I'm afraid there is not simple, one size fits all, formula for "ideal"
beam to length ratio. Way too many variables. If you want to learn
more about it, join the Yahoo group "boatdesign" & read the archives,
then post questions. I'm sure John and others can recommend several
books to read: Dave Gerr; John Welsford; Beuhler; Bolger; et.al. If
you just want the short answer, without doing the research (no
particular reason to if all you want to do is build one boat), my
answer is no.
By that, I mean - I'd be highly skeptical of using such an arbitrary
ratio to guide the reconfiguring of this existing design (by a very
sharp, proven designer) in such a radical way. If you're set on
stretching MG this much, I'd suggest commissioning another designer
to: advise you whether it's likely to succeed; suggest how the
handling characteristics of the new boat might differ from the
original; and - if it seems advisable to proceed, go ahead and
reconfigure her for you and create new drawings. Anything less would
be highly experimental. Given the amount of money & time one would put
into a boat like this, it's not a bet I'd make. I don't know of any
other Atkin designs that would amount to the equivalent of a 31' MG,
but there are lots of designs out there that might suit. I'd start by
going to Duckworks Magazine's design index for the length you're
looking for. You could also post inquiries on othere Yahoo groups,
etc. Whatever you decide, good luck!
"Always glad to share my opinions and my ignorance. I've got plenty"
--- In AtkinBoats@yahoogroups.com, "mike" <circvildawg@...> wrote:
> as i've been thinking of building a stretched martha green, i've found
> many thoughts on the subject from various builder and designers web
> sights. one said that in an ideal situation beam should be close to
> 1/4 of the boats length. as mg has a beam of 8'4" this would equate to
> a length of a little over 33'. i don't think i would want to go that
> far but i think that a loa of 31'would be okay. she might roll a
> little more at displacement speeds but the added loa might give me
> less resistance, and more speed with the same hp due to better