Importance of Airfoil shape on swing keel?

[thisoldspouse]

I didn't want to hijack the "downgoes the keel" thread. I understand the need for an airfoil shape on a rudder and maybe on a "race" boat or cruiser, but on your average trailer sailer. Does the shape really matter? The swing keel isn't pretty. It's just a basic hunk of metal, there is some shape, but more weight for counterbalance. So, my question is: Would your average sailor notice if the keel were airfoil shaped as opposed to a basic plate steel keel?
Eric
I'm planning for disaster. I've never dropped my keel to check the bolt or area around bolt. I did replace the winch and cable.

 

[flynfol]

Yume betcha! The weight keeps you upright, the foil allows you to point better. A barndoor will fly with enough power, but the drag curve will be HUGE. The most efficient centerboard would be an assymetrical foil, but then you would need two of them. One for each tack. Even my nasty iron swingkeel on my V25 has a foil shape.

John

 

[flynfol]

If you have a square slab centerboard, you will need more rudder angle to correct for lack of lift, that increased rudder angle creates more drag. More drag, slows you down.

 

[timebandit]

Most likely not with 30 knts. of wind and a 150 genny up.

 

[flynfol]

Yikes......I'd be grabbing for the ejection handles

 

[Paul Brinkley]

My Boy Scout Troop built sailing rigs for their canoes. Both rudder and centerboards were made from 1/2" plywood with just rounded edges. They worked fine, but at higher speeds, both would vibrate, undoubtedly holding the speed back some. I expect a greater thickness and an airfoil shape would have improved this. So a flat slab will probably work for a larger boat, but will not be as efficient. -Paul