Damp and down

[kitsapcowboy]

I was refraining from saying so because I often get flamed for it, but you're right...

I think your points are well taken, and I believe the true state of nature is actually a fairly complex interaction at the nexus of a variety of both environmental and metabolic factors.

Here, for example, at the summer solstice time, it's actually a fairly unseasonably humid 79% relative humidity at just 66F. Our summers are usually reasonably dry and not too humid, especially toward Labor Day, even if the temperature climb. That said, the relative humidity at some times of year will approach 100% -- literally the full carrying capacity for water vapor in the ambient air, and it rarely drops below 60%. At high humidity levels, even if your body heat is working for you, there is quite simply almost no place for the moisture in your down quilt to go, and so the expected evaporation is negligible. You can certainly get by with a moist down quilt, depending upon the temperatures, but the degraded performance may be noticeable in certain conditions.

I thinks Shug's advice is sound, as usual: be diligent about taking every opportunity in adverse conditions on long trips to do things like dry your quilt in the sun, recharge your power bank or Luci Light, etc.

[WalksIn2Trees]

I was refraining from saying so because I often get flamed for it, but you're right... your body warmth with help drive moisture out and away from the quilt, just as it does in dry conditions with your own body moisture. What I get flack about is telling folks to not wear layers of clothes so that your body heat more efficiently increases temps inside the quilt as hot air is trapped by the down. What I've seen is conditions where there is a lot of reason to blame the damp conditions for lack of loft and subsequently, being colder than expected for outside temps. In many cases, I believe the real issue is folks putting on more clothing because they are chilled in the damp conditions and then their down never lofts like they expect it to - both due to lack of warmer temps in the down and outside pressure from humidity.

I don't actually like to ever say that it's not possible, or that something is absolute, just that my experience leads me to believe something... there's plenty of assumptions that have been posted on these forums that are generally taken as gospel but which i myself have disproven, and usually they're based on finding a fix before discovering the root cause and not understanding the true nature of why the fix worked.

I'll be the first to state that I'm not sure of the reason that my body heat seems to push the moisture out of the quilt... and also that not all of it is pushed out. at my best guess, it's due to pressure differential... body heat is traveling through the quilt and radiating out through the surface... that's a direction of flow, wether it's a strong enough effect to be the reason, I'm not sure, maybe it's capillary action that only works in certain conditions... maybe I'll ask my physicist buddy at LSU, he might already know the answer, having spent a portion of his career doing investigative science.

[dakotaross]

Agreed, lot of opinions that seem based on experience in construction rather than hiking.


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[cmoulder]

generally I've found with Down, and this happened to me with a synthetic sleeping bag too, in foggy conditions everything will feel clammy, but once you get in your body warmth will drive the moisture out, and as long as you stay in... like let's say it gets foggy after you go to bed... your warmth will prevent it from penetrating. I've never had any of my kit get wet enough to be drenched enough from fog or dew that it still wouldn't be dry 2 days later though

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My experience with Climashield is that, yes, it will be very damp but will still maintain loft with little compromise in warmth. In my Senceca/Spruce experience, I was inside a MLD Duomid (single wall pyramid) and rain drops outside were knocking off condensation inside and it was misting straight onto the quilt for many hours. The sun didn't come out for the entire trip, and between bouts of heavy rain the humidity remained high... simply no opportunity to dry it out.

Seneca Creek first afternoon: Seneca_Creek_Day_1.jpg and third afternoon: Seneca_Creek_Day_3.jpg

[Five Tango]

Dont try this at home!
https://www.youtube.com/watch?v=sWfB0laaP28

[cmoulder]

Dont try this at home!
https://www.youtube.com/watch?v=sWfB0laaP28

I would be interested to see what it's like after being stuffed inside a backpack for 10-12 hours. 3-4 days in a row with high humidity and no opportunity to dry.

Straight-up observation, not to pooh-pooh it, because I really hope it works. Because I have some EE quilts with Down Tek.

[SilvrSurfr]

I was refraining from saying so because I often get flamed for it, but you're right... your body warmth with help drive moisture out and away from the quilt, just as it does in dry conditions with your own body moisture. What I get flack about is telling folks to not wear layers of clothes so that your body heat more efficiently increases temps inside the quilt as hot air is trapped by the down. What I've seen is conditions where there is a lot of reason to blame the damp conditions for lack of loft and subsequently, being colder than expected for outside temps. In many cases, I believe the real issue is folks putting on more clothing because they are chilled in the damp conditions and then their down never lofts like they expect it to - both due to lack of warmer temps in the down and outside pressure from humidity.

You get flamed for that? I consider it gospel - don't wear a bunch of layers. Let the down do its job. The more layers you have on, the less likely the down will be able to perform as expected.

Down does an incredible job of using one's body heat to move the damp out of the quilts. However, add a bunch of layers and that mechanism no longer works. It took me a long time to accept this as fact. Of course, my "facts" are someone else's lies!

The less I wear, the warmer I am, and I've found that to be true even down to -3* F.

[ChrisJHC]

For a detailed (and somewhat technical) explanation, look at this discussion from another forum:
http://bushwalk.com/forum/viewtopic.php?f=15&t=28061

[cmoulder]

We all have to go with our experiences and what works for us.

For protracted (days on end) high relative humidity/fog/rain, I go with synthetic. If down worked all the time there would be no need for synthetic insulation such as Climashield Apex, Primaloft, etc.

[BillyBob58]

Agreed, lot of opinions that seem based on experience in construction rather than hiking.


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My opinions are based more on experience hiking, and almost none on construction experience. I figure: whatever works for an individual based on their experience. Although, we ( all of us ) often have amazingly different experiences, and then some of us ( like me ) opine based on that experience, which is so different than another persons experience. Not much we can do except add the old "HYOH" and "YMMV".

I have posted this experience before, guess I might as well again. Took a trip along side the Hoh River in Olympic National Park over several days, with lws in the md to high 40s, and maximum humidity, mist and lots of light rain. No one got even a few drops on their gear from rain, the tarps did a good job. I had the HHSS for bottom insulation(synthetic open cell foam), and a synthetic Cat's Meow bag for the top. Which I proceeded to SOAK the foot end of both the very first night. This was caused by use error when I failed to follow instructions to use the danged 2 oz space blanket on top of the HHSS OCF pad. Thus a lot of condensation occurred in the foot end of both the bag and pad. But I still slept toasty warm and did not even notice any of the bunch of moisture until I exited the bottom entry HH. But then I noticed it big time, and felt some anxiety as it was time to pack up and go, which we did. But there was no sun anyway, and there was none for the rest of the trip, not enough to dry with anyway, mostly fog and mist. But no worries: even packed up wet, by the time I crawled in that night all seemed bone dry and puffed up to the max. And since I used the space blanket for the following nights, all stayed dry. Every thing was fully puffy on the last day.

My friend had a down TQ, and for the life of me I can't remember now what he had below for warmth. He used a 50F PeaPod for the next trip, but I can't remember for this one. I'm sure he didn't sleep in any more than the thinnest base layer at most, because it just was not very cold and he is a warm sleeper. His big tarp kept all the rain out easily. But last day of the trip, he said he was glad we were headed out, because his untreated down had obviously lost significant loft. I showed no evidence of dampness whatsoever, even though I started bad with that soaking of the foot box and pad on the 1st night.

Go forward 1 year, same buddies but this time back in the Wind Rivers of WY, way less humidity but colder(down in the 20s). This time I had a down 20F Pea Pod + warm clothing, my buddy had the same down bag used as TQ used inside a 50F down Pea Pod augmentd with a pad under the hammock/inside the Pea Pod. There was the occasional rain storm and a light snow on the last night, but again no problems keeping external moisture off with our tarps. We were camped beside a lake, but had no fog or mist to deal with. For whatever reason, my buddy once again had significant loss of loft by the end of that trip, maybe 4 or 5 nights, and was a tad chilly that last night. I don't know what he was doing wrong, as I had no noticeable loss of loft in my 20F PeaPod. Same for another guy in a 20F Pea Pod. My son was in a Polarguard Cat's Meow and my Climashield Yeti for his 1st ever hammock hang, and he had zero issues with dampness, as expected.

I don't think his problems (with damp down and lost loft) can be blamed on too much clothing on that 1st trip as I think he slept in minimal clothing. I really have no idea what kind of clothing he slept in on that 2nd, colder trip,but he tends to take the minimal clothing and gear. And on the 2nd trip, where we both used down, I don't know why he had problems with damp down and loss of loft, it was not from external moisture. It's any one's guess why. But in both cases he was relieved that we had no more nights out to lose even more loft and test his ability to stay warm.