The surfboard fins in the photograph are the FCS fin system. I used this system to put a skeg on my strip built kayak and was very pleased with the result. I would not use the fin box, instead get the plugs for a centre fin, it is important to emphasize that it is for a centre fin as the plugs for the side fins are offset a little. The fin has two tabs that slide into the female portion of the plug and are locked into place with an allen key.

: Hi All;

: My surfboard building buddy stopped by the house this morning to check out my
: kayak progress. He showed me a surfboard he was building and when I saw
: the "fin" mount I couldn't help but feel it might have value for
: kayaks. The attached pic shows a center fin mounted in a plastic box that
: was glassed into the board. The long slot will accomodate the many
: different shapes/sizes of fins available, and will allow for positioning
: the fin fore/aft as necessary. The fin he has currently installed also
: snaps into a rear mount, but that isn't necessary with other types of fins
: I believe.

: Seems like snapping off a fin while cavorting in the rocks would be a simple
: matter of clipping on the spare. Plus, the fore-aft adjustment and various
: fin shapes available would allow for experimentation with handling. These
: are off-the-shelf items, and I think they're pretty cheap - I can't find
: my surf supply catalog at the moment - Also, notice the 5-fin arrangement
: the surfboard crowd has evolved over the years - - All snap-in.

: Best Regards, Spidey