Howzit Otis, I found one when I was going through my stuff to ship when moving and I think i kept it but haven't gone through all the boxes yet, They had a screw that was angled downwards at the front of the adapter that was supposed to hold the fin in the adapter but I found you needed to drill just a slight indentation in the front of the fin where the screw tip touched the fin and that held the fin in for sure. Those adapters were infamous for losing fins if you didn't do the indent like just the tip of of a drill bit. Aloha,Kokua
"Adapter allows you to change from a traditional longboard fin to a FCS thruster set up in seconds, perfect for loosening up your longboard. The adapter is adjustable for deeper longboard boxes."
I just don't know Otis....What is your plan...What's your goal....
One day A guy told me that side bites were "training wheels"....wow ...that really struck me...I'm not Mr. Super Surfer but if I want to loosen up my longboard the first thing I would do is ditch the side bites.....and then work on fin size..and flex of the fin. It sounds like another sales pitch to me.....but...I'm not a big fan of FCS.....and I only surf weak San Diego reef breaks.
I was lucky enough to have 2 of the 80's thruster centre fins, the ones that fit in a longboard box. I've still got one of them. I use it on my midlength as a thruster and the board feels a foot shorter, comes off the top super quick, pumps down the line great, cutbacks good too. Changes the board completely. I like to trim, but sometimes its nice to get angry with a wave.
my plan? briefly, I am a shortboarder. Probably would have to agree with you that the FCS center fin range/spectrum is geared toward short boards. But have never given it much thought.