I doubt I'll ever do this. Not any time soon. I've got too much on my plate already and not enough years left to do it all.

Somebody needs to make an extra-extra-wide SUP board. The Dayak profile would be a good starting point.

SUP boards are fun and popular and stupid. You have to be a circus acrobat to ride one without falling over. There will be limits to how wide one could be made. The wider a SUP board gets the longer the paddle would have to be. But still. They could be a lot wider than they are. And they aren't. It all started with surf boards I guess, and once started nobody wanted to change what already seemed to work.

But it could work better. For rivers anyway. And for fishing. Wider is more better.

Glue 6" inch styrofoam together. Shape it with a sureform file. Fiberglass it up. Buy or make long paddles.

On second thought.....scrap the stand up part. Make something like a solid, 5" or 6" thick Dayak with a pointed front end. Out of styrofoam covered with glass. Lots of rocker but mostly at the ends. Relatively flat in the middle. Mount a seat and oarlock towers. Use 8' foot lightweight oars.

You could run the Grand Canyon with that boat. Or stand up and fish. Maybe with a bolt on bolt off anchor system. You want that anchor for fishing but definitely not for white water.

There are some good YouTube videos on how to make a surfboard. All you need is wide. Wide. Wide is all you need

It could be rowed while standing, facing the destination: forward rowing like certain dories in New England. I primarily row the BB while facing forward. I will essentially be a flats style boat with the ends bent up.

I used to have this dream of building a boat with a 40+/-" beam. Similar to the Dyak it would be sealed; similar also to a sailboard. One would sit on top like some kayaks and it would have almost no rocker and also very little dead rise.
The purpose would be to explore ultra shallow natural streams that course through historic and otherwise private urban neighborhoods during spring higher water levels.It should float in 3". Carbon fiber and graphite on the bottom.

I like it. For me I'd carve it out of solid styrofoam like a surfboard. And then glass it up. Have snap rings all around so you can strap on a box of fishing tackle and a sandwich box. Make it like a low but extra wide sit on top kayak. Could be light enough to carry with one hand.

Being a lover of wood I completely forgot about foam and would likely have forgotten tiedowms. Thanks