Types of fabrics for yacht sails

Types of fabrics for yacht sails

For over 100 years, people have used artificial materials effectively in the manufacture of sails. They are more durable, more expensive, and weigh much less than their ancestor - a sail made of material. Renowned brands offer materials with a range of qualities. Let's consider them in more detail.

Fabric sail

The threads of the fabric for the sail cross each other along and across at an angle of 900. The weave is quite dense. Such fabrics tolerate stress in the form of stretching and folds well. Modern production has replaced flax and servants with artificial threads, which has given the material additional useful qualities. For instance…

Polyester

DuPont invented a fabric called Dacron®.

This material is the most popular today for making sails. It was invented during World War II and replaced natural linen and cotton fabrics with it. The material is quite lightweight, wear-resistant, durable and inexpensive. Although nowadays the branded "Dacron" is quite expensive, many yachtsmen buy lesser known and not expensive brands of polyester for their yachts. A versatile material used for many types of cruising yacht sails. In addition, a wardrobe for motor boats is sewn from such polyester.

Nylon

A lighter material than dacron, but just as strong. Nylon is more flexible, so it easily absorbs overload caused by squally wind. This material is widely used in the manufacture of spinnakers and gennakers.

This material looks very impressive, since it can be painted in various colors, while the staining is very stable.

Nylon has one significant drawback - it is very sensitive to household chemicals and preparations containing chlorine. The slightest exposure to these substances will damage the sail. And it will be impossible to restore the tissue.

Due to its properties, a sail made of modern fabric can serve from 10 to 20 years if it is correctly and efficiently sewn. It will not be difficult to reshape or repair such sails with your own hands. Unfortunately, over the years, the sail loses its original shape, which leads to a decrease in efficiency. This is a significant disadvantage of such sails. Fatigue builds up in the fibers due to variable tension and stretching of the fabric (especially due to oblique loads falling diagonally to the interlaced fibers). As a result, the gradual displacement of the “belly” (deeper part of the sail) backwards leads to ineffective consumption of wind energy, the boat sways, and the tractive effort decreases.

At present, the technology for the production of polyester sails involves the processing of fabrics with different compositions, mainly various resins of synthetic origin, cutting according to certain technologies, combining polyester with different composite fabrics. Unfortunately, this does not prevent the sail from stretching, although it slows it down. Racing boats suffer the most from the stretching of the sail, as the sail is subject to higher loads. The sail combination on racing boats has to be changed more often than on recreational yachts, which makes all the tricks for maintaining the quality of the sails ineffective. In this regard, a new type of sail was invented - a laminate sail.

Laminate sail

These sails have a composite structure. The inner layer of the fabric is made of elastic fibers, which allows it to withstand strong and long loads, and the outer part of the fabric is flexible and very durable (laminate), from which the body and profile of the sail are sewn. To protect it from ultraviolet radiation, mechanical damage and moisture, a layer of elastic fibers is sometimes applied to such a sail.

This feature of the structure of the fabric allows the sail not to lose its effectiveness over many years of use. Reduce the negative effects of exposure to wind, sun and salt water. As long as the laminate layer remains intact, the unique properties of the sail remain intact. Likewise, a laminate sail can be compared to a laminate flooring board.

In the manufacture of a laminate sail, other materials are also used in addition to polyester. In addition, the distinctive characteristics of materials, which have their pros and cons, also depend on the chosen base.

Aramids (or aromatic polyamides)

In the early 1970s, synthetic fibers were invented that are strong enough to stretch 2.5% -4% before breaking. Aramids are resistant to high temperatures up to 4000, as well as to the chemical effects of various substances, even hydrochloric and nitric acids are of no concern to them. But there is a big drawback - aramids are weak before exposure to ultraviolet radiation. A sail with such fibers quickly becomes fragile. In sailing, aramids are twisted into filaments and coated with various special compounds.

The most popular aramid fabrics currently are:

Twaron® and Technora® – produced by Teijin (Japan).

Kevlar® – manufactured by DuPont (USA).

The weight of sails made from such fabrics is much less than simple polyester sails. They wear out less and retain their useful qualities. At the same time, fabrics are susceptible to creases and folds, and are also susceptible to the damaging effects of sunlight. The presence of these negative factors will lead to the loss of the properties of the fibers of the fabric, and it will collapse.

The price of the fabric depends on a number of indicators (weight, stretching, elasticity), as well as where it will be applied. For example, for high-speed yachts, fabrics with increased initial elasticity, such as Kevlar 49 and Twaron 2200, are used. Technora fabric is more durable than Kevlar, although its chemical components are very similar to it. However, when exposed to UV rays, this property is still lost. A sail made of this fabric is covered with a black compound to protect it from the sun.

Ultra PE (or ultra high molecular weight polyethylene)

Recently began to be used in yachting, although it was developed in the mid 50s of the last century. Such a fiber is easily UV-resistant, moisture-proof, and also easily tolerates the effects of most acids in comparison with aramid materials, and is also lighter in weight. Ultra PE is 30-40% stronger than aramid fibers and Kevlar and less stretchable. This fabric is mainly supplied by the American company Allied Signal and its subsidiary Dyneema in Europe.

Spectra® / Dyneema® materials are often used in conjunction with other fibers in the same sail and are very similar in properties to the previous material. Ultra PE is more durable in creases and folds than Kevlar, is not afraid of UV rays, but less resistant to high temperatures, and also more stretchable. Therefore, they are not suitable for racing boats.

PEN (or polyethylene naphtholate)

Improvement of conventional (PET) plastic. The fabric made from this fiber is much better than traditional polyester. It is the strongest and most stretchable and also very resistant to acids and chemicals. In comparison with aramids, it is less susceptible to the negative effects of UV rays, but less stretchable and less durable. The big advantage is the price of a PEN sail. The yacht owner buys sails with a good set of characteristics, better than polyester sails, but more profitable in price than aramid sail.

Pentex® PEN fabric comes from the USA, manufactured by Allied Signal, and is widely used in certain racing boat models (for example, One Design), if the use of aramid fiber sails is prohibited due to class rules.

LCP (or liquid crystal polymers)

Invented in the 1980s. Very resistant to high temperatures, acids, reagents, chemicals. But it is also required to additionally protect the fabric from UV rays.

For example, the sail of the German company Hoechst, created from Vectran fabric, is almost as strong as a Kevlar (medium module), also resists stretching, tolerates kinks very well and is less prone to tearing.

Mylar

Back in the 1950s, the American company DuPont invented a synthetic polyester / lavsan film to replace plastic packaging films. In 1955, Mylar began to be used when sewing sails.

The mylar sail did not lose its profile. With any movement of the vessel relative to the wind, it gave a full view, did not stretch out of shape, did not deteriorate when exposed to UV rays and water. A huge disadvantage was the deafening slamming when the vessel changed its position. On a hot day, so to speak, "fry" the helmsman, turning swimming into torture, creating the effect of a greenhouse on the deck. And also the technological capabilities to glue such a sail from various parts greatly limited its size. The strength of a Mylar sail is greatly influenced by the thickness of the film, which cannot be increased to infinity.

Nowadays, mylar sail is used on small yachts, but mylar film is also used in the base for the production of laminated sail for use on sailing yachts for sea sailing, in combination with various aramid fibers, PEN fibers and with dacron fabric. The special arrangement of mylar threads in the direction of the expected loads makes the sails almost wear-free. The sail almost does not lose its shape and is usually used by professional racers, as it is quite expensive. Various frictions on a part of the boat's hull should be avoided, as this can damage the parsa and completely disable it.

Carbon (or carbon fiber)

Its threads are composed of crystals formed from carbon atoms. In yachting, this material began to be used at the end of the 20th century, although it was invented in the 19th century. The inventors twisted it into flexible threads, which was used in the manufacture of sails. At the 1992 America's Cup, carbon fiber laminated sails performed well. Their weight turned out to be quite small, while they stretched less than aramid ones, and were less susceptible to UV radiation.

But such sails were quite expensive. For their advantages literally had to pay. The price exceeded up to 40% of the cost of aramid sails. Moreover, such sails were more sensitive to mechanical stress. Despite this, today, inventors continue to improve these fibers, as the material from them is most suitable for racing sailboats. When laminating the sails, pure carbon is used, as well as it is combined with aramid fibers.

Sail characteristics

The properties of the fabrics from which the sail is made also depend on its capabilities. The main characteristics of fabrics that should be given special attention:

  • UV resistance – use time until the material loses 50% of its strength when exposed to sunlight
  • Tensile strength – the load at which the fiber of the fabric will break
  • The cost
  • Strength loss factor – percentage of initial strength, the sample is bent sequentially 50 times at an angle of 180°
  • Elasticity – shows the ability of a fabric to regain its shape after applying a load

The table shows the characteristics of the materials for ease of comparison:

Fiber name
Elastic modulus, g / den *
Tensile strength, g / den *
Loss of strength,% Resistant to solar radiation, months Resistant to solar radiation, months
Nylon 20 7 - 9 0 3 7 - 8
Dacron 80 5 - 8 0 6 5 - 7
Pentex 250 9 0 4 24 - 40
Kevlar 29 460 24 25 3 48 - 75
Kevlar 49 520 24 30 3 60 - 100
Technora 574 27 20 2 50 - 80
Vectran 600 25 0 13
with lamination
> 100
Spectra 1000 2200 35 0 12 60 - 90
Dyneema 1200 35 - 43 0 12 50 - 80
Carbon 1500 - 3000 10 - 24 35 - 100 Almost not affected > 100

Unfortunately, all the excellent qualities of modern fabrics do not guarantee the successful use of wind energy. Correct sail cutting also plays an important role.

Cutting the sails: different options

Usually the body of a sail is made up of panels (pieces) of fabric, certain compounds. The segments have different shapes and sizes, their location on the fabric relative to each other is also different. The most popular cutting options:

  • Cut vertically. The panels have an elongated shape, and the angle of inclination to the horizon is greater. This option is the least popular due to the lower strength of the sail with this cut. This method is used for sewing the sails of small yachts.
  • Cut horizontally. Most of the panels are elongated rectangles and truncated trapezoids, which have parallel bases, and the seams are made almost horizontally.

The main advantages of linear cutting are easy calculations, ease of development and stitching, little waste and few seams, as a result - the cost of sewing is also reduced.

The ratio between the price of a sail and the efficiency of its use remains optimal for a longer time. In this regard, the owners of cruise yachts use the horizontal method for cutting, which is the most popular these days. Unfortunately this cutting method cannot be used on laminate sails. For this type of fabric, a radial cutting method is used. The fabric cuts generally have an elongated triangle shape, their tops are grouped at the corners of the sail, while the seams diverge along the radius.

The types of cuts differ in the number of corners used in the cut:

Full-radial

Cuts diverge from one (clew) corner. This cut is suitable for small boats used for coastal sailing. Ideal for winding sails into masts, as well as for conventional reefing methods.

Biradial

Sections of fabric with their tops converge at the corners with the most weighty loads. The obverse of the sail is cut from stronger fabrics. It is good to use this type of cut with a height to width ratio of 2.5: 1, used at high wind speeds and large angles of inclination. Most often it is a rear sail.

Triradial

Separately cut panels are joined by seams coming out of 3 corners. Therefore, it becomes possible to use stronger materials where the stress is strongest, so that the load is distributed evenly throughout the sail. This is the best sail cut from laminate fabrics, as it is possible to use combinations of different types of fibers, while the overall efficiency of the sail is increased without increasing its weight. With a height to base ratio greater than 2.5: 1, this type of cutting is the most optimal and recommended for racing boats.

The main advantages of sails with such types of cutting are considered: the ability to maintain the profile for a longer time and use it effectively, the loads are distributed more evenly, it is possible to use several materials with different properties at once. But there are also negative aspects: in comparison with other cutting methods, such cuts are more difficult to mark and collect, mostly many seams, and they are longer. Material consumption becomes more uneconomical. At a price, a triradial sail, for example, is 30-35% higher than sails with simple cut types, and a biradial sail is 10-15% higher for the same area.

Let's summarize some of the results. Let's make a conclusion

You should not chase the latest and fashionable types of sailing fabrics, there are a lot of them. For a cruising yacht, a perfectly cut horizontally set of good polyester sails will suit, even for long voyages you will have enough of them for many years.

In the future, to improve your wardrobe, for example, dacron sails can be successfully replaced with PEN sails, which will not significantly affect your budget. Plus, it's okay to have two sets of sails or more. For example, one for racing and one for family cruises.

Are you gaining successful experience in sea and ocean crossings and want to increase your speed? Time to think about sails made of biradial or triradial laminate, aramid fabrics or hydrocarbon materials. Maybe new types of fabrics and fibers have already appeared on the market? The frequency of new products is almost annual.

The main thing to remember is that success depends on mastered skills and skillful, hardworking hands. This will allow the efficient use of wind energy using the most common sail. And the latest technology will help you with this.

Discussion

To add a comment, please log in