Sail Cloth

Discussion About Sailcloth

As outlined earlier, years ago there were limited sailcloth options for sailmakers using Dacron for cruising and racing sails. That was then. The “this is now,” like most things, is a lot more complicated. We’ll put aside hi-tech racing sail material for now and talk about cruising sails – serious offshore, club knock-about racing, inshore, mom-and-pop – the sails that make up 75% of what we do. Unfortunately for the new sail buyer, sailcloth manufacturers have seen fit, for reasons of competitive pricing and the need to compete with offshore sources for OEM sails, to offer several grades of polyester fabric for sailmaking. Additionally unfortunate is that most of the brand name lofts, and the little guys too, use the not-so-good stuff for their “cruising” market and it’s difficult for the layman to tell the difference. The reason they do it is that the OEM cloths are so much cheaper. It’s very compelling.

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Generally. there are four quality levels of woven “crosscut” sailcloth available to the sailmaker, including those custom woven for the really big lofts. The most popular producer of woven Dacron sailcloth, Bob Bainbridge’s Challenge Sailcloth, offers four “brands” of sailcloth that is used by most sailmakers, big and small. Their price reflects their quality. For example, the popular cruising weight cloth, 8 oz. plus, in the lowest quality, Performance Cruise, is $9.78 per yard. The next level up is their High Modulus which is $10.50 per yard. This High Modulus style is the most popular for practically every sailmaker’s cruising sails, except Mack Sails.

Challenge’s premium brands are called High Aspect and Marblehead. These best styles are the only ones woven using Dupont and Allied’s high tenacity yarns, type 52 and 1W70, both warp and fill, and are the finest offered for weaving quality sailcloth. The quality is reflected in the price. High Aspect is
$14.15 per yard, and Marblehead is $15.01. This is the price sailmakers pay. The yarns for these best cloths are very tightly woven on specialized looms with emphasis on high crimp (slow, strong looms that super pack the heavier fill yarns against the warps yarns in the weaving process). High Aspect Dacron has heavier fill yarns that locate in the load direction of most mainsails and skinny jibs. Marblehead style is more balanced (fill and warp yarns of a more even denier) and is the absolute best for properly designed Dacron headsails and is particularly well suited to Mack Sails’ miter-cut roller reefing genoa. These fabrics are the finest most tightly woven fabrics in the world and rely on the quality of yarn and weave, rather than impregnated resins, to maintain integrity. Also, a big feature of these quality yarns chosen for the best cloth is their ability to shrink in the finishing process. This further tightens the cloth, locking the yarns together for better shape holding over time. The cheaper, more resinated loosely woven cloth breaks down rapidly allowing sails to become overly full with their draft migrating aft quickly. This is why we only stock and only use High Aspect Dacron and Marblehead Dacron for every one of our sails. Unfortunately, many sailmakers “bait and switch” as it’s difficult for the average sailor to tell the difference. We keep samples of all the styles and are happy to point out the subtle signs of difference between the common and the excellent.


See our “Built Like a Mack Sail” page for a list of all our construction features.

Besides the shape problems of using common cloth is one of physical longevity. Practically all cloth has heavier fill yarns – the ones that are parallel to the leech in the way most sails are cut. These fill yarns are totally encapsulated by the warp yarns that are woven over-and-under them – which means these smaller warp yarns are the ones that take the full brunt of ultra violet and flexing. These are the two biggest enemies of sail life. The high quality yarns used in our cloth withstand UV much better and are far superior at flexing. Almost all sailors have seen the leech sections of their sails break apart long before the rest of the sail fails and this is why. This is also why we use the best cloth to resist this problem and why we also two ply the leeches of all our sails.

This discussion has been all about standard cross cut (and our miter cut) sails. Almost all sailmakers also offer radial cut cruising sails, usually styled in one of the available cruising laminates. We do as well, and have examples on our own boats. While our cruise-lam sails are beautifully executed, we are cautious about recommending them to most customers as they are not the best value for longevity and performance. In spite of attempts at addressing the problem, laminates are still subject to delamination and mildew. Mildew is a special problem in roller furling sails, headsails and, especially, furling mast and boom sails. We really don’t want any disappointed customers.


Of course, we also make racing sails in all fabrics including the latest exotic styles, and in the next section we discuss our most popular styles of all our sails and how we design them.