Is a bivy necessary with a tarp?

Jarod,

The need for a bivy is going to depending on the conditions that you are expecting for the time of year and location you will be hiking.

If there is a chance of rain and cold winds, I would take the bivy.

Are you dealing with high humidity…if so, the Contrail might be the way to go. Unless you are okay with sleeping out and bugs are not an issue.

They not all that heavy and can give you protection from rain spray that could blow in/under your tarp and can increase the warmth of your sleeping system by up to 5 degrees.

Perhaps, more importantly, would you be comfortable within the tight confines of a bivy?

They are not for everyone.

For the past year or so, I have been using a poncho tarp and bivy and find that it has worked really well for me…..have not used my Contrail in quite a long time.

Hope this helps.

-Tony

I think my biggest reason I'm hesistant is the Confining issue. Honestly I use a half-zip summer sleeping bag (Kelty LY 40 Down), and it drives me nuts about 75% of the time, not being able to fully vent (clammy legs). Could it getting windy in the rain on those AT ridges, oh yeah.

For me…

Tarp ~ 5' X 8' requires a bivy.

Tarp ~ 8' X 10' does not require a bivy.

A large ~ 8' X 10' cuben tarp is going to be lighter than almost all smaller tarp/bivy combinations.

my experience is w/ poncho/tarps which are roughly 5×8- these IMO require a bivy, it's possible w/ a larger tarp you could get by w/o one, but my bivy also provides bug protection, so even w/ a larger tarp my bivy would be going- at 6 oz and packing up smaller than a pop can it's no great hit on weight or volume

At the very least I would go with a bug bivy. There are some pretty roomy bug bivies on the market too

FWIW, the 6×8 tarp I made I added netting around for the bug issue and designed for a half pyramid pitch for storm proofness. Because I did not have a bivy, I also made a storm door I could attach to the open side if the weather turned nasty. It worked out quite well but I'd prefer more head & legroom. My next design may be along the lines of a Wild Oasis or thinner Lunar Duo to solve that.

I use a 5×8 tarp with no bivy. But I'm in the Sierra and you're in the east, so YMMV.

I use a homemade bivy with a smaller tarp, mostly for extra rain protection for my down bag. With an 8×10 or larger, not as big a deal. In colder weather, there is no reason to close the bivy against bugs, so it doesn't feel as confining, and I can just use my bag as a quilt anyway. (But my bivy has a full circumferential zipper, rather than the typical chest slit zipper, so it opens a lot more. Much nicer.)

In October on the AT, I'd bring my bivy just for extra wind/cold protection, and use it all the time. Or I'd bring a solo tent. Depends on whether I'm planning to use primarily the AT shelters or my own carried shelter.

I would definitely carry a bivy sack with a 5×8 tarp in late October. Actually, I do and will be carrying a bivy sack and 5×8 sil tarp when I do various hikes in New England this fall. As others have said, it helps a lot with the wind and other coverage issues.