From photographs and reports
of ocean storms we conclude that storm waves are generally not regular or
stable, that is, each individual wave does not retain its shape for very
long. The wind forces cause the wave crest to steepen until a white cap
forms and takes energy from the wave. Of ten two or more waves intersect
forming a complex pattern of wave additions and subtractions. The
occasional dangerous breaking wave is a product of a random combination of
a wave steepened by wind forces and a second wave which adds energy to the
first.
In constructing a
mathematical model it is obviously not feasible to consider the detailed
interaction between a variety of boat types and a spectrum of wave types.
However, it is possible to construct a generic model which permits us to
study the significant engineering problems (as distinct from the
scientific problems) associated with breaking wave capsizing.
The major engineering concerns are:
 Construction of a theoretical framework to assist in interpretation
of model tests and fullscale events.
 Obtaining a working understanding of the relative importance of the
factors involved in a breaking wave capsize.
 Developing the capability to predict loads on the boat and drogue
system with sufficient accuracy to permit rational design of the
equipment.
Although this problem is
extremely complex, the model tests show that much can be learned by the
application of a relatively simple mathematical simulation. For this
investigation the analysis was divided into two separate programs. First,
a simulation of the boat and drogue in regular waves, and second, the boat
and drogue being stuck by a breaking wave.
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