- April 30th, 2010
- in Yachting
Cruising Cloth: The Evolution of Sailmaking
Sail technology is evolving at a rapid pace these days, driven by intense competition between sailmakers. Where just a few years ago the material of choice for all types of sailing was a polyester known largely as Dacron (its DuPont trademark) in the US, Terylene in the UK (an ICI trademark) and generically by its chemical name, polyethylene terephthalate or PET.
This material, used in bottle making and container fabrication, also appears in film form as Mylar. One of the most ubiquitous polyesters, PET appears in many forms, from birthday balloons to carpeting to sailcloth. Its enormous versatility has also made it something of a commodity and it is no longer protected by patent, hence its diminished attractiveness to the sailmaker.
Demand requires it, of course, for everyday use on boats ranging from Optimists to offshore cruising yachts—there's nothing quite as user-friendly as Dacron. A sailor can sew his own repairs, tape up a tear, even cut and shape his own sails if need be. The downside, as most sailors know too well, is its tendency to stretch, resulting in a baggy blown-out sail that creates excessive heel and weather helm but will, of course, keep on pulling a boat along until it finally rips into shreds, like a favourite pair of jeans.
Racing requires a sail that won't stretch and that will trim flat and maintain its shape over time. The search for such a material has led sailmakers down some interesting paths and has resulted a blizzard of patents, trademarks and copyrights that are the bread and butter of corporate marketing. Nothing suits a sailmaker better than to offer an exclusive fabric or material. Often, the first to exploit a technology has a few years jump on the competition and can bank profits while the competition has to fight on price and service. That's business anywhere, of course, but sailing is a luxury business really—an owner facing budget restrictions can always keep his sails another season or two. These days, a lot of the sail lofts' business is in repairing and refurbishing sails rather than selling new ones.
For those who can afford it, though, this is an exciting time for sailing—new formulations and new applications of old materials have shaken up the sailing world. The recent America's Cup displayed an even more advanced technology than mere sailcloth when Larry Ellison's BMWOracle sported a solid wing—and won the competition. Although we won't be seeing a solid wing atop an IC24 any time soon, the AC this year did sound a kind of muffled death knell for sail technology at that top level. Who knows where it will lead.
Cruising yachts have their own particular requirements and, whilst Dacron-type sails are still the sail of choice for most, performance cruising sails are being built of more exotic materials which have been developed in the racing environment and have extended their reach.
The primary considerations in any sail are resistance to stretching, resistance to abrasion or tearing, and resistance to UV light, which will degrade the fibers. One of the first materials to replace Dacron for sailing applications was Kevlar which has, since the 1970s, been a byword for strength and resistance to tearing—it's the material bullet-proof vests are comprised of. It is susceptible to UV damage, however, and must be handled extra carefully as it loses strength when folded roughly or when it flexes and flogs excessively. These latter qualities make Kevlar less than ideal for cruising but excellent for racing, where there are plenty of crew to tend to the sails. Twaron is a polymer very similar to Kevlar in composition, though with better UV resistance. Another material is Vectran which is a liquid crystal polymer, a kind of polyester, which is well suited for the hard hauling of cruising. It's almost as strong as Kevlar but has better UV and abrasion resistance. Perhaps the newest formulation is carbon fiber which is almost impervious to UV light and extremely resistant to damage from tearing and mishandling. Carbon fiber can be formulated in many different grades to offer various degrees of stiffness or softness. Another material is Pentex which is a type of resin-impregnated polyester which can be bonded to sheets of film, such as Mylar, for stability.
Photo courtesy of Quantum.
In practice, the sails that end up on cruising boats are often a mixture of all these types of materials. Kevlar, for instance, can be sandwiched between sheets of Dacron for protection from the UV light and as a barrier against abrasion. Quantum has a line called Fusion which incorporates Kevlar and carbon fiber together for strength and resistance to degradation as well as a savings in weight. Doyle has a product they call Stratis for performance cruising, fabricated from Twaron and Vectran fibers and protected by a shell of synthetic taffeta laminate.
Often a yacht might sail to a venue using Dacron-type sails and rig a high performance suit for racing. The variants are as many as there are dollars in the budget. It is fair to say, though, that the further one gets into the wild beyond, the fewer will be the variants. In the far reaches of the Pacific, in the small atolls or in the fjords of the high latitudes, it will be the good old white polyester you'll mostly see.