Question Insulation question for "Just in case" half sack

Moondog55

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I also asked this question over at "Bushwalk" but so far no opinions.
Another Covid lockdown project.
How much insulation would most members think was adequate to stop me freezing to death/ suffering bad hypothermia if I got caught out again and the safest option was to hunker down and wait out a storm/ broken gear event.
The last time I had to bivvy it was a long, cold, shivery night with very little sleep and it took me about 3 days to catch up, no bivvy bag just the proofed nylon windsack, just my Powerstretch tights and my windpants down low, up top I was fine as I had my DAS parka plus the Goretex. It was my legs that lost all the heat.
The Thinsulate won't compress well enough to make if a viable option so it's either the 3M LiteLoft or APEX
I have plenty of 40GSM Liteloft but only a small amount of 75GSM APEX. I was hoping that 2 layers of the 3M stuff would be just enough. I now own a pair of Patagonia DAS pants and while plenty warm as camp clothing I don't thiink they provide enough protection for bivvying in, due to insulation degradation because I got them used on eBay fairly cheaply and they were only 90GSM to start with, about as warm as the OR Neoplume pants but not as warm as the Rab Photons.
Thoughts and comments please and hopefully I'll be fitter and better kitted out in 2021
 
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Moondog55

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I have thought about that and I do own one,but the bivvy sack is much lighter and more compact. I'd carry it when the grandkids would be with me tho
 

Slowman

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The problem with a bivvy sack though is that you end up lying full length on the cold ground with little or no insulation between you and the ground. With the bothy you shelter sitting up and can usually at least use your daypack as a seat to get some insulation that way. If you "google" bothy bag compared to bivvy bag you will find some articles about such things - including one by Andy Kirkpatrick who is a fairly well known climber.
 
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Moondog55

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This is one of those compromise you make when solo. With 2 people I would take the extra weight of the bothy but still take the bivvysack. Digging a foot hole and sitting on your packs a couple of people warm up fast and it is possible to use a stove to make a brew etc. On my own I don't think I have the body mass to keep one held down in a severe wind, where as in a bvvy sack even a shallow trench gets you out of the wind. I contacted Andy and asked for his opinion but I don't really expect a reply; me being no longer a climber and all. I do need to do something about better insulation from the snow tho, the old T'Rest that was the frame of my daypack is now leaking badly and I can't find the hole, I think it is simply old age and urethane degradation
 
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Spence

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This is one of those compromise you make when solo. With 2 people I would take the extra weight of the bothy but still take the bivvysack. Digging a foot hole and sitting on your packs a couple of people warm up fast and it is possible to use a stove to make a brew etc. On my own I don't think I have the body mass to keep one held down in a severe wind, where as in a bvvy sack even a shallow trench gets you out of the wind. I contacted Andy and asked for his opinion but I don't really expect a reply; me being no longer a climber and all. I do need to do something about better insulation from the snow tho, the old T'Rest that was the frame of my daypack is now leaking badly and I can't find the hole, I think it is simply old age and urethane degradation
A small pad of closed cell foam. Cut from an old yoga mat or similar. I posted a while ago that I had read that it’s popular with BC guides. Comfortable when sitting on rocks, keeps cold out on snow, can improvise as a splint and in extreme circumstances can be chopped up and add to a fire to create a smoke signal. And super light weight. Fits in avi pocket of pack easily.
 

maelgwn

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A three season quilt might be made from 5oz/yd2 Apex ( i.e. greater than 150GSM), so assuming similar warmth between fabrics, it would imply four layers of liteloft.

Saying that, there are so many variables here it is hard to suggest anything particular!
 

Moondog55

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Pantaloons would be damned good Covid project if I didn't already have some.
MSR eBivvy is a good one, no cash to buy one, I just wasted my stimulus payment building a small deck outside our back door.
$750- buys a lot of treated pine and decking boards and The Boss did think it was time to replace the old S/H pallets that have been our back step for the last 7 years
 
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skifree

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Well if you need a project I’ll send you a list and you can work your way thru it for me.

First up are some curtains.
 

tcornall

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I have recently been using 2 or 3mm floor underlay foam with a reflective backing for a tent footprint on snow and it works very well. Not nearly as good as a proper sleeping mat but a heck of a lot better than bare ground or snow. Not sure how much the reflective backing helps, but it goes someway toward making the foam a bit more tear resistant. (Not much, still tears easily). You can get it (without the reflective layer) pretty easily as discarded packaging material, left-over floor underlay (with the reflective layer) or buy rolls of it from various places like Post offices, Bunnings etc. I imagine a narrow pad of it put into the bivvy bag and just left there would improve the night quite a bit. Folded up a coupla times would make it an almost comfortable sitting mat. It doesn't compress, so a full 2 person tent footprint makes for a chunky package, but it is very light.

And, Pantaloons. I made some using a lightweight very breathable nylon and teh sort of synthetic 'wadding' used in cheapo sleeping bags. Make me look like a Wally (no offence to any Walters out there) but very nice and warm. Bit bulky though. The Liteloft would be good there.

Some varying opinions I've heard over the years as to a bag versus trousers and also some question as to how well the Liteloft (or any other compressibly insulation) handles being sat/laid upon. i.e. does it compress to uselessness? Do a test on cold concrete/ground/snow and compare it to a less compressive foam. Maybe a quilt on top and and a pad below is the best answer? And maybe a hybrid 'bag' of the two is even better to stop air leaking in at the sides.
 
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Moondog55

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I'm a bit fat to wear the Chineseasy gear, their XXXXXXXL is just big enough. A shame they only go up to 4XL which fits a 38" -40" waist from memory
Looks like 2 layers of Liteloft or wait and get some 65gsm APEX from the USA, when not in my daypack it can be used as a liner for a LW down bag or over it if made large enough.
 
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pegasusSki

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Just one moment whilst I google all the fabrics Moon ;):whistle:

Interesting to hear about legs, I find if my core is warm I can forget my legs.
 
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pegasusSki

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Just one moment whilst I google all the fabrics Moon ;):whistle:

Interesting to hear about legs, I find if my core is warm I can forget my legs.

and your post came up, so no help there...:)

A small pad of closed cell foam. Cut from an old yoga mat or similar. I posted a while ago that I had read that it’s popular with BC guides. Comfortable when sitting on rocks, keeps cold out on snow, can improvise as a splint and in extreme circumstances can be chopped up and add to a fire to create a smoke signal. And super light weight. Fits in avi pocket of pack easily.

A sit mat? Never owned one, but need to.
 
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Ian

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One of my skiing mates has one of those 3/4" thick closed cell foam kneeling pads they sell to elderly gardeners.
Big and thick enough for one boney arse, softer than sitting on your upturned skis.
You could use it to stand on while putting your boots on in a snow cave.

Not expensive, if it doesn't work you could give it to your Mum for Christmas.
1a49f1da-6c68-4979-8e8e-ca8d4502c5f2.jpg
 

Spence

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One of my skiing mates has one of those 3/4" thick closed cell foam kneeling pads they sell to elderly gardeners.
Big and thick enough for one boney arse, softer than sitting on your upturned skis.
You could use it to stand on while putting your boots on in a snow cave.

Not expensive, if it doesn't work you could give it to your Mum for Christmas.
1a49f1da-6c68-4979-8e8e-ca8d4502c5f2.jpg
661162EB-DB23-4737-AB60-A49133C1EFFF.jpeg

This is me yesterday lunch break. I’m the one sitting very comfortably on the snow bank on my bit of closed cell foam. Two buddies stood to eat and one sat uncomfortably on a tree branch. The day before it was a similar scenario with me sitting comfortably on a rock.
It’s a winner. Especially this season when you don’t want to venture indoors to the plague pits.
 

Spence

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I have a piece of foam that I carry with me for day touring on skis. I always carry a life systems space blanket ultra light hooded sleeping bag / bivvy bag. It could save my life and it is compact and light.



I love that second video. So informative but also so ‘human’. And he kept talking to camera without his teeth chattering. Good video.
 

Mister Tee on XC Skis

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661162EB-DB23-4737-AB60-A49133C1EFFF.jpeg

This is me yesterday lunch break. I’m the one sitting very comfortably on the snow bank on my bit of closed cell foam. Two buddies stood to eat and one sat uncomfortably on a tree branch. The day before it was a similar scenario with me sitting comfortably on a rock.
It’s a winner. Especially this season when you don’t want to venture indoors to the plague pits.
Here is my green foam seat from my last day for skiing the BHP for 2020( due to the Stalag 13 lockdown).At least I got one powder XC ski day all to myself, ungroomed and fresh conditions on the Bogong High Plains.
_SAM7164.JPG
 
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Moondog55

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BPL in Melbourne have the OMM half sack on clearance at an almost affordable cost and weight
https://www.backpackinglight.com.au/omm-mountain-raid-pa-10-1-2-sleeping-bag.html
Experience tells me that 60GSM isn't enough but it should be if used with the LW insulated pants
and hardly worth sewing my own at that price but Anaconda also have a down blanket labled Mountain Designs that might also work as part of a system

https://www.anacondastores.com/camp...ags/mountain-designs-outdoor-quilt/BP90138891
Mind you this is all hypothetical, I may not ski next year either if those greedy buggers in Canberra won't give me the pension I've already paid for
I think that the OMM half sack has a very small footbox and my booted foot might find it short of room
 

Moondog55

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This is a "just in case"insulation piece.
I have the 40GSM double scrimmed Thinsulate there in the shed, if I am always going to have the bivvy sack with me why do I need a shell on the insulation?
We are selling this stuff for $5- a metre, if it get trashed in saving me an uncomfortable nite freezing to death all it would cost me is $10- and some tape.
I am going to do a mock-up as soon as I've finished sewing up the sleeping bag expansion I am working on today
 
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Moondog55

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This is the 950 gram project, what I am aiming for is something similar but around 500 grams, just need to sew in the tube for the drawcord and add a cord lock to some elastic there
 

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Moondog55

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It's a plastic bag.
No insulation at all
I've actually used similar and they are next to useless and no better than a rubbish bag, they are however very good for use as a VB liner
It really is and was a question about how much insulation is needed to avoid freezing to death/ becoming hypothermic at -5C to -10C.
Using a LW or UL footsack is more thermally efficient than pants in the same way as mittens are warmer than gloves.
It is more a question of how light I can go and still get a bit of sleep because not sleeping is the debilitating part of bivvying.
My Kathmandu XT bivvy bag weighs 720 grams and I'll be putting that in my daypack as a matter of course now that I have it.
The modified sleeping bag I just sewed up is touch under a kilo, I think that is a little too heavy to carry as well as the bivvy bag because while that modified sleeping bag is windproof it isn't waterproof and our weather is so likely to turn that I think waterproofing is important.
Daypack weight is an important consideration where my skiing comfort is concerned, I'd seriously like to get the weight down to 5 kg for next year rather than the current 8 kilos, my knees will thank me.
If money wasn't a prime consideration it would be easy, I'd just get Feathered Friends Vireo and carry an UL down parka rather than the DAS but money is very much a consideration and I have to work inside my budget
https://featheredfriends.com/collec.../feathered-friends-vireo-ul-down-sleeping-bag.
Also the Kathmandu bivvy is to small to fit my modified bag inside it so it would be one or the other.
 

Mister Tee on XC Skis

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The Life systems bivvy bag is for day touring on BC XC skis with a day pack. It packs down to nothing and weighs FA x 2. It is not a substitute for a proper winter duck down sleeping bag and a 4 seasons tent as well as a properly insulated sleeping mat. Those things are set up back at base camp.
Thankfully I have never had to test the life systems bivvy bag out in a real mort ya zindagi / life or death situation.I have had a ski fall where I had to ski back to base camp with a gammy leg( level 2 hamstring injury : OUCH!). Thankfully it was only 2? kms maximum at Mt. Stirling . However in more remote unpatrolled terrain the difference and chances between freezing/not freezing to death while unable to ski out and surviving are improved with such a small piece of kit remaining in the day pack.
 
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Moondog55

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Mr T you really should do a trial bivvy one nite with such minimal kit; just see how cold and uncomfortable it can be.
I have actually tried such bags and they do not work at all well, all they do is keep the wind off and while this provides a small bubble of air that is slightly less cold than ambient they are no substitute for insulation.
Please reread my post; I will always be carrying a proper Goretex or equivalent bivvy bag in my daypack, therefore there is no need to duplicate the windproof layer and an RFL has no benefit unless there is an air-gap, if it touches your body or clothing it has zero value, in fact it may even have a negative value. This is apart from the small fact that they are too skinny for my broad shoulders when wearing my standard cold weather parka
 

Mister Tee on XC Skis

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Mr T you really should do a trial bivvy one nite with such minimal kit; just see how cold and uncomfortable it can be.
I have actually tried such bags and they do not work at all well, all they do is keep the wind off and while this provides a small bubble of air that is slightly less cold than ambient they are no substitute for insulation.
Please reread my post; I will always be carrying a proper Goretex or equivalent bivvy bag in my daypack, therefore there is no need to duplicate the windproof layer and an RFL has no benefit unless there is an air-gap, if it touches your body or clothing it has zero value, in fact it may even have a negative value. This is apart from the small fact that they are too skinny for my broad shoulders when wearing my standard cold weather parka
I comprehend your statement but I do not plan to sleep in anything in the snow less than the previously described snow camping set up. I carry such a Mylar space blanket shaped as a sleeping bag of sorts to stay alive in an emergency , not to replace the proper snow camping kit.
 

Moondog55

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You really don't get it do you.
I'm trying to advise you as somebody who has stuffed up more than once that the Mylar bags are useless and give a false sense of security.
How do you know they will keep you alive in an emergency situation unless you practice first? Somewhere relatively safe, such as next to your tent or a hut
 
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Mister Tee on XC Skis

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You really don't get it do you.
I'm trying to advise you as somebody who has stuffed up more than once that the Mylar bags are useless and give a false sense of security.
How do you know they will keep you alive in an emergency situation unless you practice first? Somewhere relatively safe, such as next to your tent or a hut
OK, I can grasp that concept.
 

chriscross

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Maybe worth taking heed of some well-meant advice from a very experienced snow camper. Not convinced the mylar bag would save your life if, for example, one were to break a leg out the back of the high plains. I carry a bivvy bag and Macpac pulsar down jacket these days (except at LM). But very interested in a light weight bag for justin. The Vireo looks good.
 

legend

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In a heavy blizzard ('90s?), several of my club couldn't locate their tents after a day trip (Paling Spur side of Youngs Hut BHP). They spent the night out with nothing but small day packs. They dug a large pit to help shelter from the wind, and cuddled each other. One had a stove so they had small cups of hot water they shared.
Since then we all carry suitable emergency equipment (down jacket, small sit mat, plus two large plastic bags (one for going over head and the other for the legs), someone might also carry a small tent fly. Certainly NOT comfortable.
Get out and experiment in your backyard when it is raining. Also experiment with your fire lighting skills when everything is wet and raining. I found the best fire lighter is the candle (it lasts for a very long time, and you can put matchstick thin twigs over it). (once the soggy bark is pealed back with your finger nails, knife, etc).
See how long you can stay put.
Just remember, you break a leg, etc - help will be over three hours away IF the 'chopper can get to you.
 

DPS Driver

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I'm a bit fat to wear the Chineseasy gear, their XXXXXXXL is just big enough. A shame they only go up to 4XL which fits a 38" -40" waist from memory
Looks like 2 layers of Liteloft or wait and get some 65gsm APEX from the USA, when not in my daypack it can be used as a liner for a LW down bag or over it if made large enough.
Not sure what size you are but was talking to my mate who owns Teton Bros clothing and they've made a full length puffy pant. Great quality product. My SOS pair are only 3/4 which are great for skiing in really cold climates but full length would be great for overnighters. Really light and pack easy.
This company is Japanese but they've started making there sizing a bit more western since launching in the US. They're still not quite there but you can check out their sizing on this page.
https://www.teton-bros.com/fw_products/insulation/hybrid_down_pant.html
 
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chriscross

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"Hybird" (sic) looks very fashionable, too. I bought the Omm half-bag on special, as it looks likely to suit my requirements (whenever that might be).
 

Moondog55

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If I don't start loosing some weight soon I think I'll be a 60 inch waist by Christamas, but nominally a 38"/97cm
The DAS pants are great and I prefer the extra layer to be bigger so they go on over more than just Powerstretch tights if need.
be. But as warm as the DAS pants are they are not quite warm enough
Those Teton pants look great, remind me of the Egge down underwear from the 70's.
I think I'll try a single layer of the LiteLoft and see what it feels like, but keeping the weight and bulk down is important so I'll use the lightest fabric in my stash
 

Moondog55

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Hey Legend was that the group who found themselves within metres of their campsite when the storm cleared?
It can happen all to easily, been there myself back before GPS were available, it also happened once when hill-walking/climbing in the Scottish Cairngorms
 

legend

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Yes Moondog - around 100m from camp. After spending a couple of hours 'exploring' the leader (one of the best navigators I know) decided to dig in, creating a snow wall and a pit so all could fit and cuddle. It was a sleepless night but all survived without injury. One of the great things for skiing and walking with a club - you have some amazing experienced people to help you out.
 

Moondog55

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I first heard this story while spending a "merry" evening at Ropers hut quite a few winters ago. Might have been my second or third season on skis
 
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Moondog55

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Get out and experiment in your backyard when it is raining. Also experiment with your fire lighting skills when everything is wet and raining. I found the best fire lighter is the candle (it lasts for a very long time, and you can put matchstick thin twigs over it). (once the soggy bark is pealed back with your finger nails, knife, etc).
.

An American mate has put me onto an even better fire lighter for that one time emergency use, a good quality paper napkin totally soaked/impregnated with a mix of candle wax and petroleum jelly, folded up tight and inside a plastic bag with a small square of foil, better because it folds up flat so it's easy to carry unnoticed in a pocket until needed and the aluminium foil lets it sit on wet ground until the fire gets going. But the sheer difficulty of starting a fire in our high country is why I now carry a tiny stove and mini gas canister. 30 years ago it would have been my SVEA, the Wasp + canister is much lighter. Anyway I am working on something using 2 layers of 40GSM LiteLoft and some old nylon taffeta I have sitting on the shelf
 

skifree

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I gave up even bothering to think about a fire over 20 years ago.

A tent (or bivy) is the best emergency provision. The number of times we have got into the tent soaked and been dry within a hour is beyond count. A way better emergency response than a fire. I do not buy the need for a fire in emergency argument.
 
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Moondog55

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I gave up even bothering to think about a fire over 20 years ago.

A tent (or bivy) is the best emergency provision. The number of times we have got into the tent soaked and been dry within a hour is beyond count. A way better emergency response than a fire. I do not buy the need for a fire in emergency argument.
An ability to light a fire is simply part of the skill set but the difficulty of doing so is why I also always carry a bivvy sack and a stove. In other parts of the world fire is much more important.
 
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