boat cover fabric

[jimmy]

I've been researching boat cover fabric on and off for years (including searching old posts here) and there doesn't seem to be any concensus what the best fabric is. I have been refining my cover design for years using heavy duty tarps cut and sewn to fit my boat, which works OK, but only lasts about a year before starting to leak. Sewing tarps sucks and I'm ready to buy some fabric and sew a proper cover that will last for several years. Some people say acrylic/sunbrella is the best, some people say cotton canvas is the best, some say polyester, some boat cover websites even seem to contradict themselves. I want a cover that will keep my boat dry, but don't want to spend a fortune on Sunbrella only to find out a cheaper fabric would have been as good or better. What have other people used successfully for their covers?

The other thing i was wondering about fabric covers is that pretty much all fabrics are described as water resistant, not water-proof. As long as the cover is sloping, not flat, I assume that water will just run down it even if it is not waterproof. With my cover design, the cover drapes over the boom (and sail) and it seems like the sail is always wet or if the sail is off, water drips off the boom. I'm not sure if this is because water is running down the mast and boom, or if water is soaking through the cover along the top of the boom/sailcover. I'm wondering if this will get worse with fabric rather than poly tarp or better since the breathable fabric will allow the sail to dry off again.

I have recently seen a special on 60" 9.75oz coated polyester (http://www.rochfordsupply.com/product_listing.asp_Q_CatID_E_419_A_SubCatID_E_487 _A_ProdID_E_3872) that seems cheap enough to use to make my first attempt at a fabric cover. Has anyone used this fabric to make a boat cover?

My boat is a 32' long wooden sailboat that stays in the water all year and I keep the cover on her most of the year. The boat is located in saltwater in southern British Columbia. I currently make a 2 part cover out of commercial/heavy duty tarps. One 20' tarp ties around the mast at the front and to the end of the boom at the back and is held down with clips and weights along the edge. A second triangular piece also ties around the mast and overlaps the main tarp with a space for ventilation and then runs over a ridge line from the mast to the bowsprit and is held on with clips to the bowsprit, wisker stays and shroud turnbuckles. The back is currently open since I haven't spent the time to figure out how to close it in aount the backstay yet.

[rbgarr]

Tough call. I've been very pleased with a winter cover professionally made and fitted with Top Gun material. My summertime boom tent is made of sunbrella and leaks as you've described. I'll be getting a new one made this spring out of a more suitable material, hopefully a lighter version of the heavyweight Top Gun.

[Dan McCosh]

Just came in from finishing putting on the winter cover. Ours is a canvas tarp made by a company that does truck covers. It is heavy cotton canvas, but don't know the weight. It has a parafin water proofing that seems to work well, but chalks off when rubbed. It's in its seventh year, as I recall, and is still in good shape.
Ventillation was an issue when we first bought it, but the framing system lets lots of air in around the edges anyway.

[Ian McColgin]

I make my covers and started a bit of a local fad for the design approach, which many others also use. I use Sunbrella and get about ten years out of it.

The secret is hoops - PVC hoops gunnel to gunnel and above - not touching - the boom(s). 3/4 is workable for most, but 1/2 might be the thing near the bow.

If you've lifelines the stauncheons make a good point of attachment for each side. I bring the hoop over top and outside the upper line and inside the lower. Then it only takes a single tie to hold it in place.

You want to set the hoops up to make a straight centerline and then start draping something cheap and a little stiff - construction paper or blue tarp or whatever - taping together to get the shape. It's a compound shape, like a sail. Run it to maybe 1' below the gunnel.

Mark where the hoops go on the inside - both sides of each hoop.

Then cut the thing into athwartships panels where the widest part (near the gunnels) is suitable for the fabrick you're using, transfer and cut the Sunbrella, stitch in a 2" or so tape to be a hoop tunnel making it end 1' or so above the lifelines and stitch them up but leave the bottom raw for now.

At the mast where the bow and main section are seperated I go for a built in fitted collar just like the mast boot you've made (we hope) for the partners except of course open. Since these openings oppose each other, it's no problem. The body of each part goes past the mast by about 2'.

I put perhaps 3' abaft the main part's foreward hem and forward the bow part's aft hem a flap to hold grommets. The flaps go outside of the main cover part and the inside of the bow part. Put matching grommets on the front (main) and back (bow) edges. The two parts lace together, thus we have a nice big 4' overlap with the bow part outside.

You'll need to fuss a bit with how the overlaps and laces work at the shrouds, but the shrouds are part of the reason for the generous overlap.

I don't finalize the lower hem till the cover's made and fitted once to work out any errors and make a nice clean fit.

The rear pannel is arch shaped bit lacing at the center under the boom hole. Your boat's boom may not go back that far but you may have to think through how to deal with the back stay. On boats like that, I've liked to make a sloping arch running just outside the backstay, right little boot on the stay and laced down the center line.

I make twoway zipper arched entrances near the forward end of the cockpit or at the lifeline gate with an exterior rain flap to protect the zipper from leaking and freezing. The arch goes down to a tad above the gunnel.

Along the bottom I usually hang detergent bottles filled with sand from strings to grommets in the bottom hem. Hang them into the water and they won't bump and flap annoyingly.

My three part cover on Goblin took me 30 minutes to take down and 45 minutes to set up again at the dock. On the mooring it took a bit longer as it had to be rolled up more tidily for deck storage while sailing. I never took the hoops out, which much facilitated manipulating the thing.

I found that a really heavy wet snowfall would stick to the top if there was not much wind wh ile the snow fell, so I made attachments top center at each hoop to accept lines from above - really just a bridle off a halyard. This is not needed over the foredeck.

I made a very simple metal disc, like a washer, through which to pass my coal stove's stovepipe.

This got to be about 20 hours of work to make once I understood the process. If y ou do your own first, expect to take 40 hours unless (as would not be hard) you're a more talented canvass worker than I.

G'luck

[Todd Bradshaw]

If anything can beat a properly made and PROPERLY MAINTAINED Sunbrella cover, I'd love to see it. Top Gun is good stuff. Tough and more abrasion resistant than Sunbrella, but it is coated and doesn't breathe as well. Odyssey (the lighter version of it) is similar, though it seems to have a slightly lighter coating. Structurally, it's a bit light for a lot of applications, but it's nice stuff. Cotton canvas (the best is Sunforger) actually has fairly good U.V. and abrasion resistance, but still has all the same problems that cotton has had for centuries - excessive shrinkage and/or stretch, making a good fit that lasts hard to produce and the old mold/mildew problems. In this case, as opposed to synthetics, these things actually get in deep and eventually eat the fabric. Treatments for it are usually arsenic-based and every time you handle it - so are you.

You don't generally want a big, totally waterproof cover. Breathability will probably do more for keeping your boat healthy because it lets it dry out when it isn't raining, rather than trap moisture inside. Since regular Sunbrella isn't coated, it tends to have the best. Keeping water out is a matter of maintaining it's flourocarbon treatment and refreshing it from time to time (303 Fabric Guard). Using the wrong stuff (like silicone spray) can actually make it leak more because it isn't compatable with the stuff that comes on the fabric. Sunbrella does need chafe patches (Truck-tarp vinyl-coated nylon, heavy Dacron sailcloth or heavy polyester tarp fabric) in places that the cover rubs on fittings since acrylic fabric is not as abrasion resistant as most of the other materials.

In case it matters, some of these synthetic fabrics burn like you wouldn't believe. They exhibit a burning characteristic called "flame-dripping" which is exactly what it sounds like and the thought of being inside a boat covered with one of them if it caught fire should scare the living crap out of you. Same thing with wax-saturated cotton canvas (think candle wick). It doesn't matter much on a mooring cover, but if it's something you might be living or sleeping inside, you want to but the fire-retardant versions of Sunbrella or Sunforger.

[gert]

303 Fabric Guard

So whats the process?

I washed Carina's Sunbrella cover once using the stuff my wife washed here sweaters in; it came a bit cleaner but not much.

[jimmy]

I have seen covers like the one Ian describes and they would make great winter covers, but if I had a cover that takes over an hour to take off and put it back on, I would go sailing even less often than I do now (which, sadly, isn't very often). I also don't have stantions or lifelines to attach a larger structure to securely. I have thought about some kind of ridge pole or line above the boom to keep the cover off the sail, but I'm not sure how well that would work and I would like to keep it simple. Maybe sewing a strip of waterproof fabric over the boom would keep the sail dry or maybe there is something that could be used as a spacer between the cover and the sail to let it breath and dry out. Has anyone tried anything like that?

My boat stays nice and dry inside even with a non-breathable poly tarp cover. The secret is ventilation. I have both large vents in the cover, and fans and lights inside and the only mildew problem I have had is with my sail.

So, nobody has tried polyester or coated polyester fabrics?

[Dan McCosh]

I was thinking of a winter cover myself. For the summer, we took a Sunbrella sail cover and had additional cloth added to the bottom edge. This ties off to the lifelines, with the sail cover open at the bottom. It goes on an off as fast as any sail cover, but adds rain and sun protection to the cockpit and cabin, also allowing the hatches to be left open in the rain. It does leak a bit, but being open at the bottom of the boom and furled sail, that's never been an issue.

Our boom is pretty long--at 25 ft., it covers the whole cockpit and cabin area with the sail cover installed.

[jimmy]

That's a good idea. Two other things I need to make are a new sail cover and a cockpit sun shade. I hadn't thought of combining them. I will keep that in mind.

[Richard Smith]

RE: "303 Fabric Guard. So whats the process? I washed Carina's Sunbrella cover once using the stuff my wife washed here sweaters in; it came a bit cleaner but not much."

After cleaning and drying the Sunbrella item, you lay it out on the driveway (or whatever) and spray away. 303 is a bit pricy and you will need a good amount of it, but it is good stuff and recommended by the makers of Sunbrella. Buy it when it is on sale.

[Todd Bradshaw]

Jimmy, plenty of people have tried polyester. Top Gun, Odyssey and a whole bunch of other common cover fabrics are polyester. Dacron is Dupont's name for their polyester fiber and there are others from different companies. I'd be careful about building covers out of fabric not specifically marketed for that purpose though. You can leave a hunk of Top Gun (polyester) or Sunbrella (acrylic) outside for five years and it will hold up pretty well. A hunk of expensive Dacron sailcloth or the cheap polyester fabric that's used for a WalMart patio shelter, on the other hand, will be toast at the end of one season of 24/7 exposure. Not all synthetics, or even all polyesters are created equal, so unless you know exactly what you're using, you don't know how long it will last.

I'll admit to being a perfectionist and very picky about construction when it comes to this type of thing, but if you intend to do a good building job I have an awful lot of trouble justifying unknown or bargain materials. If a cover is well made and well designed, your biggest investment is going to be your labor time.

[rbgarr]

Odyssey (the lighter version of Top Gun)... seems to have a slightly lighter coating. Structurally, it's a bit light for a lot of applications, but it's nice stuff.

Todd- Would you use Odyssey for a boom tent fourteen feet long and three to four feet on each 'slant'? It would have a small, deck level, triangle shaped opening on the bow deck forward of where it wraps the mast and be entirely open at the stern end of the boom and cockpit. Preferably over a furled mainsail. Lines though grommets with snap hooks to eyes on the deck edge. Open cockpit from the end of the boom to two feet aft of the mast, no cabin or stanchions.

[Todd Bradshaw]

I don't think I'd have a problem with it. I use it for spray skirts and cockpit covers and it holds up well and seems to adequately keep water out. Since it's only about six ounces, it will tend to stretch a bit more than heavier stuff, but it also is softer and considerable less bulky when you need to stow the cover. A big hunk of Top Gun or Sunbrella puts up more fight when you try to bag it. I once built a big corner to corner sunshade for an F-24 trimaran from Odyssey, which must have been 18' wide or so and the full length of the boat. Even so, it was a pretty managable hunk of stuff. With either Top Gun or Sunbrella it would have been a real beast to deal with. There is also a new form of Odyssey that has a fuzzy inner side to help prevent abrasion on varnished or painted hulls (and show cars). It sounds interesting, but I haven't actually seen it yet. Just don't burn it. My neighbor once tried to talk me into building him a tipi and since it would be pitched all summer long, I thought Odyssey might be a good choice. Just for grins, I cut a strip of it, hung it up and lit it with a match to see what would happen (since people build fires inside tipis). It took less than five seconds to convince me that Odyssey would be a really bad choice.

[MAGIC's Craig]

Say, Jimmy, if your travels take you near Sidney, stop by Van Isle Marina and make the long walk out to D-410. MAGIC has her winter cover on, made of Sunbrella with topgun and leather patches at chafe points, as Todd recommends. This cover was built 8 years or so ago by the good folk - now retired - at San Juan Canvas.

At the time, the cost really seemed tough, but it has more than paid for itself over the years in reduced maintenance. A couple of years back, we added some clear "windows" into the side curtains to facilitate living aboard during the BC winter, but life intervened and we were called away for the past few winter(s).

What also seems to help the longevity is that the cover is well-lashed and secured against flapping in any winds, thus minimizing chafe. We keep it off the boom , fore gaff and bow with ridgelines rigged from boom end to mainmast, to foremast, to stem. (somewhere here I should have a pic...)

http://www.imagestation.com/picture/sraid219/pa14cba16cf73b489c5ddb37b452ec327/ebf189d7.jpg

Ah, there! From a few years back, pre-side windows, but you can get the idea. The lower edge of the sides incorporates a lead-weighted line. (Geez! I miss her when we are away!:( )

Cheers,

[jimmy]

Hi Craig,
I'm hoping my travels will take me to Sidney soon as I am due for a visit to the Boater's Exchange. Your cover looks great. Does your cover keep the water out or is it mainly for UV off the varnish?

[rbgarr]

Thanks for the tips-

[MAGIC's Craig]

The cover keeps the boat dry from rain and the occasional snow. It is open at the stern, something like a tepee opening, and is raised up above the bow to permit a nice flow through. This will be clearer if you walk to the next dock and look back at her stern.

Give her a pat for me, ok?

Craig

[George Ray]

Pictures please! ..... sounds like a great design.

[SV Papillon]

I'll secound Craig on the quality constuction factor. Regardles of what its made out of the life of it will depend on how well its made. A good boat cover shouldn't be cheap or a deal.
Jake

[jimmy]

OK, so which is more important, what it is made out of or how it is made? Acrylic, polyester, or cotton? There are advocates for each fabric. Sunbrella gets mentioned most, but I get the feeling that is at least partially due to the fact that it is the best known fabric. I am leaning toward Sunbrella, but will wait until I get some a a good price and I will have the feeling that another non-name brand fabric would have worked just as well or better.

[SV Papillon]

For clarification I'm not saying the material choosen to do the job isn't important, only that if poorly made without adequte chaff protection and securing it will probably not last. Doing the job right getting a good fit, leathering all the little spots that need it and building the zippers, grommets etc in a way that they will stand up is time consuming equaling alot of labor.
Jake

[Todd Bradshaw]

"OK, so which is more important, what it is made out of or how it is made?"

Both. What are the alternatives? A poorly designed and built cover from great material or a beautifully made cover from less than ideal fabric? There are very few fabrics that can sit out in the sun and weather for five or ten years and survive, let alone continue to do their job. Certain acrylics and a few premium polyesters will. Cotton canvas generally will not. There are some Sunbrella clones available out there, but their prices are about the same. The Rochford polyester you mentioned is sold with the following description:

"This burgundy coated fabric will make for a inexpensive boat cover. It is 9.75 oz and 60". The best part about this stuff is the price"

Just what part of that makes you think that it's a quality material that's really suited to the job? If the best thing they can say about it is that it's cheap, I'm not terribly interested in trusting it to protect something valuable. Even the best fabrics have certain characteristics or weaknesses that need to be allowed for in the design and construction and I have yet to see anything I'd call perfect. Failure to design and build with these limitations in mind will shorten both the life of the cover and the life of what's under it. A good cover needs to be a mixture of good design, good construction and high-quality materials. Skimp on any one of these and you'll generally regret it and pay the price later.

You seem to be resisting Sunbrella (and I assume similar high-end polyesters like Top Gun) based on price or because you think it's largely hype. I don't know what your first cover will be built from, but I suspect it's replacement will be Sunbrella.

Sure, professional's can get it cheaper than you can, so the price doesn't sting as badly, but we can get any of these fabrics cheaper than you can, from the most bargain basement ones to the absolute cream of the crop. Guess what fabric sailmakers and professional boat cover makers build the vast majority of their own covers from? That should tell you something....

p.s. I don't ever use leather on boat covers because it often doesn't even last half as long as the fabric. It dries out, gets stiff and eventually crumbles away. It's simply not a good material to leave out in the weather when compared to other types of synthetic reinforcements that will last as long as the rest of the cover. For spots with light chafing potential I use heavy Dacron sailcloth or truck tarp fabric made from vinyl or hypalon-impregnated nylon. For areas that get a lot of chafe, I use rubber raft fabric, hypalon or neoprene. These will still be on the job long after leather has turned to powder and blown away.

[SV Papillon]

"
p.s. I don't ever use leather on boat covers because it often doesn't even last half as long as the fabric. It dries out, gets stiff and eventually crumbles away. It's simply not a good material to leave out in the weather when compared to other types of synthetic reinforcements that will last as long as the rest of the cover. For spots with light chafing potential I use heavy Dacron sailcloth or truck tarp fabric made from vinyl or hypalon-impregnated nylon. For areas that get a lot of chafe, I use rubber raft fabric, hypalon or neoprene. These will still be on the job long after leather has turned to powder and blown away.

Todd
You use hypalon? Do you use the rubber material for edges, such as around stays etc..? I used tanned buckskin on our boat for the various leathering, edges sail slides etc.. and it was doing ok after 6 years 3 in MX.
Jake

[Todd Bradshaw]

Yes I use raft fabric if it gets a lot of chafe, truck tarp vinyl/nylon if it gets medium chafe and white, double-folded acrylic edge binding if it isn't subject to much chafe and I just want a nice looking, neat edge. I've spent far too much time replacing rotted-out leather on other peoples boat covers to ever put it on one of mine.

http://webpages.charter.net/tbradshaw/Sails/nordica%204%20copy.jpg

[rbgarr]

Todd,

Is your boat a Nordica? If not, what design and built by whom? Have you sailed Herreshoff Twelve and a Halfs? How does your boat compare? Did you apply/paint the cove stripe yourself? I've got to put new numbers on my boat and the stripe would help the appearance of the boat. Thx

[jimmy]

Todd, I'm not resisting sunbrella, just because it is expensive. It isn't necessarily expensive if you aren't fussy about what colour you want since you can often find deals on unpopular colours. Other people that make and sell boat covers don't use sunbrella, and the people who responded saying they actually have a cover made of sunbrella didn't all say they worked well. Many people describe other fabrics as the best for boat covers. If there is no clear reason why one is better than all the others then why would you pick the most expensive one? Just because it has the most recognizable name? I don't mind buying the most expensive one if I know it will work the best, but I haven't seen any evidence that sunbrella is the best one. The only points in it's favour seem to be that it is breathable and will last in the sun for 5 years with out losing strength or it's colour fading. I don't care about colour, it isn't waterproof at all, and there is no guarantee about it's water resistance/repellancy. I just want it to protect my boat and I don't want to end up with a cover that last for 10 years, looks great and leaks the whole time. It sounds like some of the coated polyesters might work as well or better, like the Top Gun you mentioned.

Having a fabric that lasts forever is good if it works perfectly and you sew the cover perfectly the first time. I currently sew a cover out of tarps every year and improve it every year. I'm now at the point where I'm happy with the design. If I found a fabric that cost twice as much and lasted 2 years it would be an improvement. If I found one that cost 3 times as much and lasted 3 years I would be happy. Sunbrella costs about 10 times as much and is only guaranteed for 5 years.

It looks like if I go with Sunbrella, or most fabrics, I will have to devise some way of suspending it above the boom and sailcover otherwise it is just going to leak there and I will have wasted my time and money. So I'm probably going to have to change the design to accdomodate the difference of using fabric instead of tarp and it doesn't make sense to rush out and buy the most expensive fabric for this next version.

Unless I get some more useful information, I don't think I will bother at all. I was hoping to get some more stories of people's experiences making covers. So far I have heard from one person with a top-gun cover who is happy and has a sunbrella cover that leaks, one person with a canvas cover that is happy with it, 2 people who have sunbrella covers that are happy with them, but have special systems to keep them suspended above the boat because they will leak otherwise, and another person with an extended sailcover/ boat cover made out of sunbrella that leaks. So far sunbrella isn't looking that good for what I want it for.

[Todd Bradshaw]

Yes, it's an old Nordica that I bought for $700. It had been sitting for about five years, half-full of water, the gel-coat was trashed, the aft bunks had gone through the hull and it was a real mess, but a gorgeous shape. I rebuilt and painted it and eventually sold it off in one of those moments when getting rid of excess boats on trailers seemed logical. Looking back, I probably should have kept it because it was a great little boat - fun to sail, comfortable and extremely seaworthy for something less than 15' L.O.A. I haven't sailed a twelve and a half, so I can't compare them but the little Nordica is one of the prettiest and most enjoyable boats I've sailed in that size range. I still keep one eye open just in case I stumble across another one cheap. In the mean time, a friend owns this one and keeps it on a lift, so it's available any time I want to sail it.

http://webpages.charter.net/tbradshaw/Sails/nordica%206%20copy.jpg


On the Sunbrella topic, there are various ways to measure waterproofness. For raincoat fabrics it's usually done by spraying it with water under high presure. A non-coated fabric like Sunbrella won't do particularly well in those tests because there is no goo between the yarns to plug the holes. This goes both ways though, since that goo also limits breathability and prevents ventillation. In terms of sticking a hunk of boat cover fabric out in the real world in the rain, the Sunbrella fabric itself doesn't leak. Any leakage on a properly designed, built and maintained Sunbrella boat cover should be minimal. Example: Both our trimaran and the little Nordica above had full length upholtered foam cockpit cushions. They sat there all season under the cover and there was never a problem with them getting damp. My wooden Starboat sat outside year-round, from the day I got it done until the day I sold it six years later under a full Sunbrella cover. It had snow piled on it in the winter and even got struck by lightning sitting on the trailer, but at least I never found any water in it at all and the gloss varnished mahogany topsides still looked super when I sold it.

Leaky Sunbrella covers are caused by poor design, poor construction or lack of maintenance down the road. If your design lets water pool, you will probably have leaks. Over-stressed spots and poorly designed/reinforced areas on seams can also leak, especially if you use the wrong kind of thread (polyester thread should be specifically labeled "anti-wick" and is sold by the same companies that make regular thread). Excessive flapping, bad sewing, chafing or uneven support which causes floppy spots can all contribute to leakage.

In short, there is no substitute for actually knowing how to design and build a good cover and expensive fabric isn't going to make up for gaps in the builder/designer's knowledge or level of craftsmanship. If you seriously want to build a good cover, rather than a two-year temporary one, there are things you need to be aware of before you start. You should already know about anti-wick thread. You should know how to join two flat-ish panels with a catenary cut (can you build a pup tent that won't suffer from a sagging ridgeline and flap after a couple days?) You should know what thread size, needle size and stitch type and length are appropriate for that particular fabric and why? Above all, you should also be well aware that ventillation and breathability are usually just as important, or more so in building a cover than keeping rain out. Failure to understand this is likely to cause much more damage to the inside of your boat than some rainwater getting in ever would.

The idea of a boat cover which doubles as a sail cover can also be problematic and is usually worth rethinking. Your boat cover/boom tent needs to be able to be pitched solidly and well supported if it's going to be a nice smooth fit. A folded sail is usually too mushy to provide solid support for a cover. If you aren't able to suspend the cover above the sail with a halyard, roof-bows or something else that's pretty firm, the cover isn't likely to pitch firmly and free of wrinkles and pooling spots.

So I guess the real question here is how good is the design and how good is the builder at pulling it off? Spending big bucks on Sunbrella would be a waste of money if the builder's skill and knowledge levels are still at the polytarp level. Likewise, spending the time and energy required to construct a great cover and then building it with two-year, economy fabric doesn't make much sense. In any case, I'd be very careful with the whole concept of waterproofness for boat covers and remember that what can't get in also can't get out when it eventually does get in (and it usually will, even if it just condenses out of the air).... And I'd still avoid cotton unless you want to try to learn how to estimate shrinkage and build over-sized to allow for it along with the other things you'll already need to figure out.

[jimmy]

Thanks Todd, I appreciate the advice. Shopping around I have found what look like some good deals on Sunbrella. I started looking for seconds, but also stumbled accross some cheap sunbrella listed as awning fabric. It looks like it is cheap mostly because there are only a few weird colours, but I am suspicious. Do you know if there is a difference between awning fabric and marine fabric?

[Norman Bernstein]

Here in New England, if we're talking about winter covers, many folks use covers made out of 'Sunforger boatshrunk' cotton canvas. There's a sailmaker in New Haven, Fairclough, who makes gorgeous covers from the stuff, that fit like a glove... they're very expensive, and use a heavy galvanized frame system. The canvas is 10 oz., water repellant, and pre-shrunk.

My wife and I just finished a winter cover made from the same stuff, although in a natural cream color instead of the gray-green that Fairclough uses. The canvas is much cheaper than Sunbrella, 60" wide, and sews easily. It's a bit hard to find, but we managed to find a supplier by Googling the name.

[Todd Bradshaw]

If I remember correctly, the awning fabric is the same as regular 9.25 oz. Sunbrella, but was only available in 46" wide rolls and limited colors.

Sunforger is the best cotton canvas available (it used to be called "Vivatex" and once in a while you'll still see it as such). It's lovely stuff to work with, but do not confuse the term "pre-shrunk" with the concept that it can't shrink any more. Shrinkage of at least 2%-3% seems nearly automatic on any heavy cotton, pre-shrunk or not. If your 100" long boat cover gradually becomes 2"-3" shorter than the plan dictated, you may eventually run into some fit problems. I built a full, fitted cover for an iceboat for a friend a few years ago. He saw the Sunbrella cover on mine and wanted one like it. I tried to talk him into Sunbrella, but he wanted to save some money and go cotton. Against my better judgement, I told him I would go as far down the ladder as Sunforger, but nothing cheaper. I allowed a little bit of excess room for potential shrinkage and the cover came out great and fit fine. Two years later, I had to cut it in half and sew in about a 4" wide extension panel because it no longer was long enough to fit the boat. It had my label on it, so I did the rebuild for free, but that was the last time I let anybody talk me out of one fabric and into another.

In many cases, you can tolerate a little bit of shrinkage in a boat cover without it creating a problem, but be careful and allow for some if you're using cotton and the cover or it's attachment points have to fit specific hull dimensions. As a general note, you also want to wash your hands frequently when working with treated canvas in case it is one of the brands that use arsenic as a mildewcide (I don't remember off the top of my head what they use on Sunforger). The fire-retardent version of Sunforger is also the premium fabric for making big canvas wall tents, teepees, etc. that will get a lot of hard use and sun exposure.