When I started shipping twenty years ago the company I was with would simply paint rust. There’s always a chip or spot that appears and it would quickly be covered with paint. No prep, no needle gun or grinding. Just paint. There was almost no rust anywhere. Certainly no rust that lasts. It might have been one guy’s job to walk around with a paint can and brush once a week for a few hours.
Now I’m at MSC and they spend hundreds of man hours a week needle gunning and grinding with all sorts of preps and primers yet most MSC ships looks like turd stained rust cancers. I’ve tried to convince folks that weekly spot painting over new/small rust spots would save a lot of time and money but everyone here thinks I’m insane.
I’m now convinced that painting over small rust areas is vital preventative maintenance. It’s like greasing fittings. A few man hours a week greasing fittings prevents a lot of labor restoring and rebuilding a frozen block or roller later.
First give the area a quick fresh water rinse in the morning followed by spot painting in the afternoon. If after a while the area looks spotted go ahead and paint the whole area with topcoat. Do not grind off the old paint that had protected the metal all those years.
Once the rust on the whole ship is under control then repair any blistered areas. But keep up on the spot painting.