Originally Posted By kbennett
There are two kinds of bivies:

1. Truly waterproof bivies made for mountaineering -- used when sleeping on the side of a cliff. Often made of Goretex, they close up completely. They can weigh as much as 2 pounds.

These are not very breathable, and not very useful for lightweight backpackers. The REI Minimalist is this sort of bivy.


Think situations where you can not even sink a stake. Where you need to weight the bivy with rocks to keep it from blowing away when you are not in it.

I have two bivies in this category.

Integral Designs Unishelter for winter = 40.8 oz.

Mountain Laurel Designs Alpine bivy for summer = 12.5 oz.

Originally Posted By kbennett

2. Water resistant bag covers used by UL hikers under a tarp. The bivy adds wind and splash protection, and a fair amount of warmth, but requires a tarp for actual rain protection.

I like this sort of bivy because it's so versatile. It can be used under a tarp in bad weather, by itself on cold clear nights, and inside an A.T. shelter.

I don't think the #1 style of bivy is particularly useful for a lightweight backpacker. The #2 style is much more useful, and can be had for under 8 ounces. Along with a UL tarp, the total sleep system is under a pound.


I think the state of the art now for this type is KatabaticGear BristleCone:

http://katabaticgear.com/shop/bristlecone-bivy/

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"In theory, theory and practice are the same. In practice, they are not."
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