: Hi Mike,
: From the dark ages I remember an adage that you can put latex paint
: over oil paint, but don't put oil paint over latex - probably
: because the latex would be more elastic when dry. So, thinking
: about whether the oil paint you used would be more or less
: elastic than poly (of any base) I'd bet the poly would be more
: elastic. If that's true, you should be ok using the water based
: poly over the paint. I would sand the paint a bit since you're
: likely depending on mechanical adhesion, not a chemical bond.

: Just guesses though, the only way to tell for sure is to try it
: out. Good luck.

: See you in a couple of days... lots of travel ahead :-)

: Mark.

The canvas on the kayak was very coarse, and the deck only has two coats (three on the hull) of oil paint on it, but the skin really absorbed a lot of paint. I sanded lightly before recoating, but the surface is still quite coarse, and the weave is not filled. I have no doubt, that I will get a good mechanical bond. I ended up using Minwax Fast-Drying Polyurethane Clear Satin, which is an oil-based PU. It will get two coats on the deck and at least one on the hull.