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The Scoop On Clear Boat Canvass-Polyvinyl vs. Polycarbonate vs. Acrylic

How To Clean Boat Canvas?

If you have clear canvass curtains on your boat in need of replacement or if you want to add clear canvass for more protection from the elements, choosing the best material for the job is critical.

Let’s be honest, people: clear canvass for boats is not exactly a sexy subject.

But it is an important one, which is why we’ve covered such topics as cleaning isinglass on a boat and how to save your isinglass in the past. What we haven’t covered, however, is which type of isinglass is best for your boat in the first place. This stuff doesn’t come cheap and it plays an important role in protecting you and your crew in bad or cold weather, so take a close look at the options.

In some cases, cold-weather anglers can use canvass and clear canvass to turn a center console into a cabin boat… sort of.

Polyvinyl

Polyvinyl is the most flexible of the clear canvass options and is usually the best choice for sections of canvass that need to be quickly and easily secured open. This is the stuff we can roll up and secure with straps and snaps, to create passageways or increase ventilation. There are a number of manufacturers out there who make rolls of clear vinyl that’s quite economical and is used by many custom canvass shops. But it does scratch rather easily and weathers rather rapidly, particularly when exposed to the sun year-round. While small garage-kept or warehoused dry-stack boats can get away with this alternative, if your boat lives in constant sunlight the long-term results are likely to be disappointing. Specialty marine canvass manufactures, like Strataglass and O’Sea offer polyvinyls that have been treated with coatings that help boost scratch-resistance and/or UV-filtering. This can extend their usable lifetime quite a bit, and while looking through cheap clear canvasses that’s weathered will be like looking through a fog after a few seasons, higher quality clear canvass that’s properly cared for can last for five or more years.

Polyvinyl clear canvass is commonly used for everything from drop-curtains to sealing off the gap between a windshield and hard top.

The material is measured in mils (a mil is .001 of an inch) and is commonly seen in 20 to 60 mils with 40 proving the most popular. As one might expect, thicker polyvinyl sheets cost more than thinner ones but all other things being equal, they’ll last longer, too. However, there are a couple of down-sides to consider. Most importantly, the thicker the material is, the tougher it is to roll up. So if you’re fitting a panel that needs to be frequently rolled and unrolled, you may actually be happier going with lighter material. Secondly, the thicker the clear canvass is, the stronger the visual distortion is where the panel bends. This may be a non-issue with a rear curtain closing off the back of a bridgedeck, but is worth considering for a piece of clear canvass that’s up at the helm.

Polycarbonate and Acrylic

We’re lumping polycarbonate and acrylic windows together because they’re very similar; both are only moderately flexible, and can’t be rolled up. Where there’s enough clearance space in some cases it can be used as an opening, but only when there’s sufficient room to swing the entire panel up or aside and secure it, usually to the underside of a hard-top. Polycarbonate (offered by manufacturers like Rainier) is considered virtually unbreakable, but it’s expensive and can scratch more easily than acrylic. Acrylic, on the other hand, is still quite strong if not up to polycarbonate’s level, and it has better UV resistance. One popular example is EZ2CY.

clear boat canvass
On large boats like this Viking 440 Open, rigid polycarbonate or acrylic can be used for doors and other openings because there’s space to swing it up and secure it in place.

While these semi-rigid materials can’t be rolled, in many cases they’re still flexible enough to make gentle curves and bends around pipework and windshields. They also usually offer better seals against wind, rain, and spray, when compared to polyvinyl, since they secure in tracks as opposed to being zipped or snapped in place. On top of that, they aren’t subject to as much shrinkage as polyvinyl. So they maintain their fit over the years, while it may become a struggle to get aged polyvinyl to snap or zip in place where it fit a season or two ago.

clear boat canvass
Top-notch clear enclosures can provide rather spectacular views, as seen from the bridge of this Hatteras GT 54.

Which Clear Window is Best For Your Boat?

So, which of these options is best for your boat? Obviously, that depends on a lot of factors ranging from cost to space constraints to how you use and where you store your boat. Unless you’re buying a new boat with manufacturer spec’d canvass, in most cases, you’re best served by going to different custom canvass shops and discussing these options with the pros. Bring along some pictures of your boat and be prepared to discuss your thoughts based on the above factors, but also remember that local shops have a great deal of experience dealing with boats that are likely used in your climate, in ways similar to how you use your boat. When all is said and done, hopefully the right choice will be clear.

Clear Canvass Bonus Tips

  • Cut a foam pool noodle to match the length of a clear canvass panel you roll up often. Hold the noodle along the edge and roll it up inside the canvass, to make a compact and even roll, each and every time.
  • When stowing clear canvass over the winter lay it out unrolled and flat, and place a towel or sheet between the panels so they don’t stick to one another.
  • Never fold or crease clear canvass, which will lead to cracking. Also, be careful when rolling it in very cold conditions, another time it may crack.

Get lots more boating information and tips from Lenny Rudow on BD.

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Lenny Rudow …has been a writer and editor in the marine field for over two decades, and has authored seven books. He is currently the Angler in Chief at Rudow's FishTalk Magazine, is Electronics and Fishing Editor for BoatUS Magazine, and is a contributing editor to several other publications. His writing has resulted in 45 BWI writing contest and two OWAA Excellence in Craft awards. Volunteer positions have included NMMA Innovations Award judging, serving as president of Boating Writers International, and serving as the president of the Maryland Freshwater Foundation. Rudow is an alumnus of St. Mary’s College of Maryland, Westlawn Institute of Marine Technology, and The Sea School. He boats and fishes as often as possible on the Chesapeake Bay and in the Atlantic Ocean.