William,

I would glass both inside and outside or it will just crack again.....and depending on size I would initially open up the crack slightly and glue it before glassing it.

The outside may need to be sanded back so that when it is glassed it is fair with the hull

And do use Epoxy resin and glue (Bote Cote, Epiglass or similar) as the polyester will fail in time.

DKD
"Banh Sidhe"