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  1. #1
    BillyBob58's Avatar
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    Down vs. Synthetic in hammock

    OK, I realize most hammock users much prefer quilts vs bags, mainly for sheer comfort and ease of use. I can see all of the advantages. Some have actual quilts designed primarily for hammock use, others just try to make their bags function as a quilt.

    The later describes me. But, in my case, I feel that my mummy style bags are no where near as warm when I use them as a quilt, and usually if I get cold, getting in the bag and zipping up with hood over my head and neck collar sealed will result in quick improvement. Usually by what seems like a 20* (or more ) improvement. I can go from uncomfortably cold to toasty warm by zipping up.

    But sometimes when I get in the bag, it seemed to me I would also notice increased warmth on my back. But, I wasn't sure if this was because I was just warmer over all. But it did get me to wondering about the superior compressibility of down vs PG. and how this might work against you in a hammock.

    So, at morning a couple of days ago it was 58* with a steady breeze, and my hammock was up, so I grabbed my old winter PG Delta bag and went out in just my PJs. First I hopped in quilt style, with the bag very lose over the top to avoid any overheating. It only took about 5 minutes to determine that I was definitely uncomfortably cool on my back, and that I wouldn't be able to make it very long like that without getting chilled. And the longer I lay there, the worse it was getting, especially when the wind would gust a little.

    So, then I rolled the bag out and laid down on it, but not zipping up, leaving some pretty good ventilation on top. I went back in about 30 minutes later with the temp still at a very cloudy 58*. I was just fine the entire time, with no problems from a cold back at all. Not even when the wind would gust. In fact, sometimes I actually had just a slight warm sensation on my back. Both times, of course, there was no pad or quilt.

    So, this raises the question: Is PGs relative lack of compressibility actually a slight advantage in a hammock, for those few who would actually use them as a sleeping bag, rather than a quilt? Would this possibly be an advantage for both quilt and bag users when dealing with hammocks compressing insulation on the sides? Possibly allowing the use of thinner or more narrow and lighter pads or lighter UQ? Or no pad or UQ at all at a temperature that would just barely require a pad or UQ with a down bag or top quilt of any kind?

    I can't really quantify the results of my simple, quick test. Just quite uncomfortable at 58* with no bag layer under me, just fine with it. I do know that previously I did a test with just PJs ( tee shirt only on top) and no bag or quilt or pad, at 68*, and that seemed to be about my lower limit. Maybe closer to 70* when the wind would pick up. So, I'm guessing

    that this PG bag might be good for 5 or possibly 10* worth of bottom insulation. Compared to zero degrees bottom layer insulation for quilt style and probably ( guessing) about zero degrees bottom layer help inside a highly compressible down bag.

    Has any body else here noticed any similar results? It just has occurred to me that this might be an additional benefit to synthetic bags, at least for bag ( vs quilt) users in a hammock, compared to down. In addition to the possible "warmer when wet/quicker drying" advantages. This advantage would not seem as likely for a ground dweller who is already depending on a thick pad for both cushioning and insulation. At least, I use thick pads on the ground, as thick as I can stand to carry! Which is why I like being off the ground.

  2. #2
    Ramblinrev's Avatar
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    if you are laying directly on the pad and getting a clammy back that will chill you big time. The bag may serve to wick off that clammy vapor and keep you dry, therefore warmer...
    I may be slow... But I sure am gimpy.

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  3. #3
    Senior Member TiredFeet's Avatar
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    Laying on the the bag may also serve as a wind block besides the insulation value. Almost all hammocks I have tried are terrible at blocking the wind/breeze. The wind/breeze alone will cool you off quickly - it's called the wind chill factor and the weather people on TV tell you the wind chill temperature in the winter all the time.

    You can test by simply doing the same test, but using something that will block the wind alone and no insulation value - say a rain poncho.

  4. #4
    Senior Member 6 feet over's Avatar
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    Quote Originally Posted by Ramblinrev View Post
    if you are laying directly on the pad and getting a clammy back that will chill you big time. The bag may serve to wick off that clammy vapor and keep you dry, therefore warmer...
    I didn't re-read, but didn't he say he used no bottom insulation at first (bag used quilt style), and then used the bag zipped (bag-style). His cold back was due to chill creeping through the hammock material with no bottom insulation at all, not due to wet back against pad.

    This was with no pad at all, right?

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  5. #5
    Senior Member Hector's Avatar
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    You got a cold back at 58 without a pad -- no surprise. A cheap, heavy, incompressible synthetic bag underneath you provided a little back insulation at 58 -- again, no surprise. But would you have had more flexibility, been more comfortable with less weight with the right stuff? Yep. Which should you do? That's up to you, grasshopper. We all have our priorities, idiosyncrasies and preferences (rational or otherwise). Like the man said, you pays your money and you takes your chances.
    Last edited by Hector; 05-21-2008 at 09:04.

  6. #6
    BillyBob58's Avatar
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    Quote Originally Posted by 6 feet over View Post
    I didn't re-read, but didn't he say he used no bottom insulation at first (bag used quilt style), and then used the bag zipped (bag-style). His cold back was due to chill creeping through the hammock material with no bottom insulation at all, not due to wet back against pad.

    This was with no pad at all, right?

    6
    That is correct. This was simply a non-scientific quicky test of NOTHING under my back except hammock fabric( with the bag loosely on top of me quilt style) vs the bottom layer of a Polarguard sleeping bag under my back, between my back and the hammock fabric. The former resulted in a rapidly ( almost instantly) chilled back while the latter resulted in a comfortable back for over 30 minutes.

    So, I have previously made an assumption that the insulation that we lay on is essentially useless since it is compressed by our body weight. While I am still making this assumption for down bags, I am now not so sure for synthetic bags. It may not be a whole lot, but I think there is some benefit from having PG between your back and the hammock, especially with the heavier bags.
    For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
    Romans 8:18,21-22

  7. #7
    BillyBob58's Avatar
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    Quote Originally Posted by Hector View Post
    You got a cold back at 58 without a pad -- no surprise. A cheap, heavy, incompressible synthetic bag underneath you provided a little back insulation at 58 -- again, no surprise. But would you have had more flexibility, been more comfortable with less weight with the right stuff? Yep. Which should you do? That's up to you, grasshopper. We all have our priorities, idiosyncrasies and preferences (rational or otherwise). Like the man said, you pays your money and you takes your chances.
    Well, I wouldn't call it a "cheap" bag, it is a nice NorthFace bag. And when it is seriously cold, getting in that bag and zipping it up mummy style with neck collar can provide some serious, wind/draft/water resistant bombproof protection.

    And I wouldn't call it "incompressible" like CCF. It just is a lot less compressible than my 900 FP down PeaPod, for example.

    I agree, we all have our preferences. And I have both down and synthetic bags and clothing. I have owned many of both over the years, and know the pros and cons of both.

    It was actually indeed a surprise to me that there was that much warmth under my back while laying on the sleeping bag. Like I said, I have previously had some back discomfort at about 68*F. So for me to be fine at 58* ( and maybe even at a lower temp?) must mean there is at least 10* worth of insulation value in the lower level of that sleeping bag, even when I am laying on it. And I have been informed here before that most folks- especially quilt users- can't be comfortable below 75* without something under their back. I think there might be quite a few of us that were assuming that all sleeping bag insulation insulation that you lay on is pretty much useless. I now do not consider PG that is under me to be useless, though that may indeed be the case for down- bu I have not tested.

    I don't have a dog in the quilt vs sleeping bag or down vs PG debate, because I use both, depending on circumstances. I can see advantages that each has over the other, depending on ones needs.

    However, for the minority that might sometimes prefer a mummy sleeping bag instead of a quilt - even in a hammock- for when it is seriously cold and windy- and also for those who might prefer synthetic over down for any of the well known reasons, here is yet another reason that can add to the list. It turns out that there is at least some useful insulation value even at the point of maximum compression under your back, with a PG bag. And some may want to throw this 5 or 10 or more degrees of under insulation factor into the total equation of weight/bulk factors.
    For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
    Romans 8:18,21-22

  8. #8
    Senior Member Hector's Avatar
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    However, for the minority that might sometimes prefer a mummy sleeping bag instead of a quilt - even in a hammock- for when it is seriously cold and windy- and also for those who might prefer synthetic over down for any of the well known reasons, here is yet another reason that can add to the list.
    If you've already made up your mind, you can always find something to "add to the list," while ignoring everything else that doesn't agree with you. AKA "shoot arrow into wall and scrape away all the parts of the wall that don't look like a target."

    I think you need to reread what you really got out of your experiment -- you seem to be have read a lot more in there than actually can be inferred. However, by all means, Hang Your Own Hammock.

  9. #9
    BillyBob58's Avatar
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    Quote Originally Posted by Hector View Post
    If you've already made up your mind, you can always find something to "add to the list," while ignoring everything else that doesn't agree with you. AKA "shoot arrow into wall and scrape away all the parts of the wall that don't look like a target."
    Have you already made up your mind, maybe? I don't really understand the points of your responses. It seems almost as though me pointing out one possible advantage of a PG bag in a hammock, compared to more compressible down bags or quilts with zero insulation underneath, has offended you. Is that the case? If so, why?

    What constitutes " everything else that doesn't agree with you(me)"? That PG weighs more than down for a given insulation value? That down will pack down to 1/2 or 1/3 the volume of a similarly warm, and keep it's loft many times longer? I am very well aware of all of these factors, which is why I often use down insulation. If that is not what you are referring to, then what? What is it I am ignoring? Because if it is any of the above, I am already well aware of it and anyway, that has nothing to do with the conclusions to be drawn from my little experiment. Those are some of the well known advantages of down over synthetic. All I am doing is pointing out a possibly unappreciated benefit of PG compared to down, or compared to nothing ( underneath) in the case of a top quilt.

    And I am also aware of the differences in performance when wet, and now I am aware of a probable advantage regarding the warmth of a person's back when laying on hammock fabric vs laying on a layer of PG. Advantage PG.

    I think you need to reread what you really got out of your experiment -- you seem to be have read a lot more in there than actually can be inferred. However, by all means, Hang Your Own Hammock.
    Well, we fully agree on hanging your own hammock, and probably on hiking your own hike. Hector, I don't know why you might think otherwise, but I have no concern about whether you sleep in down, PG, a Persian rug or nude. Why would it matter to me? Go for it, what ever you prefer, and enjoy.


    We will have to disagree on " you need to reread what you really got out of your experiment -- you seem to be have read a lot more in there than actually can be inferred.". I think you need to reread what I have claimed and see if that is really the case.

    Because here is all I have "inferred", or observed, actually: Unlike what I have read MANY times over the years, per my observation a sleeping bag does indeed have 5 or 10 degrees and maybe more insulation available to keep your back warm, even if you lay on it and "compress the insulation". Or at least a PG bag does. Do you disagree with my observation as a result of your own testing? (This is in addition to, and separate from, a hooded bags ( down or synthetic) ability to seal several inches of loft around your neck and shoulders and head, while also defeating all drafts.)

    And from the above, I have "inferred" that people who have not purchased top quilts, and who are still getting in their sleeping bags when it is really cold, if they have synthetic bags they may want to alter their warmth to weight calculations a slight amount.

    IOW, some one who might need just barely need a thin pad under while using a light quilt on top when they are expecting lows of 70F ( depends on the person- substitute 75* or 65* or whatever), but for whatever reason they are using a PG bag instead, they MIGHT not need the thin pad. Or if they use a down UQ and are fine at 35* but need a pad below 30*, they might not need the pad until 25 or 20*. Just something to consider, and something that might alter the weight advantage of a down bag slightly, for people that use bags.

    Do you disagree with that inference of mine? If so, is that because of some testing you have done? If not due to testing, then why? Does my conclusion clash with some idea about which you had already made up your mind? As for me, I stand by my what I have inferred, based on what I observed.

    And I think there are at least a few folks who either still use bags when it is very cold. Or as Ed Speer says when advising using a bag as a quilt, "there comes a time when you are better off getting in the bag and zipping up". Or other newbies that have not yet managed to buy a top quilt yet, and are still making do with their old mummy bags, some of which are PG. Those people might find some use from the results of my little test.

    But by all means, please don't anybody get the idea that I am trying to get you to dump your 800 FP down top quilt and by a heavy, cheap walmart sleeping bag. Use whatever pleases you.

    I will continue to use down, though I have not sold my PG bags either. At the moment my main winter set up for really cold temps is my DOWN PeaPod plus either PG hooded clothing ( BMWs) and/or a summer weight synthetic 25 year old bag, which I have used as low a 10*F with no problems, or in the mid 20s with just the clothing. But there are certain circumstances for which I might choose my PG bags. I'll "make up my mind" as the trip time arrives.

    But hey everybody, let me take a load off of your minds. Because I know you are all real worried about this. I give you all full PERMISSION to either use down bags, top quilts, down UQs, UQs with pads or even synthetic sleeping bags if you desire! Really, whatever you like, go for it.

    But hopefully I will also be allowed to make an observation like " my back was a good bit warmer while laying in my PG bag than it was when I used the very same bag as a quilt" without being accused of " "shooting arrow into wall and scrape away all the parts of the wall that don't look like a target."
    Bill
    For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
    Romans 8:18,21-22

  10. #10
    Senior Member
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    Disclaimer: Newbie hammock user. So new that my hanging has been limited to my property trying to figure out this concept. Property is what most people would consider "wilderness".

    Wind chill seems to be a big factor in keeping you cold. Hanging in the Hennessy ULBP in 50's, with 12-20 mph breeze was more than cold. Added a Z-pad big improvement. My guess is that the PG vs. down provided a combination of improved wind and insulation, but more on the wind chill reduction end. One of these days I'll try comparing the old PG SnowLion ('80s vintage PG), its replacement the MtnHardware Ultralamina 45 and the down bag(Mamot Atom) in the bare HH ULBP. All have similar warmth ratings. The SnowLion compress to about 4x the volume of the Mtn Hardware.

    The cool concept in hammocks is flexibility to meet the specific needs and situation of the user. As I started to replace worn out gear I've returned to a simpler, lighter concept. One of the reasons why I've not replaced the tent and bivy. May end up with more gear than I expected in storage with all the hammock gear I'm starting to accumulate, but in the pack depending on when and where it will be less stuff. Bottom line is to each his own. Whatever works best for you in your own mind. My problem is I'm a little clueless when it comes to hammock gear.
    Last edited by koaloha05; 05-21-2008 at 12:17.

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