The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

Chapter 5 – Hull Construction Techniques—An Overview 41
built very successfully with any of the three methods of
laminating, and the decision between methods depends
on the individual project.
Hard Chine and Developed
Plywood Construction
<strong>The</strong>re is a lot of variety in hard chine and developed
plywood construction—from the simplest kit to fairly
sophisticated racing boats. <strong>The</strong>se methods offer the
beginner as well as the experienced builder hull construction
options based on standard sheet materials.
A single chine, plywood-skinned boat hull is the
simplest and least expensive method of hull construction.
However, plywood does not bend into compound
shapes easily, so only sections of cylindrical or cone
shapes are typical. This limits the shape of a hull, giving
it a somewhat slab-sided look. However, the speed with
which you can build a hull with plywood may be
enough of a trade-off to overcome the aesthetic issues.
Developed plywood shapes have been used extensively
in powerboat design and construction. This technique
blends the straight-line elements of conical and cylindrical
surfaces into fairly sophisticated shapes.
Traditional lapstrake construction in plywood works
well in small boats. Multi-chine plywood construction,
a modern variation, is used in small boat kits as well as
Figure 5-8 <strong>The</strong> 35' (10.6 m) trimaran Ollie under construction.
Ollie’s main hull was built using the compounded plywood
method.
some larger multihull designs. Variations have been
employed in very large boats, essentially interpreting
aluminum or steel designs in wood.
Composite chine construction, also known as stitchand-glue
construction, is now very popular in kits. It
reduces or eliminates many of the internal structural
members made of wood (keels, battens, and chines) by
substituting built-up fillets of glass cloth and thickened
epoxy to connect and carry the loads between adjacent
plywood panels. Using this method, you can build
a complete hull quickly, without the need for mold
stations or a strongback. While typically used in kits,
composite chine construction has also been used in
some larger hulls. See Chapters 24 and 25 for more
complete information.
Compounded Plywood Construction
Compounded plywood construction is fairly specialized
and typically found in one-off multihulls or in combination
with developed plywood designs discussed above.
Plywood does not like to be forced into compound
shapes, but can be fooled into this if the builder is clever.
Compounded plywood construction depends on fairly
thin, high-quality plywood and is usually limited to very
modest amounts of compounding. Double-ended hulls
are possible, but transom hulls are preferred where the
builder is attempting a fuller hull design. Chapter 25 can
serve as a primer for the builder new to this construction
method, but in all cases we recommend building
models of the proposed hull before committing time and
materials to a full-sized compounded plywood hull.
Later chapters deal in greater detail with laminating
procedures and these construction methods. In many
cases, the experienced builder will employ hybrid construction
techniques or blend features of more than one
method in building various parts of the boat. However,
as we warned above, the first time builder should consider
the designer’s intent before mixing or changing
the construction method spelled out in the plans.
Appendix D gives the scantlings for some hulls that have
been successfully laminated with wood and WEST
SYSTEM epoxy. <strong>The</strong>se may serve as a guide for scantlings
for each hull laminating method and may be
useful for comparison with your project.