Are Sailboat Sails Waterproof?

When you are sailing, do you ever wonder why the sails don’t become water saturated and quit working? Maybe with the wide open horizons, a cool breeze in your hair, and sound of the wind luffing against the sails, you haven’t given it much thought. But we have.

Sailboat sails are “waterproof”, depending on the materials used in their construction. Modern sails constructed of polyester blends are the most waterproof sails made to date.

Sails can be made of many different types of materials. From the old “canvas” or “cotton” sails common to the high seas centuries ago, to the current polyester blends of today, stronger materials, able to hold wind and resist molds and water damage have been pursued by sailors as energetically as buried treasure. Why this focus on waterproofing sailboat sails?

How Did Sails Become Waterproof?

Centuries ago, sailors noticed their wet cotton or linen sails caught the wind better than dry sails. Unfortunately, wet sails are also incredibly heavy, and cottons are susceptible to mold and other damage when frequently saturated with water. The development of today’s waterproof sails evolved over time:

  • Linseed oil: In the mid-19 th century, Scottish sailors developed a technique to coat the cotton or linen sails with linseed oil. This retained the improved air capture found in wet sails, without thesame level of additional weight. Over time, this material has come to be known as “waxed canvas” or “waxed cotton”.
  • Wax: In the 1930s, waxed cotton was replaced with a new process in which the cotton sailswere impregnated with paraffin wax. This process produced a fabric that was more waterproof,more breathable and less rigid than the old linseed oil process.
  • Synthetic fabrics: Today, we utilize a variety of materials including polyester blends, Kevlar, nylon and aramid to obtain a tighter weave, with a higher tensile strength than traditional cotton or linen. Even with these advances in fiber technology, additional waterproofing processes are added, to make the sails as waterproof, pliable and breathable as possible, while minimizing overall weight.

Best Materials for Waterproofed Sailboat Sails

So now that we better understand the value of having waterproofed sails, what materials are best suited for manufacturing our sails?

The most common materials used in the manufacture of modern sails are:

  1. Polyester
  2. Nylon
  3. Kevlar
  4. Spectra
  5. Dyneema
  6. Mylar
  7. Carbon Fiber
  8. Laminates

Most sails will have a combination of 2 or more of these materials in their manufacture. Each offers something unique to the durability of the sails and each lends itself to specific types of sails.


We aren’t talking about the type of polyester used in apparel. We’re talking about high quality polyester, best known by the trade name Dacron. With 4 layers of protection, Dacron is known for its durability, high UV resistance, and fatigue/abrasion resistance. Additionally, it is the most common and most affordable sail material currently on the market.


Nylon is a strong, lightweight material. Its positive attributes include good UV resistance (. not as good as polyester), excellent resistance to abrasion, and it’s highly flexible. Negatives are its propensity for a low modulus, which allows for a lot of stretch, and a susceptibility to damage when cleaned with or exposed to chlorine and other caustic chemicals.

Nylon is frequently used in the manufacture of spinnaker sails.


Not exactly the same Kevlar as you think about in body armor, mind you, but it does share some of the same positive attributes. Kevlar is known for its incredibly high strength. In fact, it has a higher strength to weight ratio than steel! From a negative standpoint, it tends to lose strength when folded, flexed or
flogged and does not withstand UV very well. Kevlar is frequently used in the manufacture of racing sails and is used as a layer in laminated cruising sails.


Spectra is a well known for its extremely high UV resistance, low stretching, high breaking and high flex strength. Probably its biggest disadvantage is its tendency to become permanently elongated over time and exposure to sustained wind load.

Spectra is frequently used in the manufacture of spinnaker sails or in the manufacture of sails for high-performance sailboats that allow for frequent sail replacement.


Comparable to Spectra, Dyneema is known for excellent UV resistance, low stretch and high strength to weight ratio.


No, not balloons. Mylar is a fabric that is generally the foundation for most laminate sails. It is known for its tensile strength, transparency and stability.

Mylar is used frequently in the manufacture of racing sails.

Carbon Fiber

Known for their extreme durability and flexibility, carbon fiber is thought by some to be the best material currently on the market. The biggest drawback is a degradation from flexing and the cost.


Laminate sails are a combination of different types of fabrics. The layers are generally glued, the laminated together under extremely high temperatures, basically fusing them together into a new combination material.

Laminates are best known for their extreme durability, efficiency in catching and hold wind and ease of handling and maintenance. Depending on materials used, they are generally highly UV resistant and feature an excellent tear strength. However, they are much more costly than other options.

If you’re looking for more information on different fibers and how they compare to one another, there is some excellent information online that goes into much deeper depth.

How Much Do New Sails Cost?

So many variables. This is kind of like asking how much does a new car cost. Just like a new car, how much you’ll spend on new sails depends on what you choose to get, what it’s made of, how big your boat is and how fancy you are looking for. estimates new sails for a 24’ Bermuda sloop will run between $1,000 and $2500. They continue estimating that sails for a mid-sized boat would run closer to $3000 to $5000 or more. Perhaps a better way to determine what your new sails will cost is to refer you to a sail price calculator to get an idea. Remember, you will want to contact your local sailmaker to get firm prices. This is simply to give you a rough estimate.

Final Thoughts

Your sails are the very foundation of your sailboat. There are few components more critical to great operation. Yet, this is an area many people choose immediate dollars over long term durability,
strength, performance and functionality.

Getting the very best sails you can possibly afford is an investment in your boat, your life and your adventure. What value do you place on those parts of your life will help determine the value you place on your sails.

All of these modern sails are “waterproof”, and all will get you where you want to go. It’s like a comparison between a Ford and a Mercedes. You know the Mercedes is more money, but you also
know it will probably last longer, perform better and you will probably have a lot more fun using it. Only you can decide if you’re a go for the gusto kind of person or more of a let’s save it for a rainy-day kind of guy.

Either way, the fabrics you select will determine the longevity of that new sail investment. Be informed on what you’re buying and why. Determine what your primary usage is, how important the various options are for your lifestyle and make an intelligent decision on how you spend those new sail dollars. Then, get out there and enjoy your life.

Happy sailing!

Recent Content