terceiro
member
Reged: 04/05/06
Posts: 52
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In my transition to UL backpacking, I tried my first tarp this weekend. To keep costs down (very important to me), I made a quickie tarp out of a 2mil polyurethane dropcloth from the paint department of a local hardware store. I created tie-downs with Eric Kingston's excellent and clear instructions (from here). Fearing the high winds and wind predicted for the Utah west desert, I reinforced all edges with duct tape as well. Total weight for a 9'x9' tarp: 20 oz.
I figured that, regardless of anything else, I shouldn't get wet. It's plastic, after all. It could fall down on top of me and I could still stay dry. I don't know if the same is true for silnylon (not that I am opposed to silnylon at all, but given my inexperiencedness, the foolproofness of a plastic tarp is very appealing).
I set it up by staking down one side taut, then using my trekking poles, then the second side. I had no quarter tie-downs in the middle of the sheet to pull it out.
Problem 1: I couldn't get the ridgeline taut, no matter how much I fiddled. It is possible that my lines weren't straight on the tarp to begin with, but I simply could not get the ridgeline from sagging. Was it my tarp or my technique?
Problem 2: Hot dang, that tarp is noisy. As the wind gusted up to twenty knots (I guesstimate), it was whipping around and snapping so loudly I am surprised I slept at all. Hold up a plastic tarp by one edge in a strong wind and listen to it snap and shake. Now have that happen next to your head, for a long time. I'm chalking this one down to a combination of problem 1 and the material. Please someone tell me that silnylon is quieter (given the same problems in the pitching).
Problem 3: At about 1:00AM, I woke (which surprised me, frankly, that I'd fallen asleep at all. The wonders of physical labor...) to discover it was sagging dramatically, and was actually pressed against my face. Everything was still staked down, but the guy lines had slipped, and it looked like some swayback old horse.
I reached out and tightened the guyline by my feet, which helped considerably. It was still sagging (like when I set it up), but not nearly as dramatically. Then all hell broke loose. One corner popped up and started whipping back and forth, smacking me in the face. It flung the stake somewhere... I didn't find it at all that night. I grabbed another stake (luckily in a sack next to my pack) and staked it back down. Then another came loose. Then another. And another. I ran around and quickly restaked down the whole tent (the earth was so wet and soft that I could just push the stakes down one-handed).
Eventually, I gave up on the two-pole, A-shaped tent and went with one pole in front, and the foot staked down flat. The ridgeline was still curved, but the noise decreased, and the tarp stayed until the end of the evening.
On a happy note, everything stayed miraculously dry. I slept surprisingly well, and enjoyed the breeze over my face. And in the morning, when we all got up, the rest of my group (who slept in tents) were actually wetter than the night before, their clothes wet with both rain and respiration. I, on the other hand, was drier than I had been when I'd gone to bed.
Still, I recognize that I need some help. Can anyone recommend resources to resolve my difficulties: books, websites, or other? Or should I recognize these problems as inherent with rectangular tarps and consider something more specialized, like building a ray-way kit tarp, or a Spires Tarptent?
Thanks for your direction, oh wise and experienced ones.
--jw
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uva uvam vivendo varia fit
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paulj
member
Reged: 01/26/03
Posts: 1603
Loc: Seattle
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Was there a line running the length of the ridgeline, or did you just have lines running from the poles to the ground?
Plastic sheet like this has little elasticity, so there is a fine line between being loose and too tight. I haven't used plastic sheets as traps in a long time, but when using blue poly tarps, I like to use lengths of bungee to provide elastic tension.
Your tarp may have sagged because the lines stretched as they got damp. Nylon stretches when wet.
paulj
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Spock
member
Reged: 01/10/06
Posts: 529
Loc: Central Texas
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terceiro,
Congratulations. Despite your tribulations, you learned that tarps can work better than tents. All you have to do now is deal with the learning curve.
1. Ridgeline. Probably the problem was technique. But the physics of ridgelines make it almost impossible to string a line without some sag or a whole lot of force. It is usually better to let it sag some. (More on this later.)
2. Plastic tarps are noisy. No way around it. However, a taut plastic tarp will not be as noisy as a loose one. (More on this later)
3. Everything coming loose. Hard to say what the problem might be without knowing about your stakes, lines, knots, etc. Poly tarps don't absorb water, but water condensing or collecting on them can make them sag. But they never sag as much as nylon tarps. I suspect the problem started with the tarp body being too loose so it caught the wind and jerked lines and stakes loose.
Fixes:
A. Practice
B. Consider reinforcing with 3/4" or 1/2" fiberglass strapping tape instead of duct tape. It's lighter and much stronger and it won't stretch. That's important. Use the strapping tape wherever you used the duct tape and along all stress lines that form when you make your favorite setup (more on that later).
C. Put one strip of strapping tape along the ridgeline. At the ends, line a section by sticking a 6" strip over the adhesive and make a loop, sticking 6" to 8" of the unlined free end to the tarp. Then you can use the tape instead of a cord ridge line. Just tie onto the loops.
D. 2 mil plastic is thin enough to need some reinforcement, and the strapping tape will let you set up more tightly. That will reduce wind noise radically.
E. Either learn to tie a prussic knot (sort of like a tautline hitch) or get some plastic or aluminum line adjusters. They are light and foolproof. Either way, put the adjusting end on the tarp and use whatever knot you want to tie to the stake. That way you can adjust tension during the night without getting up.
Consider paulj's suggestion about elastic on the lines.
F. There are lots of ways to set up a tarp - too many- it is the most vertatile of shelters, but you have to decide what to do every time you make camp. It's probably a good idea to settle on two or three and get good with them so you can set up when tired at the end of the day and in nasty conditions. The basic setups are the A-frame, leanto, canopy, pyramid, and the high-low (A-frame front with the back spread). The pyramid and high-low with the backs to the wind are the most wind proof. The regular A-frame and leanto are good general-purpose shelters. The canopy is virtually useless because it catches wind and flaps or fills with rain. You can figure it all out in an afternoon in the back yard. One thing you will learn is that the 9x9 may not be the best size for you, but it is a good, versatile size for starters.
Edited by Spock (04/16/06 01:13 PM)
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Christian
member
Reged: 01/11/02
Posts: 106
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As others have posted it isn't possible to get a non sagging ridgeline on a flat cut tarp. Only way to overcome this would be a catenary ridgeline which is impossible on a Plastic sheet.
Noise and pulling out of the stakes is probably caused by one circumstance- too much flapping on a tarp that has little stake out points.
Use loops at he side of the tarp as well- at least 2 per side and stake them down. This would help to stabilize the long sides (less noise) and would take away force from the corner stakes.
On more option is to make your tarp smaller. Not lengthwise (you need the overhang at the ends to protect you from windblown rain), but make the tarp narrower. I used my 9 x 9 feet tarp a lot when I was younger, but now I allways use much smaller tarps. You might find that an 8 feet width tapering to 6 at the foot end is comfortable enough. For two persons a 9 x9 is just fine of course.
Also remember that pitching the tarp lower in high winds makes more stable.
Edited by Christian (04/16/06 03:27 PM)
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EricKingston
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Reged: 11/01/02
Posts: 240
Loc: Michigan
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Well, ultimately, I guess it's nice to hear that the tarp (and yourself) held together in the strong winds. I'm glad to hear that. Solutions?? Just keep trying!
The Pitch:
Learning the proper way to pitch a tarp just take experience. In some situations you'll find that some pitches work better than others; though, I think most tarp users end up using one setup more than another (myself, I prefer a Very low general pitch, with the foot end even lower. Tarp sides touching the ground). When it comes to size, once you get used of sleeping under a tarp, smaller = better. It makes it much easier to pitch, and they're more wind resistant. Plus, if it's pitched right, there shouldn't be any worries about getting wet.
The Build:
I'm curious as to why your ridgeline sagged so much. Mine seems to hold up pretty well. Spocks idea with the packing tape sounds good. I know that stuff is nearly impossible to tear. It's definately worth a try. The great thing about that tarp, is that you can easily add or remove anything on it with just some tape and scissors. Also, in regards to wind and noise, I've found that silnylon is nearly the same (maybe just a touch quieter) as the plastic. Tyvek is the absolute worst!
Eric Kingston
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CJC
member
Reged: 04/16/04
Posts: 695
Loc: Southern Nevada
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Be patient and get a used tarp someplace and practice pitching it. The plastic painters tarps will give you the answer to the yes I like it or not I don't to tarping, but it will usually sag, tear, flap noisely, and radiate lots of sun and heat under the tarp. If it doesn't tear then it will keep you dry, but the lack of sleep will make you CRANCKY!!!  Lots of ways to set a tarp up and then there are the tarps with doors or flaps that can be over layed to act like doors that work nicely. Check em all out and enjoy!
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Anonymous
Unregistered
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You may want to add some tie out points onto the body of the tarp. this will make it more taught and give you morehead room. I don't know how you would do it on poly tarps except to use grip clips. http://www.shelter-systems.com/ultra-light-nylon.html These things look awesome for DIY tarps and cloaks.
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Howie
member
Reged: 06/02/03
Posts: 302
Loc: BC Canada
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Here is what I have recently bought at a home show. They seem to work very well on poly or whatever. I haven't actually used them in the great outdoors yet but I believe they will save me a lot of time and trouble. They aren't very expensive either. I got a dozen of the plastic connectors and a dozen of their bungy tie downs, all for $20.00. The bungies seem great too.
Howie
http://gadgetbrothers.com/tarpclamp.html
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paulj
member
Reged: 01/26/03
Posts: 1603
Loc: Seattle
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Here is Grip Clip's comparison with its 'competition'. I haven't tried this myself.
http://www.shelter-systems.com/gripclips/competition.html
Another design is the cylindrical Grabbit. Have used a set of mini-Grabbits that I bought at REI.
http://www.cbcproducts.com/MG100/MG100Home.htm
In some configurations they are easier to use, though they can come apart if tarp is too thin
paulj
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Howie
member
Reged: 06/02/03
Posts: 302
Loc: BC Canada
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Mine seems to be different than those designs Paulj. I tried to pull mine off, once it was clamped in place and it seemed quite impossible. It would tear the material or plastic first. The only thing that might be wrong with mine is it might be hard on fabric. Howver, if we are talking about cheap poly who cares? I plan on experimenting in my back yard and see what develops. I'll sleep outside. The neighbors will really think I have lost it 
Howie
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oregoncarver
member
Reged: 10/06/05
Posts: 129
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I have used these tarp grips and they are fantastic--they will not come off!! I've used them on blue poly tarps and tyvek in windy/rainy conditions and they held fast (winds were gusting around 40mph). The only difficulty using these is applying them--it takes a little practice to be able to do it quickly.
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Anonymous
Unregistered
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Haven't read all of the posts in this Thread, so please excuse me if I'm "late to the party" and this has already been mentioned. Came across this idea a month or two ago elsewhere on the Web.
Regular, plain, old, everyday, soda bottle caps also can function in a pinch as a cheap, substitute. Just place the cap on one side of the tarp, wrap the tarp material partially around it, loop a guyline over it, and tighten. Voila - a po' man's Grip Clip.
Again, if this has already been mentioned, please post back and I'll "blank out" this post. [I dislike "re-runs" too.]
-H
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terceiro
member
Reged: 04/05/06
Posts: 52
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Quote:
Haven't read all of the posts in this Thread, so please excuse me if I'm "late to the party" and this has already been mentioned. Came across this idea a month or two ago elsewhere on the Web.
Regular, plain, old, everyday, soda bottle caps also can function in a pinch as a cheap, substitute. Just place the cap on one side of the tarp, wrap the tarp material partially around it, loop a guyline over it, and tighten. Voila - a po' man's Grip Clip.
Again, if this has already been mentioned, please post back and I'll "blank out" this post. [I dislike "re-runs" too.]
-H
I think you're the first to mention it. (BTW, try clicking the button that reads "flat" at the top of the thread to view all messages in a thread at once) I'm a little nervous about how it would damage a more delicate fabric like silnylon.
I think I saw the same thing at Tinny's website... or maybe I just projected it upon Tinny, since it seems like something he would do.
Speaking of Tinny, has anyone built/used a Hasty Hooch? I like the $20; I like the 20 minutes; I'm OK with 20 oz. Combine that with a Gossamer Gear G4 (or a GoLite Breeze or whatever) and you're still just 2 oz over two pounds.
If it works, it would be great for me. Anyone have any experience with a Hasty Hooch?
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uva uvam vivendo varia fit
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Anonymous
Unregistered
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>>"I'm a little nervous about how it would damage a more delicate fabric like silnylon."
Good point.
Here's a possible solution.
Using duct tape, masking tape, athletic tape, medical tape, or even scotch tape (scotch tape is often used in knife self-defense training to render a knife blade "safe" from cuts), apply the tape all around to the edge of the cap, covering any edge which is not rounded. The other surfaces are smooth, and I would guess, shouldn't cause any abrasion to the silnylon.
-H
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paulj
member
Reged: 01/26/03
Posts: 1603
Loc: Seattle
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'Survivorman', on the BC mountains episode, used a pebble (or pine cone?) and a length of video tape to close the end of his survival blanket shelter.
It would easy to test whether a disk or sphere shape would work best in this role - mainly I'd be concerned with bunching of the fabric (apart from possible abrasion issues).
paulj
Edited by paulj (04/19/06 08:48 AM)
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