There is a method in the Many Ways to Potter that is simple and works well.
I understand it is a method that was used on non-RC model sailboats. It
keeps the boat on a constant heading relative to the wind direction.
This method as described requires that the mainsheet be routed along the
boom, as Potters are normally rigged originally. Connect a length of
surgical rubber tubing from the leeward rail to the tiller. Then route a
line from the tiller through a block on the windward rail, and attach it to
the mainsheet at the boom (between blocks), using a snaphook or something
similar. Leave everything slack until you have the main trimmed for the
desired heading using the mainsheet, then cleat the mainsheet. Adjust the
tension on the rubber tubing and the line to the tiller to maintain the
heading. The boat then responds with a tiller correction each time the heel
increases or decreases, as signaled by changing tension in the mainsheet
I tested this method at Clear Lake one day in a light breeze and it worked
beautifully. I was singlehanded and soon discovered I could walk all over
the boat and the rig would steer better than I could. I even stood on the
bow, holding onto the mast and the boat remained on course.
I never felt secure enough to try it in a strong or gusty wind (it will
head up automatically but can't release the mainsheet), and it's not
practical for tacking up a channel, of course, since everything has to be
reversed for each tack. I have an eyestrap on each rail for the rig, and on
the tiller I have a fairlead and some kind of v-jam, so it's easy to adjust
the tubing and line. But I didn't have another opportunity to use it for a
while, so the tubing became rotten and I discarded it.
I think it would be useful on open stretches of water with relatively
gentle winds, although I seem to remember that De Marsh used the setup in
stronger winds. I found it was most sensitive at Clear Lake when I had my
mainsheet rigged with an additional purchase - making the mechanical
advantage of the mainsheet a 3.5:1 instead of the usual 2.5:1. It did work
at the usual 2.5:1 but was less sensitive, as I recall.
When this was last discussed here, someone reported that it did not work
well on a run, which is probably true.
This may not be practical for your application, Jeff, but the hardware
requirements are minimal. Now that you have me thinking about it, I will
find some more surgical tubing and try it again - this time with my lateen
rig. I don't think it would work as well with light bungee cord instead of
surgical tubing, but you could try it. The surgical tubing is possibly
available at hobby shops.
Harry Gordon
P14 #234, Manatee
Mountain View, CA