Sail Cloth Terms




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Dacron: The most basic and most common material used for building upwind sails. Dacron is actually a brand name for the Polyester (or PET) fiber. Dacron is easy to handle and fairly durable in terms of abrasion and careless handling. Dacron sails will last a very long time before they actually fall apart, but will not keep optimum sail shape as long as more modern fibers or laminate sails.

Nylon: The standard material for spinnakers and other downwind sails, all of the downwind sails we offer are nylon, or a nylon derivative

Woven: Any sailcloth that is made up of a solid weave of fibers running at right angles to each other like conventional fabric.

Laminate: A term used to describe any sailcloth that is made of multiple layers of different materials fused together under high pressure. Laminate sails can use Dacron or high tech fibers such as Pentex, Kevlar, Spectra, or Carbon Fiber as their primary structure. Racing laminates typically have an inner layer or “scrim” made of small bundles of fiber sandwiched between two layers of Mylar plastic film. These sails are semi-transparent and are strong and lightweight but must be handled somewhat carefully and do not tolerate abrasion or UV exposure very well. Cruising laminate sails usually add a thin layer of woven Dacron on each side over the Mylar (called a taffeta), this greatly improves durability and ruggedness, but does make them a little heavier to handle than a lightweight race sail.

Cloth Weight: Sailcloth (especially woven cloth) is usually described by weight, 5 oz, 5.5 oz, etc. While manufacturing differences from brand to brand make this weight per yard of cloth number less than exact, it is a good guide to how heavy, durable, and stiff a specific cloth is. Heavier is not necessarily better. Heavier sails will perform less well in light wind, are stiffer and more awkward to handle, and beyond a certain point really offer very little added life to the sail. While very durable, many people will find our offshore 6 oz mainsails more difficult to handle than they want, anything heavier will seem like trying to fold cardboard when you flake it and will likely not fit inside your standard sailcover due to it’s bulk. The MacGregor factory sails are 3.9 oz cloth, relatively soft and easy to handle and very unintimidating for the beginning sailor, but not as long lived as they could be. A 5 or 5.5 oz sail is a great upgrade for most sailors, if you feel you need a stronger or lower stretch sail than that, it’s likely time to move to a laminate sail.

Most cloth manufacturers use a "weight" numbering system for their various cloths that end in a common number within a cloth design group, these numbers do not necessarily exactly equal the published number. An example would be the Challenge Sailcloth High Modulus Dacron we use in our BWY exclusive sails, Challenge markets this cloth as 4.93 and 5.53, we round it to 5 oz and 5.5 oz to for simplicity.

Although we do offer mainsails and 100% jibs for some models as heavy as 6 oz, most coastal or inland sailors find these a lot to handle. We feel that the optimum sail weight for upwind sails on any of the trailerable Macs for most sailors is in the 5 to 5.5 oz range with some hank-on sails being lighter. All of our BWY Exclusive sails are either 5 or 5.5 oz with most mainsails and genoas being 5 oz and most Jibs being 5.5 oz, these weights give the best balance of performance, durability and ease of handling for each sail type. All of these sails will seem a little stiffer than your old factory sails, but not to the point of being unpleasant to handle This added stiffness will seem more dramatic to you if your old sails are quite tired, as they are probably as soft as bed sheets when they should be crisp.

Laminate cloth is not generally described by weight, but rather by strength modulus, a number that isn’t very helpful unless you are a sail designer. We try to provide an approximate weight equivalence number for the laminates we use to make it less confusing to know how the sails will handle. Laminate sails will be far stronger than the equivalent weight Dacron sail.