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Re: Hammock camping experiments

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  • Coy
    Hi Paul I think there is more going on than just sweat. A thicker pad might be the solution. I have observed that when I dont have enough pad I get no
    Message 1 of 5 , Feb 25, 2006
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      Hi Paul

      I think there is more going on than just sweat. A thicker pad might
      be the solution. I have observed that when I dont have enough pad I
      get no condensation. When I had bearly enough pad I got quite a bit.
      When I had plenty of pad I didn not get any. Ive thougth about it
      some and the only resonable explination I can come up with is a glass
      of tea sitting on the counter. In a well insulated glass you wont see
      any moisture on the outside. With a poorly insulated glass it gets
      soaked. Now in a hommack you are the warm outside air and the bottom
      of the hammock is the inside of the glass of ice tea. Moistur will
      try to build up on the warm side. But with a thick enough pad this
      goes away. Dont know if this is whats happening but pads were used for
      the past decaded or so on the ground and you seldom heard all the talk
      about moisture problems. Strange it crops up a lot more with
      hammocks. Some is real, some may even be preception from all the talk.

      Coy Boy


      --- In hammockcamping@yahoogroups.com, "Paul V." <cruisenewsnet@...>
      wrote:
      >
      > Hello - I haven't posted here for a while but I have been doing some
      > hammock experiments, and am trying to work out a cool weather
      > (30F-50F) hammocking system.
      >
      > Based on a couple of overnights, I'm at the point of thinking that
      > closed cell pads are not the way to go in cool weather due to
      > condensation issues, and I'm hoping that the underquilt that I ordered
      > will improve things a bit. I am also working on a Risk pod to use as
      > a windbreaker.
      >
      > I really like the clothing combination:
      >
      > (windbreaker - fleece - wicking undershirt)
      >
      > and I'm trying to imagine a similar combination for a hammock:
      >
      > (windbreaker pod - down or synthetic underquilt/topquilt - polypro
      > longjohns)
      >
      > The goal here is comfort and I think this combination offers the best
      > way of getting a lightweight comfortable cool weather system.
      >
      > I have been putting some thoughts and campout notes on a webpage,
      > mainly so I can escape to the woods when sitting at my work desk
      > cubical. I'm ready to go out and try again, but I'm patiently
      > waiting on my underquilt.
      >
      > skylark
      > http://cruisenews.net/backpacking
      >
    • LHM
      I think perhaps the explanation lies in the concept of *dew-point* ... I don t know much about hammocks but this is how it might work if it were similar to the
      Message 2 of 5 , Feb 25, 2006
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        I think perhaps the explanation lies in the concept of *dew-point*
        ... I don't know much about hammocks but this is how it might work if
        it were similar to the wall of a house:

        let's pretend we're curled up in our nice warm dry sleeping bag...
        the air close to us is at 80 degrees F (feels nice and warm) and is
        at 50% relative humidity (50% saturated with water vapor).

        The "dew point" of that air is about 60 degrees F.

        In other words, if we take a sample of that air and cool it to 55
        degrees F., it's going to have to deposit some water somewhere -- as
        condensation.

        Obviously, on its way out of the sleeping bag, the air is going to
        encounter colder and colder temperatures -- and as soon as it arrives
        at the place where the temperature coincides with the dew point,
        condensation happens.

        If we use almost enough insulation, we can arrange for that point to
        be far away from us -- i.e., the condensation will occur near the
        outside of the sleeping bag. We may be warm and dry, but the
        sleeping bag will be a little bit heavier every morning, unless we
        can dry it out during the day.

        However, as the moist air migrates outward, it is also encountering
        and mixing with the cold dry outside air, and it is getting "diluted"
        -- it is drying out, so its dew point is dropping, because its water
        burden is spread throughout a larger volume of air. As long as its
        dew point *at a particular point* is below the temperature *at that
        point*, no condensation occurs.

        So if we have lots of insulation *and* the insulation is loose enough
        on the outside to permit the outside air to mix with the outgoing
        moisture-laden air and dilute it, *and* the outside air is dry enough
        to absorb the extra moisture as it mixes with the outgoing air, we
        can end up with a system in which no condensation ever occurs.

        It obviously helps a whole lot if we can prevent that moisture from
        migrating outward, by using a vapor barrier which is *inside the dew
        point* (closer to our body than the point at which the actual
        temperature coincides with the dew point of the air). As long as the
        air outside of that barrier has a dew point at or below the
        temperature of the World Outside, then we stay warm and moist (not
        necessarily wet) inside the vapor barrier, and the sleeping bag stays
        dry outside of the vapor barrier. In order to be merely moist and
        not actually wet, we have to regulate our level of exercise and
        amount of insulation so we don't get overheated and sweat, thereby
        saturating the air within our vapor barrier and causing condensation
        next to our skin. We can also try to vent that moist air to the
        outside without letting it pass through the sleeping bag, get cold,
        and drop its moisture as condensation.

        That's basically how we manage condensation problems in houses.

        So here is what I *think* might be happening:

        At 08:45 AM 2/25/2006, Coy wrote:
        >Hi Paul
        >
        >I think there is more going on than just sweat. A thicker pad might
        >be the solution. I have observed that when I dont have enough pad I
        >get no condensation.

        The dew point of the air near your body is below the temperature of
        the outside air, so no condensation ever occurs. Cold, but dry.

        > When I had bearly enough pad I got quite a bit.

        Dew point is between your body temperature and the outside air
        temperature, so condensation happens at the point where the inside
        air migrates outward through the pad and gets cold enough to reach
        its dew point. Almost warm enough, but wet ... and the effectiveness
        of the insulation keeps going down, and the gradual evaporation of
        the condensation keeps stripping the heat away.

        > When I had plenty of pad I didn not get any.

        There is no point between your skin and the World where the dew point
        exceeds the current temperature. By the time the moist air gets to
        the World, it has been diluted/dried to the point where its dew point
        is at or below the dew point of the outside air. The fact that your
        pad is acting to some degree as a vapor barrier (blocking or slowing
        the migration of moist air toward the outside) helps a lot. The
        situation is stable, in that the effectiveness of the insulation is
        not degraded by moisture, and the heat gradient across the insulation
        (once it is established) is essentially constant.

        >pads were used for
        >the past decaded or so on the ground and you seldom heard all the talk
        >about moisture problems. Strange it crops up a lot more with
        >hammocks.

        I think perhaps this might be because there is so much more
        variability in the hammock situation ... 30-degree ground is
        30-degree ground, but the difference between 30-degree air at 35 mph
        with a dew point of minus 10 degrees and 30-degree still air with a
        dew point of 29 degrees is pretty noticeable :)

        Here's an interactive Java app for exploring the relationship among
        temp, dew point, and relative humidity:
        http://profhorn.meteor.wisc.edu/wxwise/museum/a7/a7exercise2.html

        Here's the formulas:
        http://www.engineeringtoolbox.com/relative-humidity-air-d_687.html

        Please tell me if you think this analysis might be correct.

        Lou



        >Some is real, some may even be preception from all the talk.
        >
        >Coy Boy
        >
        >
        >--- In hammockcamping@yahoogroups.com, "Paul V." <cruisenewsnet@...>
        >wrote:
        > >
        > > Hello - I haven't posted here for a while but I have been doing some
        > > hammock experiments, and am trying to work out a cool weather
        > > (30F-50F) hammocking system.
        > >
        > > Based on a couple of overnights, I'm at the point of thinking that
        > > closed cell pads are not the way to go in cool weather due to
        > > condensation issues, and I'm hoping that the underquilt that I ordered
        > > will improve things a bit. I am also working on a Risk pod to use as
        > > a windbreaker.
        > >
        > > I really like the clothing combination:
        > >
        > > (windbreaker - fleece - wicking undershirt)
        > >
        > > and I'm trying to imagine a similar combination for a hammock:
        > >
        > > (windbreaker pod - down or synthetic underquilt/topquilt - polypro
        > > longjohns)
        > >
        > > The goal here is comfort and I think this combination offers the best
        > > way of getting a lightweight comfortable cool weather system.
        > >
        > > I have been putting some thoughts and campout notes on a webpage,
        > > mainly so I can escape to the woods when sitting at my work desk
        > > cubical. I'm ready to go out and try again, but I'm patiently
        > > waiting on my underquilt.
        > >
        > > skylark
        > > http://cruisenews.net/backpacking
        > >
        >
        >
        >
        >
        >
        >
        >
        >
        >Yahoo! Groups Links
        >
        >
        >
        >
      • Dave Womble
        Welcome back to the site Paul. Hammock camping can work very well for the 30F to 50F temperature range. There are a multiple of schemes that folks have
        Message 3 of 5 , Feb 25, 2006
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          Welcome back to the site Paul.

          Hammock camping can work very well for the 30F to 50F temperature
          range. There are a multiple of schemes that folks have sucessfully
          used for bottom side insulation for their hammocks in that range of
          temperatures and I'm sure many of the folks here will share their
          experiences, thoughts and favorites with you. I doubt that there is
          an agreement on one scheme that is best for all possible conditions
          as the conditions can greatly vary with almost an infinately varied
          combination of wind, water, temperature and humidity. Most any
          scheme has conditions where it perform best and conditions where it
          performance may be marginal or not as desired as another scheme might
          be. For instance, when it is windy you might want something to keep
          the wind off of you, while when it is dead air you might want nothing
          to impede airflow. I have slept using a number of different
          underside insulations or combinations without problems over those
          temperature ranges-- closed cell foam pads, self inflating pads, down
          air mats, down insulation on the outside, etc. My feeling is that
          regardless of the scheme you chose to use if you understand how to
          use what you have-- appreciate and respect what it does well and what
          it doesn't do well, then you will likely do fine with it.

          There are certainly issues regarding overheating, sweat, wicking
          materials, breathable insulation and non-breathable insulation that
          one should understand just as one should understand issues regarding
          wind, evaporative cooling, wind blocking insulation, non-wind
          blocking insulation. Often what is the best solution for
          condensation issues in still air contradicts what is the best
          solution for staying warm in windy conditions so we usually just have
          to work out 'our best compromise' in selecting insulation schemes and
          deal with what comes along. Don't forget to be adaptable with what
          you select to use, just as you are adaptable with the clothing that
          you wear as you add or remove or zip-up or vent as conditions
          dictate. As the temperatures drop, mistakes are less forgiving and
          your most valuable asset is often the knowledge that you carry with
          you.

          I do like your site, thanks for sharing.

          Dave

          --- In hammockcamping@yahoogroups.com, "Paul V." <cruisenewsnet@...>
          wrote:
          >
          > Hello - I haven't posted here for a while but I have been doing some
          > hammock experiments, and am trying to work out a cool weather
          > (30F-50F) hammocking system.
          >
          > Based on a couple of overnights, I'm at the point of thinking that
          > closed cell pads are not the way to go in cool weather due to
          > condensation issues, and I'm hoping that the underquilt that I
          ordered
          > will improve things a bit. I am also working on a Risk pod to use
          as
          > a windbreaker.
          >
          > I really like the clothing combination:
          >
          > (windbreaker - fleece - wicking undershirt)
          >
          > and I'm trying to imagine a similar combination for a hammock:
          >
          > (windbreaker pod - down or synthetic underquilt/topquilt - polypro
          > longjohns)
          >
          > The goal here is comfort and I think this combination offers the
          best
          > way of getting a lightweight comfortable cool weather system.
          >
          > I have been putting some thoughts and campout notes on a webpage,
          > mainly so I can escape to the woods when sitting at my work desk
          > cubical. I'm ready to go out and try again, but I'm patiently
          > waiting on my underquilt.
          >
          > skylark
          > http://cruisenews.net/backpacking
          >
        • Steve Joiner
          Coy, from one Alabama boy to another - I appreciate the glass of tea analogy! ;^) Makes me think of having a cold glass of sweetened iced tea on the front
          Message 4 of 5 , Mar 3, 2006
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            Coy, from one Alabama boy to another - I appreciate the 'glass of tea'
            analogy! ;^)



            Makes me think of having a cold glass of sweetened iced tea on the front
            porch at my grandma's - sittin' in the glider, swattin' at flies..



            Steve



            _____

            From: hammockcamping@yahoogroups.com [mailto:hammockcamping@yahoogroups.com]
            On Behalf Of Coy
            Sent: Saturday, February 25, 2006 8:45 AM
            To: hammockcamping@yahoogroups.com
            Subject: [Hammock Camping] Re: Hammock camping experiments



            Hi Paul

            <clip> Ive thougth about it some and the only resonable explination I can
            come up with is a glass
            of tea sitting on the counter. <clip>


            Coy Boy





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