Inflatable SUP Paddleboard Fin Box

This is the finbox I used to add a centre daggerboard to my inflatable SUP. It is made with a large flange so it can be glued to the bottom of the board with a ring of PVC cloth around it as well for better adhesion.
I designed the finbox I so it doesn't need supports. I have altered the slot to that the top of the slot is a 45 degree angle instead of a 90 degree overhang. It's a bit of an experiment, but I think will work for low impact uses. On the hatchet fin I made to go along with this base, there is an angled lump, that's to help tighten up the fin against the extra room left by the 45 degree slant.

No guarantees that this will work for you, it's a bit of an experiment!
Also, I am not 100% sure this is the same width as a standard U.S. Finbox, it might be just a smidge wider.