Making up a hollow spar

Solid plugs

Glue and clamps


Solid plugs

Mast partner

Tenon for step


Wedges driven to compress sides at each clamp

Tangs and sheaves Spreaders

Glue and clamps figure 18-10

Cross sections of hollowed spars

4-stave round spar with wall thickness Vs the diameter at its inner corners

Staves would be at least 1 Vb" thick to yield a 6" diameter.

4-stave hollowed round spar

4-stave hollowed round spar




Two staves, hollowed and glued

Hollowing plane we know now (and had he thought he could convince the owner that we, uh, he had meant to do it that way), he would have laughed off that little mistake almost as a childish error, and instructed one of the gang to lengthen her out as called for. Just one more instance of the New Freedom in the post-glue era, more useful even than the elliptical patch, which brings forth exclamations of wonder and delight from casual observers, and hides a hideous knothole from the owner's eye. And yet one more: someone comes in with a splendid boom broken clean in two, and the sad story that it will take six weeks to get a new one from the factory— what then? Let's first lengthen that mast.

Look to Figure 18-11. We'll dress the butt to a flat wedge with our standard one-in-twelve slope exactly the same on both sides. This is most easily controlled and accomplished with the aid of another scarfing jig, one slightly deeper than the diameter of the mast with a fairly snug fit along its sides. Clamp the butt in the jig, as shown. Make saw cuts across, whack off the chunks, and dress the result down with a long plane that rides toe and heel on the wedges. Turn it over exactly 180 degrees, exactly at the same fore-and-aft location in the trough, and do the other side likewise. Now saw out. (or build up of two pieces glued together) two slabs, rectangular in section, each about lA inch wider than the diameter of the spar, and Vs inch thicker than the half-diameter (and, of course, long enough for the desired extra length ). Cut a chisel-style scarf on one end of each, using the same jig and technique. Clamp them together, and try them for fit to enclose that wedge on the butt of the mast. Finally, glue the works together, taking extraordinary precautions against endwise sliding and creeping out of line. Dress down the new part in the square to the proper size and taper, then round and smooth it to match the rest, of the spar. If you paint it, nobody'11 ever know what happened. (We've lengthened out a gaff-headed mast as much as 8 feet, to convert to jib-headed, and we've replaced 3 feet of masthead that went soft beneath the eyes and sheaves.

In every case, the operation was successful, and it sure beat making a new mast.)

As for that broken boom: simply do the same joint twice, as shown in Figure 18-12. scarfing your two side pieces to the wedges cut on the two broken ends—with a flat between scarfs, of course, calculated to restore the original and proper length of the boom. Or maybe you'd like to make it a bit longer this time, while you're at it. Use this method if you've broken your best, spruce oar, or your boathook handle, or your beautiful 7-foot curved tiller—scarfing and gluing can get to be a mania.

And one last thing. To hide and seal that porous knot, to restore wood to the spot where your broadaxe has sliced too deep, you proceed thus: Scoop out a depression in way of the defect, smoothly curved from end to end and perfectly flat across. A compass plane, set to the figure 18-11 To lengthen a spar—

(1) Clamp butt in scarfing jig.

(2) Dress the butt to a flat wedge.

(4) Slabs flipped, aligned with the butt, and glued together

(2) Dress the butt to a flat wedge.

(3) Slabs dressed separately to the same slope

(5) Slabs faired with the remainder of the spar

(1) Clamp butt in scarfing jig.

figure 18-12

Re-joining, or lengthening, a broken boom


Scarfs cut to the same slope in the same jig

Stringers, nailed— to prevent migration of the ends during gluing

Joined slabs arc you want, is the best tool to use on this dip, but you can do the job perfectly well with a smoother. If you want some sort of figure to go by, let's say that the radius of the arc of the depression should be no less than 24 times the maximum depth of the scoop. Make a template, if you wish, with a 12-inch radius, which will, according to the above, give you an acceptable length for a patch Vfe-inch deep. This sounds overcomplicated, and is thrown in only to scare you into making that cut long and easy, so that the slope of the glue joint will not be abrupt at the ends of the patch. (Look at Figure 18-13, and ignore most of this wordiness.)

The next move, of course, is to fit and fasten a patch that can be rounded off to look as if it had grown there. You can cut this to fit, if you wish, or you can bend it in—in one piece, or in several laminations. Whichever you do, you'll appreciate the long and easy shape of that curve.

Clamp as shown, with careful spreading of the pressure. Dress fair, with a drawknife, plane, and sander—and be smugly modest when the audience marvels at the perfection of those joints. "Nothing to it!'' says you. "Any craftsman can do as well." And between vou and me, that's the hell of it; he doesn't even have to be a craftsman.

And that, I think, is my final word on spar-making. All you need is a jig, some clamps, glue, a hand plane, and a little confidence.

figure 18-13 Elliptical patch

Porous knot

"Dished out" (flat across, smooth curve lengthwise}

Patch laminated from thin stuff pressed down into the "dish"

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