There are a few PVC canoe designs online. Clearly, they are better constructed the the ones shown in the article. However, as one builder pointed out they first tried theirs in a pond and in shallow water.
It’s understandable that someone could find a design and try a build. The idiocy is thinking that the first trip would be with a group of Boy Scouts who would load up and start down the river.

https://www.instructables.com/...-Tape-and-PVC-Canoe/
https://pvc-innovation.wonderh...and-plastic-0133023/

Should have sprayed them with Flex Seal .