Plywood has always been a favourite material for home builders. Unfortunately plywood has not
always enjoyed a good reputation. Poor quality vessels have been launched by builders who did not
have a good understanding of required techniques, or chose to ignore them. At the same time,
however, many fine vessels have been built to high standards, with excellent results.
The increased availability of good grade epoxies has made this all possible. Epoxies have further
enhanced the reliability of plywood-constructed vessels to a level that they can now compete in
weight and strength with aluminium and fiberglass building methods. The Gougeon brothers' wood
epoxy saturation technique (W.E.S.T.) has advanced the use of laminated wood structures to a point
where yacht hulls can be built far lighter and stronger than was previously thought possible using
any other materials. By using composite construction involving the use of fiberglass cloth, epoxy
resin, thickeners and fillers it is possible for home builders to produce high quality, light, strong
plywood hulls, at very reasonable cost. The use of plywood rather than multiple layers of veneers
reduces labour time drastically.
Today's plywood is manufactured to high standards. Grading and testing is rigorous and a
uniform program of inspection is followed within the industry. Only those companies consistently
meeting all the requirements of this program are licensed to use the registration certification mark on
their products. Failure to meet the established standards of quality results in de-certification. Quality
control tests include boiling for 4 hours, drying for 20 hours at 140 - 150 degrees F, and then boiling
for 4 hours to check for good glue bond.
Many major design competitions have been won by plywood boats, with the majority of designs
for home building submitted in plywood. The numerous plies give high multi-directional strength and
help make the plywood stable by neutralizing dimensional changes. At the same time large panels
reduce labour time over cold molding. New methods of development for multi-chine hulls produce
rounded chines with section shapes very similar to the I.O.R. racers. Research done by my
company, Bray Yacht Design And Research Ltd., has lead to the development of a plywood system
called the New Epoxy Wood System (N.E.W.S.) suitable for home building or limited production and
one off building. In most cases the hull is built on 1/2" plywood frames, spaced 3'-6" apart. 1"x 2"
battens are secured to each frame between chines. Berths and settees form two box spars, port and
starboard, and tie in with the bulkheads to form a very rigid egg-crate type of construction that is
spacious and functional. Two layers of 6 oz. fiberglass cloth cover all exterior surfaces for a low
maintenance fiberglass finish. 24 oz. woven roving is used inside and out on the chines to tie the
boat together. There is no planing of chine logs etc., and although joints should be well made, epoxy
Other pages: : 1 * 2 * Next>>
|
You are here:ASK Boat
-> Boat Material
-> Content
Category: Home
-> Boat Material