Wednesday, December 24, 2008

Winter tarping

On my recent hikes I've been using my bivy with no other weather protection. I bring a tarp just in case but on all my recent trips I've known that the chance of rain was slight. Snow would also not a problem. Last winter I went on a night when 8 inches of snow was predicted. I slept in the bivy with my frogg toggs rain jacket draped over my face. In the middle of the night I was awakened briefly by the soft sound of snow falling on the bivy. It was quite pleasant and so I just went back to sleep. In Missouri we don't have these snow storms that they have in the Rocky Mountains where feet of snow may fall accompanied by high winds. Snow fall in Missouri is gentle and accumulation is generally just a few inches. So a bivy and rain jacket is a perfectly adequate shelter.

The winter weather you worry about in Missouri is rain, or rain mixed with ice. This can be much more dangerous than snow storms because you can be wet through on a day where temperatures are hovering around freezing. And these storms are often accompanied by high winds. So I've been experimenting in the back yard to find a setup I would trust. The past few days there has been wind and freezing rain so I thought it was a good opportunity for a backyard test.

I've used tarps quite often of course but mostly with hammocks and that is a little easier because the tarp is tied to trees and the hammock holds you up close to the tarp so it's easy to get a very weather worthy setup. (In fact a hammock and tarp combination is the driest setup you can imagine. Brittany and I were out in hammocks on a night when it rained 8 inches during the night. In the morning the ground had become a swamp. Anyone in a tent would have been miserable because the water and mud would have risen high enough to get in. We were warm and dry all night.) On the ground it's potentially more difficult.

In my last blog entry I showed how I set up an A-frame pitch using my trekking poles and my Equinox 8x10 silnylon tarp. This is a pretty cool setup but since it is open on both ends you would have to face it 90 degrees to the wind to keep windblown rain from getting in. And with the broad side to the wind I'm not sure how it would stand up to strong winds. It might do better with two trees rather than trekking poles but that requires you to find two suitable trees. (Finding two trees the right distance apart in Missouri is easy, that's why hammocking is so convenient, but for ground sleeping you need two trees AND a flat space between them -- that combination is a little harder to find.)

Sgt Rock has great backing site in which he describes several tarp pitches. I choose to try the one he calls the Trapezoid pitch. He recommends it as a very weather-worthy pitch. You tie the middle of the 8 foot side to a tree and stake the opposite end out into the wind.

Then you stake the corners near the tree out.

The resulting space is quite sheltered and long enough to lie in.

I took my bivy and pad out and set them out under the tarp. I napped there for a bit during the rain and wind and it seems reasonable. There was a little spray on my face which I think was caused by turbulence around the the top of the tarp. But I didn't know whether it would be a problem. I could always drape my rain jacket over my head after all. To experiment I left the pad and bivy in place for the next 18 hours. Afterward there were chunks of ice stuck to the tarp but underneath it was quite dry. However the cumulative effect of the spray at the head end (which is the lee side) ended up being pretty substantial. So I'm not sure I like this. I'll need to think some more about how to handle that turbulence issue.

Part of the problem may be that my tarp is a flat tarp. Many ground sleepers who tarp use shaped tarps. There are many types of these but at the least you typically have a "beak" on the end so that the highest point is not open to the elements. This idea was first popularized by Ray Jardine, the father of ultralight backpacking in general and tarping in particular. Now you find beaks on many tarps.

Another area of concern is stakes. I use Gossamer Gear Tite-Lite titanium stakes. These stakes are lightweight but they have a problem or two. From the picture below you can see that they are rather dull in color. Not a problem up against the wood table in the picture. But imagine trying to find one in the woods after a gust of wind has yanked it out of the ground. About a year ago I was experimenting in my back yard and lost one this way. For all a know it's still there because I never found it.

In the picture you also see two products I was testing for adding some color to the stakes (titanium doesn't take paint well I'm told). One is reflective tape and the other is shrink tubing that electricians use (I don't know what they use it for).

The shrink tubing is really cool. You just cut a piece about an inch long,...

slip it over the head of your stake, and heat with a lighter (or some other heat source).

The result seems just as good as the reflective tape (can you tell which is which in the picture below?) because the colors are bright enough that they stand out well in nature. I've never lost one since I did this treatment.

But now that I'm experimenting with winter tarping I'm finding another problem. The ground in my backyard was frozen and getting the stakes in was a challenge. In fact when I pulled the stakes up I found that one of them was bent. It makes me wonder if I need a more robust set of stakes for winter conditions.

Sunday, December 14, 2008

Stephanie and Dad camping!

Stephanie, my two-year old has noticed that camping is something Dad does and that he often takes kids with him. I've noticed her talking a lot about it lately and I think she was dropping a hint. She's not really up to camping but a few days ago I did set up a tarp in the back yard and we "camped" for about 20 minutes. She's been talking about it ever since. She'll just walk up to me and say "we went camping!" She loves to look at these pictures too.

The tarp I used was my 8x10 foot tarp and I set it up between my trekking poles rather than tying to trees. The poles are just setting on the ground, not stuck into the ground. The tension of the tarp keeps the poles upright which in term keeps the tarp up.

The thing you see hanging from the tarp above us is my candle lantern. It's kind of cool thing. It's just a candle that is sheltered from the wind but it gives quite a bit of light (which you can't tell here because of the flash).

So here we are snuggled in our quilts and warm clothes. Stephanie was so excited she kept getting up and jumping up and down, hitting the tarp with her head. After about 20 minutes though we headed back in. I knew she would never be able to get to sleep in this new and exciting environment. But that didn't matter. What did matter is that she and her dad went "camping" together!

Friday, December 12, 2008

Western Taum Sauk to Bell Mountain

Ever since I hiked the Eastern Taum Sauk trail with the scouts I've been wanting to go back and hike the Western half of the trail. So this weekend I did it. Well technically I only hiked as far as Bell Mountain but since I had caught the the rest of the trail when I hiked to Bell Mountain from the highway A trailhead I have completed the whole Taum Sauk section of the Ozark Trail. Well, even that I will have to qualify because there is a section of the trail between the East and West sections that is closed to hikers. More on that later.

These two maps cover the area I hiked. On Friday night I parked and camped at the North Bell trailhead (top right of the top map). The next morning a friend, Bill Fordyce, picked me up and drove me to the start of my hike at the bottom of the lower map. I hiked all day Saturday and the camped on top of Bell and Sunday morning walked down to my car and drove home.

On these maps you can see several way points marked. For some of them I have pictures and you can also click on the way point number and be taken to a Google map of that area.

TS11 -- Because of the reservoir breach in 2005 the middle section of the Taum Sauk trail,which passes through Johnson Shut-Ins state park has been closed. This temporary drop-off serves in place of a trailhead for those who want to hike the Western Taum Sauk Trail. This sign post was just off the road. It says 13 miles to the Bell Mountain Wilderness but that's just to the edge of the wilderness. I camped about .8 miles past that on the peak of Bell.

TS10 -- 1.6 miles. Power line crossing. You can see it if you click the satellite view google maps you can see it. Not tremendously interesting but I was able to get a good shot that shows that there are pine trees in the Ozarks as well as hardwoods like Oak and Hickory. I think these are white pine. I understand the white pine used to dominate the Ozarks but over time the hardwoods have taken over. Not sure why.

TS9 -- 2.8 miles. Near the top of Goggins Mountain there are glades (visible in satellite view with google maps)

TS8 -- 4.2 miles. There is a side trail here which forms a loop (the Goggins Mountain Trail) which is supposed to be quite nice. But it is also closed for construction (unrelated to the Johnson Shut-Ins construction). Didn't matter anyway because I couldn't find the side trail. As near as I can figure it was somewhere near this boulder field.

TS6 -- 7.2 miles. The remains of an old house are here.

Not interesting in and of themselves but Bill Fordyce, who knows the area well, told me that behind the house is a spring. I filled up my water bottles at this spring.

Crossing for the Padfield Branch which is a creek that empties into the Middle Fork Black River (which empties into the Black River, etc).

TS4 -- 9.7 miles. More glades with a view. Considered the southern tip of Bell Mountain even though the landscape goes down again before rising up to Bell proper.

The view is of Goggins Mountain that I had just come down from to the Padfield Branch crossing. This was one of three places I had cell phone reception on the trail. The top of Goggins Mountain and the top of Bell Mountain proper were the other two. I stopped here and made myself a hot lunch.

TS3 -- 11.1 miles. Fork in the trail.
I was coming from the right in the picture. If I were to have continued I would have come to the the Hwy A trailhead where I started the last time I hiked Bell. (Hwy A trailhead is where the Taum Sauk section of the Ozark Trail meets the Trace Creek section. Council Bluff lake is a side trail off the Trace Creek section). So at this point no matter which way I went I would be going over trail I had hiked. The picture is taken looking down the Bell Mountain trail which is where I went to get to the peak.

BM2 -- 13.8 miles. The glade at the summit of Bell where I met some fellow hikers. We had planned on coming to see the meteor shower but the weather clouded over so we didn't see any meteors.

The guy in the yellow tent is Bill Fordyce. It was his idea to meet on top of Bell to look at the meteors. He's a really cool guy. He lives up there in the Ozark mountains.

Here was my camp setup.

I knew that the weather was going to be windy so I knew a hammock or a tarp wouldn't be very fun. So I went with the bivy. The temperature wasn't very cold so I used the Air Core pad with just my Nite-Lite torso pad under my shoulder-to-hip area. My legs could feel the cold of the air pad so I put my coat under my legs and I was warm. Actually I was almost too warm. During the night I stripped my thermals off. In a bivy you always worry about condensation. Interestingly I found no condensation on the top of the bivy where I would expect it but I did found condensation under the air mattress. It seems that some of the moist air from my body drifted under the air mattress and condensed against the cold underside of the bivy. Not really a problem though since moisture under the mattress can't get either me or my bag wet.

North Bell Trailhead. -- 17.3 miles. Where I left my car (and where I camped on Friday night). I hiked this last 3.5 miles pretty fast, about 75 minutes. I was with a fellow I met on the mountain. He likes to hike fast as well and do long miles. We're thinking about doing a trip together at some point.

I did some pretty serious hiking on Saturday (I was trying to make it to the summit before sundown). I'm a little sore today. I'm afraid I didn't sleep very well Saturday night because the wind was so loud. It's funny, I always think to use ear plugs in the summer because of bugs. But here it is December and I needed earplugs because of the wind! Not what I expected, but there is always something unexpected when you are backpacking.

Tuesday, December 9, 2008

Layering Clothing for Winter

One thing that surprises people when they begin to hike in the winter is how much your need for insulation can fluctuate. Natalie and I found that out on our recent hike up Buford Mountain. It was something I should have remembered from my distance running days.

When Natalie and I arrived at the mountain it was several hours after dark and the temperature was in the mid 20s with a wind blowing. Stepping out of the car at the trailhead with my little girl I thought "what have I done?" We bundled up in our warmest coats, hats, and gloves (my fingers quickly became numb while trying to adjust my pack straps) and began walking. I was dreading the evening ahead of us. But within a few minutes we were unzipping the coats. As the climb became steep we were removing our hats and gloves. I would have taken the coat all the way off but it was inconvenient with the pack. So we were hiking with winds and below freezing temperatures and feeling hot.

You should think about your body the way you think about a car or a steam engine. It's hard to get going in the cold but once you get started moving your muscles produce a tremendous amount of heat. When I was running I learned that if I were comfortable at the beginning of a long run then I would be sweating 15 minutes later. You need to start by feeling a little cold.

The difference between hiking and running is that typically you only stop running at the end, when you are about to get into your car or house and go for a hot shower. But during a hike you may stop to rest many times. At these times you find out that your muscles quickly stop heating you up and you get cold in a hurry. If you were sweaty when you stopped then that heat loss is hugely accelerated and you can quickly begin to suffer from hypothermia.

So it's important for a hiker to dress in layers that can be easily removed and put back on. Also each layer should be made of some material that will wick moisture but still keep you warm when it's a bit moist. So cotton is OUT. The saying among search and rescue teams is "the best-dressed corpses wear cotton."

Natalie and I did some things right and some things wrong on this trip. I'll show you what we wore.

Base Layer
The layer closest to your skin is called the "base layer". Here is a very unflattering picture of me wearing my base layer.

The two types of materials most favored for base layers are polypropylene and wool. Here I am using both. My shirt is an Icebreaker 200 merino wool top. My bottoms are polypropylene thermals. My socks are Smartwool hiking socks.

Most people are used to thinking of wool as being scratchy and not something you would want against your skin. However merino wool is much finer and softer than other wool. The icebreaker top I'm wearing is as soft to the touch as any cotton T-shirt. Wool is a great insulator and will keep you warm even if it is wet. The advantage of wool compared to synthetics is that it seems to never absorb odors. I know this sounds unlikely but I have tested it. I have worn this top on a number summer hiking trips and got pretty sweaty (particularly my back because of the pack). In between I didn't wash the top. After 5 or 6 times I was stunned that it smelled the same as it did the first day. Synthetics don't have this property as any runner (or their family) can tell you.

The polypropylene bottoms I picked up at a military surplus store. In the military they wear something like this as part of their Extended Cold Weather Clothing System (ECWCS) apparently. They are very warm.

Insulation Layer
Over your base layer you put on a layer that can be removed if you get too hot. Some people call this the "fleece layer". That's a marketing gimic made up by the people who sell fleece material. Fleece makes an excellent insulation layer and is warmer per ounce than wool. But wool has other advantages as I've mentioned. Here is Natalie and me in our Icebreaker tops that we use for insulation layer. Mine is a 260 zip top (in the picture it is zipped all the way down) and hers is a hoody. We love our Icebreaker tops but they are very pricey!

One interesting thing about my top is that it has a thumb hole in the sleeve. You can put your thumb through that hole and if you pull anything on over the top (like a jacket or gloves) the sleeve will stay down by your wrist rather than sliding up your arm. Pretty clever.

Wind Layer
The problem with insulating materials like wool or fleece is that they are not windproof. A good stiff wind will cut right through to your skin and steal your warmth. Many people react by getting a warmer jacket when all they really need is something to stop the wind. This is my wind shirt that my lovely wife made for me using the Liberty Ridge kit from Thru-Hiker. He sells materials and patterns for backpackers who like to make their own gear (I bought the materials for my synthetic quilts from him). This top is made of a very thin but water resistant/breathable material called Momentum 90. The entire thing only weighs 2.2 ounces! It's so small that when I take it off I can put it in my pocket when I feel warm and want more ventilation.

In the picture I'm also wearing REI Sahara pants which are made of nylon. These are actually convertible pants so you can zip off the bottoms and have shorts. I have no use for that in the winter but I can't see a reason to have summer pants and winter pants. In both cases you need a wind layer on the bottom.

Now you'll notice that I'm wearing 3 layers on top and only 2 on the bottom. That's pretty common. My bottom base layer is extra warm and so it's sort of a combination base layer/insulation layer.

Now for Natalie I didn't have any insulation layer that would fit under her nylon camping pants so I had her wear these snow pants. Perhaps overkill but remember that I'm a paranoid parent. The sides do unzip (as you can see here) so she could ventilate if she needed to. Underneath she wore a thin base layer.

The mistake that Natalie and I made was to bring warm coats. I didn't even put my wind shirt on because a coat is essentially an insulation layer and a wind layer in one. But therein is the problem. A coat is not adjustable enough. I would have been better off with a down vest that would fit under my wind layer (I have a larger wind shirt I could use for that purpose). That would make one small piece that I could take on and off easily. On Saturday when we were hiking and it got above freezing it was too hot to wear a coat but not warm enough to do without it entirely.

We'll do better next time.

Saturday, December 6, 2008

Father and daughter on Buford Mountain

My daughter Natalie (who is 10) and I just got back from an overnight backpacking trip to Buford Mountain. Buford Mountain is in the same general are of the Ozarks as Taum Sauk, Bell Mountain, and Council Bluff Lake, all of which I've blogged about recently. The terrain is very rocky with occasional glades from which there are views.

View Larger Map
The entrance to the park is straight south of the peak, just off Hwy U in the above map. In fact you can see the first part of the trail in that map as well. It looks like a road that comes off of Hwy U and goes straight north and then ends. In fact it appears that you used to be able to drive closer to the mountain than you can now. The current parking lot is right off U and the first part of the trail is along the old road. In the trail map below you can see a place called "old lot". That's where the road dead ends and the trail begins. It appears it used to be a parking lot for hikers to leave their cars.

Buford is a fun mountain to climb because once you get on the trail it's nearly a straight shot north and you are at the top in under an hour (I probably could have done it in 30 minutes but Natalie can't go that fast).

Natalie and I didn't start until quite late at night because we got off late. So it was all night hiking. The moon wasn't full but it was fairly clear while we hiked and so it was surprisingly light. We used my little LED light to keep from tripping on rocks. We got to our camp site at about 10pm.

As you can see from the map the peak is fairly flat and that's where we camped. I planned to camp there because it was the only flat spot and we were going to be sleeping on the ground rather than in hammocks (it's amazing how convenient hammocks are in terms of site selection). It was forecast to be in the 20s overnight and so I worried a lot about us getting cold.

Now I have to laugh at myself because I made some of the same mistakes I was joking about in my post about heavy weight backpacking. I was so concerned about my little girl getting cold that I ended up carrying too much weight. But at least it was me that was being burdened down and not her. I'll go through what gear I brought and what was useful and what was just along for the ride.

First of all I should point out that in a winter backpacking trip the parent is going to be carrying quite a bit of the child's gear. If I don't like to carry more than 20% of my body weight then I really shouldn't expect a child with immature bones to carry anything like that much. Now Natalie weighs 50 pounds soaking wet so I want her to carry less than 10 pounds. In the summer that's easy. In the winter it's hard so I carry a fair amount.

We own a very old child sized down mummy bag from my wife's childhoood. It's an REI bag that dates to the 70s I think. But down lasts a long time and when you fluff it up it has a lot of loft. It weighs 42 ounces which is a lot for a down bag, even a child's down bag. I'm guessing it was originally a zero degree bag. When Natalie is fully snuggled in it it's hard to believe she could get cold at night.

Of course when winter camping there is always the issue of cold face since your face has to be exposed to the cold air so you can breath. Natalie handles this by wearing her stocking cap to bed and then pulling it down over her eyes and almost over her nose, leaving just enough space to breath.

For myself I think I hit on a good but different solution. I have a down coat with a hood that zips off. I snuggle my quilt under my chin (so I don't breath into the down quilt) and wear the hood to bed. Then I sleep on my side and turn the hood so that it covers most of my face. I can see just a sliver between my pillow and the edge of the hood.

Part of the weight I was carrying was an extra pad for Natalie. Since I knew the ground was going to be rocky I brought the Big Agnes air pad for me and I a Therma-Rest Trail Lite in size small (48 inches) for Natalie. The terma-rest pad weighs about 20 ounces. Interestingly it seems that they don't make that size any more. In addition I wanted each of us to have two CCF pads, one for under the air mattress and one for over the air mattress. I own a full length RidgeRest and I bought her a short one. She carried that one (it's only 9 ounces). It's designed to be a torso-length pad but for her it works as a full length path since she's only 48 inches tall. She used that under her air pad and she used the NiteLite pad (that I use for my pack frame) on top of her air pad. I used a Walmart CCF pad for under the Big Agnes and the RidgeRest for on top. So in total we had 6 pads of which I was carrying 5.

I also decided not to carry an ultralight stove. I had heard that the best kind of stove for cold weather is a "white gas" stove. So I called my mother and asked her to send me my SVEA 123R that I had received as a scout. It was used when I got it but it 25 years ago but it still works great. It's one of the most popular backpacking stoves ever made.

The stove comes with it's own windscreen and a small pot (1 1/2 cups) and potholder. However I wanted to use a larger pot so I just took the burner.

The burner itself is an interesting piece of engineering. When you open the fuel cap to fill it you can see a long wick curled inside. It runs up through the neck up to the burner. To get it started you can put some fuel in a little dimple at the base of the neck and light it. This will heat the neck and pressurize the stove. Some people carry a separate bottle of fuel (or even alcohol) just for this purpose. But there is an even easier way to do this in cold weather which I tried on this trip. In the morning the stove was very cold but I was warm. I held the base in my hands and it absorbed heat from my hands which created pressure inside the stove. Then I turned the key and fuel began gently bubbling up. I lit this fuel and in a few seconds the stove was roaring away. Truly a brilliant design! But it's not lightweight by modern standards (19 ounces).

When I bring an alcohol stove or an Esbit stove I carry the stove (and windscreen and pot) in a ziplock container that I can use for measuring water for meals. In this case I decided to carry the large windscreen I made for my woodgas stove. I decided to carry this in a Lexan water bottle I owned. I know these aren't lightweight but it was a convenient way to carry with windscreen (rolled up small) and it still left room for my candle lantern and matches.

We also mixed our hot cocoa in this Lexan bottle so at least it served some useful functions. The candle lantern was just along for the ride though. We had originally intended to read Watership Down to each other at night but since it was so late we left it in the car (Natalie had read to me while we were driving) and went straight to sleep when we set up camp so the lantern wasn't used at all. It only weighs 6.2 ounces so I can't feel too bad about that.

But the biggest waste of the trip was an extra blanket I brought. It was one of those "last minute worried parent" kind of things. I saw it in my car and just threw it in so we could us in case we got cold. But with our sleeping setup (including my down jacket which I could take inside the quilt for extra warmth) it served no purpose. It wasn't even very lightweight at 22.8 ounces. It's meant for picnics. I did roll it up as a pillow but that's a pretty heavy pillow!

In the "minor wasted weight" category I have two entries.

1. I realized afterward I had brought four extra pair of socks! Now two would make sense: extra liner socks and extra wool socks. But in addition I brought one more pair of wool socks and some sealskinz waterproof socks. I suppose I could be forgiven for the sealskinz since there was a (remote) possibility of snow that night and so keeping my feet dry would have been important in that case.

2. Upon arriving home I realized I had also carried my water filter. Now that was just along for the ride. At this time of year you won't find any liquid water so a filter is superfluous. I just hadn't realized it was at the bottom of my food bag!

I did bring more food than we needed and also more water but I don't count that as a waste because you never know when things will go bad and you might need to spend a few unplanned hours in the backcountry. Having not enough food or water in that case makes a bad situation worse.

In the morning after our cocoa and eggs (actually quite tasty! could be the added MSG I suppose) we hiked some more. We didn't have a lot of time because Natalie had an commitment back in Chesterfield at 1:30 but we did make it to the second peak north of the main peak. We stopped in a glade and rested. It turned into a really nice day. There seem to be a higher proportion of hickory trees on this mountain than I have seen on other mountain in the Ozarks (although there are always plenty). The whole trail was littered with hickory nuts. One thing that was really cool were all the Frost Flowers that had formed during the night. We didn't get a picture but here is one I stole off the web. They seem to grow around the stems of dried plants most often. They are amazingly delicate, fragile even. We wanted to bring one home but we ended up crushing it by accident. I have no idea why they get so beautiful. Many are quite large and the shapes are quite varied. The picture below isn't as pretty as most of the ones we saw.

In my next blog entry I'll talk about cold weather clothes: what I currently use and what I want to change for my future winter trips.

Sunday, November 30, 2008

Building a Woodgas Backpacking Stove

In previous posts I've mentioned that I generally use an alcohol stove or Esbit tablets to boil water for rehydrating meals while backpacking. However the concept of using a wood stove is beginning to catch on among backpackers. The reason is that the fuel is available in the forest so you don't have to carry any fuel. I've been experimenting with this for a few months and I now have a design I like and am confident enough with to use on backpacking trips. In this post I'll show you how to make it.

Now in general I am opposed to collecting firewood in the wilderness because dead wood plays an important part in the forest ecosystem and if every hiker made a fire then the forest would suffer. However I am going to show you how to build a stove that can cook a pretty big meal with literally a handful of twigs (what most people would use as kindling to start a regular fire) so the impact is very small.

There are two keys to this efficiency. First we will cook with flames rather than coals so we don't need to wait around until coals have formed. Second we will design the stove for more efficient combustion. In fact what we will burn is woodgas. Woodgas is the gas that is formed when wood is heated. It's an excellent fuel. In fact during WWII there were tractors with internal combustion engines that used woodgas for fuel. Our stove will be a downdraft gasifier, meaning that the wood will burn from the top down. The stove design I will be following is basically the Garlington woodgas stove with a few modifications in the windscreen and potstand.

To begin with take a normal soup can and cut the top and bottom off. It's nicest to do this with something like a Good Cook can opener which leaves no sharp edges.
Next decide which end of the can will be the bottom of the stove. Cut some tabs in the side of the can and bend them toward the middle. Now cut a circle of hardware cloth (or wire mesh) to fit inside the can. The tabs will hold this up.
What you are looking at in the picture above is how we get primary air to the stove. Air comes in the holes at the bottom that we cut the tabs out of and then flows up through the hardware cloth to the wood.

Now we need to make some holes for secondary air. This is the air that will mix with the woodgas to produce the flame we will cook on. Flip the can over and cut some slits in the side of the can near the top. Then insert a scredriver into each hole and bend the can so that the slits turn into vents leading from the outside of the can up and into the can.

At this point the stove itself is done. We fill the stove with twigs about the diameter of a pencil broken into pieces. I've found that it works best if I make the pieces about 3 inches long and put them in the stove the long way. The other approach is the make shorter pieces and just pour them into the stove. I find standing the twigs upright seems to help with airflow.

Now we can put a little kindling on top and start a fire. This is counter-intuitive because we are used to starting a fire the other way, with kindling on the bottom igniting wood above. But in this case it is very important that the fire burn from the top down. What happens is that the top layer quickly forms into a layer of charcoal. The wood below is heated and woodgas and air rise through this charcoal and a reaction called pyrolysis takes place. A main product of this reaction is hydrogen gas and that is what will burn when it meets the secondary air coming in from the holes at the top. In fact the way you know your stove is working correctly is that a few minutes after starting you will see that the only flames appear to be shooting into the stove from the secondary air holes. The flame will be quite steady and fairly blue in color (perfect combustion would yield a blue flame, yellow indicates some lack of efficiency).

Now in order to make this a good system for heating water I needed to rig some way to suspend a pot above the stove. I also needed some way to block the wind so it doesn't carry all the heat of the flame away before it can heat the pot. Actually a wind screen serves a secondary purpose in this case. The air around the stove inside the windscreen will become quite warm and so the secondary air entering the stove will be preheated, contributing to more efficient burning.

I built my windscreen/pot-stand out of a sheet of aluminum roof flashing. I drilled two holes and put wing nuts in them to hold the flashing in a cylindrical shape. Then I cut triangular holes in the bottom for air to enter. Last I drilled four holes about 1 1/4 inches from the top into which I can insert two tent stakes. The pot will sit on these stakes about 1 1/2 inches above the top of the stove. Using tent stakes is a perfect example of a dual use item. My total pack weight is reduced by carrying items I can use for more than one purpose. I always have to carry tent stakes for my tarp. So I might as well put them to good use.

The pot I use is an AntiGravityGear 3-cup aluminum pot. It's a great little pot. About the right size, very light, inexpensive, and the outside is already black so the black residue from the fire won't make it look bad. I sized the windscreen to allow a gap of less than an inch all the way around the pot for fumes to escape.

In the pot is 16 ounces of cold water (I kept it outside overnight and the temperature was in the high 30s). After a few minutes I have a nice rolling boil. That's not smoke in the picture, it's steam. A good woodgas stove produces almost no smoke. After a few minutes of boiling the flame begins to die down. Inside the stove is a pile of glowing charoal. After a few minutes this has been reduces to a fine ash, probably about 1 tablespoon full. So in this way also the impact on the forest is very small.

The downside of a downdraft woodgas stove is that all the fuel has to be in before you start the fire. You can't add wood later. Another way to build a backpacking wood stove would be to make a very similar system to the one I have built but also allow a space for wood to be fed in. You also get fairly efficient burning (better than a camp fire) because of the secondary air supply but it's not a true woodgas stove. However in some instances that might be better because it would allow you more control over how long a burn you need. You could keep such a fire going indefinitely if needed. However I like this system better. Mostly just because it's so cool!

Saturday, November 22, 2008

Review of the GoLite Ultra 20 down quilt

I picked up a new piece of gear this week. My homemade quilts are synthetic and quite thin, perfect for spring or fall camping but not good for winter. So I bought a new quilt which is down-filled. It's an Ultra 20 from GoLite. It's rated at 20 degrees, meaning that it's supposed to keep you comfortable at temperatures of 20 degrees or higher.
Down is the warmest insulation you can get for it's weight (for those interested in the down vs synthetic debate scroll down to the bottom of this post for my thoughts on the subject). GoLite uses very high quality down in this quilt (800 fill power) so it's amazingly light. In addition to being light weight down is also highly compressible. Amazingly this quilt can be put into this tiny stuff sack.
The quilt and stuff sack together weigh only 20.1 ounces on my scale.

I had heard mixed reviews about this quilt. Some people feel that the company was too optimistic in calling it a 20 degree quilt. It's always been reasonably priced ($225) but I found an amazing sale and got it for $168.75. I figured that for that price it couldn't be too bad. So on Friday night I took it outside for a test. It was 22 degrees, just perfect to see if this bag would really live up to it's temperature rating. The short answer (for those who don't like to read all the way to the bottom of an article) is that it passed with flying colors. I love this quilt!

Temperature ratings in general are nonsense. There is no amount of insulation that is right for every person to sleep comfortably at a given temperature (if you don't believe that then get married). Fortunately I only needed to know if this bag would keep ME comfortable in the cold. I tend to be a warm sleeper anyway (I use very few blankets at home). And like most lightweight hikers I sleep in my hiking clothes. So I wore the clothes I would be wearing on a hike in this weather (two layers of wool on my upper body, thick polypropylene thermals on my lower body, thin liner socks and wool socks over them). So this makes it more likely that this quilt would be adequate for me personally. On the other hand most people understand a 20 degree temperature rating to mean you would be comfortable in a tent. I'm not a tent person anyway so I was conducting this test under the stars: no tent or bivy.

I mentioned in a previous post that I had been cold while sleeping on top of Taum Sauk mountain when using two summer quilts. Looking back on it I think that was not all the fault of the quilts. I think I made a mistake in how I set up my sleeping arrangements. On that trip I used an air mattress for comfort. It is a good quality air mattress but air mattresses are problematic from a warmth perspective. The bottom side of the mattress becomes cold against the cold ground while the top is warmed by your body. Convection currents within the mattress bring the cold air up to your underside and cools you off from underneath. My Big Agnes Insulated AirCore mattress has some Primaloft insulation inside to try and cut down on these convection currents but it can't eliminate them. Last night it was much colder and I noticed it right away when I lay on the air mattress alone.

I had read that the warmest way to sleep in the winter is with 3 pads. You put one closed-cell foam pad on the ground, the air mattress on top of that, and another closed-cell foam pad on top of that. So I tried it. I put my Walmart CCF pad on the bottom and my RidgeRest on top. That's a lot of pads and a lot of weight but since it was just in the backyard I didn't mind experimenting.

One interesting thing about the Ultra 20 is that it has detachable straps which can be used to hold the quilt down to the pad as you can see in this photo from the manufacturer.

However in the picture they have a short RidgeRest and I own a full length one. The footbox of the quilt is too narrow to allow the pad to lay flat inside it. I think the idea is that if you have a full-length pad you should let the pad be outside the footbox. But I bent the edges of the pad up into a half-pipe and shoved it inside. I think that was a great idea actually. It held the bag away from my feet. My feet were wonderfully warm. In fact after a few minutes I had to take off my wool socks and just leave my liner socks on. But I noticed that if I reached up with my foot and touched the corner of the footbox it felt cold. So I think I will try this strategy again in the future on very cold trips.

I was toasty warm, even without the wool socks. In fact I probably would have been fine with only one layer of wool. I was very impressed. Of course part of this may have been that I was also very careful to keep my head warm. I wore a down hood that I zipped off my parka. Preventing heat loss from your head goes a long way toward keeping your whole body warm.

Many people make a serious mistake with their down bags. They store them in their stuff sacks so the down is fully compressed. This can cause the down to lose it's lofting ability over time. To maximize the life of your down bag or quilt you should store it fully lofted hanging in a large bag.

The Down vs Synthetic Debate

Warning: verbose explanation of obscure branch of knowledge follows.

Backpackers are divided about whether down or synthetic insulation is better. It is well known that down is warmer per unit weight and packs down smaller. Since backpackers are so concerned about weight (and, to a lesser extent, bulk) you might think that everyone would prefer down. However there is a "downside" to down if you will pardon the pun. Synthetic insulation is not much affected by getting wet. Both synthetic insulation and down will survive a wetting of course, that's not the concern. What I mean is that the insulating properties of synthetic insulation are much less affected by whether the insulation is wet or dry. Dry is better of course but if you and your gear got soaked on a cold day (say you fell in a stream or got caught in a winter rainstorm) and you wrapped yourself in your wet synthetic sleeping bag it would keep you warm and could save your life -- a down bag won't under the same conditions.

To understand why you must understand why insulation (natural or synthetic) works. The purpose of insulation is to trap tiny pockets of air. Your body produces heat in your muscles and this warms whatever is next to you. Convection will carry that heat away from you as the warm air next to your skin rises away from you and mixes with the colder air around you. Insulation prevents this by trapping that warm air. Now a balloon traps air but surrounding yourself with filled balloons won't keep you very warm. That's because inside the balloon convection currents would occur within each balloon which would exchange heat from the warm side of the balloon (your side) and the cold side of the balloon (the side away from you).

Insulation is something that traps air in such small spaces that no convection currents can be established. So most of any insulation is air pockets. They aren't sealed pockets like a balloon though. But they do make it hard for air to move around. Now if you squeeze the insulation the air will escape and the insulation will no longer function. So the insulation must be allowed to maintain it's loft in order to keep you warm.

Now go back to your wet sleeping bag. When a down bag or quilt gets wet the down clumps together and you have no loft. Synthetic insulation doesn't lose it's loft when it gets wet. So if you have a down bag you must be careful to keep it dry.

That doesn't sound like much of a concern does it? You can keep the down quilt in a waterproof bag in your pack so that rain or an accidental drop into a stream won't wet it. And presumably your shelter will keep water from getting on you while you sleep (it's not much of a shelter if it doesn't). Proponents of synthetic insulation will say that "the best laid plans ...". Of course it's the unforeseen accidents that could end up being dangerous. Hypothermia is nothing to mess with.

Fair enough, if you go with down you have to be extra cautious. However there is another problem. Our bodies are constantly giving off water, quite a bit over the course of a night. Our breath is the biggest source but not the only source. Our pores are constantly giving off moisture to keep our skin from getting dry. This moisture gets trapped in the insulation with the warm air. If it stays warm then there's no real problem. But on a cold night the moisture will condense in the outer layers of the insulation. In fact it may even form ice crystals. So in the morning you ought to air out your sleeping bag and let it get warmed by the sun if possible. If it's too cold then this won't be possible. Climbers on Mount Everest report that their sleeping bags get heavier and heavier each night as the ice accumulates. If the bag is a down bag then each night you lose a little insulation value too. Not a good thing.

What can you do to minimize the moisture in your down bag? First of all don't breath in the bag. There's a temptation to cover your head and keep your face warm. But then all the moisture from your breath enters the bag. Instead I like to drape a jacket over my face when it's cold at night with a little space for my breath to escape. Second, in extreme cold weather you need to keep the moisture from your skin from entering the down by using a vapor barrier. A vapor barrier is a waterproof layer than keeps the moisture from your skin from leaving. A thin plastic bag is the simplest type. Very soon after you put it on the humidity next to your skin will rise to a level at which the body no longer worries about the skin drying out so it stops releasing moisture through your pores. This cuts down on your heat loss as well as protecting your bag.

So where do I come "down" in this debate? Well I feel that you should always use the right tool for the right job. The greatest danger from hypothermia is actually when temperatures are above freezing, like 40 degrees. Think about this: compare how cold you get when you get rained on compared to when snow falls on you. Or compare falling into a snowbank to falling into a puddle on a cool day in terms of which is more unpleasant. When the water around you is solid there is little danger of getting yourself or your bag wet so down is fine (provided you take proper precautions). In the spring and fall when cold rain is likely to fall I want to have synthetic insulation in my bag as an insurance policy.