I need to repair a crack. About 2" long, diagonally across the hard chine. Cracked through the varnish and resin clear down to the glass (and the glass itself is slightly torn).

I figured on resining in a piece of 2" seamed glass tape across thre crack, sanding down the seamed edges of the tape and applying another thin coat of resin.

However...should I sand all of the varnish off in the area where the new resin will be applied or can epoxy resin be applied directly atop the vanish coats?