Tarp Sag and Condensation

[Scouter811]

So this summer I upgraded from my starter tarp (a Yukon Walkabout) to Mountain Wilderness Monster Tarp in silpoly. Now I know a lot of folks had issues with Charlie, but aside from his longer lead time I didn't have any of those issues, and I have what appears to be a great piece of gear. I've used it several times now, but I've had a few issues with it that I'm not sure are issues with the tarp, issues with my other gear, or just plan old user error with a new tarp.

So I went with silpoly to avoid the sag issues that I read a lot of folks were having with silnylon, but I still have issues with the tarp flapping through the night. I'm using a Zing-It CRL, with guy lines made from braided masons line. The guy lines are prussik based with the prussik loop attached to the d-rings with a larks head, and then a bowline on the other end to hold onto my Y-stakes. There are three tie outs on each side. The door panels have shock cord to a single stake for entry/exit. I have tightened the lines down to the stakes so much that it's pulling the ridge line down, but I wake up with a saggy and flapping tarp in the middle of the night. This is not an issue I ever had with my old Yukon using the lines that came with it. This issue was made worse on my last night out when fog rolled in and I had a ton of condensation inside my tarp before I was even in my hammock. Every time the wind shifted I got rained on. It made for a cold and rather miserable night. All my gear was soaked by morning. Is that kind of condensation common in silpoly? What about other materials?

I have another trip coming up in a week, and I was hoping to find some resolution or at least some things to watch for on that trip.

• My first thought was did I get the right tarp? Could there have been a shipping issue and I have silnylon not silpoly. Is there a good/easy way to tell the difference? I don't have any samples of each other than this one tarp
• My second thought was could the CRL be slipping? I don't think it is, but if I just tied a small knot onto the CRL would it stay in place all night to verify if the prussik is slipping?
• Could the Masons line be too slippery to hold the prussicks? I was thinking about marking the lines with a knot or electrical tape like the ridge line to see if I can find any slippage there over the night.
• Everything I've read about this particular masons line state that it has very little stretch, but how can I test for that? I have a whole spool of it here to mess with.
• Any suggestions on how to reduce or vent that condensation out?
• I know I can put some shock cord on the lines to add tensioners, but I was hoping to avoid adding any more line, weight or complexity to my setup, but if this tarp or line material stretches then I may have to do that.

Does anyone have any other suggestions to try? This is a great trip to test at as my group will have some Adirondack shelters that I can bail out into if things go too far sideways.

Thanks.

[Caminante]

I have two silpoly tarps with none of the issues that you mention. Condensation is neither better nor worse, I've never noticed it as a problem.

I don't have experience with silnylon and therefore don't know how one would know the difference, but my silpoly really does not stretch. If I was having sagging/flapping issues with my silpoly, I would assume that my lines were slipping.

[zukiguy]

Hmmm....I really haven't had slipping problem with the zing-it CRL I use on all my tarps but I use cord other than mason's line. I bought a roll once and tried it for guy lines but it seemed to "stick" to all the forest litter and make a mess. You might try some different, stiffer line for attaching the tarp to the CRL and see if that helps. Also, scuffing up the zing-it a bit will help. The line is treated with an anti-friction coating (lubricant) that helps it slide over pulleys or tree branches (lash/zing-it). That makes it hard for the friction knots to bite. Also, I had good luck going with a klemheist knot over the prusik knot.

All of my tarps are silnylon or coated polyester so I can't say about the difference in stretch/sag of the sil-poly. I'm leaning toward most of the problem being a combination of sag and weather conditions. Do you still have your old tarp? Maybe set them both up in the yard overnight and get a side-by-side comparison or check out the other hanger's setups on the next campout.

[Boston]

A lot of mason line is made from nylon and will stretch, especially when exposed to moisture. Change out your guy lines for something like zing-it.

Hand the tarp higher to reduce condensation. This isn't dependent on material.

[sqidmark]

I have a 10x12 DIY silpoly winter tarp and have no such issues. Just a thought, maybe the fabric is not really silpoly (i.e. waterproof) and moisture is coming through it.

EDIT: I use zing-it mini-ucr's for both ridge and tie-outs. No slippage. No shock cord except for on the doors. If you're in a real heavy fog and the wind is blowing under tarp edges, a uqp or sock may all that could help(?).

[Scouter811]

A lot of mason line is made from nylon and will stretch, especially when exposed to moisture. Change out your guy lines for something like zing-it.

Hand the tarp higher to reduce condensation. This isn't dependent on material.

Yeah, I just looked at the Lowes website and this is in fact nylon masons line. Bugger, I didn't suspect that before you mentioned it here. I don't have enough zing-it handy today, but it looks like I'll need to order some to upgrade this.

My tarp was very low that night. I was hanging from my TurtleDog in a field at scout camp. Not the most ideal situation. Thanks for the advice.

[Scouter811]

Hmmm....I really haven't had slipping problem with the zing-it CRL I use on all my tarps but I use cord other than mason's line. I bought a roll once and tried it for guy lines but it seemed to "stick" to all the forest litter and make a mess. You might try some different, stiffer line for attaching the tarp to the CRL and see if that helps. Also, scuffing up the zing-it a bit will help. The line is treated with an anti-friction coating (lubricant) that helps it slide over pulleys or tree branches (lash/zing-it). That makes it hard for the friction knots to bite. Also, I had good luck going with a klemheist knot over the prusik knot.

All of my tarps are silnylon or coated polyester so I can't say about the difference in stretch/sag of the sil-poly. I'm leaning toward most of the problem being a combination of sag and weather conditions. Do you still have your old tarp? Maybe set them both up in the yard overnight and get a side-by-side comparison or check out the other hanger's setups on the next campout.

Thanks, I had considered the klemheist, but wanted to confirm I was seeing slippage before retying everything. I did keep the old tarp. My son has been using it. I like the idea of a side by side test.

[SilvrSurfr]

Lose the mason's line. I use Zing-It for all my tarps. I don't think silpoly sags so it's your prusiks that are slipping, or the nylon line is stretching - no need for shock cord.

Condensation occurs regardless of fabric type. Ventilation helps. You probably always had good ventilation (and susceptibility to blowing precipitation) with the Yukon tarp.

[W8lkinUSA]

I've only got one hang for actual experience, but have researched much..

I reckon the wet tarp caused the CRL knot to slip due to added weight (wet Zing-it won't help either). Now that the tarp hangs lower, all guylines appear to have loosened. This, in turn, led to a flapping tarp and rain coming through.

I don't believe the cord from tarp to CRL would've have slipped substantially.

Also, if the tarp dropped significantly, rain may have run down the CRL, under the tarp, then onto the hammock.

[hutzelbein]

A long time ago, I did use a single Lash-It ridgeline with prusiks and my tarp was always sagging in the mornings - no matter what the weather was. I assumed that the prusiks were slipping, because the issue disappeared when I switched to a split ridgeline with Dutch Stingerz. I'm still using the same silnylon tarp.