Cloth Term Dictionary

Cloth Term Dictionary

Construction Details

Warp: This refers to the yarns that are running the length of the fabric. The are the length of the entire roll.

Fill: These are the yarns that are woven across the width of the fabric. Since cloth rolls are typicaly 54” wide each of these yarns are no longer than that.

Bias: The direction across the sail that’s at a 45o to the lenth and width of the cloth.


Denier: A system for coding yarn sizes. Low number represent smaller sizes (and more yarns per inch) and larger numbers are for larger yarns (fewer strands per inch).

X-Ply: Strands of fibers run on the bias direction in laminate sails to help reduce bias elongation.

Dacron: DuPont’s trade name for polyester fibers.

Kevlar: DuPont’s trade name for their high strength aramid fibers.

Carbon Fiber: A very strong and elongation resistant fiber used in composite engineering and high end sails, usually but no always racing sails.

Pentex: Modified polyester with 250% less stretch.

Scrim: A Non woven formed sheet held together with resin.

Spectra: Modified polyethylene fiber used mostly in laminate materials but also used in some very high end woven sail cloths.

Taffeta: Light woven fabric used on laminate materials to add durability and abrasion resistance.

Twaron: A family of aramid fibers (like Kevlar) used in racing laminates.

Nylon / Rip Stop: A elastic polymer  that is woven and coated into lightweight fabrics which most spinnakers are made of. They typically are made in such a way as to resist tearing.

Performance Properties

Creep: The tendency of a fiber to gradually stretch under a constant load.

Elongation: Amount a cloth stretches under load from it’s initial length. Usually measured in 1/100ths of an inch.

Elongation Recovery: The percentage of which the elongation of a fabric is.

Modulus: The measure of the stretch or elasticity of a fabric. High Modulus = Lower Stretch.

Sailmakers Ounces (smoz): Weight of a 36” x 28.5” piece of cloth. This is the size used for discussing cloth weights (e.g. Your sail is made of 7 Oz Dacron Cloth).

Tenacity: Breaking strength of a yarn or fabric stated in force per unit of a cross-sectional piece.

Tensile Strength: Ability of a fiber, yarn or fabric to resist breaking under tension.

Primary Yarn Direction: The direction (warp, fill or balanced) that a cloth resists stretch the most. Most crosscut cruising Dacron is fill oriented.

Hand: How firm or soft a fabric feels.