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post #531 of Old 10-09-2012
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Re: Full or fin keel?

Originally Posted by PCP View Post
I say that one is more stiff than the other? You have any doubt?

The stifness of a boat is directly related with the boat displacement and the sail area the boat can carry (SA/D). You can see that big difference yourself. Paulo
Yes, I definitely have a doubt that you know the racer is more stiff than the Benneteau Oceanis. Stiffness is a characteristic of the hull dimensions and weight distribution and has nothing to do with SA/D.

I am sure there are many readers scratching their heads at your post.

Specifically, stiffness is related to the moment of the area of the waterline and the volumetric displacement. It has nothing to do with sails.

You are inferring the stiffness from the SA/D. Problem I see is that the racer would tend to carry more dacron that the cruiser given the same stiffness. The way I see it, most good racers have a hull design that increases the stiffness dramatically with heel angle. This could even lead to a boat less stiff than the Oceanis at low heel angles.

Originally Posted by PCP View Post
There are several ways of obtaining a seaworthy boat and mass and a relatively high CG is one of them, unfortunately one that gives slow sailboats.
My discussion is not about seaworthyness. That discussion has been hashed out in the multitude of threads about "Bluewater".

My discussion is specifically about rough water characteristics. And a higher CG by any stretch of the imagination most generally results in a poor rough water boat.

But ignoring that for a moment; again, you are assuming that everyone is willing to sacrifice everything for performance. Most cruisers are not.

Originally Posted by PCP View Post
You should try to understand how that massif seaworthiness (that is a fact) is obtained in a boat that contradicts the ways it was obtained 50 years ago instead of, against the reality, assuming that boat cannot be seaworthy because it is not designed accordingly with the principles that 50 years ago were used to design seaworthy boats.
The principles of boat design have not changed in 50 years. Only the boat designs have changed in 50 years.

Again my discussion is not about seaworthy boats. And this thread is not about seaworthy boats.

My discussion is specifically about a charateristic of boats. That characteristic is pretty much what most cruisers are concerned with.

To put it into words that you might understand: Most people prefer that their masts stay pointed up and their keels stay pointed down.

To further this idea, people prefer that their masts stay pointed up even when the boat is going over waves.

Your two boats are boats that exhibit the above characteristic poorly. Rather, their relatively high hull siffness causes both boats to heel exactly with the waves. In this case I am relying on your clearly poor interpretation of stiffness.


Last edited by BryceGTX; 10-09-2012 at 07:09 AM.
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