If you could only carry one in your survival kit, which would be better to have...a space blanket or an SOL emergency space bivy bag?

I know you could use the grommeted space blanket to build a shelter and reflect the heat from a fire back onto you, but the bag would cover you completely and protect you from the elements.

Which would keep you warmer?

I haven't used the bag-style before, but I've found the blanket formation gives me some flexibility of use (rain cover, etc).

I usually carry the bag, figuring I could always slit it open if I wanted to use it as part of a shelter. Of course, you could always tape a blanket into a bag. I doubt there is a huge significant difference in real world use. Either one would benefit from improvised components to improve effectiveness.

I EDC a heatsheet blanket but I carry both in my kits. One for in and one for under. That said, I'm still a card carrying member of over-packers R Us.

I was "camping" two years ago with my son's elementary school, and one of the guys who was chaperoning along with me had apparently been homeless by choice for a 12 month period of time and learned how to sleep outside rather well, in all sorts of weather. Despite the constant rain for the duration of the trip, he slept in a bivvy bag on a pad - no tent!

He told me that he basically lived in the bivvy bag and it was "all you really need"

EDIT: it was one like this:
http://www.campmor.com/outdoor-research-...ci_sku=81533BLU

That "bivvy" is a borderline tent, both in cost and weight. A "true" bivvy would be about one-quarter of the weight, and easily one third of the cost. What is nice is that there is a continuum ruanging from 8 ounce bivvy sacks on up to one person tents weighing about 24 to 32 oz (and higher). You can pick whatever suits your fancy and circumstances.

My reasoning exactly...



This is where I start to disagree... Taping a blanket into a bag isn't something I would plan for. Fumbling with flimsy heat sheat material and tape when it's raining, blowing and my hands are shivering... Nope, not my kind of fun. This is exactly when a pre-made bag really would shine.

If I could only carry one, it would be the blanket just because of the flexibility, especially if it is a bright color for signalling.

Blanket: Smaller, more likely to have with me. Some models have grommets, making it easier to user to make shelter instead of using as a blanket.

Bivvy: Warmer and easier to use for sleeping. Can be converted to blanket with a knife.

For me, the bivvy is too big to go in an on-body kit but I do have one in my BOB.

Can I choose emergency poncho?

A space blanket is really a small lightweight tarp IMO. Its utility comes from being cheap and lightweight.

I am more worried about getting rained on than much of anything else. Space blankets and bivys do not make very good ponchos, while a poncho can be readily pressed into the same kind of service as a space blanket, at a slightly higher weight and volume price.

A bivy cannot be readily used as a poncho either, although I suppose one could curl up inside one and wait out a rain shower.