423RE: Hammock Camping Bottom Almost Quilt for HH...
- Feb 5, 2003
MessageWhile I haven't tried exactly what you're suggesting Flyfisher, I have noticed that any dead air space is better than none at all. Of course the smaller the dead air spaces in an insulating thickness, the slower the overall heat loss and the better it works. For instance skirting around a moble home works wonders keeping out cold wind; thus the house is warmer and heating bills are lower. However, my limited experience with large dead air spaces beheath my hammock is that they are significantly colder than filling those spaces with insulation. In fact it is often warmer to eliminate the large dead air space and relpace it with a much thiner insulation. For instance, when my PeaPod sleeping bag is kept open on the top, it can sag below the bottom of the hammock and create a large dead air space there (6-10" deep). It can be significantly warmer on my bottom to tuck up the PeaPod to elmininate this dead air space and bring the 0.8"-thick PeaPod insulation right up to the bottom of the hammock.The Clark Jungle Hammock, a very adequate camping hammock, has 6 large gear pockets beneath the hammock fabric. The pocket fabric is the same non-breathable fabric as the hammock. Filling the pockets with gear, clothes, leaves, etc. creates a bottom insulation similar to your ideas (and others posted previously on this List). While the bottom pockets are handy, they must be fully stuffed with gear or clothes to provide adquate insulation in cool weather; I found that only overstuffing them with leaves worked in below freezing temps. Thus, in cold temps, the bottom pockets worked best when large dead air spaces were replaced with tiny dead air spaces.The double-bottom idea you mentioned is employed in several hammock models--but I suspect, it's still necessary to add proper insulation in cold conditions.Dead air space is the best insulation---it just takes a hell of a lot of them to be warm! But even a sleeping bag which has millions of dead air spaces does not stop heat loss--it only slows it down long enough for one to get a good night's sleep. If you have too few dead air spaces around you, the heat loss is too fast.The various systems most folks are describing on this List employ a combination of items, such as 1) one or more wind blocking fabrics to create a large dead air space, and 2) one or more insulation layers consisting of millions of tiny dead air spaces. Some of us also emply a radiant heat reflector fabric...Ed
Ed's use of leaves between the hammock and the pea pod bottom started
me thinking of other ways to have a breathable dead air space. I
began to think of carrying just a nylon shell which velcros to the
bottom of the hammock and which could be stuffed with dry leaves.
But what if there are no dry leaves? Well, clothes could work in the
space under the hammock... or rain gear, or rucksack.
But if that works, why not just the nylon shell alone hanging a
couple inches below the hammock - or perhaps two layers which are not
quite the same size, so they hang away from each other. How about
sewing "tubes" which self inflate because the bottom cross-section of
the the tube is a little longer than the top of the tube and the
bottom hangs down a bit more?
True, there will be convection currents in the air filled spaces
which will not work quite as well as space filled with down or other
insulation... but it might be quite good enough for most cases.
Rick aka Flyfisher <><
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