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U.L. Overbag?
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Brad Groves
(4quietwoods) - MLife

Locale: Michigan
Re: re: on 05/14/2009 12:41:08 MDT Print View

Alli-

Short version: You're dreaming. Stop. You do need a warmer bag.

You're trying to get a 30*F bag to keep you warm to -15*F. It's not going to happen, no way. Neither a 30* or liner bag are constructed in a way that will conserve your precious heat in those conditions. Now, if you had a 0*F bag and needed another 10*, that might be an option--if you had a bomber hood, a great poofy draft collar, beefy draft tube--double draft tube would be nice.

If anything, your Montbell would be the liner bag for a 0*F bag. But you're definitely not talking about a light or packable/low bulk solution.

You can make do on a lot of the options in your pack. A winter bag really isn't a make-do option. It's your safety insurance. And your comfort. And although it might cost a little more up front, far more economical than the emergency room or funeral bills from trying to take a 30* bag and liner to subzero weather.

Allison Sayre
(TeamAlli) - F

Locale: PNW
BA? on 05/14/2009 15:08:45 MDT Print View

Anyone used the Big Agnes Battle Mountain (-15)? It's on the heavy side (5lbs) but it's fairly cheap.

Brad Groves
(4quietwoods) - MLife

Locale: Michigan
Re: BA? on 05/14/2009 15:28:01 MDT Print View

Alli-
One concern with the BA bag is that it's pretty huge inside. Keep in mind that sleeping bags don't produce any heat; they just trap the heat you produce. In other words, you have to heat up the sleeping bag, then keep it warm. Much harder to do in a big bag. You might consider Mountain Hardwear's Lamina series, 0*F if you want a more versatile post-trip option, or -15*F. Priced $185, $225 respectively. Their 600FP down series Clouds Rest 5F @ 325, -15F @ 350. In the spirit of full disclosure, I am a dealer for both these brands and others I might mention, but I'm not trying to or interested in selling you a bag. Just giving you info. There's a couple of North Face synthetics that might be up your alley, too... priced well and decent options. I like that their 0*F Snowshoe, for example, uses Climashield and it comes in womens sizing for under $200. I'd also check the gear swap; there have been a couple of great older down bags on there recently.

Ross Bleakney
(rossbleakney) - MLife

Locale: Cascades
U.L. Overbag? on 05/14/2009 15:39:39 MDT Print View

What Brad says makes sense. A five pound synthetic also sounds about right. It looks like -10 degree bags made out of the finest down (900 or so) are bit over 3 pounds (if you look at Feathered Friends or Western Mountaineering). So, a single bag with a good synthetic might weigh about five. There is no way you can get two bags which combined weigh 3 pounds and have anywhere near the warmth of the FF or WM bags. It just wouldn't make sense. The FF or WM bags have only one zipper, one inner layer, one outer layer, etc. They are optimized to get you enough room inside to sleep comfortably, and nothing more (wide series versions of the same bag weigh a bunch more). So, the idea that a synthetic weighs about five pounds while a down bag weighs about 3 1/2 makes a lot of sense.

Allison Sayre
(TeamAlli) - F

Locale: PNW
Re: Re: BA? on 05/14/2009 18:20:37 MDT Print View

The BA bag comes in a short version. But I'm liking the price of the MH Lamina, it's on sale for $180 at backcountry.com

s k
(skots) - F
Re: U.L. Overbag? on 05/14/2009 19:19:52 MDT Print View

I experimented on three non successive nights last winter, sleeping in sub zero temps. I walked less than a mile before I unrolled an MEC yellow closed cell and an old 2" Thermarest. I wore a pair of MH insulated pants and a micropuff jacket, and slept without a tent or tarp. I have a synthetic overbag with 3 or 4 ounce pl sport, and on the first night I used a FF Condor that has about 20 ounces of down. I moved the down away from the center of the bottom, and during the -6F night I removed both the pants and jacket.

On the second -11F night I exchanged the Condor for our Nunatak Dual quilt, also with about 20 ounces of down. Within an hour, I had the insulated pants pushed to my thighs, and the jacket off, but around 5am, I had them back on. This was the most comfortable night.

The forecast was colder for the third night, so I switched back to the Condor. I woke up around 12:30 AM, warm and sweating, figured I'd blown the experiment, and was close to packing up and leaving. Instead I got up, peed, removed the micropuff, and went back to sleep. The temperature dropped to -23 that night, and again, around four, I had the jacket on again. When the temps were at their lowest, both shoulders were cold when I slept on my side. The top back of my shoulders were cold when I was lying on my back. This was the only night when I felt cold enough to wear my three ounce BPL hood. I should add that none of the bags has a hood, but the overbag is long enough to pull over my head. And yes, it was wet, but the tunnel shape that I tried to maintain in the overbag was relatively warm.

For this experiment,the inner bags in each of my kits were inefficient in their use of down, but in sum, I agree with Dave O. The synthetic overbag contributed more warmth than I expected and I noticed condensation only near the head of the down bags. Frost was prolific on the top of the overbag.If I was making an overbag for your situation, I would use the 5 to 6 ounce insulation Dave recommended, enclose in bag shape, with a short side zipper and an uninsulated bottom sleeve for some variation of GG Thinlight padding.

But I would be wary of the meager 10 ounces of down in your NO 3. Fifteen plus ounces would be a lot more comfortable at -10F. Can you wear insulated clothing in your Montbell? Maybe place a jacket between the bags over your torso? Maybe a vb? Will you take insulated pants?

Nick Gatel
(ngatel) - MLife

Locale: Southern California
Re: -15F on 05/17/2009 16:35:22 MDT Print View

Alli,

I have done a fair amount of cold hiking in my lifetime, but my no means am I going to try and pass myself off as an expert.

At -15F and the realistic possibility of a storm that could be colder, you don't skimp on a bag. If you want to do the course, you just need to invest in the proper gear or rent it. If you can rent it, that solves the investment issue.