: That's six feet / two metres of water column! Should be enough for a kayak,
: no?

The "waterproof" fabrics I've had contact with (no pun intended) are waterproof for awile from rain, snow etc. but eventually they seem to wick up the moisture and then become much less "waterproof". I would also worry that the moisture coating would mean that whatever you'd use to truely waterproof the fabric then wouldn't penitrate well an might not stay stuck.

Bill H.