23-Foot Cabin Cruiser "Beaver". Part VII.
Do not let two butts come in line, one under the other. "Break butts," as boatbuilders call it, by making the joint in the next plank come two or three frames forward or aft of the first one. There should be at least two planks intervening between butts in the same frame space. With your "spile staff," find the shape the top of the next plank must be to fit the lower edge of the sheer strake, and with this shape marked off on a plank you are going to cut it out of, measure the widths 4 inches amidships, 3 inches forward and, say, 2 inches aft, whatever it may be, and sweep in a fair curve with a batten for the lower edge of the plank. After working three or four planks down from the top put some more on at the bottom, working toward the middle, until only one plank remains to be fitted. That is known as the "shutter" plank, and its fitting in in shipyards used to be the signal for a drink from the boat-builders. Old timers would predict all kinds of disasters to the boat whose shutter was not "wet" to assist it in going in. The boatbuilders got the "wet." You may feel the joy that inspired this tradition when you realize that that plank completes the job of planking; anyway, you'll be happy and proud, too.
There used to be a great deal of mystery thrown about the job of planking a boat. It does call for some skill, but the foreman who laid out the planking always took good care to conceal the manner in which he did it.
The "planking scale" was a mystery in which none were to be initiated, and the lucky man who could pry into and understand the system at once became a power in a boat shop.
It is laughable how instructors in boatbuilding, when they come to a description of this subject fall down — as the author of one book I have in my library remarks, when he comes to describe planking: "I have never been able to find anyone who could explain this operation so as to make it clear, and doubt my own ability to do so, so will leave you to puzzle it out for yourself."
I don't want there to be any puzzle about it, and so I shall tell you hear what the planking scale is, and tell you how to use it on this boat. For the scale plane up a thin slat of wood like a lath about an inch wide and Hi-inch thick, and as long as the distance around the frame from the top strake to the garboard. To use this scale, bitt one end against the top edge of the garboard or second strake, if it is on, and tack it lightly. Then bend the scale around the face of the midship frame, and mark where it touches the lower edge of the sheer strake. That is the distance to be planked, and as we have already decided our plank shall be 4 inches wide at this point, mark that spot 4. Then do the same forward, where we found the planks were to be 3 inches wide. Mark that distance as 3 — the great mystery consists of dividing that distance between 3 and 4 into eight equal parts, and so making a scale on the slat of wood. Continue those same divisions up the scale to about 2, and you have a planking scale. On the top strake, at the second frame, mark two as the widths of all planks on that frame. To find the width on each frame butt one end of this scale on the top of the plank, on the bottom and where the lower edge of the top strake crosses the scaled off part of your batten or planking scale you can read the width of the plank from it. The widths so marked show how wide each plank is to be on each frame.
Another method for laying out a plank where you have determined the widths of the two ends and middle as we did at first is to strike a half circle, Figure II, with a radius of 4 inches, the greatest width we decided for our plank. Measure up square to the base line to where the curve is 3 inches high — that is, the widths of the planks forward — and on the other side to where it is 2 inches. Divide the remaining space into any number of equal parts and you can measure the widths at these places and lay them out at corresponding intervals on the plank you are lining out on the board previous to cutting them out. This will give you a true, fair sweep for the other edge of the plank. The three or four short strakes of plank to form the raised deck forward will be easy enough to anyone who can do the rest of the planking.
Each plank can be riveted up as it is put on. Punch the nail in solid then, with one man holding a heavy weight on against the head outside, another can get inside, put a copper "burr" — as the flat washers are called — on the nail, punching it on with a short piece of either brass or iron piping just big enough to go over the nail, cut it off within about 1/16-inch of the washer and rivet it up. Don't hit it a couple of smashing blows, as that will only buckle the nail in the wood. Take a light hammer with a ball pene end, like a machinist's hammer, and tap it all round the edge until it curls, or "burrs" over; then hit it a couple of good taps in the centre to expand it.
Plane off the uneven seams and any hard spots that may show on the planking, then go carefully all over and test all loose looking knots, and punch them out. Those with a black ring, which is a sort of bark, are the loose ones.
Details of Constraction of 23-Foot Cabin Cruiser "Beaver".
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