Plas­tic may be fan­tas­tic, but metal was here first and still makes ex­cel­lent boats.

Power & Motor Yacht - - IN THIS ISSUE - By Mike Smith

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.

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