If you are making a bivy bag I suggest you consider incorporating a pointy top in its design. Here's an example with a green bivy/tent that hangs under a shaped tarp (fly).







The added pointy top, in this example, added about 1 ounce to the bivy's overall weight of about 6 ounces and required little, if any, more work than making a more traditional bag shaped bivy. The 45-48" height of the bivy allows me to get up on my knees when changing clothes and to hang things (e.g. light, wet socks, etc.) from the peak of the bivy.

With a pointy top the "feel" of the bivy is more like a tent than a bivy.

Daryl cool looking bivy tent design did you make it?
Terry

Terry,

I designed it. Bear Paw sewed/dlued the cuben fly expertly. I made the (7 D fabric?)inner tent poorly. I also made the carbon fiber poles. Tent, fly and poles = about 20 ounces total.

Daryl

Neat. But realistically, calling that a 'bivy' is a stretch. No?

I'm pretty certain this is already called an "inner tent" by the industry and community. Granted they are usually made of mostly bug netting, but many MYOG versions will use a ripstop fabric instead for weight, sand, spindrift, or warmth reasons.

You are right though, for the weight they are a lot more functional. The only downside is if you don't setup a tarp due to good weather, all that extra material floating around you can be annoying to deal with.

I like it. Another great design from you, Daryl!

A (probably silly) question, though: would your hiking poles (assuming that they're adjustable, and that you use poles) work in place of the carbon fiber struts? It'd be a negligible weight savings, but at the weight of the system, it might actually show up as a decent percentage of the total.

John,

Yes, hiking poles would work.

The current poles (two vertical and one cross pole) weigh about 4 ounces so there are a few ounces to be saved. As you mentioned, that's a pretty large percentage given that the bivy/tent, fly and poles total about 20 ounces.

Daryl

Sometimes its good to know the reason behind the design:

This is Daryl.

Well, Rab calls this a bivy so I suspect one can call an inner tent anything they want.

Nice job thinking outside the box.

Edit: meant to ask- could the inner bivy part be secured to the corner loops on the cuben fly, or do they have to be staked independently as shown?

Edited by COHiker on 06/29/2012 13:55:51 MDT.

Or by that picture even an outer tent, aka fly, aka tarp...

I'd give Rab a little leeway for being British, they can't tell the difference between their ar$e (really profanity filter?!) and their boot.

Nice. What I would like to try out is something with a similar design to the bear paw minimalist or the MLD bug bivy but made not from mesh but from 10d or similar. I have got some grip clips that I plan to use with my MLD super light to lift it away from my quilt and make a sort of mini inner.

Hrm...nearly twenty percent of the weight. Now, the question becomes, is it worth the hassle...

Anyway, thanks for the specs!

Steven,

That's the last time I send you a personal photo of me. I told you not to share it! I hope you get my point.

Daryl

Daniel,

The inner bivy/tent is normally secured to the fly/tarp and doesn't have its own stakes. I set it up with its own stakes for the photo so it could be seen without the fly obscuring it.

The four corners of the inner bivy/tent are tethered to the fly/tarp corners with bunji cord and mitten hooks. The pointy part of the inner bivy/tent is connected to the midpoint of the cross pole using a quick release buckle. The inner tent is hung after the fly is set-up and from inside the fly....out of the rain.

Daryl