This was my first MYOG project completely from scratch. I did my homework in the MYOG forum for a few months and then last december tackled a fully enclosed winter bivy with a storm porch/awning. I plan to use the bivy for two uses, first as my inner tent under a GoLite SL2, second and more exciting I want to use it as a stand alone shelter on fast and light trips where a small weather time table requires speed and therefore a very minimal, light and simple kit. The trip I have in mind as an example is a winter presidential traverse, 17-19 miles depending on route mostly above tree line. The statistical weather in the winter is 2 out of 3 days will have nasty weather… So if you get a good weather window you have to hit it hard quickly.
So here are the materials and dimensions. The bivy is a wedge 1'-8" at the foot 2'-6" at the top by 8'-6" long by 8.75" tall. The bathtub floor is 1.1 silnylon the top is M90. The porch is an additional piece of M90 8" wide x apx. 12" along the head and then 3-4' down one side. The porch has two tie outs (one at the top corner and one at the bottom by the end of the zipper) that attach to my hiking poles driven into the snow. Picture the porch over your front door. A water proof zipper runs 3' from the head down under the "porch". I pitch it as a solo shelter by digging a 9' x 4' (top) x 2' (bottom) x 2' deep hole and bury my hiking poles about half way in snow. The two tie outs have zPack tensioners. The tie outs serve two purposes, it gets the top fabric away from my head, and tensions the porch. I haven't had to yet, but I should be able to cook under the porch regardless of what weather is going on. The bivy is also long enough to fit my winter pack in the inside at my head as a pillow.
Final weight is 10 oz including seam sealing. Packs down to a little larger than a softball.
fake snow with a scary winter monster for scale
close up of the porch area
compressed and ready to pack.
