[PSUBS-MAILIST] Re:

[Carl Kem <dustyut@lasal.net>]

Dale, excellent query!  While the principle is similar to aerodynamics,
hydrodynamics is indeed a bit different with a twist.  The twist is
while you really cannot compress the water with the airfoil design, keep
in mind that you are acting against a liquid object.  Water has more
mass than air does.  So when you use the airfoil, you are not
compressing it as much as you are directing it.  You may be able to
direct it in a ditch or canal, but in a lake or ocean, you are directing
yourself.  You are moving, and you are by far smaller than the ocean
itself.  Therefore when you direct the water with the rudder/plane
you're telling the water, "Hey, I wanna go over here!".
Carl


Dale wrote:

>  I have a question for the group.. I am a pilot, and know the theory
> behind lift on the wing..I noticed on some posts, that there were
> airfoil shapes being used, to produce lift (in a downward direction)
> on submarines, submersibles  etc..   my question is , how does that
> work??  Water will not compress, or expand, being a liquid,  therefore
> the pressure difference between the top of the "wing" and the bottom
> of the wing will be the same, there fore no lift..  or am I missing
> something?? dale.

--
"In times like these, it helps to recall there have always been times
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