Winter Overbag

[Thomas Conly]

I do a decent amount of camping in the winter here in Manitoba, but it gets awfully cold at night. The last trip I went on, it dropped to -35 degrees overnight. I always use quilts in the summer and shoulder seasons and love their simplicity and lack of constricting zippers. In the winter I use a -40 Mountain Hardwear Gost bag, and although it's very warm, I've always wanted that adaptability and simplicity of a quilt. When I saw the Sierra Designs backcountry beds, I thought that that would be a pretty good solution, but they don't make ones warm enough for our winters.

However, it occurred to me that the backcountry beds are essentially insulated over bags with a quilt inside. I figured, why not just use the quilts I already have and duplicate the entry and exit method that the they use. Not only that, but I had a synthetic quilt that still had some life left in the insulation, but the nylon was just a little too stinky after a thru-hike to be very useful anymore. So, I pilfered the insulation and put it to new use.

The bottom is silnylon and the top is 1.1 oz nylon, both from Ripstop by the Roll. The insulation is Polarguard 3D and it has 1.5" of loft. It's designed to have the sleeping bag inside the overbag so it is very generously sized to accommodate my Downmat 9, my two quilts and myself. It also has a little room left over for clothing if it's extremely cold.

My summer quilt is 1.5" of loft and uses 800 fp down and M90 from the-hiker. The warmer quilt is 3" of loft and is 900 fp down, M90 on the outside and M50 on the inside. They both have draft stoppers around the edge similar to those used by Ray Jardine. I will be attaching them together using velcro or buttons.

The weights are:
Summer quilt – 14 oz
Fall quilt – 18.1 oz
Overbag – 26.5 oz

Total – 58.6 oz, or 3.7 lb. That's lighter than my winter bag and a lot more versatile.

I made the opening a straight line so the gap would be smaller. I chose not to use a zipper because they're a nuisance with mitts on. I added two toggles to keep it more-or-less closed. My head pokes out of the top gap and I'll wear a down balaclava I made. If it's really cold, you can turn on your back, tuck your head in and breath out the hole.

In total, I have at least 6" of loft over me which should be warm enough for all but the coldest nights. I tend to overheat for the first half of the night and then get chilled for the second half because I'm damp. I am looking forward to being able to slide my feet or arms out from under the quilts but still in the outer bag to stay cool.

Summer quilt on down mat

Fall and summer quilt together

Overbag with mat and quilts inside

Opening with toggles

My comfy bed, waiting to be slept in.

[Les M]

I’m interested how this worked out in the field for you. I’d like to do some Manitoba Winter camping myself and would rather diy something than buy a new bag or quilt that might not get much use.

[Thomas Conly]

Hey Les,

I haven’t actually tried out the bag yet. I made it later in the winter last year and it hasn’t been quite cold enough yet this year to try it either. I’ll keep you posted on how it goes though. Although I like how it turned out, I would do a couple things differently. If it goes well and you’re still interested in something similar, I’ll send you some of the plans I used.

[Thomas Conly]

So, I finally got out in this bag over the Christmas break. It was -10C overnight and I only used the fall quilt inside the overbag. I wore a puffy layer on my top and legs and slept warm all night. It definitely was convenient to get in and out of and I was able to vent the excess heat at the beginning of the night, but it was a little drafty. I couldn’t manage to tuck the quilt under me like I do in the summer. I think that the bag would probably have a lower limit of -20C with the additional quilt.

Although there is promise in the idea, I would make a lot of changes if I were to do it again. For one, it is very wide when no one is in it. The whole thing flops down flat when empty, unlike a mummy bag. I would also consider having the sleeping mat on the outside of the bag. I think this would keep the sides of the quilt closer to me, reducing draftiness and preventing the bag from flopping flat.

One interesting thing I noticed was that there was a decent amount of frost on the inside of the outer bag. I’m not sure if that is the result of the extra layers of nylon impeding moisture transfer or simply because that’s where the dew point was in my bag. I suspect that the frost I found would have stayed in my traditional mummy bag too, but I just wouldn’t have know it. A system similar to this would certainly make drying the bag out easier.

[Author]

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