I’ve used futures fins on my last few shortboards and have grown to really like their feel, but all have been installed on flat bottoms or vees. I was wondering how to install them into a board with bottom contours because it seems like the leading edge of the box would have the flange slightly above the foam. I don’t know if that would be okay or if there is some way around it. Any insight would be greatly appreciated.
as with any pre glass install system you should cut the hole in your blank deep enough so that the box is flush with the lowest part of the hole. That way you'll ensure no sanding through the laminate on the edges of the box. You should find that a heavy application of hotcoat over the box area should allow you to retain the shape of your curves after sanding. The worst case scenario is on extreme curves and your box is sunk so deep so you can't cut through the hole for the fin...in this event I'd suggest some very careful trimming through with a stanley knife (craft knife) adn then file/sand up to the edges. But this wont ususally happen.
Cheers
Rich