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danmcph
Nov 21, 2003, 2:50 AM
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I am Thinking of getting a half bag and using my down parka for a sleeping system. I don't have any experience with these, or even seen one. What is the take on the system? Pros, Cons? Who makes a good bag? How cold can you go with one of these?
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lambone
Nov 21, 2003, 4:01 AM
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http://featheredfriends.com
They make some of the best bags around and I believe they offer a nice light half bag, can't remember the name.
It is a great system for three-season alpine climbing when you will be carrying a belay parka anyway.
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jbrd528
Nov 21, 2003, 4:51 AM
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Wild Things makes a Half Bag. I have never used it but I have seen it and it seems to be build very well like most of there equipment. I do now that it is generally matched with there Belay Jacket. I do own the Belay Jacket and I can tell you that it is awesome. I have been in temps down to about -15 F and have never been cold. I would think that the half bag would be warm down to 0 F or so. The hole system depends on what you are sleeping in and what you are sleeping on.
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jhump
Nov 21, 2003, 5:41 AM
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Sounds like a recipe for pain. Miserable, but survivable in all but the worst conditions.
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pico23
Nov 21, 2003, 6:16 AM
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In reply to: Sounds like a recipe for pain. Miserable, but survivable in all but the worst conditions.
Sounds like alpinism to me!!!!
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jhump
Nov 21, 2003, 4:19 PM
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I have a Wild Things belay parka. It is very warm, but it would be unfathomable to try to lay down and go to sleep in it alone. It is miserable even when worn with all other clothes on inside a 20 degree bag. This experience being in pretty cold conditions in New Hampshire 0F.
Sleep was only barely possible.
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chalkbag
Nov 21, 2003, 5:50 PM
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In reply to: It is miserable even when worn with all other clothes on inside a 20 degree bag. This experience being in pretty cold conditions in New Hampshire 0F. Sleep was only barely possible.
No wonder - wearing a parka inside a sleeping bag is quite meaningless as it only prevents your body heat from ever reaching the sleeping bag, thus effectively making no use whatsoever of the bag's insulation. Instead just layer the parka and other spare warm things underneath yourself for better insulation from ice/snow.
I spent many sufficiently comfortable nights at -10F in a +15F cheapo sleeping bag. But then I sleep pretty warm so YMMV...
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buckyllama
Nov 21, 2003, 6:29 PM
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In reply to: No wonder - wearing a parka inside a sleeping bag is quite meaningless as it only prevents your body heat from ever reaching the sleeping bag, thus effectively making no use whatsoever of the bag's insulation. Instead just layer the parka and other spare warm things underneath yourself for better insulation from ice/snow.
Oh really? care to explain the thermodynamics of this a little better?
On second thought, don't bother, it's complete BS. Insulation is insulation. And all any of it does really is keep the warm air close to you and the cold air away from you. Anyone who tells you that you need to sleep in the nude for a bag to work is trying to sell you something. By your theory your parka is a perfect insulator and no body heat escapes it. Were that true then you'd not need the sleeping bag at all, now would you, and the whole concept of a 0 degree bag or a -20 degree bag would just be silly.
Further, while it is important to insulate the ground a decent pad does a fine job. Thin insulations like fleece do sort of ok but a down parka is nearly worthless if you are laying on it. With down and synthetic fill insulations the thing which does the insulating is the air itself. And compressed down has very little air trapped in it's fibers.
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njbourne
Nov 21, 2003, 6:45 PM
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In reply to: http://featheredfriends.com It is a great system for three-season alpine climbing when you will be carrying a belay parka anyway.
If you are three-season climbing why would you have a belay parke?
Since this is the Alpine&ice forum it is probably use in the fourth season that he is curious about. If this is indeed the case then use a light weight
synthetic bag, otherwise you gonna freeze.
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gat
Nov 21, 2003, 6:58 PM
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In reply to: wearing a parka inside a sleeping bag is quite meaningless as it only prevents your body heat from ever reaching the sleeping bag
:shock:
Ummm, what?
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chalkbag
Nov 21, 2003, 7:04 PM
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In reply to: Oh really? care to explain the thermodynamics of this a little better?
If you insist.
In reply to: Insulation is insulation. And all any of it does really is keep the warm air close to you and the cold air away from you.
Sure. And if it's good enough at it, as your sleeping bag undoubtedly is, adding any extra insulation on top or underneath is totally useless.
In reply to: By your theory your parka is a perfect insulator and no body heat escapes it. Were that true then you'd not need the sleeping bag at all, now would you, and the whole concept of a 0 degree bag or a -20 degree bag would just be silly.
If you read what I wrote without turning it upside down you'll see that I said nearly exact opposite: your sleeping bag is a much better insulator than your parka, that's why you need it. Otherwise you'd be perfectly fine sleeping in the parka alone.
In reply to: Further, while it is important to insulate the ground a decent pad does a fine job.
Oh yeah? Ever slept on glacier ice? If not, it's not even remotely the same as sleeping on snow. I'll put every damn piece of spare cloth underneath to isolate myself from the ice; a half-decent sleeping bag plus some thermal underwear/fleece do more than an adequate job isolating me from the air and keeping the heat close to my body though.
To rephrase this a little: there are much better ways to use parka overnight than just wearing it inside the bag; if nothing else, just spread it on _top_ of the bag like a blanket - the sleeping bag wil trap considerably more warm air around your body than a tight fitting parka. Or even spread it inside - but _wearing_ it inside is nearly the worst possible way you could come up with for that extra piece of down...
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cracklover
Nov 21, 2003, 7:17 PM
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Don't do it. Just buy the full bag and sell to your friends what you don't need in dime bags.
What? Alpine? Oh, nevermind! :oops:
GO
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jhump
Nov 21, 2003, 10:21 PM
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Yeah. Never wear clothes inside the bag. You either heard this from the Marines or some salesman who had never slept out in the cold before. Ask anyone who has ever been out in severe alpine cold, and they will tell you that all the clothes go to bed with them. Consult Mark Twight's Extreme Alpinism
page 193....
"If you expect temperatures down to -20 degrees at night, is there any reason to carry a bag rated to -20 or colder? No. Climbers already carry insulation to stay warm during the day in their outer shells, pile clothes, and belay jacket. By sleeping in clothes at night, a lighter bag will suffice, and the clothes will dry out over the course of the evening. The total insulation load will contribute warmth all the time. Wear the belay coat over the shell and get into the bag. Upon waking there is no need to dress."
page 88...
"If the belay jacket gets wet as you're wearing it, it will dry out overnight while you wear it inside your sleeping bag. Placing the jacket deep inside the temperature gradient- that is, inside the sleeping bag- also will dry a jacket even if moisture has frozen in it due to extremely cold temperatures.
Wear your clothes while sleeping. You carry the insulation anyway, so make it work for you 24 hours a day. Factoring the clothes into the sleeping system permits a lighter sleeping bag. In Alaska during the winter I carried a bag only rated to 20 degrees on Mount Bradley and a similar bag on Mount Hunter."
This is but one opinion, but it is the opinion of a man who has walked with icey death a thousand times. Consult other alpine climbers and I am confident you will hear only the same. Still don't agree? You will suffer and there will be plenty of cold for you to eat for breakfast as you bail downward knowing another night like that would not be survivable. :lol:
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cryder
Nov 22, 2003, 12:11 AM
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One thing not mentioned in extreme alpinism is that the amount of time you spend in a bag has quite a bit to do with how long you can stay warm. A 10 hour rest is MUCH different then a 4 hour rest. And the likelyness that you get stuck in a storm exposed at some point during your climbing career is likely.
Dont get me wrong - I am totally down with Twights thinking, but the light and fast ethic plays by external rules as well. If a storm happens, you bail. Having less sometimes means being able to deal with less. There is a happy medium that requires independent thinking for every trip and every situation.
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fear
Nov 22, 2003, 12:25 AM
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In reply to: In reply to: wearing a parka inside a sleeping bag is quite meaningless as it only prevents your body heat from ever reaching the sleeping bag :shock: Ummm, what?
He's from Jersey... cut him some slack....
-Fear
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jhump
Nov 22, 2003, 12:38 AM
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In reply to: [quote="cryder"]One thing not mentioned in extreme alpinism is that the amount of time you spend in a bag has quite a bit to do with how long you can stay warm. A 10 hour rest is MUCH different then a 4 hour rest.
Exactly. But the rules of thermodynamics are constant. More insulation is warmer than less insulation. Be it 4 minutes, 4 hours, or 4 days. It seems as if the sleep-naked theorists believe that having layers between you and the bag somehow keeps the bag from insulating. This is false. Were it true, then the bag would be unnecessary as all of your heat would be contained inside your layers. Man I wish that were true.
If the sleep naked approach was best, then the following is also true...
1. wearing layers during climbing is a bad idea because all of your heat is trapped in your 1st layer- you don't need anything beyond your long underwear...ever.
2. Never wear a liner glove.
3. vapor barrier theory is wrong
4. you dont need boots because your socks will keep your feet warm enough
5. water bottle parkas aren't needed to keep water in liquid form because all of the heat in the water is trapped by the bottle
6. never wear a hat because your hair keeps the heat in.
7. don't insulate your house because the drywall and siding will do the job
On and on. Hot air goes to where it is colder. The more stuff in its way, the longer the object giving off heat (human body) stays warm.
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jhump
Nov 22, 2003, 12:51 AM
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In reply to: No wonder - wearing a parka inside a sleeping bag is quite meaningless as it only prevents your body heat from ever reaching the sleeping bag, thus effectively making no use whatsoever of the bag's insulation.
Another thought...why would I want my body heat to ever reach the sleeping bag? I prefer that it stays as close to my skin as possible. The further you go away from the heat source (human body), the harder it is to maintain a high temperature. If you were sleeping naked, you would also find that the down closer to you is warmer than the down near the bag's shell. It is inevitable, heat will permeate throughout the clothing/bag setup resulting in heat loss out of the bag. Fight this with more insulation...either in the form of carrying a heavier bag (sucks) or by making use of the fat/bulky winter clothing you already have. Seems like an easy choice when you are going light.
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valeberga
Nov 22, 2003, 2:40 AM
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In reply to: 3. vapor barrier theory is wrong
careful there... actually you've pointed out a problem with wearing a big jacket to bed. You don't want any void spaces or air passages inside your bag, because the slightest movement during sleep, or even ambient air current, causes an unperturbed and immediate exchange of warm air for cold due to pressure differences, as the warm air shoots out of the sleeping bag and is replaced by cold air. Seems like wearing a jacket to bed could potentially create a lot of void volume and air channels for vapor exchange in other parts of the bag. Your chest would stay toasty, but you'd risk letting cold air pass freely into your bag and freezing the crap out of everything else.
So to make a long story short, wearing the jacket might weaken the vapor barrier.
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jhump
Nov 22, 2003, 2:53 AM
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I don't use VBLs in sleeping bags. I want to be able to heat my layers so as to dry them as I sleep. I was speaking of vapor barrier theory in general. As far as movement flushing out heat, my bag has a collar that goes around my neck which I sinch tightly to prevent heat from flying out of the face portal.
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punk
Nov 22, 2003, 3:47 PM
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What a speculative argument of 2 cocks that never tried the product
Well here it goes;
Half bags are fine (not ideal) for 0F with adequate nutrition, and organized insulation
Before u hit the sack make sure u eat well and 15- 20 minute prior to sleep drink about 3 to 4 oz’ of oil then do a quick physical exercise for a minute or two and hit the sack
As far as insulation goes;
Anything that doesn’t have balk (puffines) goes underneath the bag (i.e. sleeping pad, rope, backpack, and fleece) and anything that has insulation goes on top (i.e. extra insulation, shell)
Now here is the reasoning;
Oil will release a high energy to the body in case of triggering it by little exercise but it will take a little time to metabolize from the moment it consume (that’s why the warm feeling is delayed for 20 or so minutes)
The insulation will be crash under the body weight therefore making the insulation worthless if u put the “Air Trapping Garment” underneath u also u do NOT want extra clothing to be warn to a point that they fit tight or snug…constricting the body blood circulation will make u cold (staying hydrated is critical too for the same reason)
the body stays warm by releasing heat to the insulation that trap it in the “Dead Air Spaces” the more designated DAS the bigger and thicker the garment is the warmer we feel
Now if u all know the basic rule of physics of “HOT air rises”
therefore u trap it on top putting your extra puffy insulation on the bottom where it is bound to get compress is defeating the purpose
So to say it in short half bags are Great as long as u know the limitations and how to deal with them and aware of the comfort tradeoff (sometime make the whole difference. after a hard day looking for the comfort of sleep…)
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cryder
Nov 23, 2003, 1:24 AM
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[quote="jhump"]In reply to: In reply to: One thing not mentioned in extreme alpinism is that the amount of time you spend in a bag has quite a bit to do with how long you can stay warm. A 10 hour rest is MUCH different then a 4 hour rest. Exactly. But the rules of thermodynamics are constant. More insulation is warmer than less insulation. Be it 4 minutes, 4 hours, or 4 days. It seems as if the sleep-naked theorists believe that having layers between you and the bag somehow keeps the bag from insulating. This is false. Were it true, then the bag would be unnecessary as all of your heat would be contained inside your layers. Man I wish that were true.
My point was that Twights thinking requires moderation. Its an ehtic, not a rule book. Do works for what the situation calls. Yes, wear layers for sleep, especially drying damp clothes. I have no issue with that point. I simply wanted to draw the distincition that a half bag has limitations. Thermodynamics are indeed a constant, your bodies ability to provide heat for insulation to insulate is not a constant. That is why people get hypothermia in the warm waters of Hawaii if they stay in too long (numerous fatalities of people caught by rip tides or thrown overboard support this - they die of hypothermia after around 8 hours of exposure). The water acts as the primary insulating condition at 80 degrees, however, it does draw small of amounts of heat from the human body at 98F and the human body compensates to make up the difference. Its also why bears slow there heartrate and metabolism to make sure that they can produce enough energy to last the whole winter in dubiously insulated environ.
The body degrades its ability to generate heat during extended periods of inactivity or a lack of food... which means that a half bag works great for a short sleeping periods in moderate conditions (0 degrees and above). It wont work great when your hosed and stuck in a exposed bivvy for 24 hours or longer and out food.
- n -
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jhump
Nov 23, 2003, 4:22 AM
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In reply to: What a speculative argument of 2 cocks that never tried the product
I assume I could be one of the "cocks" you speak of. Needless name calling. Speculation? Maybe. True, I have not used a half bag, because as I have said, the suffering I've experience inside of a 20 deg bag with the belay parka on is enough to know a parka alone is inadequate. Even with a refined attention to detail (nutrition, hydration, equipment, psychology, etc) I have been out in many a night that were not survivable in a belay parka alone. This kind of rig is tailor made for Alps or Summer Cascades. I feel however, MOST scenarios in Alaska, Himalaya and other greater ranges do not allow such shortcuts in insulation. A light full length bag and all of the insulation you carry makes the most sense.
On another note...I just remembered a trick I found last winter to keep warmer. Wear all the clothing layers into the bag, with the parka as the outside layer. Suck your arms into the belay parka, pulling the parka's arms in also. Layer them over your chest. Lay your arms at your side. Suffer slightly less :)
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zigzag
Nov 23, 2003, 8:28 PM
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I own a couple Feathered Friends products... a bag and a jacket. they are exceptional. I almost purchased the half bag but went with the full mummy since it was less than a lb. heavier and I didn't want to buy a bag and a jacket at the same time (talk about pricey)! Then I found a jacket on Ebay for dirt cheap and sangged it. It all depends on how you sleep and what kind of environment you are in. I think you'd like the half bag since it is soooo light and small, especially if you already have a warm jacket (so long as you aren't on Denali). But if you are an ounce counter like myself, the half bag is the ticket. Also, this guy was trying to sell a vireo, the FF half bag, on ebay a month or so ago, he kept reposting it because no one would bid on it. It was down to 140 last time I looked. Epic shell, which is nice but not 100% waterproof but durable. His email was MinotMaser@aol.com if you are interested drop him a line and see if he still has it. Good luck, hope you stay warm.
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chalkbag
Nov 24, 2003, 5:54 AM
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In reply to: Another thought...why would I want my body heat to ever reach the sleeping bag? I prefer that it stays as close to my skin as possible.
I was actually waiting for a similar statement:) The reason you do want the heat to reach the sleeping bag and even further if possible is the dew point - the point where the vapor in the air turns into water again. If you sleep with the parka inside your sleeping bag when you are inside your tent and it's only -10F outside, that dew point is almost certainly going to be inside your parka. As a result, you'll wake up because your clothes are wet and you feel cold. Moreover, since that dew point is inside the parka, there is still some vapor trapped there. You are not going to take off your parka when you get out of your bag in the morning, are you? Well, once you get in contact with the colder air outside, all that vapor is going to turn into ice trapped inside your down parka. BTW, that's why you need to put your sleeping bag into the compression sack as soon as you get out of it in the morning - this pushes the damp air out of the bag before it has a chance to turn into ice.
Unless it's desperatey cold, you'll sleep more confortably if you don't pile up all the clothes. I've seen many more people sleeping with too many layers of insulation than with too few.
You may want to take a look at an article about winter mountaineering by Andy Kirkpatrick on planetfear, he has quite a lot of suggestions about keeping warm in thhe cold:
http://www.planetfear.com/...nuary2003/jan03.html
Or his article on sleeping bags:
http://www.planetfear.com/...april2003/apr03.html
And btw - if your down jacket is wet by the time you get into your sleeping bag, you are quite screwed regardless of what Mark Twight says. If you use down, you better keep it dry...
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andyk
Dec 18, 2003, 5:06 PM
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Hi
Although I've wrote about this I still have problems understanding how this principle works (and so do all the bag manufactures).
I've just spend 7 nights biviing on the Lesure route on the North Face of the Dru above Chamonix (mega 30 pitch M7), where I had a good opertunity to think this over. We both had inadequate sleeping bags for the job, and my partner wore all his clothes and inner boots on every crap sitting bivi. He suffered badly, rubbing himself from about 2am till 5am every night (i.e. no sleep). Heating up a nalgene bottle worked to keep him warm for a few hours (although he just stuck it in the foot section of his bag which was a waist as the better option is to hold it bewtween the thighs - warming the blood to the feet and rising the temp of the body of the bag). I was using a MH Spectre bag with no bivi bag, and although it did work really well (glued waterproof shell), it got wet because I couldn't remove all the ice, snow and spindrift of my patagonia soft shell gear and harness.
Anyway instead of wearing all my clothes I turned my DAS parka back to front, pulled the arms inside out and wore it loosely over my body, loosening all my layers underneath. I took of my mixed master jacket and put my feet inside the sleeves (I took of my inner boots and stood on them ((I was sitting remember), and zipped up the body around my lower legs). I weas careful to let the heat escape out of my wool base layers (opening my flys, side zips etc) so my body heat warmed up these insulation layers, both becouse I think they generate heat faster (high insulation pieces get you hot) both to keep me warm and dry out the bag (rather then writing it off as knakered on day one). Things whent like this for the 4 bivi's on the face and I remaioned comfortable (well warm anyway), and my bag dried, something that wouldn't happen if you slept zipped up in all your layer?
On the 5th night we bivied on the summit of the dru (cold and windy winter conditions), and having had no food for 2 days (well 2 powergells and 2 packetrs of M&Ms), and having a laying bivi I layed my DAS parka and Mixed jacket on top of the bag and sleeped warmer the on any other night (I didn't use a waterbottle). MY partner froze as on all the other nights (he didn't belive it that taking gear off, or unzipping it would work).
Anyway I can offer no exsplanation of why this approach works, but it does for me and had saved my bacon on many occasions - all I can think of is that if you put an ice cube in a flask - it stays an ice cube.
Cheers
Andy
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