[DelmarRey]

My suggestion would be to sandblast the affected areas, fare them in with epoxy with a filler, then paint with epoxy paint as far up as need be to keep it out of the water. And the same under the SS pintles. Tape off an area around the pintles and paint under them. SS tends to speed up the corrosion process when mated to aluminum (electrolysis). Or you could just paint the whole rudder in epoxy, If you want to go that far................Del