Dan's Outside

I go, I see, I do, I walk, I think, I like…

My Take on 'Sleeping Systems'

Having just read a post at the Mt. Whitney and Eastern Sierra Hiking Blog (see “On Backpacking…Sleep System“) I thought I’d add my two cents on this topic.

To my way of thinking, a backpacking “sleeping” system includes several components: sleeping bag, pad, ground sheet, shelter, clothing – and for some, a pillow.

Sleeping Bag – My current first-string sleeping bag is the Marmot Helium that I purchased a few years ago. This is a really fine sleeping bag with 800+ high-fill down, great design features, and a weight of around 2 pounds. The high-fill down decreases the weight and allows the bag to stuff smaller, taking up less space in a smaller pack. The version that I use has only a half zipper – this decreases the weight and cost a tiny bit and isn’t a significant drawback for me. The 15 degree rating is sufficient for me into the colder October season in the Sierra and is more than warm enough for typical summer conditions.

I have also used a lighter 30 degree bag, a Marmot Arroyo – also using with high-fill down to maximize its insulating ability and reduce weight and packed bulk. (I do not think that Marmot makes this model any longer, but they do make bags in the same market niche such as the Hydrogen.) I liked the extra-small packed size and light weight of this bag, but using a 30 degree in the Sierra requires some adjustments. While such a bag is usually warm enough, it is just barely warm enough on occasion, and sometimes it is not quite warm enough by itself. I adopted a strategy with this bag of wearing light long underwear tops and bottoms (which I carried anyway) and being ready to put on additional clothing in cold conditions. While this is not quite as convenient as carrying a 15 degree bag and not thinking about it, it does work.

(I think there is one other possible downside to the marginal weight/loft super lightweight bags. Over time down tends to lose some of its resiliency and loft. With a bag that is a bit warmer than you actually need you’ll likely never notice this change, but with a bag that is marginally warm enough when new there is a very good chance that you will notice the change eventually. I did with my Arroyo.)

Sleeping Pad – There are a bunch of trade-offs to negotiate when selecting a pad: its ability to cushion, how much insulation you need (snow camping?), willingness to combine the pad with other gear, willingness to fuss with inflation, weight, bulk, desire to use the pad for things other than sleeping.

I’ve been satisfied with the super lightweight half-length versions of the Thermarest pads. While some find it hard (pun not intended but duly acknowledged) to sleep on these thin and short pads, I adapt quickly and they don’t bother me. I do perhaps inflate mine a bit more than recommended so that I’ll get a tiny bit more padding. I position the pad so that it comes up to about my shoulders. I make a sort of pillow by stuffing a few available items (down jacket, etc) into the reversed sleeping bag stuff sack and laying a shirt or similar across the top of it. This probably sounds awful, but in practice it is really quite comfortable.

Some prefer the non-inflatable lightweight pads recently made popular by ultralight backpackers. I’ve thought of giving them a try, but the small decrease in weight hasn’t seemed compelling enough… yet. One of my ultralight friends uses one of these, but one reason he does is that he carries a very light and unpadded pack – the pad goes inside the pack in place of the padding that the pack doesn’t have.

Others carry much heavier thicker and longer pads that I’m will to carry. While I acknowledge the potential comfort advantages, I can adapt. In addition, this small comfort increase comes at a fairly substantial – at least from my point of view – weight and bulk penalty. I see folks with these very large pads lashed to the outside of their packs, while my pad compresses down to a small package that fits in the bottom of my pack.

Ground Sheet – I’ve tried a few different things in this regard. I used to use plastic sheeting from the hardware store that I would cut to size. This solution has cost advantages and it lets you customize the shape and size of the sheet to your heart’s content. However, it began to bother me that I was often throwing away one or more sheets of this stuff every season. Recently I’ve switched to fabric ground sheets which cost more but also last longer. I’m using a sheet that I purchased at an online outdoor gear outlet store – it was the ground sheet from a discontinued one-person tent. Another option is the custom cut Tyvek sheeting made popular by ultralight folks. At least one of my friends goes this route and seems to be happy with the result.

Shelter – This topic is too big to cover here, so I’ll simply describe some of what I do. Unless you sleep out in the open – and when it is appropriate this can be the best thing to do – you’ll need to think of what goes over or surrounds your sleeping bag as part of the system.

Sometimes I use a tent, but not as often these days as I used to. In really bad weather, especially if it lasts for awhile, there is no substitute for a tent that gives you a bit of “moving around space” and a place to lay out your gear. If I am concerned about weather or if I’m going to base camp I often take a one person tent that weighs perhaps close to 3 pounds.

However, these days I’m more likely to use a bivy sack. These range from very primitive almost literal “sacks” up to what really amount to tiny one person tents. Mine is somewhere in the middle – the lower section is essentially a sack, but the upper end includes a pole-supported section, a mosquito netting window/door, space inside for some gear, and a long enough zipper that getting in and out isn’t too difficult. I like the low weight and tiny packed size of the bivy, and I’ve also come to like the “nearly sleeping in the open” feeling it provides, in contrast to the “almost indoors” feeling of a tent.

Weather can be a problem in a bivy. (I’ve posted one story here.) An afternoon shower isn’t a big deal, though you have to think carefully about how you will get yourself into the thing if your clothes are wet, and once inside you’ll probably want to avoid going in and out unless absolutely necessary. Although I haven’t experience it myself, I hear from friends that a long rainstorm or a snowstorm can be a mess in a bivy. On long trips with a bivy, I often print a long a small 8 oz. ultralight tarp and rig up a bit of extra shelter over the head of the bivy.

Clothing – When people talk about temperature limits for sleeping bags/systems, they often ignore the fact that clothing is part of the system. In fact, if your approach is to carry more sleeping bag insulation than you need, this many never become an issue. However, one way to shave some weight from your system is to think about how your clothing can become a part of it – either on a regular basis or as an emergency buffer.

As I wrote above, when I used my ultralight 1 pound 30 degree bag I planned to wear long underwear tops and bottoms at night. So my sleeping system became “sleeping bag plus clothing.” This probably added at least 5 degrees to the low end useful range of this bag. (I should mention that I also thought carefully about the role that the long underwear played in my clothing system – I could take lighter pants if I planned to add long underwear and even my rain pants in extra cold conditions.) If things get a bit colder you add socks, a beanie, and perhaps even a warm shirt or jacket. In the end, the very light bag works fine the majority of the time; you can stay comfortable in most colder conditions by wearing a bit more clothing; in the very worst conditions you are likely to encounter you’ll have just enough insulation if you wear everything.

Summary and Closing Thoughts – What works for me may or may not work for you – you may sleep warmer or colder than I do, you may backpack in very different conditions, and your notion of “comfort” may well be different than mine, as may be your inclination to carry extra weight to achieve that comfort.

I arrived at the system that works for me over quite a few decades (don’t ask how many… :-) of backpacking. There is a good chance that it may take you almost as long to figure out the “best” approach for you.


May 31, 2008 - Posted by | Commentary, Equipment, Technique | , , , , , , , , , , , , , , , , , , , , , , , ,

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