Challenge Sailcloth from Fareastsails.com
Below are quotes from the challenge web site on their Dacron Sailcloth;
"High Modulus Weaves are very tight constructions using the highest modulus,
highest tenacity P.E.T. polyester load bearing yarns available: Allied 1W70,
and DacronŽ 52. High Modulus Weaves are only available from Challenge. "
"Highest Performance Cruising mains, jibs and genoas of all weights. This is
Challenge's top of the line racer/cruiser range of sailcloths. Re-engineered
continually to take advantage of new weaving and finishing technology, High
Modulus Fabrics have large fill yarns to counter leech loads but tight weaves
to resist genoa bias loadings. "
"Allied Signal 1W70 and Dacron Type 52 High Tenacity High Modulus P.E.T. are
used wherever possible. ("Dacron" is DuPont's brand of polyethylene terepthalate,
or P.E.T.). We consider these the best sailcloth yarns in the world, due to low
stretch (for strong leeches), and high shrinkage (translates to lowest bias stretch
and best durability sail shape that won't blow aft). We use Type 52 in 200, 250,
350 and 440 deniers. 1W70 is made only in 220, 250, 500, 840, 1000 and 1300 deniers.
Where these are unavailable, standard Dacron P.E.T. is used to maintain the
precisely engineered density rations needed to achieve maximum fill yarn efficiency,
and lowest stretch. "
"Moderately large fill (width direction) yarns, about twice the size of the warp
(length) yarns are used in the light to medium weights. In heavier weights where
loads are higher, the ration is 3:1, or more. The purpose of the weave design is
first to keep the high load bearing fill yarns straight, (bending or "crimping"
results in stretch as the yarns straighten out under load) and to force the warp
yarns to bend acutely over and under them. High counts of warp yarns ("high sleys")
accomplish this, as there is no space between warp yarns into which fill yarns can
bend. The warp yarns effectively create tunnels which encapsulate the straight fill
yarns. Second, the loom is geared up to a "High Beat Up" level, (high "pick" or fill
yarn count) in order to obtain a tight weave and high number of yarn interlacings
to resist bias loads, prolong sail life, and keep the sail shape from blowing aft. "
"Challenge finishes 100% of its sailcloth in house. (The largest U.S. based sailcloth
maker to do so). The fabric is heat-set, and because of the high shrinkage of the
Dacron and Allied 1W70 yarns, we attain up to 20% shrinkage. The durable Stablilised
finish is achieved by immersing the fabric in a bath of suspended resin. The resin is
absorbed by the fibre. The cloth is then fed into a long oven where the liquids are
driven off, leaving the resin solids bonded to the fibres. The result is the tightest
possible weave, lowest stretch, and maximum durability."