: I used a water based polyurethane to seal the frame of my canoe; is this
: different stuff? Is it an exterior product, and does it have UV
: inhibitors?

I used cheap interior urethane for the initial filler coats. The last 2 were the more expensive Varathane exterior product. It has UV in it. Both appear milky with a slight blue tint in the can. They dry clear. No amber tint like spar varnish. I also used the interior stuff to seal the frame. Urethanes are not 100% water proof. If they sit in the water, they will eventually lead to leakage and pealing. But, since the boats don't stay in the water that long, that shouldn't be a problem.
Bill