Definitely want to try upwind. For downwind, there were plenty of
homemade options that didn't require drilling holes for masts. I don't
know yet how successful I willl be sailing upwind, with no sailing
experience, but I will have a pretty versatile rig.

So a leeboard is a good idea. Maybe something like this:

http://www.abdn.ac.uk/~ltu006/images...s/leeboard.htm

Or using a spare paddle like this:

http://www.sailboatstogo.com/img/cat...stabilizer.jpg

Or some modifications to the rudder to make it fatter and a little bit
like a centerboard.