Yep, a rusty keel. It's made of cast iron. It will slow you down - especially in very light air. So, instead of a wire brush, I'd use a grinder (protect your eyes and lungs, use gloves, etc.) and clean it up to make it smoother again and try to get all of the loose rust off for sure and get down to bare metal, which will be nearly impossible (I know - that should have been several sentences instead of one). Then you want to clean the dust with a solvent and apply a good epoxy primer over the keel as soon as you can because it will immediately start to rust again. Pettit's Rust Lok steel primer works as well as Interlux' Interprotect 2000 etc. Then to get a nice smooth surface, you can use an epoxy fairing compound over the primer (not over the steel) after the paint primer is dry. Sand the fairing compound smooth and apply your fav antifouling paint. Of course, you can only do this with as much keel as you can reach. So, to do the best job, you should drop the keep, which means you have to remove the 4 hex head bolts holding the pin hanger into the hull. You really need an overhead for that to lift the boat, in which case a boat yard would be your best option. You can pay someone to do the work, or maybe you can pay someone to remove the keel and when you are finished with it, pay them to put it back in the boat again. You mentioned lowering the keel. Did you know that a Catalina 22 is only self righting when the keel is in the down position? Obviously, if you can get the boat lifted off your trailer and put on a cradle or jack stands where you can lower the keel, you should be able to clean and paint most of it by lowering the keel, working on what is accessible and then raising it to work on the leading edge.
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