[pct-l] Re: Gear Tradeoff -- Tents versus Sleeping Bags

[mardav@charter.net (Marion Davison)]

Absolutely, one should add in these factors.  Two bodies warming up a small
space will add greatly to the warmth inside.  My four-person dome is huge, and
two people can't warm it up, especially with all the cold air coming through all
that mesh.
I took an alpine survival course at Yosemite Mountaineering  School in the 70's
in which the instructor discussed  sleeping under the stars (no tent) versus
sleeping in a tent.  He contended that one sleeps much warmer in a tent because
the roof over your head reflects your body heat back to you and warms up and
stills the air space you are sleeping in.  If you sleep under the stars all the
body heat just ends up in outer space.  He also pointed out that clear nights
are the coldest nights, because all the solar heat retained by the earth and
rocks during the day just goes out into space at night.  A cloud cover will
reflect some of that heat back to earth, so cloudy nights are warmer. On cloudy
nights there is typically much less wind as well.   Sleeping in a tent is like
bringing your own cloud cover with you wherever you go.
Since none of us sleeps in an electric sleeping bag, body heat is all we have to
warm up our bag and our tent.  Everything we can do to retain that is for the
good.  Hence the need to go to bed well fueled and properly housed.  I won't cut
corners in this area.
This is all very elementary, but worth revisiting from time to time.  I consider
nighttime rest and comfort essential.  I can't hike a 15 mile day (typical
distance for me and my llama crew) if I didn't sleep the night before.
The issue of condensation is tricky.  Of the three tents I discussed, the Meteor
Light had the least problem with condensation that ended up on the occupants.
The Sphinx tended to collect it on the inner wall, and the vertical ascent
collects it on the inside of the fly, which can build up to the point that it
drips onto and through the mesh onto the occupants.  I keep a trail towel handy
to mop it up.  The tent works fine in rainstorms, and it is very nice to have
all that living space when we are pinned down for many hours in a prolonged
storm.
Marion Davison, "llamalady"

"Reynolds, WT" wrote:

> Marion's posts seems to confirm my earlier impression that the weight of a
> good tent is offset by the weight of the sleeping bag.
>
> This summer I slept out at 27F one night, then slept alone in a Stephenson
> 2RS another night where the temperature was approximately the same. The
> difference was amazing.
>
> Also, my experience is that the smaller the tent the more heat retained. I
> believe that Marion's data showing the difference between the Sphinz, the
> Meteor Light and the Vertical Ascent is partially the result of tent size
> rather than design. Standard double wall tents are designed to pass water
> vapor through the inner wall, mesh or not. Condensation typically occurs on
> the rain fly.
>
> Finally, my data is with two people in the tent, not one. Sleeping with two
> people in a Stephenson 2RS, the condensation is noticable but the tent is
> very warm inside. With one person there was very little condensation but the
> temp differential was less.
>
> In general I think that a single wall tent, or Tarp, is about as efficient
> at keeping heat inside as a standard double wall tent. On cold nights, if
> one closes down the tent, or tarp, it will make a big difference. My
> experience with Stephenson Tents indicate that the double wall design with
> BOTH wall impervious to water vapor creats a storm window effect. The
> Stephenson sleeps ten degrees warmer than the average double wall tent where
> the inner wall is designed to pass water vapor.
>
> Tom
>
> -----Original Message-----
> From: Marion Davison [mailto:mardav@charter.net]
> Sent: Friday, September 20, 2002 10:09 PM
> To: Hiker97@aol.com; PCT List
> Subject: Re: [pct-l] Netting Tents
>
> ALthough this has nothing to do with ultralight tents, I do have some input
> on the quantity of netting in a tent and temperature range.  When we
> backpacked, we used a Sierra Designs Sphinx.  It had very little net (a
> front door and a small back window).  It got a lot of condensation but had a
> 10 degree temperature differential from outside (consistently ten degrees
> warmer than inside.  We know this because we like gadgets, and carried a
> talking indoor outdoor thermometer.   When we took up llama packing we
> switched to a Sierra Designs Meteor Light, which has very large mesh panels
> on top and a full coverage rain fly.  With the fly on the temperature
> difference dropped to six degrees.  There was a lot of cool air traveling
> through all that mesh.  We got even more luzurious over time, as we
> got a third llama, and last year got a 4 man 9 pound dome tent made by
> Vertical Ascent that is all screen starting at about 6 inches off the
> ground.  With the full coverage fly on, there is only a three degree
> differential.  I have also noticed that the screen cuts down on  light wind.
> But we really enjoy this tent.  We get in to camp, put it up and assemble
> all our gear inside, lay down and watch the sun set, the alpenglow climax
> and fade, the llamas graze, the stars come out, the bats fly over.  When we
> are ready for sleep we put on the fly.  There is nothing like having that
> 360 view in complete comfort in a gorgeous place every evening  for a month.
> Marion Davison  "llamalady"
>
> Hiker97@aol.com wrote:
>
> > I am currently using the MSR Bug Hut 1 tent (under 2 pounds).  I was
> wondering if others have similar experiences when using net tents (I use a
> Integral Design tarp for rain).  Maybe I am imaging things, but it seem it
> is warmer in the tent than outside.  I think it has something to do with any
> breeze/wind being broken up by the netting.  Inside it is always calm and
> nice.  Weird.  Also, the netting seems to have some minor rain shedding
> characteristics.  For more room, you can just roll up your sleeping bag for
> the foot area (making it higher) and you have a nice full length
> freestanding one person tent.  Great for a meritorious combat nap in warm to
> moderate weather.  Have others found the same things using a netting tent?
> Off to Mt. Whitney country this weekend. Thanks, Switchback
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