More grinding. I'll keep going until all damaged fiberglass is removed and the edges are bevelled out about 3" past the damaged area to either side. I ground off more glass and alot more gelcoat than you see here, but I didn't stop to take a picture.
Did you notice the puncture in the white rubrail hanging below the deck joint? Whatever hit Redwing was sharp and pointy enough to go right thru the 3/16" rub rail that covers the joint.