Bivy Questions

What are the benefits of using a bivy? I don't believe they're very effective as rain protection because the only bivies that are truly waterproof are condensation nightmares from what I understand. Is there any material that is waterproof or close to it and breathes well? I don't think so unless it's some type that's phenomenally expensive. I think Gore Tex's waterproofing/breathability qualities are to an extent hyped. A groundsheet such as Tyvek or Polycro folded over into a pocket that covers the feet is an effective, durable, cheap option that protects against whatever rain may get past the end of a tarp. If a bivy is used to increase warmth or shield form the wind wouldn't a sleeping bag sleeve work better for these purposes, and wouldn't a few ounce net wrapped around the head and suspended from the face be a better option at keeping the bugs and rodents out?

If used properly with a tarp, then a bivy can make good sense. It protects all of your sleeping bag and, as such, one can utilize a smaller tarp, which enables more availability for campsites.

eVent is a fabric that is waterproof and has very good breathability.

This has been asked and answered - including a very recent thread you may want to review by ndsol, about a dozen threads down from this one. Do a search, setting the time frame to 6 months or a year, and you should get lots of good information.

What is a "sleeping bag sleeve?'

The various alternatives you suggest would work for the most part, but not in my view, as effectively or efficiently.

In the past few years, I've always used a bivvy. One among several advantages it offers, is the ability to dispense with a groundsheet.

My particular sack is merely water-resistant on top and waterproof on bottom, so I can't directly address the question of breathability of various materials. My impression is that it's not generally a big deal.

Bivvys are often sold as primarily a replacement for tents. The disadvantage often mentioned is that they are cramped. They are certainly not more cramped than a sleeping bag, which is exactly what they are -- a bag in which one sleeps. Hence I don't understand this typical objection.

They make perfectly lousy tents, but are somewhat better than nothing. I don't view them as a tent substitute, but rather as an invariably useful sleeping bag accessory.

Well... I'd have to say that there isn't much diffence between a bivy and a bag-wrap topped with netting. It's just put together nicer. My bag has goretex, and the only place it gets condensation is along the inner seems. It takes some fiddling around with the ventilation in the middle of the night to keep rain from getting in, but it's doable.

I used to sleep in a bivy for years, but I've recently switched back to using a tent. The only thing I'd use a bivy for now is an emergency 4-season shelter.

I just got home today from a 11-day trip in the Sierra with a bivy. The first two days it drizzled from 2PM until dark. The rest of the trip was nothing but clear blue skies, one night with frost, the rest fairly warm. Most days were very windy because I camped between 10,800 and 12,000 feet every night.

I have the MSR basic bivy. The key for me is that it has little loops that with three tent stakes I can basically set the base of the bivy. This is important because I like to sleep on an incline and this way I do not slide down the hill! It also has a loop on the top (head area) so that I can tie it up on my trekking poles. Thus, I have a very little tent. The bivy stays in place when I roll around at night. I also take a small tarp that is either a ground cover when I do not expect rain, or a "vestibule" when I expect rain so that I can cook while in the bivy. As far as rainproof, I have been totally dry in major downpours with just the bivy.

Conclusion - the bivy worked well. Because I set it up using my trekking poles and I camp at windy locations (to avoid bugs) I do not have condensation problems. I enjoyed looking at stars at night. With 11 days food and a bear cannister, the bivy is nice and compact and fits in my mid-sized pack. The tarp set up for a drizzle is a bit fussy. I had to find just the right rock with a flat sandy spot next to it to get it all set up right. If I had to depend on a tarp only, I would find it very tedious when I camp primarily above timber and often at places where there is not even a big rock to attach a tarp to. And I ofen camp in very windy spots.

If you are going to spend considerable time in camp, I would not use a bivy. If you are going to hike most of the day and just crash at night, a bivy works well in a climate like the Sierra. The advantage of a bivy over just a tarp, is that you do not get wet from underneath or horizontal wind driven rain. That said, if I expect it to rain every day, I would use a tent.

A bivy is not for everyone. You really have to LIKE being out there in the elements.

"I have the MSR basic bivy."

I didn't know MSR made bivies - are you testing a new product? Can you share any details?

Sorry- it is an Outdoor Research (OR) basic bivy.