Hola,
After riding my homemade superflowerpower singlefin longboard (see avatar) for some sessions, I wonder how would it ride with extra side fins. But only looking around for FCS plugs here in Spain makes me having a headache.
I have some 8mm thick polycarbonate scrap at home so I thought I could use it for building a simple finbox system.
It will use a 8mm wide X 140mm long X 20mm deep slot made from 8mm thick polycarbonate pieces, then glued (loctite). Fin should be fit into slot, then slided back and finally fixed to the box using a screw.
Could it work???
I think drilling the vertical hole would be the most difficult bussiness…