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post #4 of Old 12-07-2007
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The angle of vanishing stability and capsize screening formals can be found at:

They don't take into account nonstandard weight distributions of the hull or keel and they don't count the cabin house as part of the hull.

Basically, narrow, heavy and deep boats get the best numbers. 120 degrees is usually considered the minimum AVS for offshore sailing. My 1960s keel/centerboarder is considerably over the minimum: it's narrow by present standards, and heavy, but not deep.

I did own a boat that passed the formulas but I knew was too tender. I had an inclining test done (moving known heavy weights from rail to rail and measuring the change in list) the results of which alarmed the naval architect. Turns out the lead ballast on the plans (used for the formulas) was actually much lighter iron. A few hundred pounds of internal ballast helped but didn't solve the problem.

Most quoted AVS are provided by the manufacturer and. looking at typical modern designs that are light and wide, one wonders at their accuracy.
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