The Ultimate Guide to Caring for Clear Plastic


Our upcoming special report on marine plastics touches briefly on one of the most conspicuous plastics on many cruising boats–clear vinyl windows. On many older boats, the windows on dodgers and cockpit enclosures are often the first to show visible signs of age, first yellowing and then cracking. Over the years we’ve looked at various ways to delay the inevitable degradation and restore windows that are past their prime.

Look at any boat more than five years old, and chances are, the clear dodger windows aren’t so clear anymore. By comparison, the windows on one of our test boats remained crystal clear for 15 years. Is clear vinyl really that vulnerable, or are boat owners doing something wrong to shorten its life? The answer to both questions is, “Yes.”

One of the best known manufacturers of clear plastic windows for dodgers and cockpit enclosures is Fort Lauderdale-based Strataglass. The company has perfected a highly scratch-resistant coating for clear plastic, originally intended for the automotive industry. It has since become the product of choice for high-end yachts.

Strataglass recommends using its own Strataglass-endorsed cleaners and protectants, made by Imar. These have done well in our previous tests of clear plastic cleaners and protectants, and the prices aren’t significantly more than competing brands. But as usual, we remain skeptical-and curious. What about homemade cleaners, like our anti-mildew concoction that is 35 times cheaper than what you buy at West Marine?

With the hopes of finding a cheaper way to protect our $150-plus Strataglass dodger windows, we tested other cleaning products and protectants on the company’s two types of clear plastic. Two years into the test, we found that other non-Imar products-as well as some combinations of products-effectively protected Strataglass.

Strataglass online users maintenance guide states the following:


  • Use Windex, Rain-X, Pledge, Plexus, Simple Green, Orpine or any other harsh cleaner to clean Strataglass products. This will void the warranty.
  • Use a car wax or any kind of wash and wax to protect Strataglass products. This will void the warranty.
  • Use cleaners, polishes, scratch removers, or any products intended for commercial grade vinyl or plastic. This may damage the Strataglass and void the warranty.”

In addition to Strataglass’ warnings, we were surprised to find that some everyday products-including sunscreen, bug spray, canvas treatments, and mildew cleaners-can do irreparable harm to Strataglass.


There are many common boating chemicals that can ruin vinyl windows and are rough on other plastics:

Sunscreen: Sunscreen handprints on vinyl are difficult or impossible to buff out. Sometimes, the handprints occur when a guest helps roll up the windows, and you may not see them until the next morning, when dew develops them, inside the vinyl. Keep a washcloth handy for wiping hands, or better, wash hands before touching the clear vinyl.

Insect repellent: DEET will melt vinyl. Even a fine spray will haze many plastics. We recommend politely asking guests to use insect sprays well outside of the cockpit area, away from all windows, and to wipe or wash their hands thoroughly when finished. Consider banning aerosol bug repellents from your boat.

Vinegar: If rinsing your vinyl windows with fresh water and polishing them with a spray polish does not remove all of their spots, the spots are very likely calcium deposits. Use a 10-percent solution of vinegar and water to clean them, rinse thoroughly after use, and apply a protectant.

Canvas water repellents: As we reported in our report on canvas water repellents, some canvas waterproofing treatments are quite tough on vinyl and can ruin it within minutes. If you treat your canvas, be certain to apply a fresh protectant coat to the windows before you begin, cover the windows, and then wipe the vinyl with a cleaner/protectant after you are finished.

Silicones and solvents: All manufacturers advise against using products on vinyl that contain silicones, petroleum solvents, or alcohols. Small amounts of certain alcohols are permitted in some cleaners but not the use of alcohol-based glass cleaners.


Covering clear-vinyl windows offers fool-proof protection from harmful UV and dirt. The downside-other than cost and the added time before and after sailing-is the risk of abrasive wear between the cover (typically Sunbrella) and the window. We’ve heard of folks using textured Phifertex covers and finding that their windows have a fine checkerboard pattern within six months. Weve also heard reports of damage in windy harbors from the covers constant flapping; in the wind, the best solution seems to be consistent cleaning and use of protectants.

Some folks use Sunbrella with an integral lining, but dirt can imbed in the lining, resulting in worse abrasion than plain fabric. Wear is very often related to the size of the dirt particles, and lined Sunbrella can hold larger particles than unlined Sunbrella.

For the best of both worlds, we suspended awning covers over the dodger windows. Theres no chance of abrasion even if the window is salt- and dirt-encrusted; UV and bird bombs are blocked; and they can even provide expanded shade and reduce the need to close the windows for a passing shower at anchor.


Follow the maker’s instructions for cleaning. Each product varies a little, but they are generally spray-on/wipe-off products. Some makers advise not applying their products on hot days in direct sunlight and this is good advice across the board. Use only soft polishing cloths to clean clear vinyl. Clean cotton jersey (T-shirts or polishing cloths) are safe, but paper towels may leave scratches (grit left over from the paper-making process is much harder than vinyl). Microfiber cloth is a favorite as well, but it must be kept very clean as it quickly attracts dirt.

Rinse the windows with water after each sail and before each polishing. Change to a fresh cloth every 5 to 20 square feet, depending on how clean the window was at the start. Turn the cloth frequently.

Storing Windows

Only roll up vinyl windows when they-and your hands-are clean. Salt spray is abrasive and can cause minor scratching. Its better to squint through salt-encrusted vinyl until a freshwater rinse is practical than to have your view blocked by scratches for years to come. A handy fresh water squirt bottle can help rinse at sea. Alternatively, remove the window panels. If you’re rolling up the windows for storage, roll them with soft, clean fabric to keep the vinyl from touching itself and potentially abrading the surface.

If you plan to roll up your windows regularly, youll likely be happier with a thinner vinyl material (30 mil vs. 40 mil) or more flexible products (OSea and Regalite, vs. the stiffer Strataglass) since less force is required and less scratching results.

Cold Weather Care

While many folks put their boats away for the season as soon as they need socks, some sail into the fall or even year-around; the further north, the greater the urge to stretch the season. As temperatures plummet, we become more and more accustomed to the chill, and by January, some think 32 degrees is quite comfortable for a day on the water, if dressed for it. However, vinyl does not acclimate, and depending on the gauge-thicker is stiffer and more vulnerable-rolling or flexing old vinyl windows at temperatures below 60 degrees is just asking for trouble. The more worn and hazed the windows become, the greater the urge to clear the view by rolling them out of the way, and suddenly the window has a crack running halfway across. A good rule of thumb is to wait to roll windows until hats and gloves are forgotten (over 60 degrees). If there is dew or frost on the windows, wait for the sun to remove it.

Scratch Removal Products

Our early testing suggests the actual vinyl-restoration process might compromise the materials protective coatings and lead to premature weathering, even if applied to just a few scratched areas. We’ve added some restored windows to our long-term test racks, but it is clearly better to keep windows scratch-free and UV protected than to restore damaged vinyl.

If your vinyl windows have some damage or weathering, and standard cleaning and polishing is not doing the trick, try laying them on a flat, towel-covered surface and polishing very firmly with Imar Protective Polish. This was effective in removing light oxidation and providing deep cleaning as the polishing, without the risk of abrasion or coating degradation. For a more complete report on specific products, refer to our test of clear plastic restorers. That report also compared the the value of a professional restoration as compared to a do-it-yourself solution.

For the Planet Ocean’s most complete guide to caring for your boat, our four-volume ebook “Marine Cleaners, The Complete Series,” will save you hundreds of hours back-breaking labor each year and ensure your boat is always looking its best.

Darrell Nicholson
Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 50 years. Supported entirely by subscribers, Practical Sailor accepts no advertising. Its independent tests are carried out by experienced sailors and marine industry professionals dedicated to providing objective evaluation and reporting about boats, gear, and the skills required to cross oceans. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser who has been director of Belvoir Media Group's marine division since 2005. He holds a U.S. Coast Guard 100-ton Master license, has logged tens of thousands of miles in three oceans, and has skippered everything from pilot boats to day charter cats. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida. You can reach him at


  1. Thank you so much for your research and article. Wondering about plastic windows that sometimes fog up under certain weather conditions. I have a Dodger on my sailboat with plastic windows that are in excellent condition. I find that sometimes particularly towards the end of the day and Into the Night, my windows often fog up, making navigation very challenging. Do you have any suggestions on any products that might help prevent fogging of these windows without causing any damage to them?