: Do a few searches on the Coanda effect or Bernoulli's vs. Coanda
: effect. Coanda effect is the surface attachment of the flow as
: it exits the surface. The curve of the foil increases the push
: without causing stalling. It is why a sharper paddle edge works
: better.
: Play with different shapes under the running water faucet and
: notice how it wraps or shoots outward.
: All that being said, I have just redesigned my skeg box design
: using flat 1/4" King Starboard stock for the blades.
: Here is a link to start with.
: http://amasci.com/wing/airfoil.html

: Hope this is helpful,
: Reg

Actually for a conventional shaped skeg, I really doubt that the shape matters, the angle of attack is always pretty tiny. For a skeg with a very short chord it might matter, might not, short chord wings stall much easier. Testing is in order.

Drag also might not matter, speeds are pretty slow, a foil shape has more frontal area than a flat plate and frontal area matters. Again testing is in order.

For a rudder a foil shape is definately better, but you're dealing with higher angles of attack and usually much shorter chord foils.

Bill H.