Using correction factors like that is nothing more then fitting the errornous formulae to reflect the data. And there that formula become extremely limited in its use. Afterall you must already now the REAL max speed to even calculate the correcttion factor needed. Additionally you screw up the relationship and you magnify the error.

Max. hull speed is nothing more then Froude's law with a different (and often errornous) intepretation.

Froude's law says that a wave with a wave length of X has a speed of Y ;

Wave speed = 1.54 * (wave length)^2

For alot of (displacement) sail boats this coincides with their maximum speed their hulls can travel through the water as their hull get trapped between two wave tops with insufficient drive to overcome the rapid rise in hull drag.

A good number of other sailcraft design DO HAVE enough drive to overcome this rise or have reduced the magnitude of the increase in drag to such an extend that it no longer plays an important role. The standard example of that is the catamaran hull shape.

It is of no use to use a corrector factor and just IMAGINE that the wave system is actually travelling faster then it is in real life just so to assume that that this corrected wave system encloses the cat hull at much higher speeds than it does in REALITY. We can just as well think up a story then little goblins start pushing against the bow of the hull at 20 knots; it has the same amoun to reality value = none.

That is the eternal myth of the max hull speed formula. And it is indeed immortal as in 12 months time we'll have this discussion AGAIN. In the mean time you can read this law 10's of times on so called professional boating magazines because the bulk of those journalists don't know squad about science as well AND because this formula is pretty accurate for heavy yachts.

And this is the way the "max hull speed" formula survives.

Wouter