Bart wrote:
I like your logic Jeff. My opinion also. The danger of going too
small
is not a happy one, while going too big is not a terrible penalty.

Well, it costs more money, plus loss of space in the boat &
added weight. It's a case of "more is better" (up to a degree).


Jeff wrote:
One thing I forgot to mention is that the number presumes a reasonable
prop - one that's about 55% efficient. If you use a 2 blade folder, you
might think you're underpowered.

Yes but with a too-small or ineffective prop, more
horsepower isn't going to do much good, it's only going to
make bubbles & waste fuel.


.... Mine work OK, but given my light
weight (10K lbs) and slippery hulls (11:1 length to beam) I really
expected to be able to power over 10 knots, but 8.5 is the practical limit.


Wouldn't have expected that... is that full RPMs? Do you
think it's the props?


Also, while I think you have enough juice for your needs, I don't think
you will be overpowered. If you were using it as a motorsailer, and
expecting to exceed hull speed even when fighting a headwind, you'd want
100 hp or more. And you'd probably be swinging a 4 blade prop, although
you can make a good case for a big variable pitch prop on a motorsailer.

Yes, that would be the way to go. As for horsepower, we have
become lazy & spoiled... most boats could do quite well with
far less than the owner think acceptable... and I mean
sailboats, not the obscenely overpowered motor boats (for
example, my own motorboat is overpowered by about 30%, which
I would not call obscene but it's got one of the smallest
engines I've ever heard of in a boat of it's type & size).

Fresh Breezes- Doug King