I I have hull number 854 and have finally decided to strip the peeling and mottled multiple layers of bottom paint on the keel.  My plan is to apply Pettit metal primer 6455 on the bare lead and then Pettit primer 6627 before bottom paint.  I am struggling with stripper and sanding to get to bare metal.  I can't figure out all the layers.  Did Catalina use some kind of coating over the bare lead keel??  Any suggestions would be appreciated.  Thanks very much.