When the planer board is fully open the aluminum bar pivots around the bolt and stops against the board on both ends. The action of pulling the planer should keep the boards at full open no problem.

So far I see two problems. In the second pic you may be able to see the board is being dented by the bar, and it has yet to see the lake. The other problem is the hardware is not 100% available like the other planer boards I made. I was trying to keep these easy to build.