View Full Version : 2 season + 3 season bag: layering
littlebiglane
04-03-2009, 20:55
Okay...I am relooking at sleeping bag arrangements.
I am investigating the layering approach to sleeping bags - with a two season down bag and a three season down bag - used each on their own or in combination/together to give me 2 -3 - 5 season coverage.
Any advice, pointers or recommends on this approach and which bag should be the bigger one and go on the outside, which one should be snugger and go on the inside? Any performance issues with compression of loft of the inner bag etc.?
I know the major drawback will be bulk.....but is the only trade off a more versatile set up?
Any pointers / advice / cautions most welcome.
......And will adding a 2 season bag to a 3 season one really give true 5 season performance? Or is this guesswork on our parts?
LBL
synthectic outer bag with a down inner bag may work better, that way if the outer bag gets damp you wont lose any warmth, down doesnt work well when damp or wet, just a thought
Gailainne
04-03-2009, 21:56
Spoony good point, I'm pretty sure thats the way we did it last winter in Sweden, down to -17 deg C.
The only problem with it is the synthetic bag will be way bigger and heavier than the lower temp down bag, perhaps a better compromise would be a pertex or gortex bivi bag as an outer ?.
littlebiglane
Both the US and British army do a combo sleeping system, are you aware of them ? both include a outer waterproof bivi bag.
Good luck anyway, nice project
Stephen
I'm interested in this........mostly 'cos I freeze :o
I have a Nanok -something or other, think it's a 10, a buffallo bag and it's pertex cover (thanks Sandbender :You_Rock_ ) and a silk liner.
What's the best way to set this lot up properly ? and should I really just bite the bullet and buy the 0 oC Nanok too ?
cheers,
Toddy
MartinK9
04-03-2009, 22:16
I use a British Army warm weather sleeping bag inside a Softie 9 for when it gets too nippy and that's fine for me in the hammock or I stuff the lot into a Bivvibag
littlebiglane
05-03-2009, 07:00
I will be using a bivy bag as a matter of course (I have the excellent modified dutch M90 version) - so I won't worry too much about getting my down damp. I have never been keen on synthetics and having a synthetic outer will add considerably to the weight I feel (when compared to down). I am expecting the inner and outer together not to be any more than 2kg tho' but take me down to -20 when the two bags are combined. So for example a Alpkit 600 SH standard size with a Alpkit 400 SH large size as an outer. Paired with a bivvy bag should take me down to around the high -minus teens in temperature....
Whatdoyathink?
LBL
I tried this over winter with a 0c inside an Oversize -2c, both were synthetic and when inside the bivi with the mat as well the bed roll ended up quite bulky. I didn't check the weight as it was not overly heavy and the walk was less than a mile.
In use it was more than enough to cope with -4c, the outer had to be opened a couple of times. But I did use thermal underwear also.
Getting the weight down to 2kg for the flexibility offered would be very advantageous, I suppose my bundle was nearer 5kg.
VirusKiller
05-03-2009, 08:48
AlpKit are planning a synthetic bag (0°, £50, 900g) which will fit over a PipeDream. They reckon a PD400 (-3°, £110, 750g) plus the top bag would get you down to -10°. Not the cheapest option, but it never is if you want a good down bag. No idea on timescales though.
forestwalker
05-03-2009, 16:30
I've done this, using two 3-season bags (the slim down inside the larger synthetic fill bag). It worked well, except it gets complex; two bags, one bivy sack, and it all got a bit too much to deal with when tired in the dark.
This is interesting, i have just got a snugpak elite 3, and planned on using this with an older snugpak summer bag, both are synthetic, and would be inside a bivvy/tent.
Here's a guy with a load of experience of this sort of stuff:
http://www.andy-kirkpatrick.com/site/main_articles/double_up/
VirusKiller
06-03-2009, 08:08
Here's a guy with a load of experience of this sort of stuff:
http://www.andy-kirkpatrick.com/site/main_articles/double_up/Excellent link. Thanks!
littlebiglane
06-03-2009, 08:26
thanks for the link! its gives some spot on advice. great!
Well got my new bag, excelent service from Baxters, got it out to day, and found its got a left hand zip, what is that all about ?, i know its been a long time since i bought a new bag, (1992 ish)but won't be using my other inside it as its a right hand zip. hmmm...