Yachting Monthly - November 2015

(Nandana) #1

TECHNICAL


NOVEMBER 2015 http://www.yachtingmonthly.com 67

An alternative way of stopping
woven sailcloth from stretching
is to coat it in a plastic fi lm called
Mylar. Laid over the woven sail,
it is heated and pressed onto the
material, with special attention
to ensure that there’s no air
caught under the fi lm to avoid
delamination at a later stage.
This works well, but sailmakers
soon realised there was no need
to weave the cloth so tightly.
Instead, they can lay the yarns as
a scrim (a very light weave) and,
once laminated, it will still be just
as strong. As with woven sailcloth,
the laminate ‘cloth’ is cut up and
sewn back together, to add shape
and optimise it for the panel’s
load. A taffeta membrane can be
added on both sides of the sail,
increasing durability. However,
this coating weighs 90grams per
square metre (gsm), which for
both sides of a 40m^2 sail is 7.2kg.
While it may not sound much, this

is weight up the mast – the worst
place for it. Racers can opt for one
side of taffeta, or even none at all.
The yarns used in laminate
sails vary from cheap polyester
to more expensive, performance-
orientated carbon and Kevlar.
A cruising sail can use the same
polyester yarns as a woven sail,
but lamination makes it far more
resistant to stretch.

While woven polyester sails
rapidly stretch and lose their
shape, they can last for decades.
In contrast, a laminate sail might
last half that time but will have
an effi cient shape for most or all
of its lifespan.
These laminates can be made
with just polyester, or other
Ultra-PE yarns introduced to
add extra stretch resistance.
Problems occur when either the
sail delaminates or the taffeta

and Mylar fi lms wear, exposing
the fi bres, which break. Because
there is less fabric in the sail,
patching an area is more diffi cult
than with a woven cloth.

How they’re made
Polyester, or Ultra-PE fi bres are
laid in a scrim on top of a
mylar fi lm and further
strengthening yarns
are added; these
aren’t woven, but

laid fl at so there are no bends
or weak points. The scrim is
glued together and then coated
in Mylar, or an equivalent fi lm,
which seals in the yarns. Special
attention is taken to ensure no
air is under the fi lm, as poor-
quality sails can delaminate. This
laminate sail can be coated in
Taffeta, which is a durable fi lm
that protects the sail from wear,
increasing its life.

Laminate sails


Laminates and


membranes


PROS
■ Better shape retention
■ Lighter than
traditional sails

CONS
■ Higher cost
■ Vulnerable to mildew
if put away wet.

What it’s made of
The materials used in
standard laminated sails vary
hugely, starting with polyester
for the cruise market, however
as the price increases, the
materials increase.

Best for
Performance-orientated sailors or
cruisers, who can justify replacing
their sails every 8-10 years.

Material such
as Aramid
(left),
Polyester,
Carbon are
laminated

Laminates are ideal for light-wind sails like a furling Code Zero

Polyester laminates offer many
advantages to the cruising sailor

PHOTO: GRAHAM SNOOK/YM


PHOTO: GRAHAM SNOOK/YM

PHOTO: GRAHAM SNOOK.COM

PHOTO: GRAHAM SNOOK.COM

PHOTO ABOVE : GRAHAMSNOOK.COM

Laminate sails look
distinctive and
retain their shape
for longer than
woven Dacron

Taffeta coatings increase
durability but add weight aloft
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