Hammocks in Cold

[MagiKelly]

Further to my pevious thread on Hammocks it looks like I will be getting one (just sorting out prices etc)

Now I have been doing some research into using the Hammock in the cold. I gather you do not need a mat for comfort but you do want something to stop the wind chill and minamise reflected heat. Foil blankets are good but the lack of insulation makes them suseptable to condensation. So here is what I have found

http://www.999supplies.com/product_info.php/cPath/66/products_id/1307

Now what do those of you who use Hammocks think? From what I can tell it looks ideal. light, reusable and plenty big. In fact it seems big enough that it will not only go under the sleeping bag but could go right round on a really cold night. Also just handy to have in your pack for emergencies. This would certainly be a weight saving on my thermarest.

So what do you experiances Guys and Gals think? I have ordered one anyway so I can try it out so we will find out eventually one way or the other.

 

[tedw]

I'm not much of a hammock user but I've got one of these - it's realy just a tougher version of the standard space blanket. There is no insulation in it, as such, it works by reflecting heat back at you - and moisture, so if you wrap it round you you'll get wet from condensation. I use it as a windproof wrap, groundsheet or improvised sunshade/tarp.
Insulation in a hammock is a bigger subject - have a look at the Hennesy website (http://www.hennessyhammock.com/) and Sgt Rock (http://hikinghq.net/gear/hennessey_hammock.html)for ideas.

Ted W

 

[Ed]

Try a piece (ie a long sheet) of packing foam, good insulation and nothin in packed weight

Ed

 

[alick]

Anyone actually seen any pics of the foam underwrap thing that Hennessey are now doing. The way they describe the foam's small pack size, ability to stretch and relative ease of damage makes me suspect it's only 1/4 to 1/2 inch thick.

That sounds like a good DIY project if I can find some suitable foam. The second skin of fabric to hold it in place could be made of any breathable nylon.

Cheers

 

[masongary44]

I always thought that the main point was to be off the ground, which a hammock, unless you are me, tends to do. :yikes:

I can understand the point about wind chill though, and as this is my first winter as a hammock user, i was planning on just putting my gortex bivi in the mix.

Has anyone tried this aproach in winter??

 

[MagiKelly]

I'm not much of a hammock user but I've got one of these - it's realy just a tougher version of the standard space blanket. There is no insulation in it, as such, it works by reflecting heat back at you - and moisture, so if you wrap it round you you'll get wet from condensation. I use it as a windproof wrap, groundsheet or improvised sunshade/tarp.
Insulation in a hammock is a bigger subject - have a look at the Hennesy website (http://www.hennessyhammock.com/) and Sgt Rock (http://hikinghq.net/gear/hennessey_hammock.html)for ideas.

Ted W

As I understand it all you have to do to keep warm in a hammock is stop the reflective heat loss and wind chill. To stop the wind chill you want something that is NOT breathable so that moisture is not passing through and evapourating. So this blanket should work. My comment about wrapping it round were misleading. It would be my intention that the blanket would only be under me and perhaps at my sides but not on top unless it was extremely cold. I would not forsee a problem with condensation because the blanket underneath me is not breathable as my thermarest is not breathable and I do not have any problems at the moment. It is probably going to be a case of trying it and seeing how it works. My trips during the winter are mostly going to be in a canoe so weight is not a problem so I will have my hooped bivi bag, thermarest and tarp with me in case of problems.

Looking at the web site quoted it seems that a lot of people are using windscreen insulators which are just glorafied foil blankets but as I say we will see. Some experiments are called for me thinks.

 

[MarkG]

There also now doing an all in one sytem so that you don't need a sleeping bag or under pad.

 

[MagiKelly]

There also now doing an all in one sytem so that you don't need a sleeping bag or under pad.

I noticed their all in one system but thought that you still used a sleeping bag with it.

 

[C_Claycomb]

I have found that I get a good deal colder in my hammock, in all conditions, than I do when on my Thermarest on the ground. The windchill is significant!

I have been experimenting with one of those foam and mylar reflectors sold for car windshields, to keep the sun out. It does keep you warm, but has several problems. It is a real pig to get it under you in a hammock, its stiffish and tends to want to fold up, won't stay lying there by itself. More of a problem is the condensation. At the Wilderness Gathering the back of my Snugpack Kestrel got wet enough to go a shade darker. Not satisfactory. Merely incovenient in the summer, it would be a real pain trying to dry out a bag in the winter!

I haven't tried using my Thermarest in my hammock and am loath to do so. If I have to cart a Thermarest around I might as well use a Basha and sleep on the ground!

 

[Danceswithhelicopters]

After my own period of experimentation and reading the various websites there are 2 things to consider. First a hammock compresses much more of the filling of your bag in 2 ways. More of your body area is supported and therefore more of the bag is squashed down. Also the tension you see in the hammock as you lie in it is repeated in your bag, unlike lying on a mat, and the loft is further reduced. Secondly as your bottom swings in the wind the surface area of your body is cooled by the moving air also unlike a still tent or bivi. My preferred solution is a half inflated thermarest, which allows it to conform to your body better,underneath and a goretex bivibag to keep out the wind without condensation. The Hennessy solution of clip on undersides etc strikes me as complex and big ruining the point of a hammock. having a bivi as well gives you 2 options for kipping out. IMHO.

 

[MarkG]

I noticed their all in one system but thought that you still used a sleeping bag with it.

From the way I read it there's an under cover to insulate from underneath (no need for a mat with that) and an insulated cover that attaches to the netting to create a pocket of warm air.

 

[gurushaun]

I've been looking into getting a Hennesy for a while, my thoughts on keeping warm in colder weather would run along the lines of a 3/4 length pad made from polyester batting that wouldmould to my shape and replace the thickness of the bottom of the bag lost due to compression.

Cheers

Shaun

 

[leon-1]

I always thought that the main point was to be off the ground, which a hammock, unless you are me, tends to do. :yikes:

I can understand the point about wind chill though, and as this is my first winter as a hammock user, i was planning on just putting my gortex bivi in the mix.

Has anyone tried this aproach in winter??

I have been using a hammock all year round for well over 6 years, it sounds like overkill, but I have a therma rest in the base of my hammock and I will also use a bivi bag as well.

When sighting a hammock try to find as sheltered a spot as possible from the windand keep it fairly low to the ground. This way you can set up your tarp almost like a tent over the top stopping wind actually buffeting your sides and reducing air flow (which wicks away the heat from your body) underneath you.

 

[Neil1]

I got my original Hammock from Leon-1, I have since made several versions to adapt to a temperate climate.
Extra insulation IS required anywhere that the insulation of your gonk bag is compressed.A hammock can be used anywhere you find trees! Leon & I have used them succesfully here for many years, even in snow.
The major problem with using a hammock in this environment is keeping insulation in place (but I have that sussed now too).
The fabric of the hammock keeps wind at bay, but carefull siting is recommended.
Moisture ingress can also be limited with a little commom sense.
I'm currently working on a hammock specifically designed for our climate, something that requires few "add-ons" and is relatively cheap and is robust (another problem - extra stitching causes weaknesses).
Anyhow - whatch this space.
Neil1