The Practical Paddler
Pattern-Making with a Jogglestick
By Tamia Nelson
tamia@paddling.net
December 31, 2002
There's nothing like the end of the old
year, with its ritual summing-up and crystal-ball gazing, to remind us
that ours is indeed an age of wonders. And these wonders aren't limited
to labs and offices. They're as near as your toolbox. Want to measure a
room in your house? No need to wrestle with a clumsy steel tape. Just
grab your electronic tape measure, point it at a wall, and press the
magic button. The digital readout will tell you all you need to know.
Sometimes, however, the old-fashioned tools are best. Suppose you want
to fit a bulkhead to your kayak, or build a custom, form-fitting wannigan
for your canoe. How are you going to make the pattern? It isn't easy. You
can eyeball the job and cut a template out of cardboard, of course, but
unless your eye's better than mine, you'll have to do a lot of trimming
before you have a good fit.
Is there a better way? Sure! Let's take a look in the toolbox of a
nineteenth-century shipfitter. You'll probably see a gadget that looks
like a pumped-up, coarse-toothed, wooden saber-saw blade. It's a
"jogglestick"— sometimes called a "pattern stick"—and it's
nothing more than a pointed wooden batten about 1½" x 24" overall,
with deep (c. 1"), asymmetrical teeth cut along one edge.
Jogglesticks are easy to make. A thin (c. ¼") piece of hard oak's
probably the best material, but a softwood furring strip will work in a
pinch. You don't want anything that's too flexible, though. Once you've
cut your teeth—it's not as painful as it sounds!—number them on
both sides of the stick with a laundry marker or black enamel, beginning
at the point. You'll probably want to leave 6" or so uncut as a handgrip,
but that's the only fussy bit. The teeth don't even have to be the same
size or shape.
Not exactly high-tech, eh? A jogglestick needs no batteries, and
there's not a single moving part. So how's it work? Easy. Suppose you
want to make a pattern that exactly reproduces the cross-section profile
of your canoe at a given point. Just clamp a rectangular piece of plywood
scrap (1½' x 1' would be about right, though the dimensions usually
aren't critical) to a thwart near the place where you want to strike the
inside arc. This is your "tally board." Be sure that it's rigidly
clamped, and that it's both (1) vertical and (2) perpendicular to your
canoe's keel line. (NB If there's no thwart handy where you want to
strike a line, or if the thwart's curvature makes it hard to fix your
tally board in place, improvise a temporary thwart with a length of 2 x
4, clamping it to the gunwale of your boat. Just be sure it's clamped
square.)
Now take your jogglestick and hold it so that it lies flat against the
face of the tally board. Put the pointed tip against the bilge or the
side of your canoe, and trace the outline of the jogglestick on
the tally board with a sharp pencil, being careful to hold the stick in
place. When you're done, write the number of each tooth on the tracing.
(You only need to identify one tooth, but a little redundancy never hurt,
did it?) Then repeat the process until you've mapped the inside of your
boat from gunwale to gunwale.
Next, remove the tally board and clamp it to the plywood sheet or
piece of cardboard that you'll be using to make your pattern. Fit the
jogglestick in the pencilled outlines on the tally board, one by one,
matching tooth for tooth and marking where the point of the stick
falls on the pattern. Keep going until you've plotted every point.
Lastly, when you've finished plotting all the points, just connect
the dots with smooth curves. You'll have a pretty near exact pattern of
the inside cross-section of your boat at the location where you clamped
your tally board.
It couldn't be easier, could it? But there are still a few things that
you should know.
The Finer Points of Joggling
- If you're making a custom wannigan for your canoe, be sure to allow
an inch or two of clearance at the inwales. You want to be able to get
your new wannigan in and out of your boat, after all! And don't forget to
take the boat's taper into account, too. If you've never done this sort
of work before, it's probably best to use cardboard rather than plywood
for your first pattern, and then check it to be sure everything's OK.
It's easier—and cheaper—to correct mistakes before you
start cutting costly materials.
- Whatever you're making, it's always simpler to take stuff off than
put it on. So it's good to err on the side of generosity when you cut
your final panels. You can easily take down any high spots with a sharp
plane, Surform® tool, crooked-knife, or sandpaper.
- In a hurry? Who isn't! That being the case, you may be tempted to do
just half the job—lay out a half-pattern—and then reflect it
around the vertical axis. After all, your canoe's symmetrical. Or is it?
Oddly enough, even mass-produced boats popped out of molds are sometimes
lopsided. Not by much, of course. Not enough to noticeably affect
stability, tracking, or handling. But enough to mar the fit of a custom
wannigan or bulkhead. The moral of the story? It's easier to do a job
right in the first place than to redo work you've botched. Take your time
and make a complete pattern.
- If you plan to use a jogglestick to fit a bulkhead in a kayak or
other decked boat, or anyplace else where space is tight, you'll need
ingenuity and very long arms—not to mention a custom-sized
mini-jogglestick. There's a better way, however. Make a profile of your
boat's outside curve. Just remember that you'll need to hold both
boat and tally board firmly in place, and don't forget to allow for the
thickness of the hull when you cut the final pattern!
No, it's not state of the art. But it works. And that's the important
thing, isn't it? The jogglestick on your basement workbench has come a
long way from the naval dockyards of the eighteenth and nineteenth
centuries. It's still ready and willing to do a good day's work, though.
Give it a try the next time you need to make a pattern and see if you
don't agree.
Copyright © 2002 by Verloren Hoop Productions. All rights
reserved.