Bimini Fabric

[Pete]

Hopefully this passes the test as Tech Talk, as it is a request for help with the properties of fabrics that can be used to construct bimini tops. Another season, some more thunder storms and my 4 yeas old Sunbrella bimini has multiple tears, and its time for a new one. The tears are all located where there is stitching. So, I am going to try to be smarter this time and find a fabric that will last longer under the stresses. Most of the problem comes from not having an enclosure. It is just a free standing bimini, and I want to stay with that. The wind gets under the top and violently pulsates it vertically until it rips. I clocked 52 knots during this storm and that was sufficient to do damage to a our 4 year old top that is out in the weather year round.

I am thinking that some of the newer sail cloth may be a good choice. I use white material, so color match should be fairly easy. Any suggestions, advice, or warnings about selecting a fabric? Thanks

Pete

[ThirdHatt]

Pete, I HIGHLY recommend that you use Stamoid brand material. It has a 5-yr warranty and holds up much better than Weblon, etc. Strong winds are tough on any fabrics and really should be taken down in any real blow as I am sure you are well aware. The Stamoid holds up extremely well over time and UV exposure without getting brittle.

I had a Stamoid top put on my boat down in Palm Beach by Canvas Designers and they did an amazing job. They have a heat-seam machine that will surely hold up better than stitching if you have a large area where two pieces need to be used, but only the larger canvas makers will have such a machine. Double-stitching would be my second choice for joining two pieces. I believe it comes in 50" and 80" wide. I have been having trouble recently trying to find a quality canvas maker that is familiar with Stamoid in the New Orleans area but it is huge in Florida so hopefully you will not have much trouble finding someone on the east coast.

GOOD LUCK!!!

[Pascal]

Sunbrella is pretty good fabric and you should be getting much more than 4 years in NC. Stitches may need to be redone after a few years though...

it's also a good idea to reinforce the fabric by doubling it around the bows or where ever stress is high. unless the exisiting bimini is really ripped, you should be able to reinforce it and save it

considering the price of a new bimini...

[GJH]

While most of my boat uses Stamoid (I like the way it cleans up), Sunbrella is good stuff and doesn't appear to be the real issue from reading your post. The key is to use Gore Tenara thread; it sounds like this would solve your problem.

George

[Pete]

The current top uses Gore Tenara thread. It is doing great. It is the Sunbrella fabric that is torn. To explain where the tears are, the SS tubing frame has a rigid bow forward and aft attached to the flybridge safety SS rails. Attached to each of these rigid bows is a hinged bow facing in the opposite direction of the rigid bows. These hinged bows basically support the middle of the fabric. The configuration thus has four bows supporting the fabric equally spaced fore and aft. Pretty standard configuration.

These hinged bows fit in fabric pockets sewn to the top. It is at the corners of each sewn fabric pockets that the fabric is torn, in both across the fabric and fore/aft the fabric. Each tear is about an inch and a half. The damage is symmetrical beyond belief. All eight corners, same damage, amazing.

Hopefully this better explains what I have and would not like to see again

Pete

[ThirdHatt]

It sounds like you need a Stamoid top with heat seamed pockets for the bows to go through. No threads to rip the material. Would that work?

[Beckytek]

There is Sunbrella, and Sunbrella Plus, and Sunbrella Supreme. My next bimini is going to be made with one of the better grades. My top has no rips but leaks. I have tried all the spray formulas for water proofing but they didn't work for me. The Supreme is supposed to be waterproof so that's probably what I'll use. Just a suggestion, go for a better grade. Ron

[ThirdHatt]

For heavy-duty use, use the Stamoid "Top" material because it is thicker than the Stamoid "Light" that is used for dinghy covers, seat covers, etc.

Sunbrella fabrics are fantastic, but I prefer it for cushion and seat material and Stamoid to cover and protect it. For a top, I don't believe there is anything better than Stamoid "Top". It is not porous like Sunbrella and will never leak. Look at what the big Broward's use for their bimini top's. It's always Stamoid. 'Nuff said.

[Pascal]

if the tears are only 1.5" it shoudl be easy to patch. looking at your description it seems like something wasn't sawn right, too tight maybe? are the bow held in place by straps or SS tubes, or are they pulling on the fabric?

[Pete]

Thanks to all for the comments and advice. Let me respond.

Stamoid does sound like a solution with heat welded seams. On my first pass I was not able to find a vendor that does heat welded seams, in the Mid Atlantic area. Anyone help with this? I will be returning to the New Bern area in the beginning of August and also thought it would be worth checking what the vendor that does new Hatteras canvas work uses.

The current bimini material is Sunbrella Natural, which is very white, and translucent. Thus any patching on the top is very noticeable, and ugly to my eye. Good reason to use a dark color, but they get so hot. I have pretty well decided that a new one is in order.

As for straps on the bows, there are none. Perhaps this is part of the problem as the only thing holding the center bows is the cloth pockets sewn to the top fabric. As the top pulsates in the wind, those center bows ride up and down rapidly and the top cloth is stressed.

I did some reading on the premium Sunbrella fabrics and as best I can tell, they all address better "water proofing" of the fabric, which is not a property that concerns me, as my installation is not an enclosure.

I have also investigated using some of the newest sail cloth on the market, most of which use some form of Kevlar, looking for a fabric that has better tear resistance. No luck here so far, as it seems that the more tear resistant the fabric, the more sensitive it is to UV degradation.

Addition thoughts would be appreciated. I am very interested in the use of "Bow to Bow" straps. Is this common? Going one step further, has anyone seen a stainless tube on the center line fore and aft going between the bows to stabilize them, or another stabilizing design? Thanks

Pete

[Pascal]

If you dont' have any support for the bows, I think this is part of your problem. The weight of the bows (SS ins't light...) pulls on the stiches and eventually they tear.

The easiest solution is to get some straps, ideally two per bow, although one on center woudl do. One pair from the forward fixed bow to the second bow, and the other pair from the aft bow to the 3rd bow. you only need to cut a slit to pass them thru the pockets.

an other solution is to secure the intermediate bow with SS tubing, on the sides. you dont' want it to be on centerline as the fabric will rub on the fittings and eventually wear thru. on the sides, you can put an horizontal tube just behind the edge of the bimini.

[(Nobody You Know)]

Pete,

you should have gotten 5 years out of that Sunbrella. It certainly sounds like someone has been using the wrong product which may contain bleach or some other harmful substance that attacked the threads. This happened to me twice over the years where within say six months to a year the threads began to fail. Even the most reputable boat detail guys do not know what is the proper products to use.

Regarding the Gore Thread please read my reply to True Grit.

BTW, both Stamoid and Sunbrella are good.

[yachtsmanbill]

One other thing to consider is the size of the stiching...
An industrial machine with an adjustable foot will space the stitching at
1/8" or more. Any closer as in garment stitching will give the material a perforated starting point. Compare the spacing to other various sewn stuff like vinyl seats versus towels, and youll see what I mean...
The sunbrella stuff on my Roamer was done in ' 85 and still performs as new! I had the glass changed a few years ago.. it was still clear, but kinda scratched (normal wear and tear) just as an upgrade. ws

[GJH]

Pete, if you might want to call Lighthouse Canvas Company in Middle River MD. 877 335 7900. They did all the Stamoid/Gore biminis, covers and EZ2CY work, as well as some upholstery for the PO of my boat and it really looks like first class work; holding up nicely after a couple years of hard use.

I don't know how hard our mutual friend Fred Schubert looked at our soft goods, but as a former upholstered furniture designer, I imagine he might have.

George