In reply to Post #15
I have. You appear to be suggesting that wearing an insulating layer within an insulating layer can somehow make you colder than just using only the outer insulating layer. The only way I can see this being feasible is if the inner insulating layer introduces moisture into the system which negatively affects the insulating properties of both the inner and out layer to the point that the thermal capacity of both layers combined is reduced below the dry thermal capacity of the outer layer only.
If the inner layer (clothing) has a thermal capacity equal to 1 and the outer layer (sleeping bag) has a thermal capacity equal to 1, then the combined thermal capacity would be;
1 + 1 = 2
If you say that a degree of moisture in each layer reduces the thermal capacity of a layer by 60%, then a "moist" combination of the layers becomes;
(0.4 x 1) + (0.4 x 1) = 0.8
and thus the combined "moist" system would be colder than the sleeping bag alone. Mechanically I can not see a way in which one thermal layer can be warmer than two thermal layers which are operating at full capacity. Logically, it doesn't make sense.
As far as lined/unlined sleeping bags go, I believe I read somewhere that lined sleeping bags perform better "worn" next to the skin rather than over clothes because the fibres stimulate the nerves in the skin which encourages blood flow and thus heating. I believe this is the entire premise of the pile lining of Buffalo clothing which is renowned for being almost too warm even when worn alone.
I have. You appear to be suggesting that wearing an insulating layer within an insulating layer can somehow make you colder than just using only the outer insulating layer. The only way I can see this being feasible is if the inner insulating layer introduces moisture into the system which negatively affects the insulating properties of both the inner and out layer to the point that the thermal capacity of both layers combined is reduced below the dry thermal capacity of the outer layer only.
If the inner layer (clothing) has a thermal capacity equal to 1 and the outer layer (sleeping bag) has a thermal capacity equal to 1, then the combined thermal capacity would be;
1 + 1 = 2
If you say that a degree of moisture in each layer reduces the thermal capacity of a layer by 60%, then a "moist" combination of the layers becomes;
(0.4 x 1) + (0.4 x 1) = 0.8
and thus the combined "moist" system would be colder than the sleeping bag alone. Mechanically I can not see a way in which one thermal layer can be warmer than two thermal layers which are operating at full capacity. Logically, it doesn't make sense.
As far as lined/unlined sleeping bags go, I believe I read somewhere that lined sleeping bags perform better "worn" next to the skin rather than over clothes because the fibres stimulate the nerves in the skin which encourages blood flow and thus heating. I believe this is the entire premise of the pile lining of Buffalo clothing which is renowned for being almost too warm even when worn alone.
In reply to Post #16
FFS ?
I am SIMPLY relaying what the mountaineering survival speaker was giving to a group of climbers at the Ben Nevis campsite about sleeping bags
MAYBE THE EXPERT DIDNT KNOW WHAT HE WAS TALKING ABOUT ? AND YOU DO ?
and it makes perfect sense to me no more no less and I took notice and for many years its stood me in good stead I feel I have done more winter fishing than most on here since I have carp fished since the 60s and being single for the past 23 years fished at least 6 weeks a year abroad 2 or 3 of those weeks had to be taken in winter time
and most weeks here 2 or 3 nights more recently on the windswept freezing banks of the Trent
SO NOBODY is going to change my opinion about the best way to keep warm on the bank in sub zero temps and getting your sleeping bag to reflect your body heat back at you
you all have your opinions you all can make your own choices
FFS ?
I am SIMPLY relaying what the mountaineering survival speaker was giving to a group of climbers at the Ben Nevis campsite about sleeping bags
MAYBE THE EXPERT DIDNT KNOW WHAT HE WAS TALKING ABOUT ? AND YOU DO ?
and it makes perfect sense to me no more no less and I took notice and for many years its stood me in good stead I feel I have done more winter fishing than most on here since I have carp fished since the 60s and being single for the past 23 years fished at least 6 weeks a year abroad 2 or 3 of those weeks had to be taken in winter time
and most weeks here 2 or 3 nights more recently on the windswept freezing banks of the Trent
SO NOBODY is going to change my opinion about the best way to keep warm on the bank in sub zero temps and getting your sleeping bag to reflect your body heat back at you
you all have your opinions you all can make your own choices
I agree with post 15 in regards to it regards to two layers having additive effects.
Warming up the bag seems a bizzare principle to me as bag isn't there to be 'warmed' and transfer that heat back to you, it is there to trap a layer of insulating air, which I acknowledge will warm up, owing to the fact air is inherently insulating (think cavity wall) as will conduct heat far less than any solid.
As a simple example, if you put a coat on over a t-shirt or where a jumper to bed you don't become colder. The jumper retains some heat, the quilt retains some of what is lost through the jumper and reduces the temperature gradient.
I believe the principle in mountaineering is based on the fact that you will sweat given the nature of the activity and want to remove the damp layers (both sweat and from the atmosphere) prior to stopping all activity and getting into the bag. And I fully agree that if you go to bed fully dressed and subsequently get hot (as the layers are additive) and sweat then you'll end up colder, but if you're cold in a bag and put on a thermal layer you will get warmer. basically make sure anything you wear in the bag is breathable/wicking and that you don't start sweating.
If anyone has a really accurate digital thermometer they could test it will a contsiner of warm water stored inside 1 Vs 2 insulating layers....
Also you've started a 'debate' and then are shouting people down for having a differing opinion, don't see why it can't be a civilised discussion. My step dad has done a lot of extensive mountaineering (Mont Blanc, Matterhorn, etc. In his younger days), thankfully I have never seen any pictures of him naked in a bag...
Warming up the bag seems a bizzare principle to me as bag isn't there to be 'warmed' and transfer that heat back to you, it is there to trap a layer of insulating air, which I acknowledge will warm up, owing to the fact air is inherently insulating (think cavity wall) as will conduct heat far less than any solid.
As a simple example, if you put a coat on over a t-shirt or where a jumper to bed you don't become colder. The jumper retains some heat, the quilt retains some of what is lost through the jumper and reduces the temperature gradient.
I believe the principle in mountaineering is based on the fact that you will sweat given the nature of the activity and want to remove the damp layers (both sweat and from the atmosphere) prior to stopping all activity and getting into the bag. And I fully agree that if you go to bed fully dressed and subsequently get hot (as the layers are additive) and sweat then you'll end up colder, but if you're cold in a bag and put on a thermal layer you will get warmer. basically make sure anything you wear in the bag is breathable/wicking and that you don't start sweating.
If anyone has a really accurate digital thermometer they could test it will a contsiner of warm water stored inside 1 Vs 2 insulating layers....
Also you've started a 'debate' and then are shouting people down for having a differing opinion, don't see why it can't be a civilised discussion. My step dad has done a lot of extensive mountaineering (Mont Blanc, Matterhorn, etc. In his younger days), thankfully I have never seen any pictures of him naked in a bag...
In reply to Post #18
This is supported by a the top few websites from a quick Google search of 'should ai wear clothes in my sleeping bag' - although I have not looked into the validity of them as sources;
https://sectionhiker.com/is-it-warmer-to-sleeping-naked-in-sleeping-bag/
https://www.alpinetrek.co.uk/blog/how-to-sleeping-bag/#:~:text=So%2C%20in%20order%20to%20get,diminish%20the%20bag's%20insulating%20abilities.
This is supported by a the top few websites from a quick Google search of 'should ai wear clothes in my sleeping bag' - although I have not looked into the validity of them as sources;
https://sectionhiker.com/is-it-warmer-to-sleeping-naked-in-sleeping-bag/
https://www.alpinetrek.co.uk/blog/how-to-sleeping-bag/#:~:text=So%2C%20in%20order%20to%20get,diminish%20the%20bag's%20insulating%20abilities.
In reply to Post #18
I can just test it with my hands mate. Wearing my Snugpak and my Prologic insulated bib n brace with merino base under both. Once in in that bag for an hour or so and im reading , my hands may be quite cold. So i put them in the bag, and its roasting in there. The outside of my clothes are really warm.
In fact, because I do overnighters and don't want to be stripping off and getting dressed all the time I purposely use a big old bag that has no doubt t lost
Much of its thermal properties. Otherwise I would get too warm.
I always smile when I see an angler talking about a coat or a bag as being
'Too' warm. What's the use of that?
I made a mistake many years ago. I bought an Alpha Industires Down coat
whilst in the States. Thick down fill. Problem was even in January and even in New York I could only wear it with a Tshirt underneath. But when you go into a shop
Or bar etc, they are roasting. So then I had to take it off and then stand there cold in a Tshirt.
That's when I learnt about layering, why I won't buy the warmest single garment
Or the hottest sleeping bag.
I can just test it with my hands mate. Wearing my Snugpak and my Prologic insulated bib n brace with merino base under both. Once in in that bag for an hour or so and im reading , my hands may be quite cold. So i put them in the bag, and its roasting in there. The outside of my clothes are really warm.
In fact, because I do overnighters and don't want to be stripping off and getting dressed all the time I purposely use a big old bag that has no doubt t lost
Much of its thermal properties. Otherwise I would get too warm.
I always smile when I see an angler talking about a coat or a bag as being
'Too' warm. What's the use of that?
I made a mistake many years ago. I bought an Alpha Industires Down coat
whilst in the States. Thick down fill. Problem was even in January and even in New York I could only wear it with a Tshirt underneath. But when you go into a shop
Or bar etc, they are roasting. So then I had to take it off and then stand there cold in a Tshirt.
That's when I learnt about layering, why I won't buy the warmest single garment
Or the hottest sleeping bag.
In reply to Post #17
I'm not saying the expert, whoever he may be, is wrong. In fact, my previous post gives a very simplified example of a scenario in which he is very much correct. However, I am saying that your understanding of the why is limited or plain wrong. An example of this is suggesting that a sleeping bag, without the addition of a third party foil liner, reflects heat which shows a fundamental lack of understanding of how a sleeping bag works. If the expert did specifically mention the bag reflecting heat within the reason, are you sure he wasn't talking about surviving within a survival blanket/blizzard bag? I can very much see (and have actually experienced this) that wearing clothes within a blizzard bag would be detrimental because they don't breath so you want to reduce the amount of sweat generated within the bag (which condenses within the bag and cools the air down).
I'm not saying the expert, whoever he may be, is wrong. In fact, my previous post gives a very simplified example of a scenario in which he is very much correct. However, I am saying that your understanding of the why is limited or plain wrong. An example of this is suggesting that a sleeping bag, without the addition of a third party foil liner, reflects heat which shows a fundamental lack of understanding of how a sleeping bag works. If the expert did specifically mention the bag reflecting heat within the reason, are you sure he wasn't talking about surviving within a survival blanket/blizzard bag? I can very much see (and have actually experienced this) that wearing clothes within a blizzard bag would be detrimental because they don't breath so you want to reduce the amount of sweat generated within the bag (which condenses within the bag and cools the air down).
In reply to Post #16
agree with that whole heartedly - however be buggered if i`m getting out of my sleeping bags in my shreddies when i get a take at 2am !!
agree with that whole heartedly - however be buggered if i`m getting out of my sleeping bags in my shreddies when i get a take at 2am !!
In reply to Post #22
I have no problem in getting out of a sleeping bag in summer in just shorts, but in winter I am going to be wearing combats trousers and a long sleeve top as a minimum. I can just about grab a jacket as I play a fish.
I have no problem in getting out of a sleeping bag in summer in just shorts, but in winter I am going to be wearing combats trousers and a long sleeve top as a minimum. I can just about grab a jacket as I play a fish.
In reply to Post #23
yes
I too have no problem in winter wearing a pair of jeans or joggers and a long sleeve fleece sweat shirt it does not restrict my body heat from warming the bag up nicely
in summer its shorts and tee shirt though
yes
I too have no problem in winter wearing a pair of jeans or joggers and a long sleeve fleece sweat shirt it does not restrict my body heat from warming the bag up nicely
in summer its shorts and tee shirt though
Having tried pre warming sleeping bags( both fleece and non fleece types) during winter session's I think it's largely a psychological benefit in the short term esp with non fleece bags. Once in the bag, as long as you're not constricted like a sardine and wear a light layer like combats& norge or base layer, body heat transfer should keep you toasty.
I often like to wear something quite raunchy in my sleeping bag.
In reply to Post #26
G string made from leadcore & a pva bag?
G string made from leadcore & a pva bag?
In reply to Post #27
The reason everyone gives advice to strip of before going in bag is because outdoor people, and especially the ones being around Fort William and the rest of Highlands will be wet 99% of the time... Wearing dry clothing will be just as warm as without, might take a few minutes maybe more to warm up sleeping bag properly. Having wet clothes on is different thing... Just having lets say a sleeping socks that you put on in the evening and take of in the morning will help a lot... One thing I am sure we will see more in the future are quilts instead of bag... Very practical in many situations... talking about fleece... hiking community uses fleece bag liners for extra warming up... So you get in a fleece liner and then in bag...
The reason everyone gives advice to strip of before going in bag is because outdoor people, and especially the ones being around Fort William and the rest of Highlands will be wet 99% of the time... Wearing dry clothing will be just as warm as without, might take a few minutes maybe more to warm up sleeping bag properly. Having wet clothes on is different thing... Just having lets say a sleeping socks that you put on in the evening and take of in the morning will help a lot... One thing I am sure we will see more in the future are quilts instead of bag... Very practical in many situations... talking about fleece... hiking community uses fleece bag liners for extra warming up... So you get in a fleece liner and then in bag...
In reply to Post #27
I ditch the fishnets in case i have to grab my stilletos if i have a run during the night.
I ditch the fishnets in case i have to grab my stilletos if i have a run during the night.
In reply to Post #26
