Fabric information

We as boat cover experts have seen a lot of different fabrics and materials that are used to produce boat covers. We have seen the bad, the ugly, and some good ones. But overall the quality of the material that is used for boat cover production is actually really bad.

Please have a look around at your local sailing club, you probably see a lot of destroyed covers. Some simply due to their age and other, -perhaps- due to their not caring owner.

The most important thing that you need to know when you buy a new cover; is the material UV proof? Please ask the reseller for a spec sheet of the material they use. Sometimes they are just trading in covers and they don't have any clue what you are talking about, if so, better run to a better or a specialized producer like Topdekzeilen.

After years of research, testing and with our experience we have come to 2 materials, Bisonyl and Bluetex. Bisonyl is a perfect material for the basic sailor. It is very strong, long-lasting, UV-proof and does not require any care during the off-season, further more Bisonyl has a very attractive price point. Bluetex is a perfect material for the more demanding sailor, the main advantage over the Bisonyl material is that it has breathability characteristics so that water vapor can exit through your cover, but rain cannot enter your boat. And last, but not least, Bluetex is awesome looking and a woven canvas.

See our summary of the characteristics of our fabric/materials used:


Color: dark marine blue

Weight: 420 gm / m2

Color fastness to light (ISO 105-B02:2014): 7/8

Solar UV protective properties (BS EN 13758-A1:2006): >50

Watercolum (ISO 811-1981): 400 cm

Air permeability (ISO 9237-1995): 0



The boatcovers of Topdekzeilen are manufactured with high-quality materials, such as the durable Bluetex and the strong spiral zippers from YKK, no.10. We also use this zipper for all our boom and mast covers. Why spiral zippers? Simply because they offer unparalleled strength, so you don't have to worry about teeth breaking, as can happen with block-tooth zippers. With a width of no. 10 and equipped with sturdy YKK sliders, we guarantee the best quality and reliability.

For our topcovers made of Bisonyl, we opt for the robust spiral zippers from Kroko, width no. 10. These offer good reliability, but at a slightly more favorable price. Of course, you can see this cost-saving reflected in the total price of our Bisonyl tarpaulins!

Want to quickly check if your tent cover has a sturdy zipper/slider? Here's a handy trick: grab the tab of the slider and try to bend it slightly. Does it work? Unfortunately, you don't have a sturdy zipper. But with boatcovers from Topdekzeilen, you don't have to worry about that! Our high-quality materials and carefully selected components ensure that your tent cover always remains sturdy, even under heavy conditions on, around, and near the water.



Kleur: navy blue

Gewicht: 375 gm / m2

Color fastness to light (ISO 105-B02:2014): 8/8

Solar UV protective properties (BS EN 13758-A1:2006): >50

Watercolum (ISO 811-1981): 100 cm

Air permeability (ISO 9237-1995): 3


Clips and Velcro

At Topdekzeilen, we ensure that your cover is not only secure but also easy to attach, particularly handy for when the weather gets stormy. We employ a clever combination of high-quality quick clips and Velcro, making closing and securing your cover a breeze.

Our quick clips are not only efficient but also environmentally friendly. Made from recycled material up to 95% and resistant to UV radiation, they provide a sustainable solution for sealing your cover. While traditional methods could be cumbersome and time-consuming, our quick clips make the process fast and straightforward. Less hassle with sandbags or complicated loop and lacing systems; with Topdekzeilen, you can close your cover in a snap.

The Velcro we use for our covers has a width of 20 mm and a sturdy hook-and-loop structure, providing optimal adhesion and remaining reliable even after prolonged use. This ensures that your cover is always securely closed and protected, regardless of the weather conditions


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