O'Day 39 1985 shallow keel how to decrease drift

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Prieus

Hi, How can I increase pointing or decrease drift besides centering the sails. I heard that an "otter tail" shaped plate bolted to the bottom of a shallow keel would help. Any experience? Thanks, Bert
 
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Cappep

Reducing Drift

Keep the boat on it's feet. That is, do not heel too much. With my 272 I start to reef the main at 12 to 15 knots and find that I can keep up to many larger boats since I do not rag my sails to windward. Charlie
 
Sep 15, 2006
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Oday 27 Nova Scotia
Winged keel

Bert - I don't know the math & am too lazy to look it up, but bolting a plate across the bottom of your keel will effectively give you a "winged" keel, which will increase the effectiveness of the keel and reduce leeway etc etc Dave Gerr's "The Nature of Boats" has discusses the theory,and I'm sure there's lots more data to be found elsewhere. The distance the "wings" have to extend out from the keel to be effective vs the increase in drag is something you'll have to find out by trial & error, or by crunching a lot of numbers. If you do create a winged keel, you'll have to be very careful not to bump into the bottom, as I imagine a bent "wing" would negate any advantage you gain. Just speculation, but I imagine that the "wings" would exacerbate any tendancy of your boat to pitch in a seaway,and increase drag in so doing. Lots of stuff for you to figure out during the off-season. Good luck.
 
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