Sails and High Technology

Sails...A historyof Kevlar. Likewise, films of Mylar, a very fine
If the wind provides the energy necessary topolyester, fix Kevlar threads whose density and
propel sailboats forward, then the sails are theangle of weave are able to withstand enormous
boat's engine power. The materials used, howloads.
they are set, the size and their shape determineThe main thing is to give a nice round shape to
the boat's power.the curve of the canvas and to give the right
Computer software has replaced the drawingshape to the depth or camber which will be filled
table for sail designers and offer the bestby the wind. Part of the boat's performance will
compromise between the objectives to bedepend on it.
attained and the restrictions which are imposed.But before the sail can grace the boat with its
Thus, depending on the type of boat to bepresence, it has to pass through skilled hands of
equipped (cruiser-racer, ocean racing trimaran or"couturiers" who must bring the panels together,
round-the-world monohull) and, in accordance withpunch the cringles into place in the three corners
the conditions which the boat is expected toand reinforce parts which will be subjected to
encounter, the master sailmakers, with theirrelentless impacts against the pars or the
computers will gradually design the boat'sguardrails.
wardrobe in the same way as a great couturierSo, on all three of the edges, the luff, leech and
preparing his spring-summer or fall-winterfoot, extra layers of cloth are added to protect
collection.the sail. Wavy straps called "bolt ropes" are also
The distribution of the cloth panels of the sails issewn along the foot and the luff (of mainsails)
fundamental in order to give the sails their desiredwhich they strengthen to enable the slides and
shape so that they can best exploit the massesother cables to fasten the sail onto the rig.
of air which are transformed into a driving force.Next to follow are the batten pockets for sails
Certain points of the sail can be put underwhich need them, reef points, pennants and
enormous strain and so panel layout and stitchingeventually the ultraviolet tape of the roller/furler
have to be sufficiently resistant, which usuallygenoa.
means placing both in the same direction as theThe mainsails
strongest effort.Depending on their size, tonnage and sailing
Traditional cloths have disappeared from theclassification, sailboats require lightweight or
landscape of modern sailing. Synthetic Fibres haveheavyweight sails, some of which is just advisable,
now replaced cotton, linen or Jute in the threadssome compulsory.
of the sailcloth. Dacron or Tergal, polyester fibres,It is not apparent from the mainsail's same but it
nylon, polyamide fibre are the most commonlyis not the biggest sail on board a sailboat. It is a
used. Resistant, easy to handle, and capable oftriangular sail, hoisted along the mast and generally
great results whatever the conditions, theyheld horizontally by the boom. Surface area can
comprise the large majority of sail wardrobesbe reduced if necessary. That's where the clew
currently on the water and are available for aouthaul, the cringle and the reef pendants come in
reasonable price.useful. Battens are slipped into their pockets and
Kevlar, aramid fibre, Spectra, polyethelene fibre,serve to stiffen the sail providing better shape
Vectran, carbon fibre are just some of the newholding in the wind.
materials. Increasingly light, varying in degrees ofA second mainsail is to be found on boats which
elasticity and resistance to ultraviolet, thesehave a second mast, for example, ketches
materials equip top competition boats.whose mizzen mast is set aft.
Whatever the material, the threads have to beGenoas.
woven first. Traditional weaving involves crossingGenoas are the big foresails, banked onto the
the threads at right angles.The fill or weft isforestay (or jib-stay) and are set fore and aft
formed by running threads across the cloth, theoverlapping the mainsail mast. Most of the genoas
warp being formed by running threads across iton pleasure cruisers are now set on roller-furlers
lengthwise. Cloth stretches mainly across the biasand can be unfurled and furled again as needed.
rather than along the yarn direction of the warpsThis avoids the delicate sail-changing manoeuver in
or the filling. Weave density is of the utmostheavy weather.
importance. In order to improve its resistance stillJibsjibs are the triangular sails which are hanked on
further, the cloth is treated, coated with a resinto the forestay and which almost all dinghies,
polymer which tempers the yarn, locking thecruisers and pleasure sailboats have. An
weave.intermediate-sized sail, the staysail, can be set
We must not overlook the famous sandwichesonto the inner forestay. The smallest jibs of all
which combine materials to obtain the advantagesare the storm jibs.
of both.Spinnakers
The Kevlar laminate fixes Kevlar threads betweenSpinnakers are the air-filled sails which look as if
a polyester film and another film whose fill isthey are well ahead of the boat from which they
made of polyester and whose warps are madeare flown.