Wing Keel - how does it work? - Page 3 - SailNet Community
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post #21 of 26 Old 11-16-2010
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Trying to think about what one could do with lift. If the wing was slightly v-shaped and fairly wide, you could get some lift as well as reduction in heeling. As the boat heels over, one wing would be level providing lift, while the other wing would be also pushing sideways, trying to straighten the boat up. I suppose the question becomes at what cost of drag. More sail area can compensate for drag. With a planing hull, it should get you on plane sooner.

Just doing some brainstorming.

Brainstorming is good! If you're really interested, have a look at the foils on a Moth..

...but you'll find that the forces required to vertically "lift" anything other than a planing dinghy are not going to do the keel on a larger boat any good, because they'll be trying to bend it at 45 degrees meaning you'll need a far stronger keel than would otherwise be necessary kind-of negating any perceived benefit.

Besides, the LAST thing you want on a displacement keel-boat is to provide vertical "lift"! All this will do is reduce your waterline length and slow you down.

Jeff_H has already explained it all much better than I can.

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Last edited by Classic30; 11-16-2010 at 03:56 PM.
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post #22 of 26 Old 11-16-2010
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Originally Posted by Daveinet View Post
I suppose the question becomes at what cost of drag.
That is generally the downfall of a wing keel.
Their benefits seldom out weigh their cost in drag.
While the wing keel did seem to be effective within
the confines of the 12 Meter Rule, all the production
builders that built wing keel versions of their boats to
acheive shallow draft, created boats that were much slower
than their fin keeled sisterships.

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post #23 of 26 Old 11-16-2010 Thread Starter
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I as thinking more along the lines of a semi-planing hull, such as the Beneteau 210. Centerboard weighs 770 lbs. If one could create 700 lbs of lift, the centerboard would have a neutral effect on the weight of the centerboard. The difficulty would be making sure some of the lift was as aimed the right direction to prevent heel, hence the V.

Seems from the responses, I need to find a good hydrofoil calculator for a reality check. Don't want to be trying something as silly as creating perpetual motion.

BTW: I've seen those moths on Youtube. They are pretty cool. I like where one guy said he got a ticket for going to fast in a restricted area. Too funny to get a speeding ticket on a sail boat. Seems that ticket is more like a trophy.

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post #24 of 26 Old 11-16-2010
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I as thinking more along the lines of a semi-planing hull, such as the Beneteau 210. Centerboard weighs 770 lbs. If one could create 700 lbs of lift, the centerboard would have a neutral effect on the weight of the centerboard. The difficulty would be making sure some of the lift was as aimed the right direction to prevent heel, hence the V.
To my way of thinking, hypothetically, if you had a Bendytoe 210 you'd be better off trying foils than any kind of winged-keel. Seeing something like that lifting off the back of a wave in a 30kt blow should be enough to scare the opposition into retirement!!

The issue with centerboards is that by nature they tend to move around in the centercase. To get any kind of 'lift' translated into something useful, you need the foils rigidly connected to the boat.

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"Honestly, I don't know why seamen persist in getting wrecked in some of the outlandish places they do, when they can do it in a nice place like Fiji." -- John Caldwell, "Desperate Voyage"
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post #25 of 26 Old 11-16-2010
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I am not marine architect. The 12 meter "formula" allows for different designs. If the mast height gets bigger something else has to be reduced to accommodate the change. But a wing keel has a limited depth and when heeled, the wing has the effect of a deeper keel. So the formula is cheated a bit. In a race that the difference is measured in 100ths of a knot, any "advantage" is positive.

I have to wonder how a wing keel compares to a fin keel when all other aspects of the boat are the same...

Joe McCary,
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post #26 of 26 Old 11-16-2010
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.....I have to wonder how a wing keel compares to a fin keel when all other aspects of the boat are the same...
There's a noticeable difference in performance between, say, a Catalina 34 or 36 wing keel vs fin keel... with the fin coming out ahead (at the expense of draft, obviously) I believe that's essentially true of any of the production boats offered in both versions.

Ron

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