I agree. Having no ability to make the stern go sideways with minimal
forward or aft motion would complicate almost as many single screw
maneuvers as it simplified for the person who knows how to use the
prop force. It's almost like having a stern thruster.

It does mean though that the boat has a good side and a bad side in
many docking situation. I have a slip on the difficult side. 75% of
the time, the wind is quartering off the dock and half the time, the
current is as well so stopping the boat with three forces pulling the
stern away is an adventure. We've got it down pat though and I even
manage it single handed very often.

That said, the tiny propeller, large lateral plane, and high windage
of the typical sailboat make the propwalk force minimally useful
except in very calm conditions. When there is any wind, you can't
make our boat do the fancy things you see the lobster boats doing.

--

Roger Long



wrote in message
oups.com...
As long as you treat "propwalk" as the enemy, you will continue to
have
problems with it and never learn to handle your boat well.
Learn to use it, treat it as your friend, compensate for it, and
you'll
soon be wondering what all the fuss is about.
Accept it..... single screw or twin screw..... prop walk is an
important consideration to your boat's handling.

Shen

Roger Long wrote:
"Capt. JG" wrote

My question was how to correct it from a mechanical view, not how
to
correct it by technique.

It's very difficult to correct mechanically. Physics are against
you.
Open wheels are always going to walk. Variations in size and
number
of blades with change the degree but the psychological effect of
spending a grand or more to reduce the problem will often be
greater
than the actual change in forces.

The difference in water density with depth makes the wheel act like
a
paddle wheel (grossly oversimplified explanation warning).

Three things you can do:

Put the prop in a nozzle. You really won't be happy with the drag
under sail of this arrangment!

Twin props. Not much better from the drag standpoint.

Angle the shaft to counteract the effect and normal backing speed.
Going forward faster and with more rudder authority, the off center
thrust will not be as noticeable.

Neither of these are practical as a retrofit.

--

Roger Long