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Gary
 
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Default Urgent ! Can anyone understand these safety data ?

Evan Gatehouse wrote:
Gary wrote:

I think the stability curves are wrong. If you plug the numbers into
the formulas at US sailing you get a much higher AVS. 110 degrees
just doesn't make sense. Not only that but the 460's keel, although
seemingly a little light, is bulbous with the weight quite low.
Something is wrong with that graph.

Gaz



I didn't find the formula at US Sailing's site but...How do you find AVS
without using a sophisticated stability program that knows the shape of
the hull?

The US Sailing formula may give an indication of ultimate stability (the
capsize screening formula) but that is a very simple rule of thumb.

The inclining experiment data, which does determine the VCG of the real
boat, is plugged into a stability program (GHS/Autohydro etc.) that
gives the stability curve.

Robert has retired fairly recently but he should be able to help you
with your questions.

Evan Gatehouse

Try he http://www.sailingusa.info/keelboat.htm
Under sailing calculators in the right find angle of vanishing stability.

The problem with the inclining data is that it only takes hull shape and
weight distribution into account. It doesn't allow for things like
pilothouses or foam filled masts. I still think the curve is wrong and
Tayanas claim of an AVS of 0 is probably correct.