wrote in message
oups.com...

Interestingly the hull speed formula varies as the square root of the
LWL.
Perhaps there is a relationship that disregards displacement or hull
shape.

Perhaps, but perhaps not. The hull speed formula is rather basic and
does not give precise results. Or would you seriously suggest that hull
shape, displacement, cross sectional area, etc etc, don't matter in the
slightest and that LWL is the only determinant for speed/drag ratios?


The hull speed formula is a rule of thumb. If anything were to change on the
formula it wouldprobably be the coefficient and not the order of the
dependence on LWL. The hull speed formula determines hull speed, not drag.
Do you think the hull speed formula is valid for wave piercing hulls where
the bow rides in the wave rather than on top of it?