Great post on the Yahoo surfski group:

clyde hedlund writes:

The reason why the wing works so well is because, if
you let it carve out its own path, it will always find
"still water" (or water that hasn't started to move
backwards). Forget about all that Bernoulli Effect.
The wing is a simple lever that hunts and seeks an
effective fulcrum, which is the water, especially
"still water." Nothing complicated - just plain old
down to earth 5th grade physics. aloja, clyde

Clyde,

I usually agree with you. But you really picked on the wrong dog this
time!

Wings are more efficient than conventional paddles BECAUSE of the lift
they create. And it's a LOT more than Bernoulli (Daniel Bernoulli is
generally credited with the formula that exchanges potential/pressure
energy of a flow with kinetic/velocity energy). Actually, NOONE has
yet published what happens here, because even incredibly smart
scientists don't "get it" yet. But there are some folks who are
figuring this out. One place is Ken Young (unfortunately killed a
couple of years ago in a car accident).

http://www.phys.washington.edu/~wilkes/post/temp/phys208/scull.lift.ht
ml

The SAME thing happens to wing paddles (but not cenventioanls). I
have a WHOLE dissertation on this topic, and wings are more efficient
than conventionals for the same reason that static aerodynamics cannot
explain why bumble bees can fly...

Al

--
Al Bowers Chief of Aerodynamics NASA Dryden Flight Research Center
al.bowers@n...
"It is my belief that flight is possible." -Wilbur Wright, 03 Sep 1900