Here’s a cool idea, 35 years on From Tom Protheroe’s “Pea Pod,” the jam cleat sail control. The mainsheet is moved by an elastic running up the mast. The sail control actually controls a simple jam cleat, as shown. Control is as follows:
Sheet in: head to wind, let elastic work, hit the jam cleat to stop the sheet in at the angle you want.
Sheet out: release jam cleat, let wind pull the sail out, hit the jam cleat yada yada.
Probably a bit tricky in practice, but if you have an eensy teensy boat this lets you use an eensier teensier servo for main sheet control without worrying if it has the power to pull the sheets in in a blow. Presumably a simple tension adjustment on the elastic could deal with wind variations.
PS. The attachment limits on this forum are a bit, er, draconian IMHO. If you want a higher resolution drawing PM me.