The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

Chapter 23 – Strip Plank Laminated Veneer and Strip Composite Construction 269
Double run method
Planks are laid out from
the keel to the bilge area
where they are trimmed
off in a fair curve
Master plank method
Locate the master plank
about midpoint along the
midship girth
Figure 23-2 Two methods for strip planking hulls.
arc to achieve a fair curve over the unmarked fore and
aft frames.
With this batten installed, you can get a better idea
about how the planking will lie on the rest of the hull.
Measure either up or down from the batten at various
points on all the frames to try to get a sense of what the
planking will look like as it approaches the sheer and/or
keel. As you work out the planking direction, try to
determine which are the most severe curves in the hull
and establish the best angle for negotiating them. <strong>The</strong>n
compare this with the angle of the master veneer (if
veneer will eventually be applied over the strip
planking). Another factor that might affect placement of
the master plank is the amount of compound curve
toward the sheer compared with the compound curve
toward the keel. <strong>The</strong> bottoms of boats are usually
compounded more than the topsides, and this may
indicate that the master plank should be curved more
toward the sheer where the planks might be more easily
bent edgewise due to the lack of compound curvature.
When you have lined up the batten and adjusted it to
suit your desire for positioning the master plank, carefully
mark its position on each station so that you can
install the master plank using these marks as reference.
Although it is normally done, it is not necessary that
the master plank be located right at this marked
midpoint position. You could position the master plank
Figure 23-3 Strip planking a mold.
Figure 23-4 Strip planking a 42' (12.8m) hull. <strong>The</strong>se strips
are being laid from a master plank from the bilge up to the
keel.
at any point above or below the midpoint marks that you
established with the batten, but it must run parallel to
and at the same distance from each mark at each station
point so that as the hull is fully planked, the planks in
the area of the original marks will run true to them.
If you decide that the shape of your hull is not well
suited to this type of planking procedure (for example,
if the hull is too fat), you can use the double run
planking system. (See Figure 23-2.) With this method,
you apply the planking parallel with the sheer line up
to a point on the hull where it begins to curve excessively.
<strong>The</strong>n apply the next group of planking parallel
with the keel, joining it with the planking that has been
run parallel with the sheer at a central joining plank.
Joining the two directions of planking as they run out
into each other at some point in the central hull area is
difficult without causing a hard spot. This difficulty is