Welcome Jaffo 76,
A friend of mine made those boxes here in the late-70’s/early-80’s, he called it the “Dove Tail”
fin system. It had a piece of waterproof foam under the front pressure tab which allowed you
to release the fin and the tab would spring back up and lock the fin in place. It relied heavily
on the wedge effect of the fin base.
Inspiration came from the “Edge Boards” made by a fewshapers here in the late 60’s. Those fins
would get a molded base then a coat of car wax. Then get placed in a slot that extended off the
tail and resin/fiber was poured in place around the fin base. Fins were held in by friction, you just
gave them a whack rearward and they would come out.
It had some issues with the fins de-bonding from the molded bases. I have his
email address if you want to try to contact him, but I don’t think he is into the system anymore
so he probably does not have any spares or fins and such.
He had all the local shapers using them, so you might see a few labels with them. I used them
on a couple dozen boards. I remember Stevie using them. John Holley and Rich Pavel also.
What shaper made that board?
Stanley Pleskunas lives in NorCal now, still inventing stuff. Had a great discussion about blank
making recently. He’s made a lot of shaping tools that you may have already seen or used as well…