The Planking Process From the Sheer Down

So there she is, set up, timbered out, rabbet faired, ready for planking. This is the biggest single job, and probably the most difficult for the beginner—not because there's anything very complicated about it, but because much of it depends on j udgment, eye, and the unconscious skill of hand that you gradually acquire without knowing it. The old pro loves to fit planks because he can do it without thinking, and it's his great talent, with a sort of timeless rhythm to it, which clothes and defines a thing of beauty.

What we're talking about here is, of course, real planking in the ancient, classical manner: fair-seamed, tapered, fitted and through-fastened to the timbers, smoothed fair, and caulked. Learn this, and you are welcome to try edge-nailed strips, battened seams, cold-molded laminates, or chicken-wire-and-fiberglass. (I hope you will sometime try a lapstrake job, because that is beautiful indeed.) But for now let's gel on with the problems of smooth planking, which keeps the water out, and the people in, better than anything else I know of, and delineates (at least for you, the builder) ihe most beautiful shape that man has managed to create.

So, first, you need to know what shape the individual planks will be, before you worry about how to mark, cut, bevel, hang, and fasten them off. This boat we are dealing with is in some ways the most difficult and complicated shape one is likely to encounter, with wineglass sections throughout, great area below the tuck, extreme variations in girth, long counter, and plank ends mitered to the cylindrical-section transom, but that is all to the good. I'm sure that if I can explain it, you can understand it, and you may as well know the worst at the beginning. It's like swinging two bats when you come up to the plate.

Lining out the sheer planking

Well then. If you will allow yourself to view the hull of our 39-foot sloop in two distinct parts, separated for our purposes approximately along diagonal D2 in Figure 9-1 (and if we're lucky, also along what has been referred to elsewhere as the tuck ribband), you will dimly discern that I have distinct approaches in mind for these areas. The areas, one above and the other below this ribband, are for our purposes completely independent of each other. Kindly ignore the lower one, and bear with me as I attempt to line out the planks that will clothe the area between this special ribband and the sheer.

The simplest way to do this (and entirely satisfactory, if you have skill and time enough) is to line out with a batten, by eye, the lower edge of the proposed sheerstrake, cut a plank to that shape, fasten it in place, and repeat the whole process over and over till you get there— in this case, to the flat of the bilge, where I hope you're planning to put in the shutter. This method is slow, laborious, and lends to irregularities, but it works.

I prefer a somewhat more precise system, which is based on the following assumptions: Ideally, all seams are to be fair curves from bow to stern; all planks are to taper exactly the same amounts from the widest point in the middle to their narrowest points forward and aft. Thus, if we have 17 planks, all exactly the same width on station number 5, we should have 17 planks exactly the same width at station number 3, and at station number 7, and anywhere else in the length of the boat. This is a simple enough proposition. Find the length, find the girths at each section, divide these varying girths equally into the same number of parts, and you've got it—the shape of the Ideal Plank, which, repeated the proper number of times, will cover the area beautifully. What we want, then, is to get this information into precise, convenient, and graphic form, so that the man getting out planking can determine in a moment the exact width of any plank at any place in its length, at or between stations (e.g., proposed butts).

And the way we do it is thus: Measure the distances between stations along a sort of Great Circle course from stem to transom—say, along the ribband that lies between diagonals D4 and D5 on the body plan of the lines drawing. These dimensions will increase as you go away from the middle of the boat. Write them down thus:

Stem to #1

46"

#5 to #6

48"

#1 to #2

50"

£6 to #7

49 Va

#2 to #3

491/2«

#7 to #8

50"

#3 to #4

48 V2"

#8 to transom

53"

#4 to #5

48"

Now find a clean board about 6 inches wide and 6 feet long, and joint one edge straight. Starting a few inches from one end. lay off these figure 9-2

Plank layout by use of a diminish board

Sheer, or underside of covering board

Wooden Sailing Boat Hull Planking

The faired line of the tuck batten is the demarcation between the "lay" of the plank on the upper and lower regions of the hull.

Wooden Boat Plank Laminate

The faired line of the tuck batten is the demarcation between the "lay" of the plank on the upper and lower regions of the hull.

: marked girths carefully measured in inches and fractions, then each is divided by the whole number of intended planks in order to obtain the Ideal Plank width at that station.

widths from sheer io tuck batten, and a similar set of equal plank widths from tuck batten to rabbet. (The lower system of planks will be dealt with separately, in Chapter 10.)

Girths for each station are measured carefully and divided into the same number of equal plank widths.

Plank widths along the stem end and on the transom will be obtained from the diminish board.

Sheer, or underside of covering board

Sheer ribband

Marked at sheer, or on underside of covering The girth lath board

Girth lath held snugly to the insi< face of the ribbands

Tuck ribband tuck batten (or ribband)

Example: --= 47/i6 plank width at station number 5

17 (planks wanted)

figure 9-3

Plank layout by use of a diminish board

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Planking Process

A sharp, fair line is marked through with a batten.

The sharp line gives the exact width of the Ideal Plank at any place along its scaled length.

Here, a width may be taken off where a butt is wanted between stations.

The length of the Ideal Plank is taken along a ribband that traverses the widest region of the 'midship molds.

The diminish board

These perimeter distances between stations are laid off to V/i" = TO"

scale on a clean board with one straightened edge.

A sharp, fair line is marked through with a batten.

The sharp line gives the exact width of the Ideal Plank at any place along its scaled length.

Here, a width may be taken off where a butt is wanted between stations.

distances, consecutively, to a scale of 1 V2 inches equals 1 foot (Vs inch equals 1 inch), and label each mark clearly (and, of course, correctly). So you will end with a mark labeled "transom" exactly 4 feet 7 V* inches from your starting point labeled "stem."

■ Leave (his board now and find a limber lath, about '/s inch thick, 3A inch wide, and 8 feet long. This is a marking stick to get the girths. As shown in Figure 9-2, bend it inside the ribbands, with its lower end resting on the top edge of the special tuck ribband, close alongside the number 5 mold and snug against the insides of the ribbands. Mark the lath exactly at the height of the sheer mark on the mold. Get the other six station girths in the same way, being very careful to measure exactly from the top of that critical ribband to the sheer mark. Don't get the labels mixed. You will have to do a bit of guesswork on station number 1, because the magic line has entered the rabbet before reaching the station mark; and the girths at the points called "stem" and "transom" cannot be measured at all.

Now measure the girths, subtract from each the thickness of the deck (1 inch in this example), and write down the results in inches and quarters. (For purposes of illustration, we're using only the girth at station number 5, which is the greatest, measuring 752A inches.)

It is now time to decide how many planks (and, of course, the maximum width of each one) are to be used to cover this space. A workable rule of thumb on widths goes like this: Maximum width of a plank should not be less than four nor more than five times the thickness of that plank. If we apply this rule here (based on is/i6-inch thickness of stock), we want no less than 4-inch width at station number 5, where the girth is greatest. A monumental effort in fourth-grade arithmetic indicates that 17 planks, each 47/i6 inches wide, will come somewhere near to filling this gap. So we divide each of the six other girths by 17, to gel the width of each plank at each station.

Now comes the moment of truth. Go back to the board with the intervals marked on it. in 1 l/i inches-to-the-foot scale. Draw a line square across the board at each station, stem, and transom mark. Now measure along each of these cross lines, from the straight edge of the board, the width of plank obtained in the process of dividing each corresponding girth by 17. Now we have a series of marks, arcing from station number 1 upward to greatestheightatnumber5 and back down to a mark on the ordinate labeled number 8. Drive a small nail firmly at each of these points. Find a flawless pine or spruce batten about V2 inch square and 7 feet long. Bend it. around inside, and touching, the vertical nails, and hold it against them with three or four nails driven snugly against the inside face of your batten. The result (see Figure 9-3) should be a fair convex curve, requiring no local forcing of the batten to make it touch all of the marks. If any great discrepancies show up (a point more than 'A inch away from the line the batten wants 10 follow), you'd better check your arithmetic. Pull down the ends of the batten beyond the number 1 and number 8 ordinates until it exerts no pressure at these two points, and accept its decision as to the correct widths at the end ordinates—stem and transom. When you are satisfied that the curve is correct and fair, mark a sharp line on the board the full length of the outside of the batten. Pull the nails, and there she is—the true width of the plank that, repeated 17 times between sheer and tuck, should fill the space watertight.

With this diminish board you can now determine the correct width of any plank at any point between the ordinates. Suppose a plank butt is to come in a bay whose center is 18 inches forward of station number 4. In the longitudinal scale used on the diminish board, Vs inch on your rule equals 1 inch on the full-sized hull; therefore, measure on the board 2'A inches (18 divided by 8) from the number 4 ordinate toward number 3, and take at this point the correct width (from the edge of the board to the curved line) of the butt end of the plank you are marking.

Let's mark and fit a few, before we face the day of reckoning that awaits us when we must go down below—down to the garboard, and the stealers, and the awesome bevels in the tuck, where your knees give out, and you hang upside-down like a nuthatch on a fence, trying to think of some way to clamp and edge-set a plank that's too hot to handle anyway.

Fitting the forward port sheerstrake

Arm yourself with a handful of fivepenny box nails, scribers, a light hammer, a crosscut saw, a bevel gauge, a half-dozen C-clamps, and a spiling staff, which is a thin board, 4 to 8 inches wide and as long as the longest piece of planking stock you propose to use. If this spiling board has a gentle S-curve in its length, it will do fine for the forward planks on the topsides; aft of amidships you'll need one with a gentle figure 9-4 Scribing the sheerline figure 9-4 Scribing the sheerline

Planking Clamps Wooden Boat

concave curve the length of its top edge. Before you're through, you'll have short, narrow (and very thin) boards, which have been used and planed off and used again until you get to know them like old familiar faces. (I have one long, crooked cedar board that's been in use for 25 years, and it is so (hin you can barely pick it up by the middle.)

Set up the staging planks on high horses, oil drums, what-have-you—so that the sheerline is waist- to shoulder-high on you. Tack a long, true batten to the stem, molds, and transom so that its lower edge delineates the exact line of the sheer.

Now get the spiling board into place—its forward end almost touching the rabbet and down 2 or 3 inches from the middle of the sheer-line right up to the batten, and its after end probably too low. Try to adjust it (without springing it edgewise) so that you can, with the dividers locked at one setting, run the whole length of it with a pencil line that will be equidistant at all points from the edge of the batten. (See Figure 9-4.) Before you draw the fateful line, however, be sure the patient is comfortable—twisted to lie snugly against the frames, relaxed all the way. (You want the shcerstrake to be cut to fit, not edge-bent to fit. With three or four strakes all around her—and under your belt, as it were—you can experiment with edge-setting as much as you want to; but get these binders on first.) Very well, then: Draw this line, representing the top edge of the sheer-strake, keeping the legs of your scribers at right angles to Lhe line of the batten. Now, very precisely, note (on the spiling board) first, the extra distance to be added to the plank to reach the rabbet line; second, the location of all stations

(molds) for the purpose of marking widths to the lower edge; third, the location of the butt. I like 10 start the sheerstrake from the stem with the longest plank available, for reasons that will be apparent shortly.

So now, as shown in Figures 9-4 and 9-5, we have on Lhe spiling board the exact curvature of the top edge of the sheerstrake, from the stem rabbet to the butt, carefully marked in the middle of a bay some 20 feel aft of the stem; and we have notations of the locations of all the molds so far covered. This, with the diminish board, providesall the information we need. Therefore we can now take off the clamps, carry the spiling board tenderly to the three horses where lies the raw plank (1 inch by 10 inches by 21 feet, probably mahogany), and mark the shape of the forward half of the sheerstrake, port side.

Set your dividers at about lA inch greater span than was used to mark the line on the spiling board. Use this span as a guide in placing the spiling board on the stock, and then, with the sharp leg of the dividers on the line, swing short arcs with the pencil end on the stock. Do this at 12-inch to 18-inch intervals along the entire length of the line you're transferring (see Figure 9-5). Now mark on the new plank all the other information you've got on the spiling board: the exact spot where the top edge of the plank will hit the rabbet line at the stem; the location of each station where the plank will cross it; and the location of the butt-

figure 9-5

cut (which will, of course, come midway in the farthest-aft bay that the plank will reach). Now put the spiling board aside, and drive a nail (fivepenny box, one tap) at the top of each of the short arcs you marked. Bend a batten against these nails (see Figure 9-6), and you should be able to draw a line along it exactly parallel to the one on the spiling board, and representing the top edge of the sheerstrake. Now get from the diminish board the exact widths indicated at each of the stations marked on the plank; lay off these widths, and the width at the butt (obtained by scaling to the right spot on the diminish board, and measuring directly from it); tap in a nail at each mark, lay the batten to them, and draw a line, which will be the bottom edge of the sheerstrake.

And now to cut this plank. The men of old did it with a hand ripsaw, and no fuss about it. Some moderns use a big bandsaw with a wide blade that won't wander. Others use an electric-powered circular handsaw, which you very likely possess—and a very good way this is, too, if you can follow the line accurately, freehand, or will take the trouble to tack a guide-batten at exactly the right distance from the line to be sawn. I use this last system if I'm dealing with a plank more than 24 feet long. But for anything shorter than that (and it can be very curved indeed) I always use the old slow tablesaw, with an 8-inch or 10-inch blade, and a wide extension table stretching away beyond it for 16 feet—and,

Laying out spiling on plank stock

Laying out spiling on plank stock

Butt mark-

Station 3

Spiling staff

Drift Boat Sheer Construction

Arcs swung from the scribed sheerline on the spiling staff may be connected with a fair batten to give the exact line of the sheer.

Plank stock -

Plank stock -

Scribed line of the sheer

Arcs swung from the scribed sheerline on the spiling staff may be connected with a fair batten to give the exact line of the sheer.

Butt mark-

Station 3

Spiling staff

Sheerstrake, ready to cut

Boat Cutting

Points locating the lower edge are stepped off from the diminish board along the station marks.

Spiled layout of the sheerstrake's upper edge is posted with brads—

—and then marked out with a lining batten.

of course, a roller 8 feet, in front of the saw and a support 10 feet beyond that. With a little practice, a sharp saw properly set, and relaxed confidence, you can with this system make a smooth, fair cut very quickly and with great precision. Do not. shrug this off with the thought that you'll cut safely outside the line anyway, and work it down to size with your plane. Maybe you can afford the time and the muscle, but you must be highly skilled indeed to end up with a curve as fair as the curve that this saw can cut for you—right to the edge of the pencil line, needing on ly one pass with a good plane from end to end of the plank. So learn to saw a line, and learn to set and file that saw. And never, never fasten a plank on a boat if it has humps and hollows on its exposed edge. That way madness lies

Go ahead then, and cut. Dress off the lower edge fair and true—and square. With your bevel gauge, get the angle between the sheer batten and the rabbet at the stem, mark and cut the forward end of the plank, and STOP right there, curb your eagerness, and go mark out an exact mirror duplicate of this port plank. But do not cut out this twin plank until you've tried the first one in place.

Now's the great moment. Pick up the plank about at its balance point, lay it up against the frames, and move it horizontally until the near-est station mark lines up with the corresponding mold. Clamp it to the nearest frame, with the top edge V* inch below the batten; go forward, and swing the end in to the stem. If it's within Vz inch of the rabbet, clamp it lightly to the fore-wardmost frame, then to the stem; go back and lightly clamp the after end (beyond the butt-mark, if it reaches) at the right height under the sheer batten. Tap the butt end with a heavy hammer, gently, until the forward end fetches into the rabbet. Beware that it has not slid up the slope of the stem beyond its proper height. (For deck thickness, remember?) If it's a good fit in the rabbet, tight inside all the way and showing a l/i6-inch outgauge, clamp it tight. If the fit is not good, swing the end out and plane it as necessary. Swing back and clamp; tap ahead again; proceed to put a clamp on every frame, being very careful to keep that top) edge at its proper distance below the sheer batten. When planking from the sheer down, I always put the clamps on the forward face of the frame, under the plank, and inside out—that is, with the threaded part inside the boat. This arrangement keeps them out of the way of the fastenings, which are always staggered according to a fixed pattern—the lower one toward the after edge of the frame, the upper one forward. Do not try to get away with any shortcuts, such as clamping to even other frame, because the two lamina-

lions of the frame must be snug together, and the face of the plank must be tight to the frame, before a screw-fastening can be put in properly.

Fastening the sheerstrake

All set, then? Get out your Vs-inch counter-

j bore, with a tapered drill to fit 2-inch number 14 screws, and proceed to fasten off, 3A inch up from the bottom edge and 1 inch down from the top. Counterbore about Vi6 inch deep—no more. This act will do things for your morale, and you have to get those clamps free before you can do anything else, anyway. (The principal difference between a professional and an amateur boatbuilder, I think, is not that one does a better job than the other, or gets more for his pains, but simply that the pro has finally managed to acquire almost, enough clamps, and has been forced by bitter necessity to learn more ways of making them work.) You will have come up against this truth while struggling to get that forward end tightly in place without hopelessly obscuring the target that your drill must hit.

And why, you may ask, did we fasten this plank with screws, when we're supposed to be using copper rivets? Simply for this reason: When you come to bolt through the sheerstrake and the frame heads to hold the sheer clamp in place, you'll find that about half the bolts will go best where you've already driven plank fastenings. Screws you can take out, to make way.

Right now, before you forget it, mark on this sheerstrake with bright red chalk the bays where the chainplates will go (see Figure 9-7). This is sacred ground, and no plank butts can be allowed to happen hereabouts until you're down at least eight strakes.

figure 9-7

Butts mated by use of the severed end

Trimmed forward section of the port sheerstrake

Rough butt-cut of the severed end gives approximate angle only.

Butt-cut squared to the sheerline and planed smooth

Width and curve must match exactly.

Parallel Curb Ramp Detail

Chainplate marks

Severed end becomes exact pattern for the matching butt.

Marked-out after section of the port sheerstrake.

Fitting sheerstrake to transom

Sheerstrake

(a) Mark the inside edge of (b> Mark the outside corner, miter on the sheerstrake.

Transom frame

Future transom frame f

Untrimmed hood end of sheerstrake

Miter

(c) Finished miter

Wooden Figure Cut Out PatternsSailboat Cut Out Pattern

(c) Finished miter

Block of transom stock held against the transom frame

Fitting the aft port sheerstrake

Ignore, now, the temptation of that twin plank all marked to cut, and make ready to fit the after part of the port sheerstrake, as shown in Figure 9-7. I hope that the plank you have just fastened on extends at least 6 inches bevond the

butt-cut (to be cut square with the top edge, up from the lower edge, with a sharp handsaw) that you are about to make. This waste end is your secret weapon. Mark it. "out port" and save it. Now clamp a spiling board from the butt to and beyond the transom frame (I'm assuming that you have stock long enough to make the distance in one piece), and repeat all the business you went through on the forward plank: scribe for the top edge; mark the station locations and the after end at the transom; indicate the exact distance to the butt from the end of your spiling board; transfer all this information to the piece from which the plank will be cut; lay off the widths, for the bottom edge curve, from the diminish board; and finally, lay that "out port" waste piece on the marks just as it would have overlapped the new plank if it had not been sawn off. This waste piece gives you the exact width and. more important, the exact curvature of both edges that the new plank must have to match the first one. You also get from it., theoretically at least, the right line to saw for this matching butt end. You will use this trick over and over as you continue the planking, so you'd best get it clear in your mind right now. This is the most, useful of all aids in getting the butts fair; and if you think that's an easy thing to do, or not very important anyway, just you wait until you've had to work a real humpy one down with a rabbet plane, and then tried to fit the next plank to the irregular curve and the out-of-square edge that you ended up with. If you're going to get clear around her with a strake a day, from now on you can't afford to have those curves anything but fair and sweet from end to end.

Having settled this, let's hang the plank. Shave the butt end to fit tight, clamp along and swing in to the transom frame, get the top edge on the marks, and look at the butt. Chances are two to one that the fit is not perfect.. So run your well-set crosscut saw up the joint, go aft, and tap the plank ahead. Repeat until the joint is airtight; then mark at the transom frame for the miter cut (see Figure 9-8a). The inner line will obviously lie along the outer edge of the transom frame; the outer line is determined by laying a piece of l5/'i6-inch stock against, the transom frame, under your plank end, and marking where the outside surfaces of each intersect (Figure 9-8b). If this isn't clear, to hell with it. Anyway, the cut will be roughly at 90 degrees to a tangent to the transom frame at the edge (Figure 9-8c). And be sure that the plank is really at the right height on the transom (you can sight from the plane of the cross spalls, and measure up to the height given in the offsets) before marking. Probably vou'd best take the whole

plank off again before you make this rut, because it's a very awkward thing to do (what with your hand trembling, and your eyes trying to see both sides of the plank at once), and the plank may need just the least bit of backing out at its after end.4'Backingout" means hollowing (or, down in the wineglass seciions, rounding off) the inner face of the plank to he snugly for its entire width against the curved frame. You can use a short bit of Winch-square lead bar, bent to the right curve, as a guide in the hollowing process, or you can use the guess-and-trv method, which works fairly well after you've practiced for a few years.

And oh, my friend, if you value your sanity, do not forget to mark out a twin to this plank before you fasten it in place. I have seen a man j ump on his hat and knock off for the day when he remembered this too late. Have you corrected

the bevel on the transom frame where the plank lands? All right, then: clamp it in place again, and fasten off.

Fitting a butt block

We've still got the butt block to fit. I'm beginning to wonder if we'll ever get a sheer-strakc clear around her.

The butt block should be a piece of black locust (or white oak, black walnut, or even dense mahogany) overlapping the adjacent planks, above and below, by about Vs inch, and with ends about that much short of touching the frames forward and aft of the butt. The block should be little, if any, thicker than the plank stock, and it should be fitted exactly to the hoi-low and twist of the inner surface of the planking. Hold it in place with C-clamps inside-out on the high corners; drill for three fastenings in each end, 1 inch back from the butt, and two more in each plank, a third of the way in from the edges and halfway from butt to frame (see Figure 9-9). Drill for l3/4-inch number 14 screws, counterbored 5/is inch deep, for the end fastenings, and for number 8 copper rivets to take the back ones. Ream those end holes (through the planks only) with a Vi-inch drill, lest you start to split. And now take the clamps off, soak the contact surfaces and the ends of the block with strong poison, reclamp, and fasten.

By now you'll know whv butts cost money, and

why the pros like to use long stock.

Getting out more planking

Now for "out, starboard, forward," which has been waiting all this while. Saw it out, run your plane the length of the lower edge (if the shaving breaks, find out why), and go to the pile of planking stock. Choose a piece 3 or 4 feet shorter than the one you've just shaped, and proceed to mark the top edge of this second plank from the bottom edge of vo.ur sheerstrake.

Lav off the widths to match the sheerstrake

widths, line out the bottom edge with a batten, and saw out. Dress off the edges fair, mark a twin; then use the lower edge of this second plank to mark the top edge of yet a third one, which will be short enough to butt perhaps two bays forward of the forward chainplate. Repeat the process to get the line of the lower edge, saw out and mark the twin. Now you have five planks ready to bevel, back out, hang, and fasten, all on the strength of the original spiling. This is Proliferation. If you could only mark those after planks the same way, life would be beautiful. It is not entirely ridiculous figure 9-9 Butt block

Point Perspective

figure 9-10 Seam

10 hope, however, that, after you have finished these three strakes all around (spiling for each of the after ones—the second and third of which will be in two lengths each), you can take another long spiling from forward, and go through the whole happy business all over again.

But right now, with a plank ready to go next to another plank, you are faced with two important problems: First, how to fit the seam; and second, how to squeeze the two together while you fasten the second one in place. At this stage, high 6n the topsides, both jobs are relatively easy to do; but the techniques are basic, and you mav as well learn the whole business now as

wait until things become more complicated.

Seam bevels

In beveling, what you're aiming for is to have all the seams open the same widths on the outside, and light-tight on the inside (see Figure 9-10). Ideally, with planking of this thickness, the opening for caulking should not be over Vs inch anywhere on the boat, and preferably a bit less than that. A joint that is tight both outside and in can be caulked, and is forgivable but not to be praised. A joint thai is tight on the outside and open inside is a terrible thing in the sight of God and man, and can never be forgiven. (Judged on these grounds, and others, of course, very few of us old pros can hope for much in the Hereafter, but there's a very slick system of

Lead Caulking Wooden Planks

bevels

Proper caulking seam-tight on the inside, beveled open on the outside. A V32" opening is about right for the seam bevels in this boat

WjVJ

Tight seam— beveled tightly inside and out. Caulking cannot be driven unless the seam is hawsed ope with a sharp iron.

"Hollow seam"— bevel opens on the inside. Caulking would be driven through to the inside. Replanking is the only good solution.

caulking a scam endwise that sure worked wonders on the last shutter I fitted.)

To proceed: the bottom edge of the sheer-strake was left exactly square, as it came from the saw. I always leave the open edge of every plank square, and do all the beveling on the edge of the plank that is to fit against it. Therefore, since the frames are practically straight up here, you need only plane a uniform outgauge of about Vs2 inch the whole length, and the seam should be right. But before we go through the business of edge-setting this plank into place, let's consider the more complicated situations that will soon arise, and how to handle them.

Look now to Figure 9-11, which shows two cross sections: one from the sheerstrake down past the turn of the bilge, and the other thr ough the reversed bend in wav of the tuck. This draw-

ing is not to scale, and merely illustrates the general characteristics of the plank seams in these two areas. Working down from the sheer, then, we see that plank number 2 in the drawing must be beveled off on the outer edge to about 87 degrees. The third plank, landing where the frame has begun to curve, needs no bevel at all, either way, at this point. But the fourth one needs cutting down on the inside edge, in order to keep the seam uniform with those above it. This need for ingauge, reverse bevel, or whatever you want to call it, increases progressively as we approach the hardest part of the bilge curve, reaching a maximum of 16 degrees (106 degrees minus 90 degrees) on the top edge of plank number 6. The bevel starts the other way on plank number 7—and by the time you've gotten down on the flat., you'll be back to the 87-degree outgauge that was necessary on plank number 2.

Now consider the other half of Figure 9-11 — the section through the tuck. We plank up from the garboard, leaving the top edge of each plank square as we fit it, making the planks narrower (and out of slightly thicker stock, if we have it) as we come into the quick turn. The cutback of the outer edge reaches a maximum of 23 degrees (90 degrees minus 67 degrees) on the lower edge of number 17, which of course is fitted to the square top edge of number 18. (Remember that these planks are entirely fictitious, and are not intended to bear any except family resemblance to actual planks.) Now, the painful part of all this is that the bevel on any given plank must be constantly changing, from bow to stern, if the seams are to be constant, uniform, and caulk-able. Therefore you've got to learn to take bevels, and develop a feel in your planing hand so

Plank bevels—from inguage to outgauge that you can roll the bevel from one spot to the next without abrupt transitions. You'll do a lot of cutting and trying to the first few planks you fit. (I'm still doing a lot of cutting and trying, after some 40 years of it, but I'm beginning to catch on.) The problem hasn't changed in 2,000 years, which is one of the things that make boatbuilding a fascinating business.

Pay no attention to that business with degrees, and make yourself a planker's bevel (see Figure 9-12). Take a bevel every 2 feet, and mark the angle on your bevel board.

Cheating with the spiling batten

If you are not using good crooked round-edged boat boards, winch provide shapes to match your spilings, then you must be using straightedged stock—medium widths from 6 to 12 inches, say, with 8-inch and 10-inch boards making up most of the batch—and you'll be shocked, if not dismayed, at. the curves you must fit to. If they are cut to precise shape, they will run to terrible waste and too many butts; therefore, you can be allowed some discreet cheating. Bend them edgewise—but not too much. Let the spiling batten do the thinking for you. Use one

Planken Radial

Bevels cut on the upper edge of planking applied from the sheer downward to the shutter plank at the turn of the bilge. Bottom edges are square.

Sheerline

Bevels cut on the bottom edge of planking applied upward from the garboard. Upper edges are square.

about 4 inches wide and not too shaggy, so that it will bend edgewise evenly; force it up in the middle, tenderly, and clamp it in place. Set your scribers to the widest necessary gap, and mark the line; if you run off the edge before you get to (he ends, resei the scribers to just under the end widths of the batten, and mark these inner lines at the ends, overlapping the original line. As shown in Figure 9-13, mark on the batten, exactly, the two settings you've used, even though the overlapping lines will show how much alteration must be made when you shift from the wide gap to the narrow one. Now, when you place the spiling batten on the stock to be marked, spring its middle slightly down, thereby making the top-edge line (which you are about to transfer, with your little arcs at 18-inch intervals) yet more nearly straight than it appears on the unsprung batten. The batten has recorded and allowed for the stresses that the plank will undergo—and kept the bending mostly within the middle third of its length, so that the ends, which can't be forced much anyway, are cut very nearly true to the actual shape required.

And don't forget to mark (on the new plank) where the butt comes on the one above it. This is the doubtful part or the curve, and should be laid out with care. And after you get one of these sprung on, put on the burrs and head up the

Spiling BattenSpiling Batten

figure 9-12 Taking bevels

Planker's bevel

Ice Cream Stick Boats

Planker's bevel

Birch ice-cream sticks (or brass)

Edge-setting the spiling batten to get a more comfortable fit of edge-set plank

Spiling Batten

Natural lay of the spiling batten

Spiling taken with two settings of the scriber

Batten forced downward

Scribed line

Marked spiling batten, relaxed stock

Plank laid out from the edge-set spiling

1 oui rrom ine eage-sei spuing «— _____________________1___________________

Edge-set fitted plank has minimal cross grain. Ends are well fitted and relaxed.

rivets on the lower edge, or it will try to make itself look like a clapboard when you drive the fastenings into the next one below. If you don't want to take time for this riveting, or can't find a victim to hold the dolly, fasten the lower edge with screws. Quiet your conscience with the thought that a few days in the good salt water will relax that plank as if it had grown there.

It would be cruel to interrupt at this point, when every thing is going well, and suggest that you shift to the garboard. So go ahead and plank her down to the flat of the deadrise. And if you go one plank too far, where it's starting to turn the other way, you'll be sorry. Shutters are bad enough, even with everything in your favor.

One other thing. As you sit inside the hull in the late afternoon, admiring the graceful sweep of the planking, you will suddenly note with horror that some of those seams, light-tight (or nearly so) when you fitted them, now look, against the window, wide enough so you could recognize friends passing by—even though, when you examine them closely, you can't get a thumbnail into the crack. I remember Sam Crocker on this subject, back in the 1930s, when I'd been trying, unsuccessfully, to keep him away from the dark side of the boat. "I knowr these seams are all right, and you know they're all right, but please get a little cotton into 'em before the owner shows up, because He Doesn't Know AnythingSo we did.

Spiling batten forced upward (gently) when applied to straight plank

Drift Boat Sheer Construction

Spiling batten forced upward (gently) when applied to straight plank

Edge-set scribed line runs more or less with the straight grain

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How To Have A Perfect Boating Experience

How To Have A Perfect Boating Experience

Lets start by identifying what exactly certain boats are. Sometimes the terminology can get lost on beginners, so well look at some of the most common boats and what theyre called. These boats are exactly what the name implies. They are meant to be used for fishing. Most fishing boats are powered by outboard motors, and many also have a trolling motor mounted on the bow. Bass boats can be made of aluminium or fibreglass.

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  • Catherine
    What does "timbered out" mean?
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    How to transfer transom drawing to wood stock?
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    How to plank a boat hull?
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