Are you going to miss having the ability to sit up in your shelter? Do you not need to store gear inside? Do you mind spending days trapped inside your bag when it's raining cats and dogs? Are you able to get in and out of it in a flash and then dry off before getting back into it if you've gone out to water a bush? Are you a mountaineer who stays on high narrow ledges? A bivy might work for you.
There are two kinds of bivy - the heavy kind for mountaineers that can't use a tarp for cover, where they are expecting to survive a rainstorm in just the bivy. And the lighter kind that provides some protection from bugs and spatter that makes it under the edges of a small tarp. If you go with a mountaineering type bivy and you are not mountaineering, you're probably going to be sacrificing the space and comfort of a tent for no reason, since some of those bivies weigh as much as a double wall solo tent, and in many cases cost more.
Edited by lori (04/12/1110:18 AM)
"In the beginner's mind there are many possibilities. In the expert's mind there are few." Shunryu Suzuki
Loc: Puget Sound, Washington
On a Boy Scout 50 miler, we got to our destination lake every afternoon somewhere between 3 and 5 pm. Just enough time to clean up and take a quick nap before dinner. I'd set up my tent, crawl in, strip down to shorts, and stretch out. Utterly delightful. It was warm and buggy outside. The bivy boys were all envious because they were just cooking in their bivy sacks, sweating up a storm trying to avoid the mossies and horseflies. Give me my TarpTent ANY day!
I have used both and two years ago met a hammock backpacker. I have never looked back. It is the most comfortable convenient shelter, as long as there are trees! You can sit up in it with feet on the ground, cook under the tarp, and it is by far the most comfortable night sleep I have ever experienced. There are several brands to choose from and I would test it out at home. There are also some hanging tricks and conversions to make to make set up and adjustments much easier. I would suggest looking into one if you are choosing a shelter.
Loc: Marina del Rey,CA
I'm with Lori on this one. If the weather is fine (as in clear skies, no wind), you need nothing more than a really lightweight bivy to keep your bag clean. I have a Bibler Winter Bivy (just a bag with a cross-zip) and used it without a tent in winter on snow-worked just fine.
But, once it starts to rain or snow, no way would I want to be in a bivy. Even my SD Flashlight was confining in a storm with two of us in it. Better with one and gear. I considered a bivy, but after thinking about it, I realized, not for me. You could get a Tarptent, a Lightheart (based on the old Wanderlust design), a Six Moon Design or something similar that weighs about the same as a heavy duty bivy, yet has far more room.
Don't get me started, you know how I get.
A tent will do everything a bivy can do. But a bivy can't do everything a tent can do. The advantage of the bivy is that it's usually lighter and simpler. But believe me, you won't care about that when it's raining buckets and/or the bugs are swarming.
Go with the tent.
_________________________ If you only travel on sunny days you will never reach your destination.*
* May not apply at certain latitudes in Canada and elsewhere.
A stand-alone bivy is a very specialized piece of equipment and is great when needed. The advantages are 1) can sleep in just about any small spot, after all they were designed for sleeping on a ledge half-way up a cliff, 2) compact so this is my shelter of choice when I want to stuff a week trip into my 2400 capacity pack, 3) high winds above timber - many who climb Mt. Rainier and camp out have had better luck in a bivy than having high winds flapping their tents all night and 4) viewing stars at night. Be warned, that MOST people do not like a bivy. If you use a bivy, then only the basic ones that weigh about 1.5 pounds are worth it. If you get a fancy one with poles, you may as well get a light single tent. A bivy will also cost you about as much as a tent. I would get a tent first, and then maybe add abivy after you get experienced.