Robi we do repairs like that one ever second week during the racing season. From what it looks like in your photo's its no where near as bad as rips we see from start line "bingles". Any decent fibreglasser should have absolutely no problem at all in making that repair back to as good as original with no visible signs that it was ever there. Just one small recommendation, don't use epoxy resin, the hulls are, I believe laid up with vynalester resin for the blade, so do the repair with vynalester resin and finish with polyester gelcoat, that way there is complete compatibility between materials.