SAIL MATERIALS

To help you evaluate all of the different sail materials that are available, and to help you make an educated decision about your sail purchase, Doyle Sailmakers has developed the following Fabric Guide. For a definition of terms, please refer to the Fabric Glossary. For a description of the different fibers used in sailcloth, please refer to the Fiber Guide.

On the most basic level, there are two different types of sailcloth: woven and laminate.

I. WOVEN SAILCLOTH
The earliest sailcloth was constructed of woven flax. In the 1800s, the switch was made to American cotton and later, to Egyptian cotton. Currently, most woven sailcloth is constructed out of Dacron, although other fibers such as Kevlar, Spectra and Pentex, see limited use.

Magnified view of tightly woven Dacron.  This is a fill-oriented weave, in which the warp fibers (running from the upper left to the lower right) are woven over and under the straight fill yarns.  In this construction, all of the crimp is in the warp and stretch in the fill direction is minimized.

Polyester (Dacron®)
Even though it was almost 40 years ago that Dacron replaced cotton as the primary sail material for fore and aft sails, it is a bit difficult to explain all the subtleties of this fabric. Dacron sail fabric has continued to develop since it was introduced in the mid-fifties. Unfortunately, the difference between a top quality Dacron fabric that will perform well for many years and a fabric that will quickly break down and distort is not discernible by casual examination. In order to make a full assessment, the specific fibers employed and the production history of the fabric must be known. Even then, extensive testing is required to ensure that each roll of fabric is of satisfactory quality.

There are four primary factors that affect the quality and cost of Dacron sailcloth:
1. YARN QUALITY
Yarn quality varies in terms of tenacity (breaking strength), modulus (resistance to stretch), creep (long term stretch) and “weaving quality”. A high tenacity, high modulus yarn produced specifically for weaving is the most desirable and also the most expensive.

2. YARN CONTENT
Yarn content relates to the aspect ratio of the particular sail. Lower aspect sails (#1s) require a more balanced weave, with fibers of similar denier and count in the warp and fill.  Higher aspect ratio sails such as blade jibs require more, heavier fibers along the load lines and fewer across the sail.

3. TIGHTNESS OF THE WEAVE
The tightness of the weave varies for a number of reasons, including:

    * The size of the yarns employed. The smaller the yarn denier, the tighter the weave.
    * The shrinkage of the yarns employed.  Higher shrink yarns will produce a tighter weave than lower shrink yarns.

4. TYPE OF FINISH
The type of finish used on the sail greatly affects the “hand”, or feel, of the material. Also, highly resinated materials often rely on the resin for stability and when, after extended use, the resin begins to break down, the sail begins to change shape. Resin quality and quantity greatly affect the overall quality and cost of the sailcloth.

According to these factors, the price of woven sailcloth can vary a great deal. Woven 8 oz. Dacron fabrics range from $.35 per square foot to $1.10 per square foot depending on the price and quality of the yarn, the manufacturing costs (smaller denier fibers require more shuttle passes and more time to weave than a larger denier fiber), yarn content and type of finish. Thus, when shopping for a Dacron sail, it is best to ask your sailmaker why he or she quoted the cloth that they did. Does the warp to fill ratio approximate the aspect ratio of the sail?  Is the stability of the weave provided by the weave itself or by a highly resinated finish? There are many different styles of Dacron for every application from racing dinghies to large cruising yachts, and your Doyle Sailmaker can help you find the right style for your boat.