Did you build a pygmy kayak kit by any chance? I did, it was the most fun I've had building something in my life. The entire "epoxy plus fibrous material" is truly a winning solution for so many applications, apparently hyper-sonic wings, too!
No, this was a high-volume play boat. About 35 years ago. And it wasn't a kit. I was boating with a club with a shop, and members who knew what they were doing.
Sorry, didn't mean to offend you by suggesting you were anything but a pro.
Me, a pro? Never. But I learned from some serious whitewater freaks. I quit because poor impulse control got me almost killed, too many times.
Those look really cool! Amazing some of the things you find on HN.