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post #131 of Old 01-23-2013
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Re: Blue Jacket 40 (new racer/cruiser)

I am not sure that we are reading the same quotes and arriving at the same understanding of what is being said. And unfortunately I do not read French.

But the good news is that you and I agree on a whole lot of points here. For example, the more stability that a boat has for its drag, the more performance it will have, since it can carry more sail area at any given heel angle.

Where we are getting into problems is in the interpretation of specific sentences. For example, take the Finot quote:

"Between two sailboats with the same wet surface the stiffest boat is the one that can carry more sail."

I would interpret this sentence to mean, if we are comparing two sail boats, and both happen to have equal drag, the stiffest boat of the two, would be able to carry more sail area. I would not interpret that sentence to mean that the term 'stiffness' would be defined as meaning a boat literally mean that the definition of the term 'stiffest' directly means the boat which can carry more sail area. And I would agree 100% with the interpretation that I am coming away with, because the net effect is that a boat with increased stiffness (initial stability) is the boat which is capable of carrying more side force which can be in the form of a powered up saul or more sail area for any given angle of heel.

Similarly, the Dave Gerr quote " power…... is also termed “stiffness" " translates to in English naval architectural jargon as meaning, "There is a term 'powerful' used yacht design discussions which refers to a hull form that has a lot of initial stability". When a naval architect says that hull form has a lot of 'power', it means that a boat has a lot of form stability and as such it is synonymous with the term "stiff" which also means that a boat has a lot of form stability.

Power in this case does not refer to 'drive', implying that the boat has a lot of sail area. All that the term 'power' as used to describe a hull form does mean is that that hull has enough initial stability to stand up to a lot of sail area without heeling as much.

And again, while the power (meaning the stiffness of the hull which simply means the initial stability of the boat) is an important factor in a PHRF rating, so is the sail area of the boat, its drag, the efficiency of its rig, keel and rudder, and so on. It is possible to have a tender, low drag boat that has a very fast rating. A good example of that would be the Olsen 29/30 or the Hobie 33.

So I still say, our difference is in the interpretation of the terms, but not in the way that boats behave.


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Last edited by Jeff_H; 01-23-2013 at 05:59 PM.
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