I will be making a pair of water resistant bivy sacks, and would like some opinions on how to make a detachable head net, and any other feedback you could give.
This bivy will be used in addition to a silnylon tarp while backpacking, but I imagine that it will mostly be used for overnights while rock climbing during (predicted) dry weather. The second sack is for a friend who will be climbing with me in Colorado this summer.
I've designed it mostly from the description of the BMW VAPR bivy with a side zip and the six moon designs Meteor Bivy, but would rather have the bug netting be more roomy than a 'window' but not so large as the Meteor.
Some features: Momentum90 top, silnylon floor with 4" high bathtub walls, 8" high footbox, and 30" side zip from head opening down the seam of the right side. The head opening will have a shock cord in the body's seam sharing a cord lock with a thin webbing cord from the head seam.
As for the head net, I'm thinking that it could simply be draped over the top of the bivy, attached to the two tie-down loops on the head of the sack and be tucked under the body, perhaps with some velcro tabs. I'm hoping to avoid a second zipper. I thought a 2 foot long pyramid would be good. Although maybe its a bad compromise: way more than enough to keep off my face but not big enough to sit up in?
I went crazy with Google SketchUp and came up with some designs. Not sure how to 'flatten' my bug net, so that I could get a 2D pattern out of it.
Oh, I'm 5'7" and my buddy is 6'2". For those who have used bivys, is about one foot of additional space about right? I don't think I will be storing much else inside, just sleeping pad and bag.