Cold Weather
Camping
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News flash! The 4-Season system has recently been tested by British
Commandos in Norway above the Arctic
Circle. Here's the review:
A TEST OF THE HENNESSY HAMMOCK IN AN EXTREME COLD WEATHER ENVIRONMENT
PROBABLY THE ONLY HAMMOCK NORTH OF THE ARCTIC CIRCLE
a Review by Ben Reynolds
Its indisputable. Hennessy Hammocks could well be the best in
the world. Light, durable, comfortable and excellently engineered
perfect
for warmer areas of the world, right? Well, you will have seen from the
website that ever evolving design solutions are attempting to expand
the boundaries of the hammock inhabitable world, from calm low lying areas and
comfortable lower
latitudes, to where the silent killer reigns supreme
. cold.
So, it was with Hennessy Hammocks Explorer Ultralite Asym, along with
elements of the insulated Superstructure
that I found myself in Northern Norway
in order to test whether the cold
can be defeated by this intruder from
the tropics.
THE TEST
CONDITIONS. The system was tested
in the area of 68º 33 37.12N
by 16º 58.54E,
east of Harstad, Norway. Initially
mild temperatures prevailed, fluctuating
around freezing, which resulted in
freezing rain, sleet and snow.
Though this is not the extreme cold
that was later encountered, it was
far more testing due to the freeze-thaw
effect and moisture content of the
air which accentuated the cold.
Minimum temperature encountered was
- 18ºC (0ºF) still air and
estimated at -30ºC (-54ºF)
with wind chill. Maximum precipitation
encountered was 7.5cm (3 inches) of
snow in 6 hrs. Click here
to read the entire review.
...CONCLUSION. The Hennessy
Hammock insulation system is capable
of supporting a lone traveller in
extreme cold weather environments
down to -12ºC (10ºF) in
the format tested. This was
dependent on the sleeping bag used
and a bag with a lower comfort zone
than that used in the test will similarly
reduce the -12ºC figure.
This figure will also be reduced by:
(1) adding insulation to the Under
Cover e.g. spare clothing/suitable
vegetation, (2) use of the Over Cover,
and (3) a solution to cooking which
would also heat the living space...However,
for those comfortable operating in
extreme cold the system works in all
respects other than the method in
which one can cook, but there must
be solutions out there.
Thanks to Ben for his detailed
and informative review!


Just thought I would share these with
you. My son and I went out this past
weekend in -10 degrees. Hammocks worked
out great.
Bruce
Nova Scotia
Letter from SuperShelter User
Tom.
I was given the SuperShelter system
a year ago as a gift and it is the
best. For starters your customer service
is number one. I had some issues setting
it up the first time out. Yea I should
have done it in the back yard but
just winged it. I called your company
with my cell on the trail. I ws shocked
when you called me back within 15
minutes personally and explained what
I was doing wrong. I had no more problems.
After more than a year of heavy use
it held up great. Going to order a
new underpad before next winter. Considering
the use and abuse of my Explorer Deluxe
and the SuperShelter system it has
proven extremely durable but everything
has limits. I am very hard on gear
and have owned my hammock for two
years now sleeping inside the thing
for weeks on end. The system alone
keeps me cold-back-free down to about
35. Toss in my jacket and sometimes
a poncho linr and I have taken single
digits with a proper sleeping bag.
But that is just me. Everyone is different.
Once weathered a heavy snowstorm inside
my SuperShelter. The wind proof bottom
cuts the wind chill perfectly. Even
in the summer I use the silnylon bottom.
Keeps the bugs off the bottom of the
hammock.
The overall comfort of the hammock
is outstanding and I just want to
thank you personally for making such
a great product and your fantastic
customer service. Thanks again for
those hammock camping tips. They came
in useful. Sincerely, Kevin Renkavinsky
"Total Satisfaction!"
I purchased my first Hennessy Safari
Asym Hammock back in January of this
year. Living in South Carolina, I
had several opportunities to use it
in February and March when the weather
was not too cold (i.e lower than freezing). Total
Satisfaction! Seem to remember
many vows of never sleeping in
a tent again during those initial
nights. However, several
weeks ago, I decided to give it a
try on a backpacking trip with the
Boy Scouts. Being the CubMaster
for the Pack associated with the Troop,
the Boy Scouts needed some additional
adult leaders for their "most
strenuious backpacking trip of the
year" up Mt. Mitchell in North
Carolina. During the second
night of our trip, at an elevation
of 6,000 feet, we were hit with what
was supposed to be a "potential
light dusting of snow". That
night, I experienced first hand how
this hammock holds up in extreme conditions
to include 30-40 mph winds, rain,
sleet, between 6-12" of
snow, and temperatures of 5 degrees
F with windchill. Surprisingly
- Total Satisfaction! Other
than what one might call "periods
of excessive rocking", I stayed
relatively dry and warm!
I used my
North Face bag rated at 20 degrees
with a Thermarest RidgeRest foam pad.
I slept in a pair of milano
wool thermals. As the sleet
started coming down, I decided to experiment
with using an old military issue solar
blanket. I placed it under my
foam pad and wrapped it completely
around my sleeping bag. This
kept me nice and toasty. Unfortunately,
the outside of my sleeping did get
a little damp from the condensation
that was collecting on the foil.
The downside was I had several adjustments
to the rain fly to make throughout
the night due to the unexpected
high winds and my lack of experience
in using the gear. In addition,
in the morning, the half-hitch knots
that I used to tie the hammock to
the trees were covered in ice and
frozen solid. I poured the
last of my hot morning coffee to melt
the ice and loosen the knots.
After that, I had the entire hammock
balled up in my pack within 2 minutes.
Given the weather conditions, I slept
very well and stayed warm through
the night. On our 8 mile
trek out in the snow, I kept hearing
comments from the scouts - that
they had never seen anyone with a
tent hammock before, especially in
the snow and how they were going
to have to get "one of them hammocks"!
- Jim Towler
Always check your gear before
you go!
Always
test your gear close to home before
you start out on your trip, especially
if you're setting our for some cold
weather camping. Everyone has a different
metabolism (in the winter, some folks
sleep with the windows open, some
with the heat turned all the way up)
and everyone needs to find the right
combination of sleeping bag and insulation
-reflector pad, closed cell foam pad
or car windshield reflector.The
hammock fly can be tied down close
to the hammock like a tent. Even in
the winter, the mosquito netting serves
a useful purpose. The fine weave of
the mosquito mesh blocks out about
90% of the wind and provides a calm
space inside the hammock, even when
the fly is not fastened down as low
as possible. For winter camping, you
should think of polar fleece clothing,
mittens, gloves & booties.
Test
Results - Winter Camping in Hennessy
Hammocks
Hennessy Hammock participated
in a gear test with BackpackGearTest
which tested the Ultra Light Backpacker
1.5 Hennessy Hammock and also tested
several radiant reflecting materials
and other strategies for staying comfortable
at low temperatures.
Radiant Reflector Theory (as I
understand it)
First you need a radiating heat source
which is your body. Opinions differ,
but somewhere between 19 and 50 per
cent of your body's heat is radiant.
Then you need a radiant reflecting
surface like highly polished space
blanket material or aluminum foil.
But most importantly, you also need
a dead air space between you and the
reflector. This is where those invisible
little wiggly red arrows radiate from
your body across the dead air space
and bounce back off the reflective
surface which causes a warming sensation,
as if you had some kind of heat source
under you. The closer the reflective
surface is to your body without touching
you, the more efficiently the radiant
reflector will work.
Without that dead air space, your
body will be directly against the
radiant reflector and your body will
conduct much of its heat right through
the radiant reflector with very little
benefit from the reflector.
The First Experiment: Emergency
Space Blanket
An emergency space blanket was tested
as a lightweight radiant reflector.
The most important feature of a space
blanket is it's ability to bounce
back radiant heat that would normally
be lost through the sleeping bag insulation
compressed beneath your body. When
used inside the hammock. it was found
to be extremely noisy whenever the
occupant moved. It also had a tendency
to shift and was difficult to adjust
beneath you. When the space blanket
was placed over your sleeping bag
in the hammock, large drops of condensation
would form on the underside of the
space blanket within 3 to 6 hours.
When the space blanket was suspended
under the hammock, there was much
less noise and and no adjustment problems.
When the space blanket was adjusted
properly and close fitting to avoid
drafts, a high percentage of the radiant
heat that would normally be lost was
reflected back to make the compressed
insulation of your sleeping bag even
warmer than the uncompressed insulation
above you.
The Condensation Factor While
the space blanket reflector does a
pretty good job of keeping the bottom
of the hammock warm and windproof,
I still consider the space blanket
as emergency equipment only. The downside
of this solution is that when warm,
moist air surrounding your body contacts
the radiant reflector cooled by the
lower temperature air moving under
the hammock, condensation will occur.
For temperatures below 50 degrees,
you will probably require additional
insulation.
One solution is to flip the space
blanket over after a few hours putting
the droplets of condensation attached
to the space blanket on the outside
where they will evaporate in the breeze.
The real solution is to put some insulation
under the space blanket to minimize
condensation and that's covered under
hammock Pads in the paragraphs
below.
To use the hammock as an emergency
heat reflector, just put it under
the hammock and tie the two corners
at each end up over the ridge line
with a small reef knot. One of the
guys at EcoChallenge Borneo showed
me this trick and the space blanket
fit like a diaper - you won't believe
how well it works!
Hammock Pads
The next step in the search for the
perfect pad was for a lightweight
radiant reflector with attached insulation
to prevent condensation build-up inside
the hammock. We are also looking for
a pad that does not interfere with
the comfort of the hammock, does not
pop out from under you in the middle
of the night and provides comfort,
efficiency, light weight and low cost.
Hammocks need a different kind of
pad than a tent. Pads for tents are
usually 20-24 wide and
thick enough to provide softness against
the hard ground. Pads for hammocks
do not need to provide any softness
because the hammock is softer and
more comfortable than any pad.
A pad for a hammock should be wider
than a pad for a tent because a hammock
conforms to the shape of your anatomy
and the pad needs to insulate more
of your body area than a tent pad.
Ideally, the hammock pad would be
as thin as possible so as to not interfere
with the comfort of the hammock and
provide enough insulation for the
seasonal conditions. Thick foam or
inflatable tent pads are designed
to lay on a relatively flat surface.
When used in a hammock, they are bent
into compound curves which act like
a loaded spring causing the pad to
pop out from underneath you when given
the first opportunity. This is most
inconvenient when you wake up at 3
AM with a cold shoulder or hip and
realize that the pad is sideways and
that you will have to unzip your sleeping
bag and sit up losing valuable
body heat find the pad and
wrestle it back under you. Then you
have to zip up the bag and try to
get warm again and back to sleep.
Auto windshield heat reflector
pad
There are several types of auto windshield
reflector pads. Some are folded cardboard
with foil on one or both sides, some
are a double layer of bubble wrap
with a layer of aluminum foil laminated
to each side and my favorite has 1/8
polyethylene foam with a piece of
space blanket laminated to one side
only.They come in all different sizes
depending on the size of vehicle windshield.
They will roll up to almost 2
in diameter and are around 4.5 oz.
One nifty trick is to put this pad
inside your sleeping bag so that it
will stay aligned to your sleeping
bag. If it does need a little adjustment,
it is inside the bag and you can adjust
it without unzipping your bag, losing
body heat or waking up too much.
Tom’s experiment with Reflectix,
windshield reflector pad, and fleece
I spent a couple of nights in the
bush in September 2001 to experiment
with reflector pads. Temperatures
were in the mid 40s F (7ºC).
None of this was very scientific,
but the results were impressive. I
used a 40" wide x 60" long
piece of REFLECTIX tapered at the
foot to 18" wide, a double layer
of bubble wrap with aluminum foil
laminated to both sides available
(in different widths) from Home Depot,
and an AUTO WINDSHIELD REFLECTOR PAD
1/8' of polyethylene foam laminated
to space blanket material. Comes in
different sizes depending on the size
of your windshield/body. I’ve
heard that Wal-Mart has the biggest
ones made for big trucks.
I sewed a piece of heavy fleece to
the reflective side of the windshield
pad but wearing a fleece suit would
be as good or better. The fleece is
important because it is fairly uncompressible
and contains tiny air spaces necessary
for radiant heat to pass through before
it is reflected by the pad back to
your body. Heat intensifies and, to
me, felt like I was laying on some
kind of solar cooker turned down to
"warm". If your body is
directly on the pad without the air
spaces, you get the insulation benefits,
but not the radiant benefits.
It was so comfortable that I did
not need to be inside my bag so I
just lay it over me like a quilt.
Quilts seem to work well because they
usually don't fall off because of
the shape of the hammock. This was
the most comfortable cool night I
can remember.
Conclusion: Reflectix is an
insulation manufactured mostly for
the construction industry. It is used
as a radiant insulating barrier in
walls and wrapped around hot water
heaters for additional insulation
and also recommended as insulation
for camping tent floors and insulation
for hot and cold food containers.
It is constructed of a double layer
of bubble wrap with a layer of aluminum
foil laminated to each side. It is
around 5/16 to 3/8 thick
and weighs about the same as foam
pads of the same thickness.
The reflectix has several drawbacks.
The raw aluminum will tarnish after
a while, reducing it's efficiency.
It is bulky and not as efficient as
as the same thickness of foam and
radiant reflector combinations. It's
biggest problem is the heavy aluminum
foil which is laminated to both sides.
While it does reflect radiant body
heat quite well, it also acts as a
heat sink and the aluminum foil will
suck heat out from under you wherever
the aluminum foil is exposed to the
cold air.
The windshield reflector pad is a
much better solution to the problem.
The closed cell foam is a better insulator
than the bubble wrap and less bulky.
The thin micro coating of aluminum
reflective material is protected under
a plastic coating, eliminating any
tarnishing or any tendency to suck
away body heat like the Reflectix
did.
The dead air space between you and
the reflector is an essential factor
in the formula for radiant effficiency.
If you sleep inside of your sleeping
bag, the compressed sleeping bag insulation
under you should have enough dead
air space to allow the radiant pad
to operate effectivelly. If you sleep
directly on top of the radiant pad
with your sleeping bag fully opened
and laid over you like a big quilt,
fleece material is probably the best
way to get that dead air space between
you and the reflector pad. For winter
use, the fleece pants and fleece top
make more sense since they are usable
both day and night. Of course, fleece
booties and fleece cap would really
top it off. When wearing fleece clothing,
you slip around quite nicely on the
pad.
A windshield reflector pad facing
up on top of a 3/8 inch thick urethane
foam pad should take you down to around
freezing. Ultralite backpackers will
cut the full size 3/8 foam pad down
to 36 inches long and keep the full
length reflector because there is
less weight and pressure on the pads
under their legs. Total weight of
this set-up is about 11 oz.
So far, this is the extent of our
search for the perfect lightweight
radiant reflector pad. The automobile
windshield reflector pad offers attached
insulation to prevent condensation
build-up inside the hammock. It is
flexible enough and does not interfere
with the comfort of the hammock, nor
does it pop out from under you in
the middle of the night. Used in combination
with additional foam pads of less
than 3/8" provides comfort, efficiency,
light weight and low cost.
Feedback:
Gear Report from Rob - the long winded.
(I call him toasty now)
Hennessey Hammock (original) -
The love fest continues. Someday
I might upgrade to the ultralight
to save a pound; otherwise the perfect
shelter. WM Aspen bag, Jagbag liner.
Reflector: Recently Tom Hennessey
has been discussing strategies for
staying warm in the HH. One item he
mentioned was a windshield reflector
with fleece sewn on one side. The
fleece provides a non compressible
barrier, creating the airspace needed
for the reflector to work. Not being
the sewing type, I hot glued fleece
to a truck windshield reflector. On
the first night, I had some trouble
getting into my silk liner while staying
on top of the reflector. The second
night, I skipped the liner and slept
directly on the fleece. Both nights
I piled the unzipped sleeping bag
around me like a quilt. Toasty the
whole time. Rob
Feedback:
Better than any tent...
I have good news for any Hennessy
users who are contemplating using
their hammock in cold (well, cold
for me) weather. I went with my sons'
Boy Scout Troop on a hike/campout
in the Jefferson Wilderness in Oregon.
Temperature Sat, night dropped to
20ºF. I am ecstatic to report
that I slept better in my HH Expedition
than I have in any of my tents, at
any temperature. Hated to have to
get up Sun. morning, I was so comfy.
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