And the winner to the best type of boat enclosure goes to...don't have a boat enclosure! I say that from a detailing perspective, but I realize how nice a boat enclosure can be, especially living here in Seattle where it's wet for what feels like 13 months out of the year. Boat enclosures provide shade in sunny climates and rain-protection in wet climates. They give you a break from the wind and allow you to have more livable space on your boat. In a way, they're a necessary evil. I say that because they get dirty quickly and are a pain to clean (or keep clean).
The two main materials that boat enclosures are made of these days are canvas and Stamoid. For those unfamiliar with Stamoid, it's a vinyl-coated woven polyester material that's supposed to be superior to canvas. We say "supposed to be" because in our line of work, we've seen a lot of Stamoid covers that didn't hold up to their promises.
Pros and Cons of Stamoid
Stamoid vinyl is advertised as waterproof, resistant to mildew and UV damage. It maintains it's flexibility with extreme temperature changes and doesn't shrink. It's coated with a "Nanotop" barrier that helps to prevent dirt from "sticking" to it, making it easy to clean and keep clean. That all sounds good to me, you say. What cons could there possibly be?
How many people actually clean AND treat their enclosure on a regular basis? And by "regular basis", I mean a few times a month, and by "clean and treat", I mean actually washing it down and using the special Imar cleaner that the manufacturer recommends and then treating the Stamoid by applying a cream conditioner to it? The reality is that very few people take the time to clean and condition every inch of their Stamoid enclosure material on a regular basis or ever because they either don't have the time, don't have the ability, can't reach every inch of it once it's installed or simply don't bother.
I completely understand because it can be a lot of work and keeping those Stamoid enclosures clean is part of my job as a detailer. We see brand new enclosures turn brown or grey with water streaks and dirt quickly if they don't get cleaned often from day one. Even when a boat owner has a detailing company washing their boat every other week, those enclosures still get dirty fast and each time, the dirt and streaks are harder to remove.
Also consider the cost. A custom-made Stamoid enclosure is not cheap! If you're going to pay your boat detailer to clean and polish them a couple times a month in order to keep them looking as good as possible, that will cost you a few hundred dollars each time because it takes a few hours to properly clean and polish them.
Even then, they will still age. Sun, wind, rain, heat, cold and humidity will affect them no matter what the brochure says. We often see where the thread comes out or disintegrates over time and where seams comes undone. So even if you've hired someone to clean and treat your enclosure every few weeks, you'll also need to repair the seams at some point.
Pros and Cons of Canvas
Canvas as an enclosure material can be just as annoying to work with, but it's a bit more forgiving when it comes to cleaning it. Dirt and mildew love canvas enclosures because they can work their way into the fabric and retire there. If washed on a regular basis though, even if it's with the same bucket of water and soap you're washing the rest of your boat with, any loose dirt and new mildew should come right out. If it's been there for a longer period of time and isn't coming out with just soap and water or the resident blue heron at your marina always chooses your canvas enclosure to rest on, then you'll need to use a scrub brush with some stronger products to get the dirt and stains out.
However, over time, canvas will shrink from the sun making it harder to work with. Stretching it to reach a snap could cause it to tear and once mildew has been on it for a while, it can be almost impossible to get out. Pressure washing canvas can sometimes be too rough for it and using harsh chemicals on a regular basis to clean it can cause the canvas to degrade over time.
The Verdict: Stamoid looks great, but unless you plan on cleaning and treating it often (and can reach all of it once installed), you may want to consider a different material. We're not slamming it at all, we're simply pointing out the fact that you need to stay on top of cleaning and treating it in order to maintain its great qualities as an enclosure material.
We say this about a lot of boat detailing products. Many of them work great IF you actually use them on a regular basis AND use them properly. A Stamoid cover will look great on your boat and last a long time, but you have to be willing to care for it regularly and properly.
Canvas is a bit more forgiving until it's not. What I mean by this is that you can let it go a bit longer without cleaning it, but if you let it go too long (especially if green mildew is building up), then it can get to a point where you can no longer get the mildew stains out because they're in the fibers. As far as pricing, canvas seems to be just as expensive as Stamoid these days, so I'm not sure how much savings there is with a canvas enclosure.
If I had to choose, I'd choose not having an enclosure. But if I really had to choose, I'd go for a canvas enclosure with elastic loop attachments. Since canvas will shrink, choose connectors that will accommodate tighter canvas, such as elastic loops or suction cups. That's right - suction cups! We saw this on a boat recently and it's a brilliant idea for canvas as long as the area you want it to attach to is a smooth window or gel coat. It's a great idea for canvas covers too.