I have purchased a centerboard model oday 25. The hull is in great condition except for the toe of the fixed part of the keel. It looks as if it banged a rock and took off the fiberglass (4" by 2.5" ) exposing a white material. Water slowly drips out of this opening (ie; one drop in three or four hours) Can anyone tell me what the white material is? Any clues as to how to drain all the water? Any good reading on how to do a good glass repair?