I have a Fanatic stby infaltable sup board. it has a center US fin box, and two thruster fins that are glued on. the thruster fins are starting to lift or peel off. any suggestions on what to use to re-glue to the board? my other option it to remove hem completely and use a bigger center fin. I don't use this much in radical conditions.

I've had good results with AZBOND C 2-Part Adhesive with other inflatable repairs. Should do the trick.
Plenty of places seem to sell it.