Gore has dropped in a new idea in insulation, basically a user adjustable dead air space called airvantage.
A thin inflatable vest is tucked inside a shell that can be inflated with a couple of breaths trapping dead air.
Okay, this has been around since 2002 mostly in snow sports but now it has trickled into a cycling jacket called the gore bike wear concept jacket.
This might fit some niche of active use in a wet climate, the only link I can find to the jacket is at performancebike.com

http://www.gore-tex.com/webapp/wcs/stores/servlet/ContentGView?storeId=10001&catalogId=10001&langId=-1&productId=10187


Great idea for compressibility. Do that with a sleeping bag and you have air mattress and insulation too-- like sleeping in an inflatable barrel. Heck you could go all the way to shelter with that idea. A bear could roll you around like a cat in a clothes dryer :)

The army had those inflatable boots for arctic use when-- Korean War era? I had a boss who used a dead air space insulation technique to keep his eyeballs warm ;)

Edited by dwambaugh on 09/14/2006 13:51:01 MDT.

I think there WAS a setup that used dead air to make a cold weather shelter system. The price was outrageous though. $2000+ I think.

I think its mentioned in Complete Walker 4.

hmmm seems like airtight deadair space rules out breathability... should be very water proof though...

Back in 1998 there was this sleeping shelter system called the Pneugear Cocoon 4. It was impervious to water and so strong a truck could drive over it (funny how they never tell you what could happen to the occupant were a truck to actually perform such a feat). The thing weighed a ton and cost an arm and a leg. People who used them swore by them though. I've always wanted to make an ultralight version.

There are just a handful of reviews of that cocoon4 out on the net, but they have all been universally positive.

The only gripes are the weight (8lbs) and price (upwards of $1000). But, the cost and weight were outweighed by the fact that the thing replaced a winter expedition weight sleep pad, winter expedition weight sleeping bag, and a high quality bivy sack.

Even going "ultralight", it would be hard to beat the protection at bottom temps for the weight and the cost.

Thanks Miguel! That is what I had envisioned, except it would be more tent/bivy like-- let's say a Thermarest with an inflateable bivy. More fabric, fewer air chambers. 8 pounds would be bearable for a complete system.

I found an illustration of the complete system:

My question has always been, how does it handle condensation, since it is watertight? Does the system work like a vapor barrier?

the impression I get is that the top and bottom are zippered together. so, while the top and bottom are vapor impermeable, the zipper section can be opened or closed as appropriate for conditions.

If it was REALLY cold and the whole thing were zipped, yes, it probably acts as a true VB. but at -45, thats probably not the worst situation... assuming you can keep your regular clothes warm and dry somehow. Or at least dry.

I would imagine that it wouldnt be too hard or too expensive for a company like Exped (down) or Thermarest (foam) to come out with a nice version of a cocoon.... unless theres some patent issue involved.

Slightly silly comment but I keep thinking about how to use Air Core pads like Big Agnes and Insul Mat to transport gear and body across lakes etc. This would be hella funny to ride on water.

Sebastian, you could just use an inflatable kayak, fill the sponsons with down, cover it with an insulmat, and you could float down the coast of Alaska or Norway in style! (^J^)/"

Edited by butuki on 09/15/2006 09:41:17 MDT.

I have been using a technology similar to this from a British company called Blizzard Protection Systems: http://www.blizzardprotectionsystems.com/acatalog/index.html

The technology is called "Thermocell" and the Blizzard Bag that uses it costed me $30, weighs about 11oz, is waterproof, and according to them has a thermal efficiency of over twice that of down: http://www.blizzardprotectionsystems.com/reflexcell/reflexcell_7.html

I can attest that this is mostly true (albeit to a low fill power of down). I've taken this bag alone with no clothing other than a t-shirt and boxers out on many summer nights, and have even been toasty warm and had to vent it. Of course, these were 50-60 degree nights.

Tomorrow (Saturday) night I will be testing it at 10350', and I will bring my Arc Alpinist as a just-in-case, which I plan to use as a liner for a very warm night if needed.

The bag has 3 layers, and the first 2 are supposed to be breathable. The directions indicate to air it out for 48 hours after use. I found that the 2 layers do seem to absorb the greater ammount of moisture, but some did still condense in the foot box area in my tests.

Overall I think this bag is a killer deal. I've been able to ditch the bivy because of its shell and in the winter plan to use it as an 11oz super-booster for added warmth. This would only add 4.5oz extra weight to the bivy I'd carry if not the blizzard bag.

Note that they also make a jacket and a few other garments that might be worth trying.

Ha! yet another reinvented square wheel.

Now, let's imagine you are inside this thing and have warmed up the fabric resting on top of your body. Now what happens?

Now the warm air will rise inside the 'dead' air space, hit the outer layer which just happens to be at 10 F, and chill down. The cooled air will sink to hit the fabric resting on your warm body, and suck the warmth out of it...

In short, without a down filling inside the 'dead' air space, it won't be very 'dead'. Instead it will be circulating quickly, pumping the heat OUT of your body. Think 'down-filled air mat'.

Cheers

You just shooting from the hip Roger? It seems you missed that it IS in fact down filled. Top and bottom. Its hard to see in the illustration with all of the features listed, as the pic is kinda grainy/blurry but it does say that it has 650down in the top, and the bottom says "thick down filled air mattress". It also says the neck gasket is filled with primaloft.

I have never seen the Pneugear Cocoon 4 in real life and so can't attest to how it really performs, but from all the accounts by users I read back in 1999, there were a lot of very satisfied customers. There is very little information on the web now about the Cocoon, but using the Wayback Engine you can take a look at the original website, albeit with some photos missing. Take a look: Pneugear Website

I'm wondering if, since fabric welding technology has made some real inroads since 1999 and is much cheaper to produce now, making something like the Cocoon would not be so expensive any more. Plus there must be lighter materials these days.

If someone could make one for about $700, and maybe drop the weight to 5 or 6lbs, I would DEFINATLY be interested in buying one for cold weather use.

> You just shooting from the hip Roger? It seems you missed that it IS in fact down filled. Top and bottom. Its hard to see in the illustration with all of the features listed, as the pic is kinda grainy/blurry

So hard to see that I couldn't see that bit at all!
In that case, I take it all back.
Bit heavy tho?

Not that heavy, for extreme cold. And not that expensive either.

Lets assume 8lbs, for the cocoon. Rated to -45degree. Lets assume $1000 pricetag.

Compair that with:

Exped Down Air Mat 9 (2lbs, $150)
North Face Inferno (5lbs $650)
Integral Designs Hooded VB liner (6oz $60)
Oware Bivy (10.5oz $190)

Total weight - 8lbs
Total cost - $1050

http://web.archive.org/web/20011216184206/http://pneugear.com/insideimage.jpg

Grrrr... I hate this utterly inelegant, feature devoid, half-baked message board software.

Anyway... the above URL (since posting links let alone images requires hand code HTML skills that Im tired of trying to remember, just cut and paste into your browser) SHOULD take you to a full size version of the notated illustration posted earlier.

Edited by RavenUL on 09/17/2006 15:09:28 MDT.

I have to wonder what this thing would weigh if Bender recreated it. Maybe with the help of Tim Marshall. Have Bender do a 30D down mat and Tim do an inflatable cuben upper.