Aramid A manufactured polyamide fibre that exhibits high strength and high modulus. Commercially known as Kevlar®, Technora®, Twaron® ect. Or an Arabian pub. Bias The 45 degree direction to the warp or fill. Also called diagonal. Calender or calendering A finishing step where the cloth is subject to heat and pressure to improve bias stability. Count Number of yarns in fill or warp direction. Usually expressed in yarns per inch or cm. Crimp Woven yarns bend up and down as they pass over and under one another. Crimped yarns are shortened due to this bending and tend to exhibit more stretch. Denier The weight in grams of 9.000 metres of a given yarn. DPI Denier Per Inch. Dtex Decitex. The weight in grams of 10.000 meters of a given yarn. Elongation Deformation made by a tensile force. In sailcloth measured in 'units'. Ends Used for expressing the amount of warp yarns in a fabric. Fill The 90 degree direction to the edge of the cloth. Also the name of yarn running from one edge to the other. Film Most films used in sailcloth is polyester. Best known brand name are Mylar® and Tedlar®. Finish A material or process applied to a fabric to alter its characteristics. In sailcloth a finish can be applied by coating, saturating (impregnating) or laminating. Flex resistance The cloths ability to resist flex. Normally measured in terms of remaining tensile strength after a 50 to 60 cycle flex. Flutter Test A laboratory test designed to simulate a sail luffing when not being trimmed. This test determines the fabrics ability to resist degradation. Hand The feel of a fabric. Not a scientific measurement. Impact flutter Where the test strip hits a board when flutter tested. Inch 1" (Inch) = 2.54 cm. Knit A type of fabric construction where fill and warp yarns are not woven together but are tied together with a small polyester knit yarn. Knits tend to have less crimp. Lab Test A stretch test done by elongating the fabric at various loads before fluttering. Lot One unit of production of one style. Mil 1 mil=1/1000 inch. ML Multi layer. MLL Multi layer with polyester taffeta on one side. Peel strength A measure of the force required to separate or peel apart two layers in a laminate. Usually expressed as a force per width (being peeled). Pick A yarn running in the fill direction. PSA Pressure Sensitive Adhesive. Scouring The cleaning process of a fabric before further finishing. Scrim Very light open-weave construction. Only usable with film or other fabrics. Sley Number of warp yarns per inch in a fabric. Or what you do to your opponents. Sm-oz Sailmakers square yards. The weight in ounces for a piece of fabric 28.5" by 36". 1Sm-oz=42.83 g/m2. Specs The units of stretch the fabric stretches when loaded in the warp, fill and bias before and after flutter. Strength The ability to resist breaking or permanent deformation during elongation. Substrate Any non-film layer in a laminate. Taffeta A plain woven fabric where both the warp and fill interweave in an over and under pattern. Traditional woven sailcloth is a taffeta. Tensile strength The level of stress where a fabric or yarn breaks under tension. Unit One unit of stretch is 1/100 inch of elongation in a 16 inch sample. 1% elongation is 16 units. Warp The 0 degree direction to the edge of the cloth. Yarn A bundle of individual filament drawn together to be used in a textile fabric.