OK. I put this in the category of failed experiments. I am sure trim tabs are great, but not on this dinghy. I think the problem is that they are too close to the tubes and outboard. Not enough room on the little transom.
We were at Roche Harbor on the guest dock with the boat facing the right way. The sun was shining, so I took advantage of the opportunity and pulled them off. And nothing fell in the water – including me.
The dinghy is much more fun now. Woohoo!