I used to be on the Catalina Direct C22 newgroup and quite a few keels have been lost. The one on my boat was nearly worn through to the top edge before I fixed it.
I have come up with a quick cheap fix. Pull the keel off and flop it on it's side. Get a short piece of 3/4" pvc pipe which measures 1.050" diameter. Put some wax on the pipe so epoxy won't stick. Then put the pipe through the hole and use putty on the bottom to seal around it and locate it where the hole belongs, and make sure it is nice and square to the keel. Mix up some epoxy with graphite filler and pour it around the pipe. When it sets flip the keel over, remove the putty and pour in some more epoxy with graphite. After the epoxy sets hard pound the pipe out with a hammer. Put the keel back on and go sailing! You can do this repair over and over again if needed, but it should last several years at the least.
Gary H. Lucas