One single sheet....

One single aluminium sheet, 122 x 244cm (4'x8') can become this canoe/kayak/contraption.

Has it ever been done ?

The paper pieces on the picture are exact proportionals to a typical commercial sheet. Glued ends to be welded in real life.

 

Yes it has been done many times in many iterations. That is often referred to as the tortured plywood method. Many a boat has been built that way with plywood. So alright, you might be able to pull it off with sheet aluminum. When I was a kid, about a hundred years ago, We built tin canoes with stolen corrugated sheet metal roofing panels. We folded the tin pretty much as indicated in the OP drawing. None of us drowned, by the grace of god, or whoever else is looking after adventurous kids.

 

I am over 60, and an 8 year old schoolmate drowned in his tin canoe made the same way - so yes, its a very old method.

The hull shape makes for very low gunnels, right where you need the most stability, and the metal hull takes you straight to the bottom of the 30 foot dam.

If this 'simplicity' intrigues you, research stitch and glue boat building techniques on YouTube.