The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

40 Fundamentals of Wood/Epoxy Composite Boatbuilding
Figure 5-6 <strong>The</strong> 32' (9.7m), 1 ⁄2-ton racer Hot Flash was built
using the stringer-frame method. This type of construction is
popular with racing boat designers and builders.
Another shortcoming of the stringer-frame method is
that it results in a cluttered interior. Both mold method
and strip plank hulls have smooth, uncluttered walls,
but the stringers and frames, which are part of the
stringer-frame method, take up valuable interior room
and are difficult to keep clean. This kind of interior
may also be less pleasing to the eye.
<strong>The</strong> idea of load-bearing skins supported by stringerframe
systems was first applied to aircraft in the 1930s
when designers found that they could greatly improve
strength-to-weight ratios by substituting wood panels for
fabric skins. <strong>The</strong> load-bearing skins became significant
Figure 5-7 Looking forward in the main hull of the 60'
(18.2m) proa Slingshot. <strong>The</strong> stringer-frame method is easily
adapted to fairly sophisticated designs for boats of any size.
in the development of modern aircraft design. <strong>The</strong>
marine industry borrowed the concept and, with a few
modifications, used it to build lightweight hull and
deck systems. Boats require somewhat thicker skins
than planes, but they are not as limited by weight.
Stringer-frame hull skins are much less thick than
mold method or strip plank hull skins. While the
other methods produce monocoque structures with
totally self-supporting, load-bearing skins, stringerframe
hulls are partial monocoques, able to bear
loads only when held in proper position and column
by supporting framework.
A true monocoque skin is most effective in areas with a
great deal of compound curve—an eggshell shape, for
example. A stringer-frame supported, partial monocoque
skin is most effective with surfaces that are either flat or
curved in only one direction. Most successful multihulls,
with their long, flat runs, have used the stringer-frame
concept to best advantage since it produces the strongest
and stiffest hulls for a given weight. Because monohulls
usually have significant compound curvature, they are