I have a 1982 25' Catalina, swing keel. It seems to be in excellent shape and I have docked on Lake Ray Roberts, a freshwater lake in Texas. The previous owner did not take the boat to any saltwater locations that I'm aware I don't know if the keelbolt has ever been examined or replaced. When is it recommended that the keelbolt be inspected and/or replaced? Also I removed the little cover over the keel's bolt location; however, it is entirely encased so I can't get to the keelbolt location to inspect it. How do I gain access to inspect and/or replace it?