I placed the zipper down the center of the last bivy I made. I really like this location for ease of entry and access to the bivy contents from outside. When sitting in the bivy with the zipper open it feels sort of like sitting in a cayak.
Here’s a photo of a centrally place zipper in a bivy that Steve at Suluk 46 made.
The zipper in Steve’s photo is 3′ long. I’m not very flexible so I made mine 5′ long.
Have others tried this location? If so how did it work out for you?

