4 Season WPB Hyperlight Thermal Hammock set-up

**2Trees** · 01-08-2014, 07:43

Just came in from another test in this set-up. Temps got down to 19* F. We had a very light dusting of snow. I used the same hammock and clothing set-up as above in my first report. Well, I slept very hot. I had to leave the ID bivy, SOL bivy, and the Exped Wallcreeper unzipped about a 7" opening to let some heat escape. I removed my GAP wool sweater, wool balaclava, and axeman leather mitts and used as a pillow and stuffed towards the foot and head end to avoid any cold spots. I consciously noted how the SOL Thermal Bivvy really radiates and reflects your body heat. Because the SOL Thermal bivvy is inside the down sleeping bag, there is very little heat loss and the heat can really build up inside this thermal cocoon. I also feel that the SOL Thermal bivvy works best around the hammock, instead of just laying inside the bivvy in the hammock. I can really feel the heat being reflected and radiated on my backside. Having the ends completely enclosed really helps hold in the heat, also. The modifications done to the bivys help completely hold in the heat and allows us to minimize our pack space and use a small diagonal tarp and still have the ends of our hammocks protected from the elements. Or use no tarp at all and just the WPB ID South Col II eVent outer bivy.

Cheers and Happy Hanging!~

**KenOutdoors** · 01-08-2014, 10:14

Nice setup and unconventional thinking. I had pretty much dismissed the use of space blankets because you can end up wet then cold. The idea of a breathable one makes a lot of sense. I use the more conventional top/bottom quilt so if they make these things in blanket form it could be a small/light way of carrying some additional insulation for an unexpected drop in temperature.

Do you think that the escape bivvy would be a good size for a blanket if it is cut and opened up? A few quick searches did not result in a breathable space blanket, just the bivvy.

**2Trees** · 01-08-2014, 12:17

Hey KenOutdoors,
Appreciate your thoughts and reply.
The SOL Escape Bivvy only comes in the mummy bag style. I too, searched for a blanket version of this or even just an aluminized-Tyvek material. Tyvek does offer an aluminized house vapor barrier material called Tyvek ThermaWrap. I can not find anywhere to order this material in a roll. I wanted to use this for the head and foot end "sleeve" modification that was done on the SOL Escape Bivvy. So, I just used regular Tyvek. Of course, I washed the Tyvek in a washing machine to help soften the material. The size of the SOL Escape bivvy is 31" W x 84" L. So, if you cut it down the side, you would technically have a 62" W x 84" L piece of material. But, the SOL Bivvy does have a hood and drawstring and not sure how that will work if you tried to cut it into a blanket. The other concern is that I feel you need to have this completely sealed (like it is as a emergency mummy bag) to both reflect and radiate your heat and hold your heat in. So, to make it into a blanket and expect the same results as the "cocoon" style might not work as well. The SOL Escape Bivvy is certainly less in the backpack in comparison to adding another goose down sleeping bag of some sort. The whole set-up packs down completely together into a 10" x 16" compression bag. We are searching for the best "minimalistic" 4-season hammock set-up. Less is more when you have to lug it around. The lighter your backpack, the easier it is to move, hunt, stalk, head off the trail, etc. The set-up is going to offer us great protection and warmth at a very compact, but minimalistic size.