The reason I asked is I can't really see how it's mounted. All I can see is what looks to be like it's sandwiched in between the platform and the boat. Which in my opinion would be very bad for the transom and the platform. If you've got the load distributed, then cool, but how? I can't really see from your pictures.

And now you mention it can be retracted. Now I'm really confused. So it can slide open and in? What keeps it from popping all the way out and down to the depths? Is it fixed to the platform bracket or platform mount somehow?

The only surf gate I'm actually familiar with is the malibu gate and it hinges on the transom via hydraulic actuator. So I can't relate your design to anything else.