Awesome project! I may imitate something like this once I finish my tarp. It has me thinking, would it be possible to make a detachable top to something like this to turn it into a true bivy if weather dictates? It seems like it could have a nice modularity to it. Or would that even be necessary?

Seriously, love the innovation.

@Ty Ty, Travis lives in Wisconsin. I would imagine that his snow issues would make the Contrail a less useful shelter, limiting it to a smaller portion of the year.

William- Thanks!

Doug- You don't have cuben bed sheets, do you? :)

Craig- It wasn't too hard to design and I'm sure you can figure something out, but I can post dimensions if you want.

Todd- "Character infused seams." Love it!

Ben- No patent. I'll put the pattern up when I get around to it.

Ty Ty- This will mostly be used in winter and shoulder seasons where bugs won't be a problem, so a netted shelter isn't a concern for me. I use a mesh inner and tarp or a Double Rainbow in buggy conditions. I either use an MLD Trailstar or HMG Echo I tarp. I have full bug inners for both of those, but my groundsheet will be used when bugs are gone.

D Johnson- I am also curious to see if the tall walls will have a big effect on condensation. Time to test it!

Brad- Thanks, yeah, I could cut off that extra fabric where the seams were made. Could save 3 grams!! :)

Ty Ty (second post)- "I just don't see the point in having all the different components, fuss of setting up the different pieces." The nice thing about this is that you just throw it down like a ground sheet. No fuss! I only plan on pulling up the walls if necessary.

David- I should have had some beer DURING the process, not just after. I'll get nice and buzzed when I make my wife's. :D

Gregory- Thanks, and yes, I can put the plans up.

Clayton- Yes I think you could add a top for modularity, but since I always sleep under a tarp I don't think its too necessary. However, I thought about making a mesh top for it for bug season....


RE: Contrail- I really still like that shelter and had I the slightest need, I'd get one. It would serve a different purpose than a groundsheet and tarp though.






1. This takes 3 yards of fabric. All measurements include a 1" seam/hem allowance because I ended up double rolling my hems.
2. For the pillow pocket, I finished all edges then folded it up on itself so the pocket is 8" long at each seam. Since the groundsheet is tapered, it creates more of a pocket when you sew this together.
3. for the foot box, I matched up the corners and measured in 3.5", then sewed at a diagonal down to where the bottom corner was. Note that some edges weren't finished because they didn't need to be. This is "inside out" to clarify.

Edited by T.L. on 02/17/2012 17:17:47 MST.

The best things are indeed simple. Thanks for putting the plans up. You should market this idea!

Edited by gregpphoto on 02/17/2012 20:11:41 MST.

I would end up with a lot of condensation on the sides and on the footbox using your draft dodger. The silnylon touches quite a bit of your sleeping bag.

Heck, I even get some condensation touching the no seeum stuff.

That is indeed an issue Im afraid of, but most of the time the walls will be down. Only when it gets windy or sloppy enough will there be a need to have the sides tight around the bag. I have thought of making the sides out of a very breathable material to minimize any condensation, which I may do if it proves to be an issue.

When I'm able to do some testing I'll be sure to report my experiences here.

In the pictures you can see that the lower shock cord is 2 feet from the end of the ground sheet. After laying in it in my living room and moving around a bit, I found that the footbox liked to fall down. I ended up moving the lower shock cord down to 13 inches from the footbox and I like this placement much better. It keeps the footbox up where its supposed to be and allows the side walls to lay flatter.

I put stripes of silicone on the groundsheet because, well, you know why. This of course adds weight.

One came in at 153 grams (5.39 ounces) and the other came in at 167 grams (5.89 ounces).

The heavier one probably got a bit more silicone, since the sizes were pretty identical.


Overall, I'm happy with how they turned out, and I can't wait to use them, especially with some Tim Marshall quilts I have coming in the next few weeks. I'll post any comments I have after I use them, especially regarding condensation.

Travis,

how did these work out in testing? Any condensation issues? Changes you would make?

Then there are fewer drafts

Jerry,

I'd thought about something very similar. I considered sewing one side of the groundsheet directly to the quilt and putting a zipper on the other side for a sort of hybrid quilt/sleeping bag/bivy.

Never made it off the planning stages though

I've used mine for years

One problem is there's an air draft channel on your sides. I put my sleeping pad inside.

Another problem is around my neck there's a huge draft channel to the outside, but I put a couple flaps that close that off.

What is the advantage of this setup over a quilt and bivy when used with a tarp. My bivy is under 8 oz, provides draft protection, ground cloth duties but also provides full splash protection under a bivy. What am missing here, there has to be a big benefit that I'm missing given the reaction to the idea? By the way, looks like a good idea for those that already have a sleeping bag they like.

It's half bivy. I like this!

seperate quilt and bivy is a good solution

with a quilt/bivy hybrid, you save the top piece of fabric - maybe 2 ounces - not a big deal

I like to have a zipper on the top going half way down, attached to both the quilt and bivy. Convenient to open when you're too warm. If you had a zipper in both quilt and bivy that would be an extra zipper, but people are happy with a quilt without zipper.

When the quilt and bivy are sewn together, the quilt won't shift around, it will always cover you perfectly.

Maybe it's more of a personal preference thing than weight or warmth

Tyler,
I've used these several times under a tarp in winter and shoulder seasons before the bugs come out. I did make a change and that was the placement of the shock cords. I moved the top one closer to the foot about 12 inches. It was a small refinement that kept the shape better.

As far as condensation goes, it's not been that bad. Actually, I don't recall ever seeing a buildup of moisture in the footbox, but I guess that doesn't mean that the condensation isn't being trapped in my insulation more than usual. Whatever the reason, it's not proven to be an issue so far.

Does anyone know if there is a chimney effect where the EE quilts cinch up at the feet? There's a little hole there and I've been wondering if much of the water vapor from sweat gets sucked out that little hole due to the temperature differential.

Greg,
My reasoning for this design was to have some of the benefits of a bivy while lessening the chance for condensation. Now to be fair, I've never actually used a full bivy, so my reasoning was pretty hypothetical. At any rate, it's served well as a groundsheet that keeps my quilt and pillow from sliding onto wet or dirty ground, and can help snug up my quilt just a bit more when the temp drops or the wind picks up. I can't prove in any way that this is better than a true bivy, but it's decently light and serves a few good purposes.

>It's half bivy. I like this!

Thanks, Justin!

Clever idea Travis! I like it!