geesh, jeffies, you CLAIM to have a degree in physics, yet it is plainly
obvious you don't even begin to understand what is going on.

You're absolutely wrong about this jaxie. Feynman would think you're a
complete
fool for invoking his "sprinkler paradox" in this case. The boat is not
turned
directly by the propeller, it is turned because a water flow is pressing
against
the rudder. "Push" and "pull" are irrelevant, and the water flow could even
come from a current, or the wash from another boat. For a variety of
reasons,
the affect is far more powerful in foreword, but it is still there in
reverse.

USSailing, and Boat/US both describe this on their websites.
http://www.videos.sailingcourse.com/...pring_line.htm
http://www.boatus.com/seaworthy/swlines.asp
And the Coast Guard
http://www.uscg.mil/hq/g-o/cgaux/Pub...crew/ch10d.pdf



"JAXAshby" wrote in message
...
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.