Somewhere in the depths of the internet I read a text about optimizing the wind vane control in light winds. I can't remember where that was. Therefore I do not want to register a copyright for this patent, but would like to recommend copying it.
At the moment we have a light wind without end that whistles at seven to nine knots. That is just enough to make the Parasailor three to four knots of speed. With this low wind, the wind vane has a hard time responding quickly to the ship's turn. With the small plastic bag, the response has improved significantly.
What we are missing now is a few knots more light wind.