What are sails made of: What is Sailcloth?


We’re all wondering what are sails made of, exactly. They’re impressive tensile strength and resilience against the elements is certainly impressive, but which material is the best? Is there a best?

Here’s what sails are made of

Sails are comprised of sailcloth. Here’s the scoop on the illusive sailcloth that holds your sails steady.

As a sailor, one needs to understand the types of sailcloth available because the material is not a one size fits all. Sailcloth consists of fiber material and film, which in turn, creates its variety.

Most sailors identify sailcloth by specific brand names or, in other cases, by the material and size properties.

A synthetic variety of fibers in your sailcloth

A clear understanding of the various fibers used in their manufacture is quite essential. The recommended sailcloth should be two things:

  1. long-lasting and
  2. able to withstand harsh sailing conditions.

Additionally, the material needs to possess structural stability and should be affordable to sailors. As we briefly touched on already, Sailcloth comes in a variety of materials.

what are sails made of

In the United States, the various sailcloth manufacturers include:

  • Dimension Polynant
  • Challenge Sailcloth
  • Contender Sailcloth

Sailcloth comes in different fibers, which determine its quality and strength. Certain factors need to be taken into careful consideration when selecting the ideal sailcloth for your sailboat or vessel.

The purpose of the boat is an essential factor to consider in terms of:

A) what it will be used for and B) the environment that it will be exposed to meaning, are you looking for live-aboard in some of the best places in the world or perhaps sailboat racing?

Manufacturers and sailors both, should consider the following:

  1. its durability
  2. ease of handling weight
  3. strength
  4. chafe resistance (definition of chafing according to Mariam Webster: “to rub so as to wear away : abrade the strap chafed his skin The boat chafed its sides against the dock”

The sailcloth should also be able to maintain a proper shape even after being regularly reefed.

More on the cloth in your sails:

The default fibre that was commonly used for sailcloth since the 1950s has been Dacron sailcloth which is composed of polyester. However, people started building bigger boats that mainly focused on performance, thus necessitating the application of alternative types of fibers.

Therefore, sailcloth manufacturers had to use fibers that could retain their shape more efficiently.

With time, other materials started to be incorporated in sailcloth manufacturing in a more specialized manner.

Such fibers include:

  1. Polyester
  2. Aramid
  3. Nylon
  4. Ultra PE, and some combinations of the latter in some particular instances.

Polyester “dacron” use in Sails

Polyester is the most widely used sail fibre whose application has lasted for decades in new sails. This is due to its strength, durability, and the fact that it is relatively affordable. In the case polyester is woven into sailcloth, it is referred to as “dacron.”

polyester sails

Dacron Suppliers

The brand name originated from DuPont’s 52Dacron Yarn, which they manufactured explicitly for sailcloth and remained as the standard fabric of the sailcloth industry for years.

New suppliers of the fabric have introduced premium polyester yarn, which is most suited for use in sailcloth manufacturing.

The benefits of premium polyester include:

A high shrinkage rate alongside its tight weaving, which produces a tightly packed sailcloth that is also stable.

This also eliminates the necessity of adding excess resins to enhance the stability of the sailcloth. Besides, the polyester fabric can be used as stand-alone as well as part of the components in laminates. Also, polyester yarn exhibits resistance to UV damage (uv resistance) on the sailcloth.

Spinnakers and Nylon Sails

Another material widely used for spinnakers and also asymmetric spinnakers is nylon. This is attributed to its low cost, lightweight, strength as well as resistance to UV damage. Additionally, it is quite elastic and stretchy, which is a good reason on its excellent stability. This causes no liability where it is used in downward sails that require a level of sail stretchiness.

Where nylon misses the mark

However, nylon is very susceptible to damage as a result of exposure to chlorine. Therefore, it is advisable never to use bleach in rinsing or washing sail made from nylon fabric.

For instance, never try to soak nylon-based sailcloth in a swimming pool that contains typically chlorine.

Aramid use in sails

Aramid is a type of material also used in the manufacture of sailcloth. It is known to be lightweight, has high breaking strength as well as high resistance. It is not surprising that aramids are the common fibre choice for the manufacture of sails used during sailing races.

It is also applicable in laminating cruising sails, although considering proper protection from UV damage and flexing.

Some of the commonly used types of Aramid fibers used in sails include:

  1. Technora
  2. Kevlar
  3. Teijin’s Twaron

Often, aramid fibers are blended with higher strength and lower stretching carbon fibers for racing sails. Aramid fibre prices range but are most inexpensive in comparison with the exotic types.

Ultra PE Sails

Also, Ultra PE is used in sailcloth manufacturing where it was originally a Kevlar competitor. The most familiar brand names to sailors are Honeywell’s Spectra and Dyneema, which is manufactured by DSM, a Dutch company.

These fibers consist mainly of intensively processed Polyethylenes which provide high breaking strength, good UV resistance and very low stretch. Also, it is not susceptible to a tendency to elongate over time which is referred to as “creeping”.

We can easily conclude that the mass of Ultra PE in sailcloth needs to be high in comparison to the expected sail load. “Dyneema/Spectra” has been primarily used on bigger cruising boats which require a reasonable strength, weight and durability.

Ultra PE fibre guarantees long sail life which causes it to be inexpensive

Since the appearance of carbon fibre in sailcloth during America’s Cup of 1992, it has been extensively accepted in Grand Prix sailing events as well as in the high-end cruising industry. Also, carbon fibre is resistant to UV damage and possesses extremely high modulus, however, it is relatively susceptible to flex.

Considering one takes a raw carbon fibre yarn and folds it between one’s fingers, it likely to snap after only a few hard folds. Crews need to be cautious to avoid hard creases and flogging when folding or flaking a sail made from carbon fibre, depending on its carbon content.

High performance breakthroughs

A breakthrough in the application of high performance carbon fibre is by combining it in a blended form with Ultra PE fibre considering their complementary characteristics are synergistic.

However, these above fibers are not the only ones in the industry since new fibers occasionally pop out of the petrochemical industry labs. They usually end up being unsuitable due to limited properties, therefore, requiring extensive testing.

More examples of sail materials

An example of such fibers is PEN which is generally known under the brand name, Pentex and is available in limited varieties of yarn. These fibers are compared to polyester but only stretch halfway. The cost of PEN is between that of Aramids and polyester.

LCP is also another new experimental high performance fibre that is lightweight but possesses impressive flex and stretch properties.

What we know so far about Sail Materials

Since the invention of sailboats and wind powered locomotion, humans have looked far and near for the perfect fibers to man the sails with – remember animal skins? At the end of the day, if you’re building a simple boat on your own or hiring a crew to replace your sails, make sure you consult with an expert sailor!

The optimal materials offer balance between synthetic fibers, low stretch, resistance, strength, durability, uv resistance, and affordability. The sailmakers dream sail contains all of these factors and elements, which one will you chose? Drop World Sailing Charters a thought!

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