cocoon temperatures

[Birdofprey]

In cold weather, most hammockers utilize some sort of cocoon / layering system to stay warm. The survival tube cocoon that I've developed seems to provide a 20 degree difference between the outside and inside temperatures (ie. when it's 38 degrees F outside, inside the cocoon it's about 58-59 degrees F). Since I'm new to using a cocoon, I'm wondering if this is a good / typical spread.

[Dutch]

20 degrees is excellent. I think 10 degrees is typical. So the question comes to mind, "where's the pictures?". I would think to get 20* you would have to have just the right conditions such as no wind, wind proof fabric, and it would have to be very dry air so you don't get condensation. So where's the pictures?

[Birdofprey]

I'll upload some more pictures tomorrow. The tube material stops any wind penetration. I've added a thin window to the top of the cocoon to allow any condensation buildup to escape. The reflective interior of the tube apparently returns most of my heat, thereby making the 20* difference possible. I've also added 2 inexpensive ponchos to each end of the hammock to prevent wind from those angles.

[sclittlefield]

You've peaked my interest. Looking forward to more details.

[Cannibal]

Pictures!
Pictures!
Pictures!
Pictures!
Pictures!

Reflective inner walls? I'm so getting one and a mini disco ball to hang from the ridgeline!

[fin]

Pictures!
Pictures!
Pictures!
Pictures!
Pictures!

Reflective inner walls? I'm so getting one and a mini disco ball to hang from the ridgeline!

Been there, done that - See v1.2 of the HECU. The upper half fabric has reflective inner walls.

I will be interested to see how BirdofPrey's cocoon works, as this fabric requires quite a bit of ventilation to keep the condensation down, and in practical experience, the larger the difference between the outside temp and the inside temp, the more condensation you are going to have on a thin wall shelter.

The other thing I've noticed is that these reflective types of fabrics tend to get stiffer than other fabrics the colder it gets. I hit 12* in mine, but I was concerned about the stiffness of the fabric in the morning, like it might rip or tear when stuffing it. It didn't happen, but I was concerned it might.

Lets see the PICTURES!!!!

[Birdofprey]

I'll test the cocoon tonight (the outside temp will be down to about 28*). I haven't had a problem with condensation yet, even though I've used the cocoon in late summer and recently during a rain storm. But this is California, and we don't have much humidity around here. Proper ventilation is important when using this type of cocoon. I have small openings at each end of the hammock, a thin window on top, and a small "window" area near the hammock hose.

The material that the survival tube is made of can be ripped (ie. by twigs, raccoons etc.). So I think I'll glue a layer of camo silnylon (found at WalMart) to the green sides of both the top and bottom halves of the cocoon. After doing this, I'll be able to attach the cocoon to my hammock with snaps (the velcro was just a temporary means of attachment while testing the cocoon). My hammock already has snaps on it from when I used a regular sleeping bag as my underquilt.

I hope the photos that I've provided are sufficient. The benefits of this cocoon is that it weighs under 2 lbs., it compresses down to nothing, water doesn't faze it and it keeps me pretty warm.

[warbonnetguy]

what is the reflective material exactly? is it as reflecitve as an emergency sb?

how big are the vents?

[Birdofprey]

The material appears to be 2 layers of a mylar-type of foil that sandwich a layer of clear plastic. This 3-part material creates air pockets which expand when the tube is stretched open. The combination of highly reflective foil backed by air pockets and a 2nd layer of foil creates a thermal barrier that helps to warm people up (they use the tubes to save people who are suffering from hypothermia).

A more detailed description of the material can probably be obtained from the company (Blizzard Survival).

The vents at each end of the cocoon (where the top half doesn't quite cover the bottom half) are about 4" square. My side window near the HH tie out is about twice that (I can easily block this window if I want to warm up the interior). The openings in the slit in the top of the cocoon are marginal (this top half was actually going to be the underside of the cocoon, before I redesigned this thing). I like the slit because it helps to alleviate claustrophobia and provides some light.

[warbonnetguy]

what about the size of the vents?