"Hull Speed" is not a carved-in-stone absolute figure.


Charlie Morgan wrote:
I believe I mentioned both the method I used to come up with that
figure, and I used the word "theoretical". Froudes formula is widely
accepted around the world for figuring approximate theoretical hull
speed.

Yes, and he still uses a more-or-less arbitrary speed/length
ratio (usually given as 1.34), and also recognized that some
hulls can exceed this more easily than others.

.... Where did you derive the notion that I felt it was carved in
stone? Do you know of some special reason (bordering on magic) why
Joe's boat would have a hull speed of 13 knots? I think the figure I
gave is probably close to the truth, or maybe even a bit optimistic.
If you think it is far off, I'd appreciate knowing your reasoning.


Boats exceed their their theoretical hull speeds quite
often. Big heavy boats usually do it for only short periods
of time admittedly. "Hull Speed" is not a speed limit but a
wave-train limit. How can an 18 foot sailboat go faster than
20 knots?

You might do better to work backwrds... start with Joe's
figure of 13 knots and then figure what speed-length ratio
his boat would need to achieve for that, and look among the
design books to see what other types of craft (if any)
acheive that ratio.

Fresh Breezes- Doug King