The last two trips out in a Rhodes 19 I have tried to demonstrate heaving to. Both times I headed into the wind leaving the working sheet cleated. I waited until the boat had just about stopped and then finished the tack to backwind the jib. At this point, the tiller gets pointed toward the mainsail.
For a few cycles, the boat gets pushed down by the backwinded jib for about 30 degrees. Then the mainsail powers up and turns the boat back up. Jib pushes boat down, main turns boat up, etc.
Yet both times I have done this, the main eventually brings the boat so far up that it tacks and starts sailing again.
Am I doing something wrong, or is it simply due to shifting winds?