Data
Hi again,
Good for you, seriously, for questioning those numbers. I don't like it when people accept things I say blindly. Let's start with the displacement question. That is a factor, but only when coupled with the length of the righting arm, and this in turn has to do with the distance between the center of gravity and the center of buoyancy, at a given angle of heel. Thus a light boat with a lot of distance between those points could be more stable -- and have higher rigging loads -- than a heavier one with shorter distance.
The load on the uppers is approximate, but not grossly so, and you can prove it, either on paper, or directly, with load cells. Same with the lowers.
As for the "intermediate backs," if you mean aft-led intermediate shrouds, they are typically at such a sharp angle that they provide negligible lateral support, and can be safely ignored. They also don't provide significant aft support, which is why runners make more sense for your boat.
Finally, it is just not possible to have an R.M. of only 12,000 or so, except at very low angles of heel. How did you derive that number?
Fair leads,
Brion Toss
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