HH UC with synthetic sleeping bag stuff

[rleathen]

I have read quite a few of the posts dealing with insulating the HH (I have the explorer deluxe zip) and am still a little confused with regards to condensation and location of vapour barriers.

My plan is to use 2 modified rectangular synthetic filled sleeping bags each rated at 0C/32F as the insulation suspended and sandwiched between the bottom of the hammock and the HH undercover. I need to be able to use my HH down to about 0C/32F

I plan on using 1 or both of the modified synthetic filled insulating sleeping bags under the HH depending on the temperature I will be sleeping in. If I need additional insulation I plan on going with the CCF pad technique inside the hammock.

My question with this setup is whether I need to use some form of vapour barrier and if so just where in the insulation stack it should go. My insulation stack from top to bottom so far is:

- HH overcover / bug netting
- top of my sleeping bag
- ME
- bottom my sleeping bag (yes it compresses quite a bit)
- optional CCF pad
- bottom of hammock
- 1 or 2 0C sleeping bags (as discussed above)
- HH undercover

Thanks in advance for any suggestions and tips.

[Chriss]

You are probably going to have to add some type of suspension to the sleeping bags (SB) that you will be using as your UQs. I don't think the Undercover (UC) is going to keep them in place (they sound heavy). I am thinking you will have to sew or fasion some corner mounting tabs on each corner, run some type of cordage (shock cord) and attach this to your suspension. Also, not being able to cinch the SB up to the hammock may create drafts as well. I am hoping someone will jump in behind me and explain things a bit better and have some suggestion for you. I would think NO on the vapor barrier at 32°F

[rleathen]

My apologies I forgot to mention that the sleeping bags that I plan on using as insulation under the HH have been modified to provide for their own suspension on my ridgeline so that I can adjust them as needed separate from the HH UC as well as toggles and loops on their edges for cinching up around the HH side tie outs of the HH and the UC.

[Chriss]

Awesome! You should be in good shape then. Go forth and give it a try. Here is a link https://www.hammockforums.net/forum/...ighlight=vapor for a sticky thread on vapor barriers. A great read and a lot of information on the topic.

[BillyBob58]

You will almost certainly need a 2nd VB if you are going to avoid either condensation or sweat gathering night after night in your under insulation which is in the HH UC. That HH UC is a sil-nylon, wind proof(good) waterproof(good) vapor barrier(can be real good or real bad depending on correct usage)

Used the way you are describing, the one VB will be the outer and coldest layer. So you know what happens when warm body vapor contacts a cold surface ( like your windshield)? Right, condensation. It can occur even on a breathable surface, as in Shug's fleece frost bib. Or in the cold air in front of your face when you exhale on a cold day.

About the only way to avoid a lot of condensation in your insulation if you have a VB as the cold outer layer is to use another VB as the WARM inner layer, such as the 3 oz space blanket recommended by HH for use with their HHSS. Or maybe VB clothing, but you still have to find a way to deal with your exhaled vapor which can hit the edges and condense and slide down into the UC. Which is one reason so far that I stick with a nice wide space blanket which can completely cover the HH pad and wrap around it partly. It is the 1st layer under your hammock, so it should be kept pretty warm by your body heat. Condensation, far as I know, does not occur on warm surfaces. Sweat is another matter, but still if you sweat where is that sweat going to go? Into your insulation?

Hope that helps. If using any form of VB, it really pays to study up on it and be sure of what you are doing. Do it wrong and you end up both wet and cold. Do it right, and not only will you probably be warm, but you will never have drier insulation, even after multi-day trips with no sunshine. Just don't use one as the outer layer by itself. If you are going to have just one, keep it close to your body to keep it warm. A cold VB is a wet VB, wet on the inside! ( One other example you will see if you have not already: the soaked underside of a sil-nylon tarp even when there is no rain!

[rleathen]

Chriss/Billbob thanks for your comments and suggestions. Billybob so you are suggesting that perhaps another VB (reflective space blanket) above the top sleeping bag but below the bottom of the Hammock is needed to ensure that sweat does not transport through the hammock and condense inside the 2 sleeping bags below. Just a couple more questions if you don't mind.

Does the optional CCF pad not function as a vapour barrier itself thus eliminating the need for a VB within the insulation stack below the hammock.

If I wasn't going the use the CCF pad does it then make sense to change the order of stacking so that the HH UC is directly below the hammock and then the 2 additional sleeping bags below that ?

I am trying to come up with a solution that is simple and less error prone. If I screw it up I am either very warm or very cold/wet.

Once again thanks for the help.

Rob

[kwpapke]

Billybob so you are suggesting that perhaps another VB (reflective space blanket) above the top sleeping bag but below the bottom of the Hammock is needed to ensure that sweat does not transport through the hammock and condense inside the 2 sleeping bags below. Just a couple more questions if you don't mind.

Does the optional CCF pad not function as a vapour barrier itself thus eliminating the need for a VB within the insulation stack below the hammock.

If I wasn't going the use the CCF pad does it then make sense to change the order of stacking so that the HH UC is directly below the hammock and then the 2 additional sleeping bags below that ?

I am trying to come up with a solution that is simple and less error prone. If I screw it up I am either very warm or very cold/wet.

Yes, you need the SB directly under the hammock. It works best if you actually use the SS OCF pad, as it will hold the SB snug against the hammock. If you use the SS OCF pad, you should be able to get by w/o 2 bags in the UC (just use 1), and the pad underneath you in the HH. There is nothing worse that trying to sleep in a hammock with a mummy bag and a pad underneath you in the hammock - its a prescription for torture.

Don't get me wrong, I always used a mummy bag in my HH during the winter in Minnesota, but never with a pad in the hammock with me.

--Kurt