the Office of Naval 
Research, the Ministere d’Etat chargé de la Défense Nationale and the Association 
Technique Maritime et Aeroanutique. 
The technical program of the Symposium was devoted to three subject areas 
of current naval and maritime interest. These subject areas are covered in the 
Proceedings in two volumes: 
Volume 1 — The Hydrodynamics of Unconventional Ships 
— Hydrodynamic Aspects of Ocean Engineering 
Volume 2 — Frontier Problems in Hydrodynamics. 
The planning, organization and management of a Symposium such as this is 
an undertaking of considerable magnitude, and many people have made invaluable 
contributions to the resolution of the myriad of large and small problems which 
invariably arise. The Office of Naval Research is acutely aware of the fact that the 
success of the Ninth Symposium is directly attributable to these people and wishes 
to take this opportunity to express its heartfelt gratitude to them. We are particu- 
larly indebted to Vice Admiral Raymond THIENNOT, Directeur Technique des 
Constructions Navales, Ministére d’ Etat chargé de la Défense Nationale, to Professor 
Jean DUBOIS, Directeur des Recherches et Moyens d’ Essais, Ministere d’ Etat chargé 
de la Défense Nationale, and to Monsieur Jean MARIE, Président de 1’ Association 
Technique Maritime et Aeronautique, who provided the formal structure which 
made this joint undertaking possible. The detailed organization and management 
of the Ninth Symposium lay in the capable and competent hands of Vice Admiral 
Roger BRARD, President de la Academie des Sciences, and Rear Admiral André 
CASTERA, Directeur du Bassin d’Essais des Carénes, who were most ably assisted 
in this endeavor by the charming Madame Jean TATON. Throughout the long days 
of planning and preparation the experienced and practical counsel of Mr. Stanley 
DOROFF of the Office of Naval Research provided continuous guidance which 
contributed in an immeasurable way to the success of the Ninth Symposium on 
Hydrodynamics. 
RALPH D. COOPER 
Fluid Dynamics Program 
Office of Naval Research 
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