It is a misnomer to believe that simply pulling water across a prop does that. It's the water moving across the rudder from the boat moving. Not while a boat is stationary.

That doesn't mean that the current couldn't produce a "hidden' result that looks like it functioned that was -- but it's just the prop doing what you thought you saw.

From Someone that I regard looked at this and observed to me that:

I am appalled that once again someone is arguing the impossible, namely that a sailboat (or ANY boat) can be turned in either direction with the rudder by -----pulling----- water over the rudder.

This was argued 70 years by a young man who would one day be a Nobel Lauriate in Physics. IT CAN'T BE DONE. In fact, today, there is a public display at MIT which anyone can walk up to, push the button to see air being pushed out the nozzles and the gear rotates, push the other button to pull into the nozzle and the whole thing stops dead, as physics says it would.

To steer a boat in reverse with the rudder with the prop in front of the rudder, THE BOAT MUST BE MOVING IN REVERSE. No reward movement, no effect on the rudder, no matter how high the motor is reved.

http://web.mit.edu/Edgerton/www/FeynmanSprinkler.html

That's the reason that tugs (and other boats which require rudder control in reverse) have a separate rudder or rudders IN FRONT OF THE (reversing) PROP.