Built my first boat two years ago with two coats of a satin finish varnish. After putting on a 3rd & 4th coat last week (wet sanding inbetween) I realized there was no UV protection in the product I picked.  Ran down to the local paint store and grabbed a can of spar/marine varnish w/ UV protection, wet-sanded, added two more coats. 

Took boat out and hit some rocks.  Varnish is now peeling off the bottom in thick layers-- like a bad sunburn...

I'd like to strip it all off and start over with the varnish, but I fear sanding down might hit fiberglass.

Should I chemically strip off the old crap?  Is there a stripping product that'll remove the varnish but not damage the epoxy?