Wave Forces on a Restrained Ship in Head-Sea Waves 
keel line according to the method based on the Froude-Krylov hypo- 
thesis and for relatively short waves. It is well known that the Froude- 
Krylov assumption is valid only for ery long waves. Would it not be 
better then to compare the results with calculations based on a strip 
method which evaluates rigorously the diffraction potential in the strip 
domain ? 
REPLY TO DISCUSSION 
Odd Faltinsen 
Det Norske Verttas 
Oslo, Norway 
I see what you mean. I have not done that comparison. The 
reason why I showed a comparison with Froude-Kriloff pressure in 
the presentation of the paper, was to make clear that there is an order 
of magnitude between Froude-Kriloff pressure and pressure accord- 
ing to my theory in the low wave length range. 
I do not agree with Dr Kim's last statement that the usual strip 
theory evaluates the diffraction potential rigorously in the strip do- 
main. The usual strip method for zero speed is based on no inter- 
action between different parts of the ship, and the two-dimensional 
Laplace equation is used to solve the problem. This can only be true 
for beam sea, 
1843 
