Strip
Construction
by Bill Durham
(Excerpted from The Mariner's Catalog - Volume 4)
I can congratulate myself in hindsight for deciding
to build the right kinds of boats with strip construction. This
technique is not suitable for most boatbuilding projects, and
I think should rarely be chosen unless there are strong secondary
reasons beside the fact that it's "simple" and cheap.
I built a careful replica of a 26-foot dugout
canoe, using 2" X 1-3/4" strips on the bottom, 1-1/2"
X 1" strips up the sides, epoxy-glued and nailed at 4"
intervals with 16d galvanized casing nails on the bottom, 8d
on the sides. I used tough 3/4" Philippine mahogany planks
as stem and sternpost, with the strips simply beveled to a feather
edge and glued and nailed to them.
On launching, the canoe leaked not a drop, and
no seams opened or wood shifted during five or six years of
careless treatment — left waterlogged in a polluted lake
winters; sun-baked each summer. A purchaser set out for the
Inside Passage several years ago, and I haven't seen the canoe
since. Of precisely the same scantlings as a 1928 prototype,
and indistinguishable from a dugout at ten feet, I felt that
the strip-built hull was a much stronger and more durable fabric
than dugout construction could provide. The canoe was structurally
100 percent successful, primarily because of the virtues of
western red cedar and gap-filling epoxy, and the suitability
of a dugout-canoe prototype.
I chose strip construction for a 20' X 54"
elliptical stern launch partly because I wasn't interested in
learning all the skills and acquiring all the materials necessary
for building such a hull in the traditional way; partly because
I planned to use the hull as a plug for a fiberglass mold. I
used 3/4" X 1-1/4" red cedar strips, resorcinol-glued
and nailed at 3" intervals with 6d galvanized nails, with
much extra clamping.
Strip construction made it easy to achieve an
almost perfectly fair and smooth surface for the fiberglass
work. The 3/4"-thick hull required frames, and I found
that inserting frames and fastening them securely to a thin
softwood skin is not easy.
On launching, the seams wept quietly in dozens
of places before they took up. "Absolutely waterproof"
resorcinol glue is rarely handled in just the right way, or
given enough clamping pressure, by amateur boatbuilders. I think
ordinary water-mix Weldwood will give better results for most
amateurs, if only because it can be slathered on more liberally.
I think that the questions usually asked about
strip construction — How do you fit the strips? How do
you scarph the butt-ends? How can I get clamping pressure? —
are not the questions that need to be asked. The main thing
is to use a completely stable and glueable wood such as western
red cedar, and epoxy glue if you can afford it or know where
to get "Boeing surplus," and to select a project entirely
suitable for strip construction. A traditional plank-on-frame
boat hull, imitated in strip construction, does not look very
authentic.
In my experience, strip-building is phenomenally
sparing of materials costs; wasteful of builder's time. My canoe
took 600 hours to build; the 20-foot launch 1,000 hours. Neither
hull had $100 in it prior to painting or decking.
I'll leave it to a professional boatbuilder to
explain the several reasons why most professionals regard strip
construction as an amateur aberration.
—Bill Durham-
