That should be able to be repaired. Grind the inside with 24grit disc and apply resin and 1 piece of 1.5 oz. mat to the entire inside of the panel, push out the air and let dry grind again and apply second piece to the inside. This will give the panel back its strength and allow you to work on the outside with out the cracking continuing. V out each crack and follow Daves instructions. Make sure you push out the air when appling the mat and resin.