For another quote go to a different yard. They can talk with you. The thing is that Catalinas use a "grid system" as the structural member that the keel is attached to. If this grid is compromised it really needs to be fixed. If you don't, the keel can literally fall off! Don't mean to be an alarmist, but you do have to prevent worst case scenarios. That's why at this point you need to talk to a couple of different professionals. It seems that one has told you it needs serious repair. OK, that sucks, but what can you do? Get another opinion, and if they both say that you need to do this repair, eithor do it, or sell it (with full disclosure). Yes, you're going to be spending/losing some money, but that's just the way it is. HOWEVER, regardless of what others may say, you just had some (pretty) bad luck. It could happen to anyone. Get some sailing instruction, get out on the water and have a great time. I've f***** up a few times, and at 67 years old I'm still sailing, and loving it. Hope you can say the same someday.