Re: Cal 28 Vs. Catalina 27 livaboard
When I had a Catalina 27 I had stainless backing plates for the the chain plate bolts. The #3 photo looks like the person that installed that plywood backing plate didn't use stainless bolts, the bolts were not sealed, he didn't use stainless fender washers, just a botched job at best.
You don't have to remove the mast to change the chain plate bolts or install a stainless backing plate. Just loosen the turnbuckles enough to take the strain off the cables, then carefully remove all but one of the bolts. Loosen the last bolt, swing the wooden backing plate out of the way, install at least one new stainless bolt with an oversized fender washer and snug it down. Now you can remove that last rusted bolt and install a stainless backing plate by reversing the process. It's not too difficult and can be done by one person.