The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

346 Later Production Steps
Staple plywood deck panels
from the center out to the
corners. This will minimize
distortion and rippling from
the compounding of the
plywood.
Figure 27-18 Foredeck framing for a 1 ⁄2 ton racer.
Longitudinals will carry cabin sides and a hanging cockpit.
job you can to hide the scarfs on top of a beam or
bulkhead, particularly if you plan a natural finish.
Figure 27-18 shows a method for applying a plywood
panel to a compounded surface. We usually staple
plywood, working along imaginary lines from the
center out to the corners to minimize distortion. First
Figure 27-19 Fitting and scarfing the 3 ⁄16" (5mm) plywood
deck on the main hull of the proa Slingshot. Note the pads
and blocking for hardware that are fit between stringers
and frames.
we divide a panel into quarters and then into eighths
and sixteenths until it is fastened around its perimeter.
Scarfing in place has advantages when applying
plywood to decks. As we have pointed out previously,
most decks have a small degree of compound curve
which might cause some installation problems if you
were to install a solid panel over the whole deck
surface. This slight compound curvature is easily dissipated
within the scarf joints when you apply many
smaller panels over the same surface.
Sandwich-Constructed Decks
With certain types of boats, a sandwich or coreconstructed
deck system may be advantageous. This
uses the basic principle of separating two load-bearing
skins with a core material. <strong>The</strong> main advantage of this
type of deck is the smooth, unencumbered inner surface
of the underside of the deck. <strong>The</strong> absence of any framework
provides a surface which is easy to finish and,
when complete, easier to keep clean. In addition, the
sandwich deck provides a significant improvement in
thermal and sound insulation properties over a
standard frame-supported deck system. In hot climates,
a deck that does not transmit heat from the sun can be
a significant feature. It is also possible to build a lighter
deck with the sandwich technique; however, this is
dependent upon the application. It is our opinion that
in most situations it is very difficult, on a weight-tostrength
or weight-to-stiffness basis, to improve upon a
well-designed frame-supported deck system.
Sandwich-constructed decks present added construction
difficulties. For most boats, a sandwich-constructed
deck takes longer to build than a frame-supported type
and is also probably more difficult to execute by those
with limited experience. A practical disadvantage of the
sandwich deck is limited versatility when positioning
deck hardware. Before you complete the sandwich
deck, you must know the position of all deck hardware
so that you can remove core material in the area of
specific hardware items and replace it with appropriate
solid blocking. Later, if you want to add some hardware
items or move others to different locations, it will be
difficult to do. With the open frame deck, you can add
more blocking easily to the underside of the deck
wherever it is needed.