Friday, September 19, 2014

Long Term Wilderness Living: Blanket vs. Sleeping Bag

Recently one of the guys I follow on YouTube had an interesting video discussing the merits of carrying a blanket vs. a sleeping bag as part of your gear when attempting long term wilderness living. I thought it was an interesting subject, so I figured I would share some of my thoughts with you. For more of my ramblings on long term wilderness living you can check out the post here.

So, for this discussion I will assume a scenario where a person is going to carry all of his gear on his back, travel into the wilderness, away from any civilization or human contact, and spend anywhere from a month to a year there. Shorter than a month is just a regular camping trip, and longer than a year becomes problematic for any set of gear. Keeping that in mind, what are the benefits of carrying a blanket(s) for your insulation as opposed to carrying a sleeping bag?


Before I begin with the discussion, I just want to say that for purposes of this post I’m assuming that we are using wool blankets of appropriate size and thickness. With respect to sleeping bags, I’m assuming we are using high quality modern sleeping bags. I will NOT be discussing the US Modular Sleep System (MSS). Very often it is presented as a representative of “sleeping bags”. The MSS is very old and outdated technology, and for that matter it wasn’t even cutting edge technology when it first came out. The current state of technology has moved way past that. I will also assume here that all other gear stays the same, and that the only choice being made is between carrying a blanket and a sleeping bag. 

Advantages of Blankets:

  • Blankets are more durable than sleeping bags. Because blankets have a solid construction and do not include things like baffle tubes and shell materials, they are more durable and easier to maintain.
  • Wool blankets are more fire resistant, so they can be used closer to a fire and can be dried out more easily near a fire.
  • Blankets lose less loft than sleeping bags when wet. Because blankets have a solid construction instead of using fill to create loft for insulation like sleeping bags, they lose less insulation when wet because their thickness doesn’t diminish due to the presence of moisture like it does in sleeping bags.
  • Blankets can more easily be used as makeshift clothing items than sleeping bags.

Advantages of Sleeping Bags:

  • Sleeping bags offer much, much, much more insulation for the same weight than a blanket. A 5lb blanket is generally considered to be good enough stand alone insulation for temperatures down to 32F (0C). On the other hand, a 5lb sleeping bag like the Western Mountaineering Bison GWS can give you a temperature rating of –40F (-40C). That is a huge difference. You can achieve the same insulation rating (32F/0C) of a single 5lb blanket with a sleeping bag that weighs 1lb or even less.
  • Sleeping bags compress much, much, much better than blankets. Since sleeping bags use fill based materials to provide loft for insulation, they compress significantly better than blankets which have a solid construction.

So, looking at the above lists, you can easily reach the conclusion that if you are going to undertake a long term trip into the wilderness, you should bring blankets with you rather than a sleeping bag. After all, they are more durable, loose less insulation when wet, are easier to dry out, and can be used in more configurations.

However, I would assert that the advantages of the sleeping bag are so significant that they trump any advantages that might be presented by a blanket, and as such, the sleeping bag would be my choice for insulation in a long term wilderness living scenario. Let me explain.

In my opinion, and from my experiences, every advantage offered by blankets can be compensated for when using a sleeping bag. However, you can not make up with blankets for the advantages of a sleeping bag. Let me give some examples to show what you can do to compensate for the disadvantages of a sleeping bag.

  • Problem: Sleeping bags are more easily damaged by fire, and as a result harder to dry with the use of a fire. Solution: A properly rated sleeping bag does not require the use of a fire to keep you warm. It can be dried out even in winter by leaving it out in the sun during the day. It can also be dried out by placing warm rocks in the bag contained in a sock, which will drive out the moisture, or keeping it by a small, well controlled fire. It’s a bit more work than drying out a blanket, but you can certainly compensate for the disadvantage.
  • Problem: You can not use a fire to supplement the warmth of a sleeping bag as you can with a blanket. Solution: This is only a theoretical problem. You do not need a fire to stay warm when using a properly rated sleeping bag. If for some reason you have to, heating up some water on the fire and placing a hot water bottle in the bag will supplement the insulation. If you have a tent with a wood burning stove, you can easily use it with a sleeping bag. Relying on a fire to keep warm during the night is only an emergency measure. It is not suited for long term living. Only half sleeping during the night in order to keep a fire burning, and then spending a large part of the day gathering sufficient fire wood is a poor long term living strategy.
  • Problem: Sleeping bags are harder to use as makeshift clothing. Solution: You can actually quite easily wrap a sleeping bag around you to stay warm. Better yet, since your sleeping bag is about five times lighter than your blanket, you can afford to bring a proper jacket and still have a lighter set up than the single blanket; and you can then use the sleeping bag and jacket together for added insulation.  
  • Problem: Sleeping bags lose more insulation when wet than blankets. Solution: There is no good solution here other than keeping your gear dry. A small stuff sack will keep your sleeping bag dry no matter what. That being said, whether you get your blanket or sleeping bag wet, you have to resort to alternate solutions for insulation. While a wet blanket is warmer than a wet sleeping bag, you will freeze is either if the weather is bad. If on the other hand we are talking about gradual moisture build up like condensation, then drying your bag out each day and using a vapor barrier liner (VBL) will eliminate the problem.

While the above solutions are not perfect, and can be annoying, you can certainly maintain a sleeping bag in working condition in a long term wilderness living situation. This is especially true if you have a tent, and even more so if you have a tent with a wood burning stove. The blanket however has no way of making up for the advantages of the sleeping bag. No matter what, for the same insulation, blankets will be much heavier and much bulkier than a sleeping bag.

Well, you are a strong lad, you may not think that is a problem. However, look at it this way: You have a limit on how much weight you can carry, whatever that may be. As such, the weight of the gear you carry is a zero sum game. For every pound of gear you add in one department, you have to take it out somewhere else. So, if instead of a 1lb sleeping bag, you have to carry a 5lb blanket, those 4lb by which your sleep system has been increased have to come out of somewhere. Now, instead of those 4lb of extra blanket weight, you could bring:

  • Five #1 foothold traps
  • 548 rounds of .22LR ammo
  • 3lb scoped rifle with 137 rounds of .22LR ammo
  • four extra sleeping bags
  • An extra sleeping bag and two jackets
  • A tent with a wood burning stove (SL3 Fly: 1lb 8oz and Titanium Goat 12” stove; 1lb 10oz)

In my mind that significantly shifts the equation. I will gladly deal with the added difficulties of drying out my sleeping bag if in exchange I got a rifle and 137 rounds of ammo, or five extra traps. For me that has a lot more benefit in a long term wilderness living situation than the fact that the blanket will get less pin holes when close to the fire than the sleeping bag.

This is the opportunity cost of using a blanket. What do you have to give up in exchange for carrying the extra weight and volume of the blanket? When compared to a sleeping bag, the answer is A LOT! Whatever benefit a blanket may hold over a sleeping bag, it is significantly outweighed by the its bulk and weight. If all other gear stays the same, by replacing a blanket with a sleeping bag, and keeping the overall weight of your pack the same, you can bring significant amount of extra crucial gear like traps and ammo.

The numbers become even more extreme when we consider lower temperatures. To achieve the temperature rating of –40F(-40C) that you can get from a 5lb sleeping bag, you will need at least five blankets (being optimistic), which will run you about 25lb. What crucial gear will you have to give up for those extra 20lb? That is about 25 #1 foothold traps. That is a full trap line and then some! Or, you can outright bring two rifles and a year's supply of ammo.

This calculus is nothing new. We keep telling ourselves that mountain men of the past used blankets, so they must have been great. The long hunters and mountain men knew that blankets were not great insulation. Virtually every journal entry or account from the 18th and 19th century where cold weather travel was involved, people had a single blanket and the rest of the insulation was provided by furs. The outcome was that gear had to be carried on pack horses or sleds, but even then no one carried five blankets. The numbers just don’t add up. The moment down sleeping bags appeared on the market such as the Woods Arctic Robe in the late 19th century, they quickly replaced blankets for the woodsman, becoming the standard for expeditions in the early 20th century. 

The usual response to the above argument is that a blanket will not be heavier than a sleeping bag because you only need one small, light blanket because you will sleep by the fire to stay warm. Let me know how well that is working out after day five of sleeping only an hour at a time so you can feed the fire, and then spending several hours each winter morning gathering fire wood for the night. Then let me know how well that is working out when you have fallen sick, or sprained an ankle or shoulder but still need the firewood so you don’t die during the night. On a short trip blankets can be fun and entertaining. For long term use however, you just have to give up too much in order to bring proper insulation comprised of blankets. With all of its limitations, in my opinion the sleeping bag is the clear choice for long term wilderness living.

No comments:

Post a Comment