I've been playing around with some of the lighter clothing-style Tyvek I bought a while back, exploring some ideas for a lightweight, fair-weather bivy. The goal is to have something for short trips where rain isn't expected but isn't out of the question either. I folded a 5- by 9-foot piece length wise and glued a seam about five feet up. It weights 6 or 7 ounces and could almost certainly be trimmed some once I figure out what to do with the head area. I was about to seal the bottom but decided to hold off because I thought that it might be nice to be able to kick the foot-end open to regulate temperature and moisture.

I was dreading shimmying into the thing when I noticed that with the open bottom it's really easy to just slip it over my head while standing up. In the process I also noticed that it might make a decent tunic against rain or cold. I walked around the back yard holding up my "skirts" and with the open flap over my head until I found a place I liked and just sat down. At that point it's pretty easy to police the ground of sticks and rocks, take off my shoes, and lie down. I'm thinking that the foot end could either be left open (maybe with the top cut longer than the bottom to avoid rain rolling down the floor) or I could fold the end over and secure it with tape or snaps or something until I want to stand up again.

I've been considering a few options about some mechanism in the head area to keep the cloth off my face. One idea is to add some tie points that might go to a tree or sticks jammed in the ground. I tested that with an improvised Fletcher-style Visclamp using leaves and a hangman's knot. It worked OK but I'm afraid of tearing something if I move around too much. Another thing that looks promising is using some hoops with the ends jammed in the ground as a kind of frame to throw the flap over. I had recently trimmed some trees and had a lot of nice, bendable branches around but I'm sure that more suitable poles could be obtained if I decide to go this way.

I plan to take this thing out next time it rains and play some more. My question is, what do you all think about an open-footed bivy?