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post #9 of Old 12-08-2004
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Columnist has said:

"That''s a hell of a capsize ratio! Is this for saga 409?

That''s better than Island Packet 40".

Refering to Chris T. statements on the Saga new boat: "...the capsize ratio is considered good at 1.86.
"The Boat has a high ballast ratio which really should give the boat plenty of stability. In addition, with a angle of positive stability beyond 120 degrees, the boat should have a very high righting moment".

Those are misleading arguments. You can simply not assess a boat stability with old formulas like capsize ratio or ballast ratio. Besides, a boat can have a very high righting moment and be inadequate as an ocean going boat. You can not confuse initial stability (stiffness) and final stability (safety stability). A boat can have (as a lot of the racing boats have) very good initial stability and poor final stability.

I would say that the Saga has a better initial stability and the Island Packet has a much better final stability (safety satbility).

I give you one example of the inadequacy of the ballast ratio as a means to assess stability :

The Saga 409 has a 37% 0f ballast ratio. The Regina 38 (a Sweedish ocean going DS sailboat) has only 32%, having apparently the worst stability of the two .
The Saga (according to Jeff_H) has only an AVS of 120 and the Regina has a much better AVS of 134.
The Regina has also a very impressive STIX number of 46. I don''t know the Stix number for the Saga, but I bet that it is a lot smaller.


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