MYOG Freestanding Hooped Bivy

[Kevin Schneringer]

Lately I've spent a lot of time looking for a freestanding UL hooped Bivy. And had very little success. I ordered some material with an idea of making my own. I was a little hesitant since mistakes can get expensive with Cuben Fiber.

Over the last 3 days I have built a Hooped Cuben Fiber Bivy. And I wanted to share my first major MYOG project. I know many people probably think a Cuben bivy like this is just a waste of time. However I disagree since I believe a bivy and tarp is the most flexible way to shelter in 3 season weather.

My idea was to end up with a bivy and tarp set up coming in at or below 15 oz. I think I barely made it.

I really look forward to your comments and any ideas to improve it.
I already know that the zipper is to short so that is a future corrective action.

Specs
W-30" Shoulders, 24" at foot end
L-88"
H-18" Hoop, 11" at foot box
Weight 276.40 grams, 9.75 oz (including 1/4" Delrin Hoop)

Uses 6 Ti Shepherd hook stakes to be free standing which add 1.5 oz

[Andy Jarman]

Very smart looking bivy, was it difficult to make? I understand why you have the large mesh area overhead, but did you consider a hood like canopy over this to dispense with the tarp on trips where you are pretty sure rain isn't expected, like a 'skillion roof' to drain condensation away to the sides and increase the temperature immediately above your sleeping bag?

I have some of Zpacks' new breathable Cuben Fibre waterproofs (see Hikelighter blog for reviews)and had I the time I'd have a go at using this fabric for a similar bivy, very expensive though!

I'm currently using a Pico bivy from Dave Miles (Miles Gear), I find the end where my feet go is a little prone to condensation on cool evenings and have thought about a hooped foot end with a flap for added venting when I know rain is not expected.

I thrash about too much to stake my bag down. I've modified my Oware Neo Bivy with a hoop over the face so I don't have to hang it from something over head. By extending the hoop beyond the floor of the bivy (the hoop is attached via loops on the outside of the bag) the hoop has to lean out away from my feet which keeps the mossie net off your face and any dew inside the bivy off your sleeping bag – a bit. Not sure this would work around the feet though, might have to resort to a hoop with L shaped feet/ends?

Would be interesting to see how your new bivy performs 'in the field'.

[Steven Paris]

I'm constantly amazed at the creativity of people here on BPL.

Very cool, well done, Kevin!

[Paul McLaughlin]

Could you tell us how long the Delrin rod is and how much it weighs?

[Kevin Schneringer]

The hoop weighs 1.875oz and is 48" long
1/4" x 5' length from McMaster Carr was $17 delivered, most of that was shipping.
Struts at foot end is a 22" Zpacks carbon fiber pole cut in half.

[Sam Farrington]

As for ideas, I got nuthin'. But wish my first MYOG project has been that great.

[Anonymous]

Pretty sweet looking. Just curious why use the cuben over the feet/shin/knee area? Even with the mesh upper, won't you tend to have some condensation buildup at the feet area?

[Mobile Calculator]

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[Kevin Schneringer]

I am not really sure how bad condensation will be over the foot end. I had thought about putting a vent on the flat end of the foot box to let air draw thru and move around a bit.
I plan to test it in the next few nights here in the yard and see.
We are forecasted to have some 40* nights with a pretty low dew point so we will see what happens.

[Valerie E]

What can I say — SWWEEET! Completely solves the problems of drooping-in-your-face bivys for very little weight.

[Paul McLaughlin]

more delrin rod questions: is it all one piece, and how do you deal with it when packing the bivy?

[Kevin Schneringer]

Well up until today it was one piece.
Today I reworked the zipper. Removed the existing one and added a 6 1/2' zip and made the delrin rod two pieces.

How I made it two pieces:
Added a 2" piece of .377 DAC tent pole into center of the sleeve the rod slides into.
I used type for Cuben to adhere it to the bivy permanently.
Then cut the rod not two 24" pieces, slide a piece into each side and join in the DAC sleeve.
I also sewed a 30" grosgrain strap to run under bivy and hold the delrin at exactly 30" and very sturdily.

I used the bivy last night with 5* temps and my Zpacks 10* bag. Nice and toasty with no condensation in foot box.
Still think it may condense in warm/moist air. But good for now.

Total weight with new mods exactly 11 oz

Edited for inches/feet and spelling

[Steven McAllister]

Regarding condensation in the foot area,
It looks like the panel is high enough to allow some air flow between your bag/quilt and the top panel.
That should significantly reduce the chance of condensation.
Of course there are times when nothing will keep condensation away when you are sleeping in high humidity and the dew condenses on everything.

[Author]

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