The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

Compounded Plywood Construction
Most people are familiar with compounded plywood construction through kit boats. “Stitch-and-glue”
kayaks and small multihulls are the simplest forms. Compounded plywood construction dictates simpler
hull shapes but, with mastery, allows more sophisticated boats. It requires high quality plywood but
reduces or eliminates the need for other set-up and most materials.
In our early years as boatbuilders, we became particularly
fascinated with the concept of the Indian birch
bark canoe. American Indians designed, engineered,
and constructed these birch bark canoes, which were
the preferred method of transport by the early French
explorers for a period of over 200 years. Here was a
craft that was beautifully shaped, lightweight, and
strong. Best of all, it was of sheet material. <strong>The</strong> Indian
birch bark canoe was built in a way just opposite to
that in which boats are normally built: the skin was
formed first and the supporting framework installed
afterwards. Birch bark was first carefully removed from
a tree and roughly shaped into the form of a canoe. A
supporting framework was then installed to support the
flimsy birch bark skin and better define the shape of
the canoe.
In 1963, we used a similar developed skin method,
using plywood instead of birch bark, to build a
trimaran. Following traditional techniques, we “folded
up” a hull and then installed interior framework to
stiffen it, to better define its shape, and to distribute
high loading throughout its skin. We have been
building boats this way for forty years now and have
refined the technique to the point where compounded
plywood construction is a practical method for a
limited range of hull types and shapes.
With this boatbuilding technique it is possible to
produce strong, lightweight hulls. We use it for catamarans
and trimarans, but it is well suited to small day
sailors such as the International Moth Class dinghy. It
may be among the best techniques for building racing
canoes and rowing shells. Lofting, setting up, and
laminating are eliminated, so a boat can be manufactured
in relatively few work hours. One disadvantage of
compounded plywood construction is that its use is
limited to shapes which can be developed easily by
CHAPTER
25
bending sheets of plywood in two directions. Another
problem is that it’s sometimes difficult to install framework
in a preformed hull. In spite of these disadvantages,
the method can be so successful that we think a discussion
of its basic principles is worthwhile.
Boat plans and design information for compounded
plywood construction can be hard to find. For this
reason, this chapter includes an outline of the various
Figure 25-1 Victor T, a lightweight, 25' (7.6m) C-class
trimaran, was built using compounded plywood technique.