I have a pine dining set that is finished with interior stain/poly combo... can I use yacht varnish over it?

I just re-finished the set last year, but now want to use it outdoors. I'd really prefer to not have to strip/sand it down again if possible, and am wondering if yacht varnish (or anything else) can be used over the interior stain (Minwax Polyshades in Classic Noir, satin finish) to make it weather-resistant?