Hi,
I wanted a recreational racer, and last year I got a good deal on a 2015 NSP Coco Race VC 14'.
The deep race-like fin was ok for flat water and less windy conditions. But I also wanted a shorter fin better for sessions with side-wind, hopefully also better for maneuvering during downwinders in light conditions. I will buy a more or less dedicated downwinder board in a while, but for now I want to fix a fin fitting issue and keep this mostly good board for the family.
I tried to buy an extra fin when taking the board out of the shop. The dealer agreed with me that the ones he had simply didn't fit well with the fin box, not nearly flush with the bottom of the board. So he recommended me to order one on my own. The original 12" deep race fin was flush, tight and just fine.
I made a note to order one during the winter, and totally forgot this issue until I received my chosen (discounted) FCS Fluid Foils Ezi Trim 8.5.
Same story, the base of the fin is a little more than 3 millimeters outside the board.
The distance, from the the rail-securing pin, to the blade (or the supposed board bottom line), is 11mm with the NSP and 14mm with the FCS.
While trying to find who is "right", I realize there's no disclosed attempt on drawing a standard.
Found nothing relevant searching stuff like longboard fin, US fin, box, dimensions, standard.
Si a little help would be much appreciated. I have no experience with other than the Futures and FCS proprietary systems on my kite- and surfboards.
Are such misfits totally negligible? Like, does the water-flow disregard this location?
Can I avoid this altogether in the future by choosing certain brands that seems to agree on dimensions? (can't even find where/if NSP is based on this planet)
Other brands with other box types? (probably not with racers/downwinders)

Thanks!