: I bought a tractor seat from Princess Auto. It is foam covered in vinyl.
: There is no backing or frame of any sort so I am attempting to make the
: back rest somewhat rigid and then use it as a kayak seat.

Greg,
In lieu of a rigid back glued to the seat perhaps a post, column or some other sort of support between the seat and the aft bulkhead would work. It would allow you to be able to pull the seat after use. If you use closed cell foam for the column it would contact cement to the seat very nicely. Make it at least 4" by 4", sloped to fit the seat back and about one half inch higher than the space between the hull bottom and the coaming. This gives it a tight "jam" fit to hold the whole thing snugly in place.
Ray