Steel Boats: A Strong Alternative
For strength and security, steel boats deserve a good look. Some, you may be surprised to discover, are even downright pretty
What About Corrosion?
Talk of steel and the word "rust" comes up straightaway. Rust is a chemical reaction and salt water speeds it up, but not as much as you would think. Ice scraped the paint off Skookum’s waterline about a meter back from the bow. Although I didn’t get around to touching it up until nearly a year later, no major harm was done to the plating. What worried me more was rust inside the hull, in the hidden corners of the bilges. Only after four years of hard sailing did we remove the cabin sole (wisely, I made it all demountable) and after a thorough scrub, we found areas of scratched paintwork. Nothing serious, nor structural -- just awkward to sand and touch up.
The steel deck, unlike the hull, is not only continually doused in salt water, but also trafficked and abraded. Anchors, chain, winch handles, harbormasters’ boots -- they inevitably knock off paint. Very soon, out weeps a trickle of brown. But at least you can see it! Unlike rot or ultraviolet deterioration or osmosis, rust gives itself away practically the day it starts. It’s not difficult to remedy, just tedious.
On Skookum we have some nuisance rust spots that repeatedly need rubbing back and touching up. Repainting means a full four or five coats of touch up, so the process is a protracted one. In every case, these bits of rust around hatches, coamings, stanchions and winches could have been avoided had I done things differently in the first place. Companies well experienced in steel boat production have developed excellent detailing on deck.
Given that recurring rust problems occur on deck, and that a boat doesn’t sail upside down, why then not construct the deck of something else? It’s called composite construction and it’s commonplace. Strong plywood decks and cabins can be built over steel framing. Epoxy and fiberglass take care of the sealing and finish. Aluminum decks can be married to steel hulls. Composite construction has other merits, such as less weight and less magnetic interference. (Tons and tons of steel certainly have an effect on a compass. Our classic five-inch-diameter steering compass stands on its own binnacle and was some 20 degrees off upon installation. Standard correctors inside the unit reduced this to a known five degrees on east and west headings. Electronic compasses can have sensors placed inside the mast or on a radar post and thus removed from steel’s magnetic clutches.)
Corrosion comes in another and more wicked form: electrolysis. Put nearly any other common metal underwater near steel and a battery current flows. More often than not it is steel that loses the electrons. Little volcanoes of corrosion erupt on unprotected steel, and these inflict damage much faster than rust. Electrolysis is a threat to any kind of boat, but especially to metal-hulled ones.
All steel craft sport little zinc pads on the keel, rudder and propeller shaft. These "sacrificial anodes" corrode instead of the hull, so must be maintained. Corrosion vigilance is the price one must pay for the reassuring strength of steel.
The corrosion specter heavily devalues older steel boats, especially if a bit of the brown stuff is visible. Boats that have not had the protection of modern paint systems might be picked up, for a "steel." If you’re planning to recondition an older steel craft, first establish if you can gain access to all the steel surfaces. Even then the cost of dismantling, preparation and recoating will be considerable.