Plastic may be fantastic, but metal was here first and still makes excellent boats.
While plastic is fantastic and carbon fiber is space-age, steel and aluminum boats are metal.
Not so long ago, building custom yachts was the playing field for folks with extra-deep pockets and a need for a vessel three digits long. The rest of us bought off the rack. But production boats are getting darned expensive these days, pricey enough for some shoppers of midsized, or even smaller, boats to consider building custom instead. Custom building gives you exactly the boat you want, with just the equipment you want and nothing you don’t. And when you’re thinking of building a custom boat of any size, I think you should also be thinking of building in metal, either aluminum or steel. For most people, it’s aluminum, but both materials are better suited to building one-offs, and both have advantages over the techniques prac- ticed in most production manufacturing facilities these days.
Steel and aluminum, by the way, were both popular boatbuilding materials from the end of World War II until the fiberglass revolution of the 1960s. Check out the Chris-Craft Roamer models of that period, built first in steel, then steel and aluminum and finally just aluminum, up to 73 feet long by the time Roamer closed up shop in 1979. (Over the years, Chris-Craft has built boats in planked wood, plywood, steel, aluminum and fiberglass.) By the mid-1970s, fiberglass was the material of choice for production boatbuilding and has now become so dominant that many shoppers never consider a boat of any other material. But there are still a few companies building nice production boats in metal— you just have to look a little harder to find them.
Or, as I’ve just noted, you can build a custom boat, either from plans you commission from a naval architect or from stock plans. Computer-Aided Design (CAD) has made building in metal easier, faster and less expensive. There’s no more laborious lofting (drawing the vessel’s lines full-size on the shop floor so the builder can determine the shapes of the various structural components), no time-consuming cutting out of pieces by hand. Today, the yacht designer, working on a computer, creates a cutting file defining the shapes of all the pieces; this file is fed to a CNC machine at the metal shop, which then cuts out the parts automatically and sends them to the builder. From there, it’s like assembling a kit—probably not something you or I want to tackle in the backyard, but an everyday project for a competent metal boatbuilder.
Give It Your Best Shot
What are the joys of metal boats? And are they even worth the effort, when the market is teeming with fiberglass? First, they are tough. If you hit something, chances are it won’t hurt too badly. Both aluminum and steel are abrasion-resistant, a far cry from the fragility of gelcoat. If you miss with the fenders and manage to scratch a steel hull, slap a little paint on it ASAP so it doesn’t rust; scratched aluminum will heal itself by growing a thin layer of aluminum oxide. If you grind on rocks or a reef in a metal boat, with any luck you won’t punch a hole in the bottom—dent it, maybe, but at least the boat won’t sink under tow to the yard.
Repairs in metal are as good as new: Cut out the damage, weld in new plates and the repair will be just as strong as the original. There’s no worry about the new laminate bonding to the old as with fiberglass repairs, no fiddling with ersatz molds or backing materials to form the fiberglass fabric into the correct shape. And while metal boat owners might worry a bit more about corrosion, they’re not concerned with osmosis, delamination or other problems due to manufacturing defects.
Moreover, the toughness of metal takes a lot of the angst out of docking. Caught in the current of New York Harbor’s Buttermilk Channel, I once whacked the end of the pier at the Coast Guard base so hard I thought for sure it must have registered on the Richter scale. Quite embarrassing. But the steel oil boat I was piloting at the time bounced off without even chipping the paint; the pilings suffered more damage. After a couple years running this boat, followed by a couple years running a big steel passenger schooner, fiberglass felt comparatively fragile when I made the switch back to yachts. I’m starting to plan my retirement boat, the one I’m going to live aboard on the Intracoastal Waterway. Since
I’ll be getting old and losing my eyesight, I’ll probably hit things, and for that I want a steel boat, even though common sense says to go with aluminum.
Steel or Aluminum
But to build in steel, or to build in aluminum—that’s the question. What’s the difference, other than steel rusts and aluminum doesn’t, and which material is better? Some boats work better in steel, but by and large aluminum is the logical choice for boats under 200 feet. Hulls beyond that length require strength and stiffness that are easier to achieve in steel. (However, Burgess Yachts launched a 253-foot aluminum megayacht in 2016 and Royal Huisman is currently building a 266-foot, three-masted sailing yacht in aluminum, scheduled to launch in 2020.)
“Aluminum is a third the weight of steel, and half as strong,” said yacht designer and shipbuilder Bob Derecktor when, many years ago, I asked him to compare the two metals. What Derecktor didn’t know about boatbuilding in aluminum and steel—and wood, too, for that matter—wasn’t worth knowing. He started his first yard in 1947 in Mamaroneck, New York, and even though Bob’s gone now, Derecktor Shipyards in New York, Florida and Maine are still building and repairing yachts, workboats, high-speed ferries and military craft.
According to Derecktor’s rule, to match the strength of steel in aluminum means doubling the scantlings—using 3/8-inch aluminum plate rather than 3/16-inch steel, for example. That doubles the weight of aluminum, but it’s still only 2/3 the weight of a comparable steel vessel.
Certainly, you’re dealing with a rule of thumb here, and like most rules of thumb it’s only an approximation, but I think it’s pretty close. Some experts estimate the structure of an aluminum boat will weigh around 50 percent that of a steel boat of the same strength—maybe, but the point is, an aluminum boat, in its structure, is substantially lighter than one built in steel. Or, a builder can match the weight of steel in aluminum, and produce a boat that’s quite a bit stronger, bearing in mind that the weight savings is in the ship’s structure, not the finished vessel. The weight of engines, joinery, systems, appliances and so forth makes up a big part of the final displacement of the vessel.
Of course, whether you go with aluminum or steel, I’m sure you realize at this point that custom boatbuilding in metal, despite its increasing allure these days, is a relatively dense and multifaceted topic. So, having now covered the basics, next month I’ll delve into some of the more advanced aspects of the subject, including a process that almost magically combines both steel and aluminum in one, singlular vessel. Until then, please remember: steel is real and aluminum is … well, you get my drift. PART II OF HEAVY METAL TO CONTINUE NEXT MONTH.
A heavy-gauge aluminum beauty from Life Proof Boats of Bremerton, Washington.
The creation of a top-shelf metal boat demands a near-artistic level of welding expertise.
These aluminum beauties sport foam-filled, RIB-like collars that make ‘em unsinkable.