Risk's Cold Weather Experiments

An Infrared Thermometer

It is important with the thermometer, to keep it warm before use. If it becomes cold soaked, the temperatures it reports are about 10 degrees too cold. I keep the thermometer in the sleeping bag for that reason.

Risk's Cold Weather

Experiments 03-04

A second year of tests!

Click here For the 02-03 cold weather tests

Last night I took the opportunity to check out one of the edges of the envelope.

The snow was peculiarly crunchy as I walked out to two exposed trees. Frigid air froze in my nostrils as I began tying the hammock up. The cloth of the hammock seemed no more stiff than normal, but those pieces of blue Target pad sure seemed a lot more stiff than usual.

I was wearing fingerless gloves so I could use my fingers to set up the hammock and its equipment. I had to stop every few minutes to warm up the ends of the fingers.

Did I mention? The outside air temperature was -5.1 degrees by my weather station digital thermometer, just before I stepped outdoors.

I was wearing a cotton tee, nylon swim suit, micro-fleece pants, a fleece top, and a pair of poly socks. On my head, I had a Psolar BX balaclava. I was wearing a jacket as well.

I set up the WarmHammock with an OverlapPad, overlapped the length of the hammock about a foot. Inside the foot box of my Risk's Bag quilt, I had stuffed a 24x18 inch piece of target pad. I rested my feet on that piece as I tucked my feet in the bag and laid down.

Over the outside of the hammock and quilt, the TravelPod was zipped up. I took the coat off and used it as a pillow and to take up space in the head of the hammock.

In my pockets, I carried a small handy wipe towel to occasionally clean frost off the inside of the TravelPod above my mouth. I had a knife incase the zipper froze and I was trapped in the TravelPod. I also carried my IR thermometer in a pocket.

Ten minutes after zipping up the TravelPod, my fingers had warmed up and I was feeling nice and toasty. Inside temperature of the quilt over my navel was 69 F. Skin temperature there was 79 F. Temperature of the coat I was using as a pillow was 28 F. Temperature of the outside of the warm hammock (inside the TravelPod) was 14 F.

I woke up about 2 hours later and did a second set of temperature measurements. Inside the quilt, it was 72 F. Inside my fleece, abdominal temperature was 88 F. The pillow coat was 18 F and the outside of the hammock was 10 F. The outside air temperature was later found to be -10 F with 10 mph wind at this point. That makes for a wind chill of -28 F.

Morning was approaching at 0430 when I decided (loneliness) to go back inside and warm up next to EllieD. I felt very warm in the hammock. However, when I unzipped the Pod and turned to put on my shoes, I found that I had involuntary cramping of both my calves. From these "Charley Horses" I believe that the muscles were a chilled.

BTW, I put my glasses on and turned on a head light as I was opening the Travel Pod. It was a total gas to see the steam rising from the sleeping pad and the hammock as I opened the TravelPod! That pod had trapped a lot of warm moist air. Now it was suddenly released into the black of the cold early morning.

I untied the knots from the trees, zipped the pod up around the quilt and hammock and carried the bundle inside, Santa style.

I went ahead and got up at 0600, dressed and took a 4 mile day hike with a hiking friend in Glenn Helen, a local park. For reasons I could not understand, there were no other hikers. It warmed up to -3 degrees before we finished at 0930!

The following paragraphs documents my cold weather experiment last night. I will try to describe the weather, the set-up, the results, and my feelings during the outdoor stay.

Weather:
Forecast for 4 F (-16 C) and windy; the actual temperature dropped for three hours to 5.0 F (-15 C) with winds of 10 - 15 mph (16 - 24 kph). Giving a wind chill as low as -15 F (-26 C).

Set-up:
I set up in open woods, which partially blocked the winds. I was not protected by walls, rocks, or any land form.

I decided to not use the tarp. I set up my new version WarmHammock, made with 2 oz nylon taffeta, and it's integral 4 ft (1.2 m) long x 3 ft (1 m) wide PG2 insulation layer. into this I put a 3/8 inch thick closed cell pad, and my Risk's Bag, used as a quilt. I put a small piece of closed cell pad in the foot of the bag to insulate my feet from the outside of the hammock, where the down was compressed. Over this, I used the 1.2 oz ripstop TravelPod. I put nothing in the travel pod under the hammock.

I was wearing a polyester bathing suit with net lining, and a cotton tee shirt. Over this I wore a medium weight fleece pull over and a pair of lightweight fleece pants. I wore a jacket to the hammock, and used it as a pillow inside the hammock once I laid down.

I left my shoes on the ground beneath the hammock with my glasses and head light in them. I kept a handiwipe towel in my left pants pocket and a pocket knife and Fluke infrared thermometer in the right pocket. On my head I wore the Psolar BX fleece balaclava with countercurrent module.

I found it most comfortable to sleep on my back, stretching out one leg, and slightly bending the other to support that leg under the calf with my head on the side of the hammock with the bent knee. I alternated sides every hour or so when I would wake with a feeling of needing to turn over. (I sleep very lightly.)

Results:
First, let me say that I was very pleasantly surprised that I slept quite warm. I could hear the leaves blowing beneath me in the wind, but had no cold spots. My skin did not cool to the touch, even on my back or bottom. I needed to get up once (at 0230) for a potty break, and the hammock warmed up quickly once I got back in.

Though the air temperature was about 7 F, (I will stick to F measure here, because of the number of measurements given) the ground and the bottom of the hammock read colder than this temperature, because of radiant heat loss. They read between 3 F and - 5 F. This was true nearly all night.

The temperature of the outside surface of the hammock's insulation layer was about 25 F. The temperature of the pad and of the top of the sleeping bag inside was a constant 78-79 F. The temperature of my skin under the fleece (top and bottom) was 90 - 92 degrees. I measured these areas almost every hour from 11 PM to 4 AM and saw no change.

The temperature inside the travel pod (actually the coat in the space above my head) was about 25 F. I did note condensation on the inside surface of the travel pod directly above my face. A small area was often moist in this area. A larger area had a thin coating of frost on it. Several times during the night, I used the lightweight towel in my pocket to wipe the frost off the inside surface of the TravelPod.

Feelings:
As I trudged down to the spot chosen for the night's stay, the ground had frozen very hard under my feet. Instead of being a smooth surface, the leaves were propped at unusual angles and the ground made uneven by knobs of frozen mud under the leaves. I thought how very uncomfortable it would be to sleep on those rock like knobs. It reminded me of pock marked rocks, or a parking lot made of stone crushed to four inch diameter stones. - not the kind of area I would like to sleep on.

I had slept in this same spot a year ago. I had not been back since. This was in the area near the barn and I wondered if the sheep would come out to investigate. They didn't, but one of the barn cats came out to see what the white devil was doing out on a cold night. (And did he bring food?) She lost interest during one of the blasts of frigid air and hustled back to the barn.

I put the layers in place, noting that the foam sheets were quite stiff in the cold. It was already 9 degrees, and forecast to get a lot colder. I thought back to my escape plan: The garage door was unlocked, and the light left on.

I had considered the possibility that my breath would cause enough condensation that the zipper on the Travel Pod might freeze. For this reason, I had the knife with me and was prepared to use it if I could not otherwise open the zipper. I saw no reason to freeze to death, frozen inside and impenetrable 1.1 oz piece of ripstop, just because I could not get the right purchase to tear its seams.

It was pleasing to again note how well the countercurrent heat exchange element of the balaclava kept my face warm and decreased the amount of condensed breath blowing downwind away from my face. It was somewhat alarming to see how fast that breath did blow away. This was not going to be a trivial night.

I took off my coat, wondering exactly what was driving me to do something as stupid as this, and quickly took off my shoes. Sliding my feet into the foot box of the quilt, I reached down and zipped the travel pod up to my waist. Laying down, I arranged the coat to be a thin pillow (insulating my head from the bottom of the hammock) and tucked the top two corners of the quilt between my shoulders and the sides of the hammock. Then I reached down to pull the zipper up to well above my head, leaving a one inch hole between my coat and the top of the zipper. I allowed my bare hands to warm up under the quilt, on top of my chest.

After a couple minutes, it was obvious I was really quite warm. I could feel no cold spots on my back, and I began to smile. This might really be a lot easier than I believed it could be. Certainly, it felt a lot better than my 5 degree stay in a HH last year.

The pad under my feet really was keeping them warm and toasty. No cold spot under the heel at all! My shoulders were warm.

I pulled the thermometer out of its pocket and took a few readings. Wow! It really was warm. Amazed again how well a body heats an effective insulated cocoon, I settled down to sleep. And each time I woke - with a bit a crick in a knee, or an itch of my nose, - usually about once an hour - I began to realize that I was not only surviving, I was comfortable. Really comfortable.

I began to run out of a desire to sleep somewhere about 4 AM. I determined to stay out until 4:30 and then go in to spend an hour with my wife. And so I did - happy that the system worked and happy to have a near ultralight system of my own devising which will keep me warm in the wildest of AT weather I could reasonable expect on a northbound hike.

The night was forecast for breezy and 17 F (-8 C). I have recently been working on the TravelPod, a simple hammock sack made of 1.1 oz ripstop. I had just completed a new version of the TP with integral support lines. The forecast looked good for a test.

I tied up the quarterweight double bottom hammock and inserted the overlap pad. I did not select a site protected from the wind in any way. Into the hammock went my 0ne pound Bag/Quilt. I slipped the TravelPod over the hammock and tied the suspension lines. I took off my three season jacket an put it between the layers of the double bottom. In the TravelPod, I put my 5x10 foot tarp and my pack with a plastic bag liner. They made for nice insulation.

I wore the PsolarBX balaclava, a tee shirt and medium weight fleece overshirt, a pair of nylon swim shorts and long legged twill (cotton and poly) pants. On my feet I had a pair of medium fluffy Gold Toe socks. I left my sandals on the ground at the middle of the hammock for those middle of the night bio breaks.

At 10:30 PM the outside air temperature was 26.6F (-3C) and wind 8 mph (13 kph).
I woke up about midnight. The outside air was 25F (-3.9C) and wind was 10 mph (17 kph). The temperature inside the hammock about 10 inches toward the tree from my head was 35 F (1.7 C). The temperature in the quilt was 94 F (34.4 C).

I woke up about 2 AM. The outside air was 25F (-3.9C) and wind was 12 mph (19 kph). The temperature inside the hammock about 10 inches toward the tree from my head was 33 F (0.6C). The temperature in the quilt was 92 F (33.3 C).

I woke up just before 5 AM, time to get up for work. The outside air was 21F (-6.1C) and wind was 8 mph (13 kph). The temperature inside the hammock about 10 inches toward the tree from my head was 32 F (0 C). The temperature in the quilt was 96 F (35.6 C). I felt my skin where it could come into contact with the hammock. The skin was a little chilly over my right knee as I had been sleeping on my side for a couple hours. My bottom was warm. Each shoulder felt a little chilly on the skin. My toes were wonderfully warm. I felt fine, but not toasty.

I had slept the last 5 hours or so with the TravelPod closed over my head. There was no condensation or frost on the inside of the travel pod. The balaclava had done its job of keeping my lungs moist and my TravelPod dry.

Lesson learned: I need to improve the insulation on the sides of the Travel Pod. For that purpose, I plan to sew a couple inside pockets to stuff my FroggToggs. Jacket on one side, pants on the other.

The question came up on the hammock group about why we might experiment with cold weather:

You good folks seem to be expending a lot of effort to be able to use the hammock in cold temperatures. Pads, pods, under quilts, space blankets, bivy sacks. Have you considered it may not be worth the trouble?

LOL! Well, as a confirmed cold weather hammock junkie, it might be worthwhile to speak to the issue.

If you just want to meet a challenge, then that's a different thing. But there may come a time (November-March???) when you must resort to a Thermarest, down bag and (Heaven forbid) sleep on the ground.

You bring up a good point. Once in a while, I need to remember why I am working on cold weather hammock experiments and equipment.

Part of it is the engineering challenge. Heaven help me, part of it is old fashioned "one-ups-man-ship.” But the real interest is exploring the edges of the envelope because hammocks sleep so much better for me than the ground. And I *want* to be able to use the hammock all year for camping.

For me to feel comfortable taking a hammock in the southern AT woods in October, I need to know from my personal experience that I can sleep comfortably at 30 degrees, because it sometimes gets down that low. To take it with me in November or December, I need to know it works at 10 degrees. I need to know that I can carry what I need to do so in an ultralite mindset.

I do have fun sharing my experience, mainly because others seem to find it interesting. Maybe they are trying similar things themselves and maybe I will learn something from them. Because of the fun we have been having.

I disagree (respectfully) that one must resort to a Thermarest and sleep on the ground from November to March. Maybe that is true for a few weeks in January. I don't know yet. I do know that with 8 ounces of TravelPod and my summer load, I can now spend comfortable nights in a hammock down to 21 degrees with 12mph winds gusting to 18. I did last night. It is the coldest night we have had in Ohio so far this year.

Personally, I *hate* sleeping on the ground in November and March-April. It rains so much! I really do not like sleeping on the ground in the rain. I worry about the tent floor. I worry about my sleeping bag getting wet. It feels so good to be a couple feet above the squishy mud.

If we can push the barrier back to below 0 degrees then the whole year is open to hammock camping for the southern parts of the AT and I can feel comfortable that a hammock thru hike can work from beginning to end, regardless of how cold early March is on a particular year.

That’s my $.02 - It's an old engineering concept. Test at beyond the conditions I ever expect to use operationally.

It got cold in Dayton last night. The prediction was for high 20s, so I put up the hammock.

Equipment: Risk's Bag, tightened around my neck, fleece balaclava, polypropylene long underwear tops and bottoms, nylon shorts. Sealskinz socks over polypropylene socks. Quarterweight hammock with bugnet closed and with Target overlap pad. 5x10 foot tarp over hammock.

I was nice and warm all night. I had been concerned about the wind when I went to bed. The tarp protected me well from its effects.

I am beginning to understand that I need to collect some data to determine how well the hammock/pad/bag combination is doing with various weather conditions. Toward that end I began recording some measurements of temperature with the Fluke Infrared Thermometer.

Equipment: Risk's Bag, tightened around my neck, fleece balaclava, polypropylene long underwear tops and bottoms, nylon shorts. Quarterweight hammock with bugnet closed and with Target overlap pad.

Process... try to be patient as I explain my thought process over the last couple days.

After I got a little cool on my backside the other night with a Target Pad at 50 degrees, I began weighing my options, and the stuff I am going to need to carry.

I rooted around behind my bed and found a semi-mummy type bag from years gone by and opened about 6 inches of the stitching down in the foot box. Then I untied one end of the hammock, brought the hammock through the hole and tied it back up. I took the pad out of the hammock. Then I sat down in the hammock, and pulled the zipped up hammock up to my neck.

I found out two things from this experiment:
- 6 inches at the foot is too much. Al that is needed is a 2-3 inch diameter hole.
- Since I felt cold air on my upper back, I realized that the bag was hanging open under me and I needed to pull it up and closed under me.

Next, I took my little quilt and opened up a 3 inch slit in the foot box. I sewed the two edges together to make a sleeping bag without a zipper. And I threaded a thin shock cord drawstring through the top edge. I put the bag on the hammock, lay down and everything seemed nice and warm. I found that I could still pull the bug net over me inside the bag as necessary. I can regulate heat very well by adjusting how far up I pull the bag.

Here is a picture of the bag:

This is very similar to Ed's PeaPod to my understanding, though I have never seen the PeaPod except in one picture.

Last night I slept out with the set-up. It only got down to 55 degrees, but it was very warm while I was in my nylon shorts and a light tee. I did find that it helps to have a clothes bag to close the space on my chest (lying on my back) or behind my head (lying on my side) so that the heat is not lost.

I am leaving tomorrow after work on a 60+ mile section hike on the AT in VA. My experience is good enough that I am going to leave all the pads at home except for the new little BS pad. I will use the quilt as a peapod and let you know how it worked afterward.

I will try to put a picture or two up on the photo site under Flyfisher in a moment. When you look at the pictures, understand that I still have a little work to do... I need to make the end of the bag so that is actually fits the end of the hammock and does not hang down.

Risk

Cold Wars: Skirmish report, invention of the BS Pad

I spent a nice night with EllieD and daMonk (son's most recent trail
name) out in hammocks last night. The weather was clear, calm, and
the temp at 6AM was 50 F. I was using my new wide pad and quilt...
However, I must not be hardened to the cold yet. About 3 AM I woke
with a little chill on the skin of my back.

Wife and daMonk were using thermarest pads and sleeping bags in their
double bottom hammocks. They were as snug as ... campers in hammocks
with sleeping bags and thermarest pads... Unfortunately, this is a
little heavy for my style of backpacking.

A little thinking of what might help led me to remember the remainder
of the target pad which I had cut lengthwise to make the wide pad.
The remanent was 16 inches wide. I cut this to a length of 36 inches
and slipped it inside my double bottom hammock from where my shoulders
lie to where my bottom ends up. I lay down and it felt nice and WARM
for the rest of the night!

What to call this little 2 oz (approx) piece of foam: The "BS Pad"
(Bottom to Shoulders Pad) Uses: During high summer, it would be
enough pad for warm low-land nights that only get down to 65 or so...
just to take the 3 AM chill away. When the temps dip from 50 to 30,
it may be exactly what is needed to extend the range of the Target pad
for the cool sleeper.

Now y'all, sleep warm!