First there is no balsa core in the hull but only dyvancell which may look like balsa core. It give structural integrity; yet, it is lightweight and not affected by water. It also allows the hull to flex. Then my question is there gel coat on the inside of that repair. If not, there will be a chemical reaction to the bare fiberglass with water over time. Then my next question, was another 23.5 hull splashed in the same spot which to make a plug from in that area to make a new section so you have the exact hull likeness. Then was balsa core, dyvancell or only bare glass added? I was not there so many questions may not be answered. Although I cannot tell but the finished product does look good and shiney.