Brard 
Section VIII consists of a brief synopsis of the present appli- 
cations of the vortex theory to ship hydrodynamics with somewhat 
greater emphasis on ship maneuverability. Attention is drawn to 
Casal's thesis about this problem. Casal's theory certainly involves 
too drastic simplifications and some among the conclusions are unac- 
ceptable. First, a ship cannot be considered as infinitely thin, and 
even if such an assumption could be accepted in a first approximation, 
it would be necessary to satisfy the boundary condition on the whole 
surface of the longitudinal plane of symmetry of the ship. It is still 
necessary to resort the empirical or semi-empirical methods. But, 
in the writer's opinion the part devoted to theory is really unsuffi- 
Crene: 
The purpose of this paper was to prompt researches in that 
direction, 
REFERENCES 
[ 1] ROY, M., '"Aérodynamique-des ailes sustentatrices et des 
hélices'', Gauthier Villars, Paris, 1928. 
[2] Von KARMAN, Th. and SEARS, W.R., ''Airfoil theory for 
non-uniform motion", Journal of the Aeronautical Sciences, 
vol. 5, No 10, August 1938. 
[3] BRARD, R., ''Mouvements plans non permanents d'un profil 
déformable.'', Association Technique Maritime et Aéronau- 
tique, No 63, 1963. 
[4 ] DAT, R., and MALFOIS, J-P., ''Sur le calcul du noyau de 
l'équation intégrale de la surface portante en écoulement 
subsonique instationnaire'', La Recherche Aérospatiale, 
No 1970-5, September-October 1970. 
[5 | DELSARTE, J., 'Included in ''Legons sur les tourbillons" 
by H.. VILLAT, Gauthier Villars,..Paris, .19350. 
[6 | KOTIR. ae and MORGAN, R., 'The uniqueness problem 
for wave resistance calculated from singularity distributions 
which are exact at Zero Froude Number", Journal of Ship 
Research, vol. 13, Nol, march 1969. 
1262 
