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Sailmaking Construction Update 2017 | |
Technology continues to move forward in both
fabrics and construction; sails that seemed exotic just a few years ago
are now becoming the norm out on the water. Over the last decade there
has been a major move away from paneled sails towards the “Load Path
Membrane” sails in the racing market, proven performance and durability
with woven Dyneema fabrics for larger cruising boats, and low stretch “crimpless”
Dacron for improved performance in tri-radial cruising and racing sails. The majority of racing sails we build today are our
PowerPath membrane sails
where the fibers themselves are laid out in the orientation to follow
the loads in a sail rather than using individual panels to align the
fibers as in a tri-radial sail. The advantages are a sail that holds its
shape better, is lighter, and in most cases is less expensive than a
tri-radial sail because of savings in material and labor costs. In a membrane sail the fibers are laid throughout
the sail to support the dynamic loading imposed while sailing. This
matrix insures that as loads vary while sailing the designed flying
shape will be maintained across the intended design range of the sail.
We design each sail the same as we would any other type of paneled sail
to produce an end product that is custom shaped to fit each boat and the
intended range of conditions. In a paneled sail this design is then
transferred to our computerized cutting system where the individual
panels are cut out and then assembled. In a membrane sail the final
design along with the fiber type and content we want for each sail is
sent to PowerPlast in Italy for custom lamination. They return a
laminated “membrane” that is three dimensionally shaped exactly to our
design. The sail is then built from that membrane rather than panels cut
from a roll of cloth; doing the final layout and measurement to insure
it matches any necessary rules, apply all the corner reinforcements,
batten pockets, leech, luff, and foot tapes, and all necessary hardware. Recent advances in membrane technology include new
membranes that are softer and take flex better, improved lamination
techniques that have pretty much eliminated de-lamination, more fiber
options, and a new “Filmless
taffeta” construction. The Filmless membranes are made by laminating
a series of fibers in different orientations with two high strength
taffetas and a UV/ Mold shield on both sides. These sails are proving to
be extremely durable for Offshore racing and high performance cruising
sails. On the cruising front we now are building more and
more sails using the Dimension-Polyant
Hydra-Net Radial fabric. This is a woven cloth utilizing a
combination of Dyneema and Dacron. With nothing to crack, peel, or
delaminate it is proving to be an incredibly durable fabric. With
stretch numbers close to a racing laminate it has excellent shape
holding and still has the durability for extended offshore cruising.
Without the mylar laminate to trap moisture it is also much less likely
to mildew. For large, highly load sails where both shape and durability
are required this has become the fabric of choice. We have used it on
both mainsails and headsails on boats between 40 feet and 80 feet,
including several large multihulls that are reporting longevity of at
least twice as long as sails made of cruising laminates. For smaller boat where the low stretch of Dyneema
is not needed Challenge Sailcloth has recently introduced their “crimpless”
Dacron for radial sails. Sailcloth is woven with fibers going in two
directions; the long direction is called the “warp” and the short
direction is called the “fill”. Because of inherent way that
conventional looms operate the fill yarns will be relatively straight
while the warp yarns will go up and down over the fill yarns. This is
called crimp, and because these yarns are not straight in the weave the
fabric will have more stretch in the direction of the crimped warp
yarns. If the fabric is loaded in the warp direction it will stretch
more as those yarns try to straighten out. When loaded in the fill
direction the fill yarns are already nearly straight and will have less
stretch. The result of this is that most Dacron sails have
to be built as cross cut sails where the panels are laid out
perpendicular to the leech. This configuration lines the fill yarns
vertically up the leech which is the area that is most highly loaded.
However a cross cut sail can never fully support the loads in a sail as
well as a radial sail because while the most load may go up the leech
there is still a lot of loading, especially in the corners, where the
load is transmitted out into the body of the sail. In a tri-radial sail
the panels radiate out of the corners and rotate up through sail in a
pattern that keeps their primary yarns more closely lined up with the
actual loading. Tri-radial sails were designed around using laminate
fabrics where the primary yarns in the warp direction are laid out flat
with little or no crimp and then laminated between two films of mylar.
This allows them to have the lowest stretch in the warp direction and
work perfectly in radial sails. The Challenge fabric, aptly named
“Warp Drive” overcomes this
problem with new patent pending weaving and finishing technology that
allows the fabric to be woven with the crimp taking place in the fill
yarns while the warp yarns have nearly zero crimp. The result is the
first true warp orientated Dacron that is made for making radial sails.
Its primary use will be in cruising sails for boat in the 30’ to 50’
range where the customer wants the longevity of Dacron with better shape
holding than you can get in a cross cut sail. For furling headsails it
also much less likely to mildew than a cruising laminate will. |
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