The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

Deck Construction
When <strong>Gougeon</strong> <strong>Brothers</strong> on Boat Construction was first published in 1979, the information concerning
deck framing and construction reflected the basics of traditional deck construction but also introduced
revolutionary procedures for light weight, high-strength deck structures. <strong>The</strong>se new procedures for
constructing deck framework and using plywood instead of planking as a decking material have proved to
be highly successful both in meeting the structural demands of high-performance racing sailboats and in
long-term use.
We have changed some recommendations for applying teak veneer decks in this edition. Using plywood
for the major deck thickness to save weight and cost and then adding a teak veneer has produced excellent
results. However, in earlier editions, we recommended using 1 ⁄8"-thick (3mm) teak set in epoxy and
stapled in place until the epoxy cured hard. <strong>The</strong> staples were left in place until the final sanding, which
ground away the crown of the staple but left the legs buried in the teak. With repeated wetting and drying
cycles, the staple legs worked up and extended above the deck. To eliminate this problem, we began
using temporary screws in the seams instead of staples. This has worked well and is the procedure
described here. Once the screws are removed, the deck has no fasteners to work loose or to cause leaks.
We also now feel that thicker teak veneers can be used—up to 1 ⁄4" (6mm)—to provide a longer service life.
This edition also recommends using 404 High-Density Filler to thicken the epoxy used to fill the seams
when applying teak veneer. This filler does not trap many air bubbles, resulting in a seam that has very few
pinholes or air bubbles exposed after sanding.
<strong>The</strong> earliest seagoing boats were built without decks,
and as late as the thirteenth century, the Vikings were
plying the seas in their open longboats with crew and
cargo exposed to the elements. During this period,
however, the deck started to become a common
addition to oceangoing vessels and for very good
reasons. <strong>The</strong> use of the deck improves the vessel in
three areas:
1. Decks keep water out of the hull, making it more
seaworthy and protecting its contents and crew from
the ravages of the weather. A canvas cover might
serve to keep out rainwater, but it would never be
adequate if the boat were boarded by huge seas. In
certain types of boats, the deck must be as strong as
the hull in order to withstand the surge of thousands
of gallons of water pouring on to it at one time.
2. Decks provide a working platform for carrying out
operations of the vessel. Deck design and layout can
be crucial to crew safety and efficiency when handling
the vessel, especially under adverse conditions.
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27
3. Decks improve the structural integrity of the boat.
A hull with no deck is usually very wobbly because
there is nothing to support the upper sheer areas.
<strong>The</strong> same hull with a deck installed becomes an
amazingly rigid structure with great resistance to
twisting or torsional loads.
<strong>The</strong> deck can also serve other structural functions.
Modern masthead rigs rely on a taut forestay to allow a
good set on their large foresails. To maintain a taut
forestay, a great deal of pre-tensioning must be done on
either the backstay or forestay. This generates forces
that tend to bend the boat in an arc, causing the ends
to raise up toward the mast. A properly engineered and
constructed deck system can resist the high compression
loads and thus prevent most of this hull
deformation.
<strong>The</strong> deck must also be capable of withstanding high
point loading wherever it occurs. Winches, cleats, and
other deck hardware can generate enormous strains
which the deck must be capable of bearing.