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post #16 of Old 10-20-2012
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Re: Fin vs bulb vs wing keels

I view the differences between these keel designs from a number of angles:

First is the performance issue to to change in resistance. Rather than calculate actual resistance, I can look at wetted surface. It is interesting to compare the wetted surface between the wing keel version of my boat (Catalina 400) to the fin keel version.

When I crunch the numbers, I find that the wetted surface of the wing keel version is less than 4% higher than the fin keel. Granted, the resistance is probably less; however this shows how little effect the wing keel has on the overall resistance.

A rough calculation of the difference between a bulb at the same draft, with the same righting moment, I would find the difference between the bulb and the wing to be a similar 4%.

One has to wonder if the 4% difference is significant. It might be interesting to look at some of the advantages of the wing keel versus the others. A quick look at Wikipedia gives a bit of insite:

Last edited by BryceGTX; 10-20-2012 at 07:17 PM.
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