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Claustrophobic bivy bags

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It’s bright orange!

I commented to Craig [1] and a couple of others earlier this afternoon that to me it seems the most embarrassing kind of tramping accident that didn’t necessarily involve idiocy might be to become trapped inside a sleeping bag. It’s just been a pet fear of mine for a while now and something I might one day like to produce a horror movie about. I find something disconcerting about completely zipping oneself up inside a sleeping bag on a cold night without the certainty of being able to locate the zipper in the morning, or having the zipper get stuck on something and refuse to move. For some reason this leads to mental visions of a giant sealed sleeping bag bounding out of the Tararuas.

The reason this topic of conversation arose was because I’ve taken the claustrophobia one layer further and bought myself a nice little bivy bag, primarily for emergencies and as a possible alternative to carrying around my Huntech 2 to 3 person fly as backup shelter when I’m not planning to camp.

I spent two or three weeks scrutinising the options, only to decide there really weren’t very many because New Zealand’s such a small economy, these days nearly everything’s manufactured overseas, and it’s uneconomic for the (usually) one national importer to ever import more than a few models of anything. Eventually I settled on what seems to be the cheapest and lightest bivy bag easily available, which is the Vaude Active Bivy that retails at around $150 before whatever discounts you might be able to get. Apparently it’s not active enough to be listed on the international Vaude website, and mostly seems to be being retailed in New Zealand and the UK from what I can tell. At 500 grams, though, it’s quite nifty for an emergency bivy bag. I’ll see how it goes, and hopefully I won’t get too tangled up inside.

For a while I had my eye on some of the Outdoor Research Bivy Bags. The two most easily available in New Zealand of the current range are their “MicroNight Bivy [2]” (also very light at about 550 grams, and around $250 in NZ — Craig loaned me his to try out) and their “Alpine Bivy [3]” (heavier, slightly more heavy duty with a pole, and about $500 in NZ). The latter seemed overkill for my needs and I wasn’t sure about the former, and after much scrutiny I decided I really wanted their “Aurora Bivy [4]“, which is in the middle. I’m not sure exactly why, possibly that marketing principle of which I forget the name whereby given three options, people will often naturally go for the middle one. I searched around for about a week though, only to discover that it’s not actually being imported into New Zealand, and to do so would be far too complicated and expensive to bother with.

It’s all done now, anyway, and I have a new toy to play with. As with many things, I suppose if it turns out to be not exactly what I want, I won’t have thrown away too much money and I can make a more informed and experienced decision about something else later on.

13 Comments (Open | Close)

13 Comments To "Claustrophobic bivy bags"

#1 Comment By Adrian On 3 August, 2009 @ 4:30 pm

Hi Mike,

Let me know once you have road tested this model as I would be interested in your thoughts. This has been on my ‘to buy’ list for a while. The main comment I have had from others is about breatheability once confined in the bag esp moisture from your breathing. Some bivy bags have a mesh section over the face which is more breatheable as well as providing a window to the world outside.

#2 Comment By Mike McGavin On 3 August, 2009 @ 4:37 pm

I’m still waiting on the testing of it, but I think it’s a general complaint with virtually all bivy bags. I might have to test it out at higher altitude tool

#3 Comment By Craig On 5 March, 2012 @ 8:54 pm

I’ve given up on claustrophobia. With cottage industry cuben fiber flies/tarps you can get a shelter for half the weight of a bivvy bag and a whole lot more comfort.

#4 Comment By Mike McGavin On 7 March, 2012 @ 1:46 pm

Hmmmmm.. I dunno, Craig. Does it come with a ground sheet? Points for general coolness, naturally.

#5 Comment By Craig On 7 March, 2012 @ 2:01 pm

380g in including pole, pegs, groundsheet….

#6 Comment By David On 26 November, 2012 @ 9:58 am

Hi Craig where did you source your cuben fiber flie/tarp and what is it as it sounds like an alternative worth looking at

#7 Comment By Craig On 26 November, 2012 @ 1:57 pm

Hi David, I ordered the cuben fibre tarp online from Joe Valesko (zpacks.com).
This is my shelter setup for UL trips: [11]

#8 Comment By Scott On 6 April, 2012 @ 7:21 pm

Actually bivvy bags are a bit of a conundrum. They seem like a great idea, but many people overlook physics…always a problem in the outdoors. First off…I love them, but only with a tarp. The whole bodybag metaphor seems relevant at this point. The second, and perhaps the only real, point is the outside air temperature. We all lose moisture as we sleep…and it’s warm…and maybe the real world isn’t. All the fancy breathable fabrics in the world don’t actually do so well when the outside air temperature is way colder than the inside…dewpoint and stuff like that…so it gets wet inside the bivvy. It’s managable, but it isn’t the Hilton. I still love them, but use a vapour barrier…not a popular option for some reason…works though, and keeps the insulation in the sleeping bag dry.

#9 Comment By Mike McGavin On 13 April, 2012 @ 8:04 pm

Hi Scott. Thanks for the points. Since I bought this I’ve taken it a lot—often as emergency shelter that I hope not to need, but I also mostly use it combined with a tarp (or open fly), or under a hut balcony.

Do you find things get as damp when using a bivi in colder tops environments? I can’t think of the physics off the top of my head but I’m sure I’ve read that the damp-ness issues are lessened at higher elevations…. which does also seem to contradict your point about moisture condensing when it hits the cooler surfaces.

#10 Comment By Craig On 13 April, 2012 @ 8:46 pm

Mike,

Yes there is less dew at higher altitudes but the temp is lower so the difference between body heat and air temp is greater which unfortunately means more condensation for single skinned unventilated shelters like bivvy bags.

#11 Comment By Mike McGavin On 14 April, 2012 @ 12:23 pm

Oh, okay. That makes sense. Thanks.

#12 Comment By Scott On 19 May, 2012 @ 10:15 pm

Damn…you all made me question my assumptions…hate that 😛
I took my bivy bag out into cold and an exposed places in the interests of science; also you made me wonder about stuff. I slept at 1450 metres in -1/1.5 degrees in a bivy bag with one half in the shelter of a tarp. Yes it was cold. Interestingly, only the exposed part of the bivy was iced over and wet inside. This leads me to think that we’re all correct 🙂 (I should be a politician). I certainly think now, that if you can keep the dew off you then a bivy bag can keep you dry and warm in lower temperatures. Perhaps if you get high enough and cold enough you’ll be warm…good luck with that. Certainly, however, protection from dew made a significant difference to my comfort levels. I didn’t expect that because the air temperature can’t have been a lot different. The problem may be slighly more complex than I thought…but nothing a tarp won’t fix .

#13 Comment By Craig On 20 May, 2012 @ 12:43 pm

Great testing Scott.

I’m not sure we have fully answered the question, but I do thank you for donating your warmth for the greater good of science. Please do not go so far as to prematurely donate your body to science.

You now have me questioning some of my own assumptions here too. Are heavy dews I experience tramping due to lower altitude = more air pressure or the presence of a water body or less air movement in a sheltered valley?

For practical purposes certainly keeping your bivvy bag dry helps. I do not know the manufacturer nor fabric of your bivvy bag but the general premise of waterproof/breathable fabrics is that they let water vapour out. What the marketing literature does not say of course is that once wet, saturation with water droplets stops the prevents “breathability” of the fabric.

Whether this was condensation, dew, or such is difficult to say scientifically. But from a having fun and being safe in the outdoors it is definitely a case of keeping things dry so membrane breathable magic can do its thing.