Selecting the Right Marine Cover Fabric

Item # X-HT-300096

Sewing a boat cover is a big DIY project, so when you set out to make a new cover you want to be sure it’s going to hold up for a few years. No one wants to resew or mend his or her cover continuously. To help your cover maintain its integrity for the next 5-10 years, it’s important to select the right fabric.

When it comes to choosing a fabric, there are no cut and dry, right or wrong options—just better choices for individual wants and needs. To make the best decision, it’s important to weigh the facts about different types of fabrics and think of what would work best for your lifestyle, your boat and where you live. We’re going to give you an overview of a few of the features we believe are important to consider when choosing fabric for your next cover project.

Sur Last boat cover

Boat cover using Sur Last fabric

Waterproof or Water Resistant?

While “waterproof” and “water resistant” might seem like interchangeable terms, they are not. Waterproof fabrics will always repel water, even if the fabric is old. Fabrics described as waterproof are usually vinyl, vinyl-coated or laminated. Water resistant fabrics do not inherently repel water but, rather, are treated to not let water soak through. In these fabrics, the coating will wear away over time and let water leak through. Water resistant fabrics can also leak when water is allowed to pool on their surface.

It seems like waterproof fabrics would then be a go-to option, and they can be, except for one trade-off—waterproof fabrics aren’t breathable. These fabrics don’t let anything through their surface and that includes air. When air and moisture get trapped underneath a cover, mold and mildew can grow and cause serious problems. When using a waterproof fabric, you’ll want to add a boat cover vent(s) for ventilation to prevent the moisture buildup. When it comes to waterproof cover fabrics, we like Stamoid™ 8.3 oz. and Herculite Riviera®.

If you decide you’d prefer breathability to waterproofness, you can use a water-resistant fabric for your cover. Be sure to give your cover a good pitch, using support poles if necessary, so water won’t pool. Re-treat the cover after a few years or after washing with a fabric treatment like 303® Fabric Guard or Aqua-Tite® to restore the water repellency. For a breathable, water-resistant cover try Sunbrella® Marine Grade, Top Notch® 9 or Sur Last®.

Top Gun®, Top Gun® 1S and Odyssey® are fabrics that fall somewhere in-between water resistant and waterproof. They are nearly waterproof but only marginally breathable. These fabrics are great options for covers; just remember that they should be vented.

Top Gun Powerboat Trailering Cover

Top Gun powerboat trailering cover by customer Dave C.

Chafe Resistance or UV Resistance?

While both chafe resistance and UV resistance are desirable in a cover fabric, where you live and sail can change which of these traits takes priority. If you boat offshore or along the coast, your top priority is likely UV resistance. The sun is harsh on the coast and boats are typically in the water year-round, so you’ll need a fabric that can stand up to all that UV exposure. For the best UV resistance, we recommend Sunbrella Marine Grade fabric. To provide extra chafe protection, add patches of Shelter-Rite® vinyl in high chafe areas.

If you sail inland or in an area with four seasons, your boat gets a break from the weather during the winter months and the sun doesn’t typically get as hot in the summer as it does on the coasts. Therefore, your priority might shift to chafe resistance. A good chafe resistant cover will last a long time inland and won’t require the extra work of adding additional reinforcing patches. For the best chafe resistance, we recommend Top Notch 9, Top Gun, Top Gun 1S, Sur Last and Odyssey.

Sunbrella sailboat cover

Sailboat cover in Sunbrella Walnut Tweed by customer Tanya B.

Strength Over Time

If you’re trying to decide between polyester and acrylic cover fabric, you may want to consider the strength of the fabric over time. Polyester is stronger than acrylic when it is new. This means it is more resistant to abrasion and is more dimensionally stable than acrylic. However, polyester will lose a significant amount of its strength within the first five years (up to eight years for Top Notch), while acrylic’s strength holds steady.

Basically the trade-off looks like this: If you don’t mind adding a few chafe resistant patches to your acrylic cover, it will maintain its integrity for up to 10 years, even in stronger UV climates. If you don’t want to hassle with patches and fixes, choose the polyester and get the better strength for the initial five years and then reassess your cover. If you live in a temperate climate, you may even be able to get more than five years out of your polyester cover.

If you decide on an acrylic cover, go with Sunbrella Marine Grade fabric. If you want to use polyester, we recommend Top Notch 9, Top Gun, Top Gun 1S, Sur Last and Odyssey.

Sunbrella mooring cover

Sunbrella mooring cover by customer Linda T.

Other Considerations

While you’re thinking critically about your cover fabric here are a couple of other considerations to keep in mind:

  • The weight of the fabric. If your cover will be put on and removed frequently, you’ll want a lighter weight fabric. If durability is more important for a storage cover, you can choose a fabric that is a little heavier. Weights for each fabric are listed on the fabric’s product page.
  • Colorfastness. If you’re going to be using a brightly colored fabric that you don’t want to fade, look for a solution-dyed fabric. This means the color goes to the core of every fiber so it won’t fade as quickly when exposed to UV rays. Great solution-dyed fabrics include: Sunbrella Marine Grade, Top Notch 9 and Sur Last.
  • Thread choice. If you decide that you need the highest UV resistance for your cover, you’ll want to also use a lifetime thread when sewing your cover. Just like polyester fabric, UV polyester thread will lose significant strength in the sun, and you won’t want to have to resew the cover after just a year or two. Learn more about lifetime threads in our “Selecting the Right Lifetime Thread” post (#300000XHT).

It’s a lot to think about, but we hope that if you take the time to weigh all the options, you’ll end up with a cover fabric that perfectly suits your needs. When you’re ready to start shopping for fabric, head over to our Marine Fabrics category and filter for "Boat Covers" under the "Marine Uses" category.

Found your fabric? Check out our great cover project videos in our How-To Projects & Tips section.