One of my first real seafaring jobs entailed an on-the-fly rehabilitation of a tug that pushed propane barges from a port on the Mississippi River to a terminal in Corpus Christi, Texas. As a deckhand on that little, welded-steel jewel, I was expected to not only deal with the barges day and night—forming them into long tows, then breaking them down for lock passages and unloading—but also deal with an eternal boat beautification project.
As soon as any rust appeared on that old bucket, my fellow deckhands and I would give it a fast pass with a power grinder, brush on a product called Ospho, and follow up with primer and paint. The approach, although far from yachty, worked like gangbusters. After only six months on board, the crew had the boat looking so good that other vessels would hail us on the VHF and give us compliments.
I believe to this day that Ospho was the key to the success of our slap-dash procedure. Essentially Ospho is a solution that prominently features phosphoric acid, a clear, watery, relatively mild liquid that has a very cheery, time-saving, work-saving capability: It instantaneously turns iron oxide (i.e., rust) into iron phosphate, an inert, hard, blackish material that actually inhibits further rusting. You simply apply it to a rusted component, usually using a brush or a spray bottle, let it dry overnight and then either paint over it or simply leave it alone.
These days, I find Ospho particularly useful on stainless-steel stanchions, stanchion bases and rails that are showing streaks of rust, typically due to fastening screws that are made of low-grade stainless or simple steel with a tendency to corrode. Unfortunately, it’s fairly common for boatbuilders to use 304-grade stainless screws to install bowrails and other fitments composed of more expensive, less-rust-prone 316-grade stainless. Go figure.
At any rate, the way I personally use Ospho is simple. I repeatedly wet a disposable 2-inch brush with the stuff and liberally but carefully dab the rusty area of a stanchion base, ladder base or stanchion with it. If the surrounding surfaces are painted with a modern, two- or three-part marine paint, I cover them with tape beforehand to prevent contamination. Yeah, Ospho is a fairly mild, tried-and-true product, but why carelessly splash the stuff around, running the risk of ruining a pricey, attractive fiberglass paint job?
The results I get are, again, not exactly yachty—the black iron phosphate is often noticeable if you look closely. But then again, Ospho gives me a decent, improved appearance with virtually no time-wasting elbow grease whatsoever. And hey, that’s totally cool in my book.
This advice previously ran in Power & Motoryacht magazine.