wayne, you are out of your league.

*push* is required under the laws of physics. If you can't see that, just take
Feynman's word for it.

It is a fact of physics that
you can NOT control using rudder by *pulling* water over it. you MUST
push.

===================

Absolutely not true.

If there is water moving past the rudder, regardless of direction or
cause, it can be used to create a directed thrust simply by angling
the rudder away from the flow direction.

The confusion arises because the prop in forward pushes a large flow
across the rudder, whereas the prop in reverse pulls only a relatively
small amount of water across the rudder. Small, but not zero.

You don't need a degree in physics to understand this, just a little
common sense. Richard Feynman would no doubt find the discussion
amusing however.