keel rust
Is your keel the kind made of several plates or a one piece casting? The options for changing it seem to be finding a used one, customizing a similar one, or getting one made. If you can't find one, you could try Mars Metal Co, custom keels,www.marsmetal.com, 800-381-keel for new.Even with a cast iron keel, rust is hard to avoid. When I had my trailer sandblasted, the guy said moisture comes from within the metal and even priming it immediately would not stop corrosion reappearing on old metal. I use Pettit Rustlok and bottom paint, but I think others have recommended an anti-rust primer with compatible epoxy paints followed by bottom paint as the most effective.Good luck and let us know what you decide; the multi-plate keels seem a loosing battle to me. The good news is an inch of rust is produced from a tiny fraction of metal, so the weight lost is not significant.