Rain passing through the tarp?

**hutzelbein** · 08-30-2010, 17:29

I have had the chance to use my hammock in some stronger rain recently. I'm generally very happy with my (silnylon) tarp - the tarp has never been wet on the underside. But I'm puzzeled about the fact that the hammock is slightly wet: you can clearly see raindrops on the netting and hammock fabric. I tried to figure out where the drops are coming from, in vain.

I first thought that the rain might have blown in from the ends, but there wasn't really much wind. I changed the angle and pitched the tarp a bit steeper. This decreased the amount of rain under the tarp, but there are still tiny raindrops on the hammock.

Does rain partially pass the tarp? I might have to add that the drops were hitting the tarp with some force. I had no issues with lighter rain.

Any suggestions what I might have been doing wrong?

**pgibson** · 08-30-2010, 17:34

Condensation??? Just a thought, I have had significant condensation a couple times this summer in cool humid conditions. Perfectly clear sky's other wise.

**turnerminator** · 08-30-2010, 17:40

If it raining really hard, it will come through, depending on the material.

I've seen it come through silnylon a couple of times in heavy rain.

**hutzelbein** · 08-30-2010, 17:42

No, it definitely wasn't condensation. The hammock looked like it was hit be raindrops; and it did so within a very short time, during the day, without anybody in it. The hammock is also partially hanging under a balcony, so the tarp is only hit by rain on one side. That was also the side where the hammock was wet. No drops on the other side.

My first thought was that the rain was splashing back up from the floor, but especially towards the middle of the tarp, the drops were only on the top, not on the bottom.

**nacra533** · 08-30-2010, 18:44

In a driving rain, it will "mist" inside the tarp, but shouldn't be enough to get you very wet. More like being in a heavy fog and everything gets damp. Also, during a rain, you have 100% humidity or close to it at ground level, so there is a lot of moisture in the air already.

Nylon is hydrophillic, which (plainly) means it absorbs moisture. That's why sil tarps sag so quickly in a little rain.

What I think happens is:
the nylon absorbs the moisture in any amount of rain/moisture.
In a driving rain, the rain is similar to someone is hitting the tarp, which drives some moisture out on the bottom side. Again, a fine mist, not droplets.

One solution is for me to put my bugnet up, that way it "catches" the majority of the moisture before I feel it on my face or body. I experienced the same thing and discussed it in this post.

http://www.hammockforums.net/forum/s...ad.php?t=21172

**jtbradyl** · 08-30-2010, 19:02

If it is a problem you should get a tarp with a polyurethane coating.

**Youngblood** · 08-31-2010, 07:03

The fine mist coming through in heavy rain is because the silnylon is only waterproof to a limited pressure, a pressure that is less than what was commonly used for the waterproofing in the heavier materials it traditionally replaced. I always figured what made that tradeoff acceptable for backpacking was (1) because of how well the DWR finish works on today's fabrics used on the rest of our backpacking gear (like sleeping bags), and (2) it doesn't rain that hard very often or for very long when it does and if it did we would be in such serious flooding conditions that that would be the least of our problems.

If it is any consolation, I have not had wetting issues from misting due to heavy rains that were as bad as I have had from high humidity conditions like I have had at times when I found myself in a fog bank or some rainy nights with the humidity so high that moisture condensated on every surface exposed to air. I'd rather not have the misting but I handle it and other wetting issues as well. I suppose I would look it differently if I didn't have to handle the other wetting issues.

**Shewie** · 08-31-2010, 07:19

Originally Posted by hutzelbein

I have had the chance to use my hammock in some stronger rain recently. I'm generally very happy with my (silnylon) tarp - the tarp has never been wet on the underside. But I'm puzzeled about the fact that the hammock is slightly wet: you can clearly see raindrops on the netting and hammock fabric. I tried to figure out where the drops are coming from, in vain.

I first thought that the rain might have blown in from the ends, but there wasn't really much wind. I changed the angle and pitched the tarp a bit steeper. This decreased the amount of rain under the tarp, but there are still tiny raindrops on the hammock.

Does rain partially pass the tarp? I might have to add that the drops were hitting the tarp with some force. I had no issues with lighter rain.

Any suggestions what I might have been doing wrong?

Are all your seams sealed ? Do you have any pin holes where there's webbing attached ?

**hutzelbein** · 09-01-2010, 03:21

Unfortunately I didn't take a photo. It wasn't mist or fine spray, but drops - which is what puzzled me, because the underside of the tarp was completely dry. You're right though: it wasn't enough to soak the hammock.

I'm just wondering when it will compromise the down quilts? If you expect heavy rain, do you protect your quilts with some kind of extra layer?

Originally Posted by Shewie

Are all your seams sealed ? Do you have any pin holes where there's webbing attached ?

I have a Superfly tarp, and it said it doesn't need seam sealing - so I didn't. I also doubt that this was the issue, since the drops were all over the hammock. It was better towards the middle of the tarp, and worse on the outsides.

The amount of drops coming through the tarp also decreased when I pitched the tarp with a steeper angle.