Paul,

I could only see a zebra's ass

Don't you fear the stations would twist in a formed sea, so that instead of a 90* plus 90* stations-to-stringers angles you'd get 110 + 70 or else ?
Also, considering the lack of resilience of pvc, won't the whole structure sweep up at ends with the paddler's weight?
So not to get a banana boat, will you use stanchions? Unless you'll run a polypro chord along the inside of the tubes in the lower part of the contraption, so as to make for the upward bend?
Pvc stations also make me skeptical.

Just a few thoughts.

: The bottom pipe is a piece of 3/4 inch schedule 40 PVC plumbing pipe. It has
: a simple slit in it.

: As you can see from the parts above it, this slit pipe can be pinched a bit,
: and it will slide into a piece of 1 inch schedule 40 PVC pipe.

: above that is an example of what you would get if you use this to join two
: pieces of 1 inch pvc.

: If you mae this joint at the location of a station frame, the narrower pipe
: can go throuh a hole in the frame, while the thicker pipes can slide close
: to each other, and hold the frame in place.

: PGJ