Yachting Monthly - November 2015

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