Thom Stewart wrote:

Doug,

Your article by Vacanti talks volumes of LIFT. You should be able to
answer your own question. Does all the LIFT describe in the article
LIFT the boat?

That's why I used the word "up"


Doug, I've spent a life time in the Oil refinery measuring liquid flows.
Orifice Plates designed using Reynold numbers
You and Vacanti have not made mention of the large "Gray Area" of the
Reynolds #
between laminar flow and turbulent flow.

Actually it does. Almost all foils will have at least a
small section of laminar flow, some rather odd foils are
designed to work almost entirely in laminar flow... even
odder ones with none. Ever seen a super-cavitating prop?


You also ignored the "Newtonian" factor and just talked Reynolds and
Bernoulli.

Actually, I didn't. I didn't write that web page


... Let us not forget that each created lifting force has a equal
and opposite force. It is important to identify these forces.


Forces are not always equal & opposite, though. If they
were, nothing could ever move. For example, the force
exerted by the wind on the sails heels the boat & drives it
forward. The boat goes faster *until* it creates enough drag
to equal the drive. At that point, forces are equal.

Have you worked on control systems that cycled or hunted? An
example of how difficult it can be to get forces to equalize
smoothly?

Fresh Breezes- Doug King