I have an 11.5ft Escape Mambo, one piece plastic hull.... it has cracked where the Keel slides into the bottom of the boat. I have tried caulking, but this year it has cracked much longer and in two places..... any ideas on how to combat/fix a plastic hull? This is plastic similiar to a "One Step" or "Little Tikes" toys but a little bit thicker and denser. Thanks for any help.