[MHml] horsepower

[Glenn Brown]

Bill Gibbs wrote:
> How do I go about figuring out how much horsepower I need to push 
> Afterburner to 20+ knots?

For the Mystere 6.0, I used the information at
http://www.maths.adelaide.edu.au/Applied/llazausk/hydro/kayak/sea/skmag/skmag.htm
to compute Horsepower as a function of speed for non-planing hulls.  I 
even have a plot of the results at www.thebeachcats.com -> Catamaran 
pictures -> beachcats people -> Glenn Brown .

However, around 20kts, wave making drag starts becoming a significant 
factor (for beach cats anyway), according to a recent F14 discussion at 
www.catsailor.com's open forum.  I don't know how to estimate wave 
making drag, but I expect its not a significant factor at significantly 
below your boats top speed under sail.

--Glenn