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Old 09-24-2011
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Quote:
Originally Posted by bb74 View Post
I read about that boat last year as well - the designer got the idea off the lake boats with the skiff like bow.

It planes much earlier (faster) but is a bit of a handful upwind. Great "one design / one purpose boat" and I'm sure some iterations of the hull will eventually flow downstream to more broad designs. I think you could see some "convertable" designs with a bow "keel" that could come down while upwind and up while downwind in the future.
I was quite surprised with the boat results and even so I thought that it was just some kind of curious amateur that got lucky. I was wrong.

It is not luck, the guy is really good. David Raison is a naval engineer and worked with François Lucas and they are the ones that first used chines for improving performance, the ones that we see today in many racing boats and some cruisers.

He says that he was looking for a way to improve performance in a mini racer and the idea of this hull shape come when he recherche the Skows:



They had that bow and hull shape for having more stability.

Than he made some computer studies and simulations on shapes and how they would perform and designed the boat accordingly. He says the boat sails as was previewed on the studies.

He says that compared with all the other racing mini protos, his boat is the fastest on a beam reach, among the top 5 close to the wind and among the top 10 downwind.

The worse performance is downwind with more than 25k wind and waves, were the boat takes a good beating.

This bow makes the boat plan more easily and gives a lot more righting moment. He says that his boat with the keel vertical has the same righting moment the other proto have with the keel canted to the right side.

It seems that one of the new designed Open 60 has a bow working on the same principles (not so radical).

Funny thing is that I read once on an old book about design and building of Caravelas (XV century discovery sailboat) that the bows should be well rounded...and I never understood why or for what purpose

Regards

Paulo

Last edited by PCP; 09-24-2011 at 05:48 PM.
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