I need a warmer sleeping bag system Opinions needed

[Edward John M]

Long time lurker and reader but only just joined.

First off let me say that I am not really an ultra lighter even tho I try and keep the weight as low as I can within reason I like to be both warm and comfortable, although my gear was “State of the Art” 30 years ago it no longer is.

I am in the planning stages of a “Bucket List” trip to the Far North in winter and I have been thinking about using the gear I haveand adapting it to suit the very cold temperatures expected as a worst case scenario [ -40 to-55C ] but my current double bag combination is probably 20 degrees south of that.

My beloved wife is in NY at the moment and just bought me a Brooks Range half bag as a present to replace my Western Mountaineering Tamarack half bag.

What is the forums opinion on the Western Mountaineering Kodiak as a base bag to use in a double bag system??

The WM Kodiak is a bit bigger than my current bag and is bout 10C warmer

My thinking was that using the Brooks Range half bag plus my old Everest duvet inside the Kodiak would be almost enough and if it did get extreme I could layer my big army parka over my foot area and scrabble some more layers on top

I’ve done some calculations using the formula and I get a comfort rating of ~-36C some 15 degrees warmer than my older system

Big question is 15 degrees and a 100 grams worth a thousand dollars?

 

 

[Jerry Adams]

how many days

how far are you carrying – how important is weight

[Edward John M]

Not more than 90 days in toakl unless visa requirements change in two years and I’m anticipating each trip will last about 12 days, some air travel will be involved and sled hauling also. I’d like to keep the sled weight below 70 kilos

My understanding is that 70 kilos is  lightweight where Arctic travel is concerned.

Maximum personal load on the one plane trip I’ve looked at is much lower 35 kilos per person

I am making an assumption here that food will be a kilo a day and fuel a half kilo to give  big margin of error.

[Jerry Adams]

I have no personal experience, hopefully someone does

These are the conditions where a vapor barrier liner is good.  Base layer, then a waterproof layer to keep water vapor from your body getting the bag wet.  http://warmlite.com/vapor-barrier/ talks about it.  Their gear is sort of heavy though.

Or, there are other threads about putting a synthetic layer on the outside to add warmth, and the synthetic tolerates having water vapor collect.

[Edward John M]

I had considered using my current bag plus my LW goretex bivvy bag and then using a LW APEX quilt over the top.

I’ve not had any feedback on people using  WPB bivvy under a synthetic quilt and it simply isn’t cold enough during an Australian snow season to experiment

 

[Brian B]

A bivy bag over your sleeping bag is still going to allow water vapor to collect in your sleeping bag, which is going to reduce its loft. The vapor barrier needs to be between you and your insulation.

-40 f is no joke. I’d be careful planning any trips using gear that “in theory” should work. Is -40 probable or possible? Either way, unless you’ve tested your gear personally, I’d be cautious.

 

[Edward John M]

I’m informed that -55C is possible but not probable but as -25 C is the coldest I have encounted during the day I want to make sure I am prepared and what works for mountaineering may not work for these type of trips.

I have only had one trip to the USA camping and walking in the Adirondacks but I coped with -25C during the day with no problems and slept very well with my LW kit

-55C is a whole new step in a different direction. I have used VB liners in the past, does anybody remember Moonstone Mountaineering?  A pioneer in VB clothing.

I still have my Moonstone VB shirt although I would need a replacement as the coating has worn/flaked off and I do own a partial VB inner bag made from soft tyvek, even at -12C i found it did make a difference over a weeks ski touring

Brian that Bivvy would go over the SB and under the synthetic quilt  or between the down bag and the synthetic over bag in the scenario I was thinking about, Or the alternative is the Kodiak with the Gore shell

I honestly have no idea if the Gore shell is a good idea on the Kodiak or not and whether or not the Kodiak is an appropriate bag to use. The reason I was looking at the WM Kodiak is 2 fold, it is big enough to use as an outer bag in a double bag system and -18C is a reasonable bag for an Australian snow season

[Bob Moulder]

If this is a guided trip, my suggestion is to contact whomever is doing the guiding and discuss your equipment concerns.

Extreme cold is not to be trifled with—small errors can well be deadly.

[Matt Dirksen]

“does anybody remember Moonstone Mountaineering?  A pioneer in VB clothing.”

Yup – they had pretty nice stuff  way back when. I hear a rumor that they were bought up by Columbia Sportswear, and might someday make a comeback!

And they had a pretty cool modular sleeping bag system, with detachable hoods & such. I remember trying one out back in the 80’s (while working for an outdoor retailer).

While the coldest I’ve slept is at around -10F, that was the outside air temp. From there, I was in a rugged four season tent, (no windchill in the tent and measurably warmer from the outside). and sleeping under a sleeping bag with an outer quilt, and on top of about R-10 of insulation (TNF Foxfire-DL 0d + synth quilt or EE Enigma-DT 40d). I don’t have any VBL experience, but understand that whatever you do, MAKE SURE you totally seal yourself up in it (to eliminate any convection), and plan to feel clammy. And as Jerry said, the only thing between your skin and the VBL is a wicking layer. Don’t forget that a VBL system only deals with your body vapor – not your breath, so your system will still need to manage any vapor coming from your breath.

Besides that, the two bag system is really nice, done it on and off for many years, and it works. Mainly because the second bag acts as a “sacrificial layer” by taking on the dew point, if it either becomes cold enough or humid enough.  So making sure your tent can adjust it’s ventilation is important, to adjust for temperature and humidity. If it’s cold and dry, you might be able to reduce the ventilation a little to compensate for the increase in humidity. But if it’s a cold and humid night, or you are camping directly on snow, plan to have good cross ventilation if practical. Being in a tent with mosquito netted windows behind a fly or a vestibule is really nice in this situation, since you can open the windows up, to increase airflow, but not introduce too much windchill.

Obviously, the sleeping bag is one essential choice in a series of other important decisions. But at that temperature potential, all of the “other” choices (site selection, weather/exposure/altitude, what you eat/drink, shelter, sleeping pad, sleeping bag, puffy jacket, hat, warm water bottles, etc.etc..) are just as important.

Matt

[Edward John M]

Bob I am taking one guided trip but that is a hot tent trip where the guiding companies gear list is for heavy woollen pants and shirts and a 0F bag plus synthetic overbag, cotton shell parkas etc Their recommended mattress is the big and heavy Exped down insulated unit

The others are with contacts I have made over the years

[Edward John M]

Matt I appreciate your answer

I do a lot of skiing here and camp out most of the Australian ski season.

I consider myself accomplished but my experience is mainly Wet Cold, extreme cold will be a new ball game.

I’ve not yet decided on my tent for this trip, all my contacts except one are hot tenters.

I am thinking of splurging on a new winter tent suitable for more than solo. Current tents are a Macpac Minaret and a Fairydown Plateau, Minaret is my solo tent the Plateau is a bomber and OK for two

Lost my Megamid to a big storm last year.

I may ask about a new tent later and separately. Is the Kodiak a reasonable choice tho??

I have had good experiences so far with WM bags, in fact I just sold my Tamarack to partly fund the new purchase of the Brooks Range half bag

[Matt Dirksen]

I don’t think you could go wrong with the Kodiak, based on it’s specs. Quite light for the temp rating, and at a temp range which offers some versatility, in case you need to strip a layer.

Not sure if the Gore Windstopper is actually worth it or not, especially since you will have shelter, and other layers to manage.

[Roger Caffin]

Under those conditions I would start with a full-length Down Air Mat, as that is where most people run short, and then go for a VBL liner. Your current down gear may then be fine.
For the Arctic I would suggest a Macpac Olympus. It can take far worse weather while you snooze. Unless the guide company can provide hot tents?
Two (or more) people in the tent will be much warmer than one.

Enjoy

[Edward John M]

I was thinking my Plateau or buying a bigger Antarctic dome from One Planet just to be on the safe side or a Hilleberg tunnel

Tent isn’t as important in my planning at the moment as the sleeping bag, and having had 2 Exped mats die on me over the last few years the minute the warranty expires I’ll stick to  my Sea to Summit Comfort plus now and buy extra CCF pads when I get there

Hot tents supplied on the guided trip and my mate in Connecticut has a couple as well as mountain domes I could bring my Minaret if I needed a bivvy tent,Part of the extended planning is finding out what is cheaper to buy in the US and what is better to bring wih me. Not everything is better value in the US

[Edward John M]

I’ve has some feedback from Backcountry dotcom and it would seem that the WMKodiak would work well as the outer bag in a double bag system but I’m still on the fence. I have also considered an overbag from PHD in the UK, either down or Thinsulate; but I have concerns that the footbox on those would be too small to mate well with my current SB and even after asking several times I’ve not seen a reply from them with the actual internal dimensions of any of their sleeping bags.

WM tehmselves are recomending a dedicted Arctic bag but a bag that warm will be unusable bck here in Oz and I intend to keep skiing and touring for a few more years at least.

I will make sure I have a VBL available, either as a single bag or as a shirt and short bag combo.

To add to my confusion is my hot tenting contact in Connecticut who just informed me that I worry too much and what I have will be fine if I use a LW synthetic quilt over the top, because I already have a synthetic overbag but it is old school and very heavy [ DIY job  a few years ago]

 

[Roger Caffin]

We are just back from a very cold pre-winter trip in Kosci NP. Night times were down to -7 to -10 C overnight, with a strong cold air flow down the valley. The tent was rigid with ice! We only had our light summer gear, so a lot of snuggling together was needed just to survive.

I should have taken our light 2-man down over-quilt as well. Using that over the top of our UL summer quilts combines most of our body warmth and works wonders. It also keeps the inner bags dry.

Opinions differ as to whether the overbag should be down of synthetic. I can see arguments both ways. With a ‘hot tent’ you should be able to keep all layers dry enough.

Cheers

[Edward John M]

I am looking forward to the hot tent trip, it is the other cold tent trips up into the Arctic and that other 20 negative degrees  that I am a little concerned about if it happened.

Honestly if we can survive a High Plains or Main Rainge winter in comfort -30C is easilly with in our comfort zone.

 

[Franco Darioli]

Hi Edward,

A mate did several trips with temps down to -40 or so and less with wind chill.

He used an eVent bivy, a TNF synthetic bag (rated -40) and was wearing his merino first layer with puffy pants and jacket ,beanie 2 pairs of socks ( i think a thin liner  pair as well on a trip or two)

Z lite in all of them (inside the bivy and an Ex[ed DM7 in all but one (that I can remember).

The other night I was reading a 1978 Paddy guide book where it mentioned the different tent fabrics in use then.

What came to mind is that inside a tent maybe the non coated Japara could work well for a bivy and that you might just have some stashed away…

 

[Nick Gatel]

Big question is 15 degrees and a 100 grams worth a thousand dollars?

Yes, if it keeps you alive vs the alternative.

 

[Edward John M]

I suppose a secondary and related question is how heavy would be too heavy for a winter sleeping system.

Franco the lightest japara I have in my stash is the midweight 90/120 GSM stuff.about the same as the EPIC

Nick the question was really about the weight saving, buying  a new down bag and reducing the “System” to 3 layers or keeping the older heavier one with 4 layers which weighs a  lot more than a 100 grams extra

The 15 degrees is the difference between the down bags. I’m pretty much convinced that the Kodiak is problably a reasonable choice, choosing between the shell fabrics will be a bit harder. The PHD down overbag with my current LW winter bag or the Kodiak with the half bag and parka will do the job, choosing between the two is harder There may be other alternatives too although I am not sure about an overquilt at these low temeratures and  the synthetic insulated sleeping shell with the integrated mattress is also on my mind

[Roger Caffin]

Shells, over-quilts, bivy bags, jackets ….
Don’t forget to upgrade the MAT! So many people keep adding to the top layer without realising their major heat loss is downwards.

Cheers

[Edward John M]

S2S comfort plus XL Ridgerest solar XL and a big thick CCF pad as well. Buying those 2 very bulky items when I get there.

I could save a grand and use what I have with a weight penalty but this is BPL after all.

This is why I asked about re-sewing my synthetic over bag to incorporate a mattress pocket in the base and move some ot the insulation to the foot and torso area, adding a short zip to make egress and entry easier

 

[Roger Caffin]

a mattress pocket in the base
This works. I added such a ‘pocket’ to the foot end of our overquilt: the width of two air mats and about 0.75 m long. 20D uncoated nylon fabric. It does indeed slip under the mats, and is very stable.

Cheers

[Edward John M]

Well if I save a thousand dollars by hauling an extra 2 kilos I could spent the saved money at Tiffanys and make my partner happier I ‘Spose

[Roger Caffin]

You could spend it at Tiffanys, but I reckon you might get much better results by asking your partner what to spend it on.

Cheers

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