I have both a Cat 27 and 30. Between the two models 13,000 boats were produced (the most for ANY sailboat). I'm sure there might be some exceptions somewhere, but I have not heard of a Catalina losing its keel. You could query the Catalina forums
, but other than swing keel pivot issues on the smaller boats (22/25), I have not heard of anything beyond the smile. :-)
My 76' 27 has rusty keel bolts (nuts), but no smile. My 77' 30 also does not have a smile, but the PO took the precaution of drilling and threading some new holes and installing oversize (stainless?) bolts. They look like new. I would suggest this solution for you. Then if you want to attempt removing (or tightening) the old nuts and they break off, no real harm done. Just reseal those holes.
Lots of people continue to sail with the smile. Probably ok unless the keel swings side to side. You should read up on the repair. Seems fairly easy to do and is very common on Catalinas. Couldn't be that much of an issue. They are still the some of the most common sailboats at the marina and continue to enjoy a loyal following.
I can attest that Catalinas are a great compromise of interior
room and cockpit
vs length. The tall rigs in particular are good sailing boats and the larger and more forward headsail pretty much corrects the rounding issue of the standard model while providing more sail area for speed. From all accounts, the standard keel on the 30 and 11' wide beam make for a fairly steady ride. I think you would enjoy owning the boat if you buy her.