Maxprop wrote:
.... Beneteau has, but does not distribute, graphic studies of net
displacement vs. stability for all of its boats built after the mid-90s.

I wonder if they assume that the center of gravity stays the same?

Not sure if the French gov't. requires them or what, but I think they are
all just computer models depicting the safety margins of their boats. I've
seen the ones that apply to boats in the size range that interests me, and
frankly it's a bit scary. Bottom line: don't overload a 39' Beneteau. And
I'd suspect the same admonition might apply to similar boats, such as
Jeanneaus, DuFours, Catalinas, Hunters, etc.= the plastic fantastics.

Probably true of any boat that is shaped like a normal sailboat. The
only way to be able to keep stability constant is to load all the weight
increasingly lower down so as to maintain the relationship between the
centers of bouyancy & gravity. Actually, as the beam/disp ratio drops,
the lever arm between CG and CB needs to increase... very unlikely!

... What
was interesting is that there seemed to be an over-center point, beyond
which the stability of the boat fell off precipitously. It was not a smooth
curve, rather it peaked, then plunged.

Maybe like a sine wave, with the peak for the point at which the
gunwhale immerses?

... I'm surprised that boat builders
don't publish a *do not exceed* load figure for each boat, even if they
don't want those graphs out and about.


Ever hear of the Plimsoll marks? For commercial ships, these figures are
published and are supposed to be kept by the captain. For naval vessels,
they keep a whole book of figures on stability.


Yep. Everything is a trade-off. That's why life is such a good metaphor
for sailing....


Aw, heck, I want it all, dammit. g


If you figure out how, let me know.

Fresh Breezes- Doug king