Tarps vs. Overcovers

[SnrMoment]

From practical experience, a "barely breathable" tarp attached to a ridge line will get wet with condensation. If it's cool out (40*) and in a very dry climate, it will get wetter, If you brush against it with a shirt or your head, they will get wet. If it's humid, or hitting the dew point, it will start dripping on you.

This is true for the 18" wide top part of one of my experimental bug nets as shown in the pic. There's plenty of ventilation, but that does not solve the problem unless it's windy. Netting is standard noseeum.

[SSGHawk]

Under certain conditions doesn't a totally closed over cover like on a Clark NX-250 also develop condensation problems. I bought and am loving my NX-250 that Mannowar sold me. Not a biggie but I found it curious that I can keep the head end unzipped somewhat to let my moist and hot breath rise out but I expected the ability to slightly open the foot end also so there could be a little air movement. I understand that the incoming air would be colder and would drop right down on my feet if I did have a foot end vent.

I am thinking through what would happen if I get caught in a couple day storm just above freezing. I guess I need to plan on heavy condensation in the conditions Senior Moment mentioned.

Good info folks.
Paul

[dakotaross]

Overcovers are only good for certain conditions, otherwise they become condensation traps, even with breathable materials. And you certainly don't want to think about a breathable hammock offsetting the cover, in which case you'd be talking about the only way out for vapor would be through your UQ.

For me personally, one of the joys of hanging is being wide open, tarp hung high, at least one side in porch mode. Would be warmer to just pull the tarp down on me, but instead I've gone to stouter quilts. I don't take nearly as much crap with me as I used to so my pack is still light, though perhaps not UL.

[Bubba]

For me its also about room. Getting in when the tarp is too low forces me to stoop and my back brushes up against the tarp when I get in and out of the hammock which gets my back wet from the condensation. I also like to have room under my tarp to move around and even do things if necessary. A very low tarp's ridgeline would get in the way of hammock suspension a well.

[goanywhere]

For me its also about room. Getting in when the tarp is too low forces me to stoop and my back brushes up against the tarp when I get in and out of the hammock which gets my back wet from the condensation. I also like to have room under my tarp to move around and even do things if necessary. A very low tarp's ridgeline would get in the way of hammock suspension a well.

Yes, I think that for newbie hangers that's a common mistake. They (we) think that it's important to have the tarp close to the top of the hammock to keep rain off, as well as heat in, but experience shows that in reality a tarp can be suspended quite high above the hammock and give good rain protection. The temptation to hang a tarp from the ridgeline as an insulation aid gives way to reality after just one try in cold weather. It's surprising how much moisture the average person expires overnight, and without either good ventilation or a well suspended tarp to let the moisture drip away from the hammock, quite a bit of 'rain' can make sleeping uncomfortable quite quickly.

Far better to use breathable insulation close to the skin than to try to make a 'hot tent' inside a hammock.

[PDA]

Asym tarps by their very nature have one side protected better than the other. .

Not corrext. An asym tarp such as the Hennessy assumes an assymetric lay by the sleeper, so that the head is covered at one end, and the feet at the other so each side is equally protected, just at different ends.. read Sgt Rock's description of hanging in a Hurricane with a minimum asym tarp and staying dry. Needs careful site selection and correct orientation, but it can be done.

Bushwacker - if your tarp is directly attached to the ridgeline, it can only be as long as the ridgeline. Hennessy asyms are a couple of feet longer than the ridgeline so that the ends of the hammockare protected and are either attached to the trees, or the suspension lines from the hammock, so are a few inches above the ridgeline. As Wisenber suggests, if you can't find a (wind) sheltered spot to hang, you will probably get wet with a minimal asym tarp.

[hikerdelita]

Ok, here is what I am wondering. Say we take an 11' hammock hung with a fixed ridge line of 83% giving just about 9' of space in the range of the hammock which is hung under a smallish tarp. What if we make the bottom of a hammock sock and the first 2 feet over each end out of a non-breathable, but the top cover between those two ends of a similar weight breathable fabric. I'm wondering if the bottom and ends (non-breathable) would protect from blowing rain, while the mid-top section (breathable) could provide protected semi-ventilation under a light tarp, or the top center breathable portion might even be a zip in bug net. Am I crazy? I really like the idea of a hammock sock, but is it nuts to do part with bug net and still use a small tarp? Smaller than a winter tarp yet good weather protection and warmth retention? I covet your comments.

hikerdelita,
a happy hiker

[MacEntyre]

I really like the idea of a hammock sock, but is it nuts to do part with bug net and still use a small tarp?

Folks have done that. It's a good approach if you really want to integrate the tarp with the sock for warm weather use.

In my experience, as a warm sleeper, and a generator of moisture, the tarp works best when it is separate from the sock. I have made socks with waterproof tops and breathable bottoms, which are in use now. To some people, the SEEP on a Molly Mac Gear Hammock Sock really wants to be a tarp. But it does not work for me.

Cold rain is where one could really use such a hybrid sock tarp. However, the part that traps warmth still needs to pass moisture. That is the fundamental problem. It works for some, though.

Above 20*F I put a tarp over a breathable sock. Below 20*F, a tarp is not necessary over a sock, and I use canvas.

- MacEntyre

[NordicNorm]

...
Above 20*F I put a tarp over a breathable sock. Below 20*F, a tarp is not necessary over a sock, and I use canvas.

- MacEntyre

Interesting. Assume you mean canvas sock, not canvas tarp?

[MacEntyre]

...canvas sock, not canvas tarp?

Yep, 4oz canvas sock for extreme cold. No tarp is necessary because no liquid water is possible.

You can read the technical stuff behind the magic of canvas in extreme cold here.

- MacEntyre