Keel
It weighs 550lbs. Fixing it is going to depend on what happened, if the bolts just came out then its just a matter of getting a pin the two hangers (if lost) and four 5/16" X 1 1/4" SS bolts (316). Then retrieving the keel and reinstall it. If however the bolts broke, then your going to have to remove the bolts if possible. If they cannot be removed you will have to replace the keel bolt inserts (can be bought at Catalina Direct or Catalina Yachts) There is of course the possibility that the Keel pin wore through the Keel, that will require a different fix, either replace the Keel (there is one for sale here in the classified) or buy a new Keel from Catalina. I know of one that was repaired at a welding shop a few years ago and is used in salt water, its still going. Good luck