Dagan 
for the two submergence depths were roughly in the same ratio as 
the square root of the drafts. Satisfactory Froude number similitude 
has been obtained for the free-surface elevation near the body for the 
two drafts. 
The breaking wave inception apparently occurs at a Froude 
number somewhere between 1.20 and 1.50, which correlates quite 
well with our theoretical prediction of 1.50. Separation at the cor- 
ner of the body profile, visible at high speeds, makes difficult the 
definition of the body shape for an inviscid flow calculation. We did 
not reach a ''spray regime" in the range of considered speeds. The 
study of the complex flow pattern of a developed breaking wave is 
the object of future studies. 
VI - GENERAL CONCLUSION. 
We have discussed the pertinent conclusions at the end of 
each of the preceeding chapters. Here, we will try to discuss their 
bearing on ship wave resistance. 
The usual thin (or slender) body first order linearized 
approximation, leading to the Michell integral, is valid for sufficient- 
ly large beam (and draft) Froude numbers. In its range of validity 
this approximation may be improved by taking into account the se- 
cond order term. It seems that the contribution of the free-surface 
correction is of the same order of magnitude as that of the body 
correction in this second order term. As the shape becomes finer, 
the Froude number limiting from below the range of validity of the 
linearized approximation, as well as the second order correction, 
become smaller. 
For moderate beam (and draft) Froude numbers and, hence- 
forth, small length Froude numbers, the linearized solution is no 
more valid and the second order correction worsens the results, 
rather than improving them. To obtain a first order uniformly valid 
solution for a thin (or slender) body in this case, one has to take a 
variable velocity distribution, rather than a uniform, as the basic 
unperturbed distribution in the free-surface condition. This basic 
flow, as well as the singularity distribution along the center plane 
(or axis), may be computed by solving for a rigid wall flow pas the 
linearized body. 
Linear free-surface conditions with variable coefficients 
have been derived also for the case of small length Froude number 
flow past the actual body (finite beam, or draft, length ratio). To 
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