Bivy question

I have used various bivies extensively for close to 40 yrs. and still always have one with me when hiking or even driving BC's highways ( it is a LONG way between towns in northern BC).

I NEVER completely close a bivy, ALWAYS leave a 4-6" gap in the zipper and this has seemes to ventilate well for me. I highly recommend buying eVent bivies over anything else and find these the driest and lightest.

Dana,
I never understood why 3 season bivys even have a zipper. I understand the logic for a zipper in an alpine situation, but when using a tarp, it would be better to just leave the zipper off and save the weight.
If anything, I just put my head inside the top portion, but never zip it up. And if it's nice, I just leave my head out.
My $0.02…

Yeah a bag cover does fine for 3 season, especially with a tarp. It is a pain wriggling into your bag without a side zip, but that is some weight. If you do get a zip, make sure it is on the correct side, same as your sleeping bag.

The MountainLaurelDesigns and IntegralDesigns eVent material bivies are nice if you want 4-sason. I have the South Col and it is a bit heavy. My trips in the summer have been short and with reliable weather, so just a headnet then.

For a summer bivy, look for abiltiy to use a tie-up, as well as that mosquito net.

"I understand the fabric is breathable but it seems like it would be very stale air in no time. Do people just not ever zip it ALL the way closed over their face? "

i don't know if you where planning on going with a water resistant or waterproof, but, since event was mentioned, waterproof fabrics are not breathable in the way you are thinking. "breathable" refers to vapor transfer, not o2/co2 transfer, so you can actually run out of air.

Dana,

I asked these same questions too.

This year I made the leap of faith to a MLD Soul Side Zip Bivy with the eVent Top paired with a MLD Poncho Tarp.

I would never close up the bivy all of the way, you'll die.

The eVent does a great job on preventing condensation by letting moisture pass through the fabric, but it is not enough to keep you breathing and alive.

When I used my bivy in the snow this past winter, I did close up the bivy so that there was a 4 to 5 inch opening and I was fine.

If you are looking to protect yourself from rain, a small blow hole opening is not going to let much rain in and if you are using a tarp with it, you should remain complete dry.

My bivy does have a loop at the head area that I attach a cord to either the underside of my poncho, which has a loop especially built in for this, or I have used my crossed hiking poles to allow me a place to tie off to.

This is key because it creates a lot of extra interior head space and keep the bug netting off your face. Big bonus is that it feels much less claustrophobic inside when I have that extra space.

If you want to see photos of how I have setup my bivy; check out the BPL photo gallery for Emigrant Wilderness and Yosemite: Lake Vernon. The Lake Vernon trip shows how I used my poles to tie off to and the Emigrant Wilderness one shows how I used the bivy & tarp together.

Hope that this helps and good luck to you.

After using this setup this year, I am thrilled with the weight savings and the more "open" feel by being able to look around 360 degrees from under the tarp.

-Tony

Consider a MLD Super light bivy or another that is compatible combined with a tarp, MLD bivy has a good size mesh window to allow in fresh air, Momentum is very breathable & also allows moisture to roll off the top as stated on it's website, this also adds warmth to your sleep system allowing you to carry less insulation combined with your clothing system. Used this set up for past 2 years exclusively solo in the Whites for 3 season outing's (aprox. 40 nights out) without looking back at solo tent set ups.
Still alive, and slept great!

Thanks everyone for all the great input. It's just what i was looking for, especially the pictures Tony (looks like you had a great couple trips!).

I think i'm going to order a Mountain Laurel Designs eVent Soul Side Zip Bivy and give that a shot. I'm planning on combining it with a SpinnTwinn Tarp from GG.

I'll be sure to report how it goes! Thanks again for the help in clarifying up exactly how to use a bivy. Now i know not to zip it up ALL the way. :)

I always thought that its ability to zip fully was puzzling, but i see that it's just for orienting your breathing hole in different spots. Makes more sense.

Oh, and Tony, here's a trick to use only one pole for keeping your bivy off your face:

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=5745

Happy trails!

Dana,

Glad that you liked the photos and yes, they were great trips.

Hopefully, the photos of the MLD bivy helped out…photos are worth a thousand words as they say.

Thanks for the link for how to use one pole for pulling up the head net area of the bivy…brilliant way of doing it!

I think that you will be very happy with the MLD eVent Soul Side Zip Bivy…love mine. Ron makes top notch stuff.

However, if you are looking to save money and are not in really wet conditions, the Super Light should be fine for you. My friend, Jeremy, who you saw in the photos has that one and it works fine. Mine might be overkill for the conditions that I am facing in CA/Sierras.

P.S. Tip for you, if you plan on seam sealing your bivy: Take your sleeping bag(s) and comforters and stuff the bivy full. By doing this, the bivy will be "puffy", which nice expose the seams, making it easier to seam seal. Also, after the sealant dries, don't forget to use baby powder on your seams so that they are not tacky/sticky.

-Tony

Tony,

Thanks for the advice, i have been looking at the Superlite as well. I'll have to take some time and really considered my options and where i'll be using it. I'm on the east coast so it's mostly AT hiking, which is pretty damp but i'll def take another look.

Great tips on seam sealing too! Never thought about stuffing it full and also hadn't heard the baby powder trick before.

Thanks again to everyone! You guys are great!

– Dana

nm