[parishht]

If you have a powder coat facitlity near by,
and you really want to use the steel in salt water,
that would be the way to go.

We powder coat our heavy truck frame rails and they are
spec'ed to last for 500+ hours of salt spray testing in the lab, which translates on the road = however long the truck lasts.
Just think of the road salt and other nasty chems that are on the road
and trucks going 1,000,000+ miles.