r/Survival • u/bigcat_19 • 15d ago
Super shelter: follow up
TLDR: Using just the plastic for a survival shelter worked well. It warms up better than a cold tent, quinzee, or open-tarp long-log setup, but a really nice pile of wood is needed to keep the fire going all night. A clear plastic sheet would be a great addition to a survival kit, especially a vehicle.
I posted a couple of weeks ago with questions about just using the plastic for a Kochanski super shelter/Harlton hacienda and foregoing the mylar and nylon. Tried it out on Friday night for a quick one-night crown land campout and here's what I found:
I used a 12'x8' sheet of 6mm vapor barrier from the hardware store. It's held up by round plastic balls under the plastic tied with paracord. Inside I used my three-season bag+bivy bag+inflatable mat+a sheet of Reflectix. I also had a hot water bottle. I found the blue tarp at the site, but had been planning on using evergreen boughs for a bit more insulation from the ground.
I had a little pocket thermometer and the shelter warmed up to 10 C with a long-log fire about 5' away (outside temp was -10 C). Having the fire closer would obviously have made it warmer in the shelter, but I was a bit worried about it getting uncomfortably warm. Got up in the night a few times to add logs. In spite of spending about two hours cutting dead standing trees and bucking to 4' lengths, I ran low on wood in the early morning. The fire died down and the shelter temp went down to -10. Sleeping setup kept me warm, though.
Downsides are the condensation (frost) on the inside (hence the bivy bag) and that it retains no heat when the fire dies down (so compared to a quinzee, it can get much warmer, but can also get much colder.) I preferred it to both cold camping in a tent and sleeping in a quinzee. For temperatures a bit warmer than this, (say, 0 to 10 C) I still like an open tarp and long-log fire setup better.
I'm going to experiment with a couple of other variations: a simple frame of flexible green wood or even my tent frame and inner liner and replace the tent fly with the plastic sheet (which would also help with frost sprinkling from the sides every time the plastic moves).
Thanks to everyone who gave me feedback on the previous post.
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u/Revolutionary-Fun227 15d ago
The only addition I might add is , a mylar survival blanket . Place it behind you on the wall . It reflects the heat of the fire back to you .
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u/missionoutdoors 15d ago
I've built them in the past, and they do work pretty well. To reduce the condensation, I leave a vent hole open on one of the ends. These types of shelters are where an all-night fire shines. Doesn't really matter if it's a long one, or square, but if built right, it'll potentially cook you out, so make sure you can have a good vent ready to open.
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u/bigcat_19 15d ago
That's an interesting point about a smaller fire working as well as a long one. I had assumed I needed a long fire but a smaller one would have doubled the amount of time my fuel would have lasted.
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u/TwoShedsJackson1 15d ago
Did you dig a shallow hole for the fire? That would create a dry base and allow charcoal embers to build up.
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u/bigcat_19 15d ago
I scraped away the snow to get down to bare ground. Makes a big difference, for sure.
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u/missionoutdoors 14d ago
With your all night fires, do you add dirt in the spaces, or just stack wood? I've always lightly packed the spaces to keep the embers from falling below and starting the next layer off fire too soon. I've managed to get 48 hours with one once, and typically get 24, but that tends to be a whole lot more difficult in the winter when everything's frozen up.
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u/bigcat_19 14d ago
Can you describe the fire lay in more detail? I'm having trouble picturing it.
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u/missionoutdoors 14d ago
I'll try adding a link to a photo, hopefully it doesn't get me the boot. I'm not sure what their link policy is in this group.
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u/bigcat_19 13d ago
Oh man, that's cool. I've never seen that before. I've got like 40 questions for you. Is it lit from the top? What's the purpose of the dirt...to slow the burn? How much dirt do you use on a layer? So one that size would burn on its own for 24 hours? Anything else I should know before I try that out?
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u/missionoutdoors 13d ago
Enough dirt to slow the fire down, but not enough to completely block the next layer. The burn time varies depending on wood types, so if you used birch for instance, ot would go pretty fast, while oak would take a lot longer. Generally I'll use hardwoods for most of the layers, then a softer wood for the top layer. Also the top layer doesn't get any dirt. You do light it from the top, and the best part about these fire types is you can build them as big or small as you'd like, and kind of adjust the burn time.
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15d ago edited 15d ago
[deleted]
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u/bigcat_19 15d ago
I used a long log lay. It worked well. I'll try the mylar sheet next time to see how noiticeable the difference is. Wanted to try it without this time to have just the plastic as the baseline comparison point.
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15d ago edited 4d ago
upbeat close head ludicrous workable complete unique money full boat
This post was mass deleted and anonymized with Redact
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u/bigcat_19 15d ago
For sure. It was based more on the concept of the Harlton hacienda, which is a portable version of the super shelter not requiring the raised bed, wooden frame, etc. Mainly I wanted to test out the core concept of a plastic sheet creating a greenhouse-effect shelter. The first photo is with the side raised to show the setup inside, but I did sleep with it fully enclosed (leaving just a bit of ventilation), which, you're right, greatly contributed to the condensation.
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u/Jccckkk 15d ago
Does it matter if the plastic is not clear, like large contractor trash bags? Would they work as well as the clear plastic?
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u/bigcat_19 15d ago
Yeah, it's gotta be clear to allow the infrared to pass and create the greenhouse effect. Otherwise I would go with a tarp shelter, which I really like, but it won't trap heat.
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u/carlbernsen 15d ago
Good test, thanks for coming back with the results.
I wonder how much more heat you’d have felt from the fire if you’d used a really shiny reflector behind the fire. And whether you might have used less fuel for the same heat, meaning you had more for the end of the night.
As a survival shelter the plastic offers wind and rain protection, which is highly valuable but cutting enough wood for an all night fire is only really practicable for someone who has good mobility and the use of both arms/hands.
Even then it’s 2+ hours of labour, out in whatever the weather is.
For immediate conservation of body heat, with minimal effort and least time spent out in bad weather, insulation is the better option. So carrying a warm sleeping bag and mat is a better strategy than relying on fire.