MYOG Bivy

[Bob Gross]

I sewed my own, but with some changes. First of all, I wanted it for wet weather, so I didn't want any mosquito net at all. If there are mosquitos, then I will use my mosquito net head bag. This is for wet protection. I have two zippers on it. One starts from my left shoulder and zips across to my right shoulder. The other starts from the right shoulder and zips down toward the right hip. That just adds a bit of flexibility in how I get in and out of the thing.

–B.G.–

[Nate Powell]

Just ordered some materials for the bivy. Bob, I like the idea of some side zipper action. I ordered extra to see if I can make something work along those lines. I'd like to try and do one continuous zip across the chest and down the shoulder a bit. I'm not exactly sure how to pull this off so if anyone reading has any hints they'd like to share I'd be grateful. Looking forward to digging into the project.

[Bob Gross]

Yes, I thought about the single continuous zipper.

Zippers can get screwed up if you try to form them into a tight curve, but a broad curve works.

Also, on something like this, you might be tempted to buy a flimsy ultralight zipper, and that may work. However, a larger and more rugged zipper might be a better choice, because you don't want to have to fight your way out of the thing in a dark situation where you can't really see which way the zipper is tracking. I don't think that continuous velcro is the solution, either.

The advantage of this MYOG stuff is that you can make the thing to suit yourself. You probably don't want to design anything that is too radically different from commerical stuff on the market. If some design feature is good, then somebody would have had it on commerical stuff years ago.

I think I sewed my new one out of waterproof nylon on the bottom, and waterproof/breathable nylon on top.

Strangely, the first one of these that I ever sewed was thirty years ago. It was waterproof nylon on the bottom, Goretex on top, and a drawstring closure. That's a little heavy, but it still works after these thirty years.

–B.G.–

[Jamie Shortt]

Nate, I think you will be fine in the bivy at 6' tall. If concerned you can always just add 2" in length to the lower section. i.e. instead of 73" just make it 75". I would not worry about the hood dimensions or changing the window location. Making the netting wider is a great idea.

I brainstormed a lot of different hood designs before I settled on the full width half strip. I had been using a MLD bivy with half moon prior to designing my own bivy. I often slept on my side and noticed my moisture wasn't escaping as well. The full width net allows you to sleep on your side and exhale by the net. It also let you see out the side of your tarp but does provide some protection from blowing rain from the tarp front. I had not seen this design done before.

Bob, Thanks for bringing up adding a side zipper. It is something I have been meaning to add to the design. Adding another zipper down either side is easy, just sew it between the seam. Heck if you want ultimate freedom you could add one on each side.I'm with Bob on the curved zipper, you can do it but it is much more difficult. The point with this pattern was to make bivy construction as simple as possible.

I also like the thought of more weatherproofing so make the entire hood out of momentum. If you want to go the other way and want to see more stars you can make the entire hood top section out of netting. If you want a summer bivy bring the netting half way down or make the entire top out of netting.

If using a Neoair I'd consider adding a few inches to the width. But as you guys are doing, just think about what you want and add some in one spot, change the taper in another or change out netting for more momentum. Making my own gear has really enhanced my outdoor experience.

Jamie

[Nate Powell]

Howdy,

I just finished my bivy based on Jamie’s Lytw8 design and the other info. Chris and Stephen have shared. I haven’t had a chance to take it out yet, but I’m happy with the way it turned out. I used silnylon for the floor, M90 for the top and Nano-seeum for the mesh panel.

I changed just a few things from the Lytw8 design. The width at the head of my bivy is 30” instead of 25” and the width at the foot is 28” instead of 25”. I also increased the width of the mesh panel to 9”, which I think will work great for stargazing, while still giving decent spray protection. Finally, I added a zipper (approx. 36”) down the side of the bivy for easier entry/exit.

Final weight came out to 6.6oz, which I think is great for the features I’ve included. Here are some photos with my Lafuma Down 650 and Therma-Rest Prolite 4 inside:

I really like the look of the Evergreen M90 with the gray silnylon body.

I added an additional tie-out at the top of the mesh panel. I attached an additional line to the guyline with a slip-knot and then to the tie-out to really open up the head area of the bivy. I haven’t field tested this but I figure it will be fun to experiment with.

Plenty of mesh to scope the night sky and hopefully keep condensation levels low.

Top unzipped and open for non-buggy nights.

The side-zipper definitely makes getting in and out much easier. Worth the very small weight increase to me.

Thanks to Jamie for the great Lytw8 design and to Chris and Stephen for posting pics and info. on their bivies. I can’t wait to try it out in the field. Next on the list is a cold-weather down quilt. Gotta feed the MYOG addiction…

Thanks for having a look!

[Jamie Shortt]

Nate, Thanks for posting the pictures. The bivy looks absolutely profession. It looks like I may be officially adding a few inches to the width in the hood. I really like the way it turned out. The side zip definately needs to be added as an option in the instructions…nice job.

I really like the color scheme. What color is the M90?

Jamie

[todd]

Wow Nate,

It's really great how you mod-ed a great design for your own tastes. I am impressed.

Todd

[Chris M]

I really like the mods the made to the bivy. I think that adding a few inches of width to the head really helped open up that space and looks a good bit cozier. Did you end up changing the length of the bivy at all? Do you think the netting would have been in the correct place even without adding the extra few inches to the netting itself?

[Nate Powell]

Howdy,

Thanks for the kind words regarding the bivy fellas. As I said, I'm really happy with how it turned out. Jamie, the M90 I used is called 'Evergreen' on the Thru-hiker site. It really is a great color. I agree with you that the side zipper would be a cool add to the instructions. I just sort of winged (wung?) it and it turned out pretty well. It does add a little bit more work, but nothing major.

Chris, now that you mention it I did add 1" to the length of the bivy. I forgot to note that in the original post. I added it to the 'hood' dimensions (area above the widest point) – so the 'hood' on my bivy is 18" instead of 17". I did that because I have a bit more height than what was stated in Jamie's design. Personally I think most of that extra 1" of length kinda got lost in the seam allowances and whatnot but it all worked out in the end. Not really sure about moving the mesh panel instead of widening it. Could be a good idea, but I could see it being a possible condensation issue if moved up so far that there was no longer mesh over the mouth/nose area for breathing. Would depend on the height of the user.

I had a lot of fun putting the bivy together and I'm looking forward to digging into another project. Thinking about heading to the Hot Springs area this weekend to test out the bivy in the wilderness. Anyway, thanks again for the posts/help/comments. Happy hiking.

[Stephen P]

I'm thinking about making one of these, but I have some questions. I'm 6'2 with size 13 feet. Currently I'm using a JRB hudson river as my 3 season quilt. It has a sewn in foot box, so the bottom of the bag is a little wider than a normal mummy style cut (about 18 to 20inches wide when I'm in it.)

I'm thinking that I would need to make some modifications to the foot box in order to fit better. Would a 10" high seam work on the bottom (5 on the silnylon bottom and 5 on the m90 top?) Or should I do a 12" high seam? I would have to adjust the bottom width as well and the overall length accordingly based on whether I go with a 10" or 12" bottom seam.

I don't plan on using a full length neoair, however I'd like to get a torso length and just use my pack and other stuff under my legs.

Any recommendations on the measurement changes I should make?

[Bob Gross]

What do you do if you are in this thing in the middle of the night, and all of a sudden there is a big rain storm?

–B.G.–

[Chris M]

I actually had a good chance to test this bivy in a storm and in getting out of it quickly just last weekend. I camped up on Black Balsam on the Blue Ridge as it started raining and I only had a minimal tarp (a poncho that wasn't actually even a poncho tarp). This bivy kept me pretty dry and definitely kept me warm even set up so poorly for the rain I got hit with on top of a windy bald. In the morning, my friend woke me up to the news that my dog had pulled out of her collar and walked off. This was the first night of the first trip ever with her, so I freaked out. I went from sound asleep in my bivy to out and running around in seconds. Luckily, my friend just forgot to mention this had occurred seconds ago and that my dog was just sitting maybe 20 feet from the tarps.

I'm not sure if that is your worry, getting out quickly to set up a tarp in the rain, but if so, it can be done. This is especially true when you know you need to get moving quickly.

As for measurement changes, my original bivy has 12" high walls, but my notes on the bivy are really bad because I was on a tight deadline finishing it (too much school work), so I can't remember my exact dimensions. I would say that you would probably want changes very similar to Nate's though. The way I think of it is with his 28" wide foot box he actually has a circumference (cause it ends up almost fitting more as a circle because of the limpness of fabric) of about 56". This may not be totally correct, but works for me mentally. If you would like to know for sure, you can take some measurements of your feet to know if this will work for you.

[Stephen P]

I think it comes out to 54" with seam allowances if I go with 28" bottoms. This should be plenty of room for my big feet. Now I need to order some fabric…

[Danny Korn]

Would someone mind posting pictures of the "corner fold" method for forming the footbox and headbox? I'm planning on doing this project sometime soon and, having not done much MYOG before (so far just a Minima vest), I'm not exactly sure what the footbox is supposed to look like. I've looked at some pictures of how people make stuff sacks, but most of them are small pictures that don't entirely make the process clear. Thanks.

[Jamie Shortt]

I finished a version of the LyW8 bivy that was done with .51 cuben and M50. The final product weighs 3.2 oz (+0.2 for hood shock cord). I did alter the dimensions slightly based on the feedback. The length stays the same at 90", the foot box stays the same with a girth of 48". The length to the chest goes from 73" to 72" (to use whole yard increments). The hood increases +1", the window +0.5" and the taper to the top of the hood is now 29" (before sewing). With these dimensions the bivy can be done with just 2 yards of each material type.

I am extremely happy with the new dimensions. The new pattern is now up on my website…

LytW8_Bivy

Here are some pics of the cuben/m50 version using the dimensions on the pattern.

LytW8 bivy with 3/4" thinlight pad and 3 season quilt inside

Hood close up

Chest Zipper

Shock cord for hood

Footbox detail

As to the question on how to do the folded corner technique, take a look at the footbox pick. It is actually real easy to do. It is just like a square bottom stuff sack. You sew the 2 pieces of fabric together along three sides. You then turn the bivy inside out and "pinch" the corner together so that the seams touch. Pull the corner in to form a wall the proper height then sew it and cut off the pinched corner. If this is still not clear I will try to draw it out.

Thanks to everyone in this thread who helped experiment with the original pattern. It really was a group effort.

Jamie

[Ernie Fuentes]

There has been concern about the making of a silnylon " tube tent" and condensation. Three questions,

Do you get any condensation on the mini tent?

If so, do you think making the top part of the tent with "breathable" M90 would help?

Is M90 a good choice for an enclosed tent where "breathability" is desired?

Thanks

ernie the eyeball
[email protected]

[Dustin Snyder]

I am 6'3" and was wondering how much longer I need to make the bivy?
Thanks
Dustin

[Jim Colten]

The floor of the SMD Meteor bivy is 84" long and is about right for me with a few inches clearance in the head area. I'm 72" tall with size 12 feet and typically would use it with a size small neoair pad. On outings where weight is less critical I use a large neoair pad and it ends up being a pretty snug fit due to rounded corners on the head end.

If I'm interpreting Jamie's pattern and instructions correctly his finished floor is 76" long. Adjust as you see fit.

[Laurie Gibson]

Here is my version of Jamie Shortt’s pattern, using .51 cuben, ultralight insect netting (both from zpacks) and M55 (thru-hiker). An added 24” side zipper is the only modification to the pattern specs. The weight of the bivy without shock cord is 3.45 oz.

For reference, inside the bivy are a 48" long, 1” thick pad, a 21 oz. MYOG quilt sized for me at 5’7”, and a Granite Gear Air Zippsack used for a pillow.

Thanks very much to Jamie for sharing a great pattern!

[todd]

Whoa Laurie!!!! Under 4oz! Saweeeeeeeeet!

[Jeff J]

I finally made my first "real" MYOG project, the reason I bought a sewing machine.

I used sil 2nds and ripstop from Quest, and my tweak to make this fit me was that I added 6". I'm 6' and about 180lbs, and I use a long bag, so the added length was necessary. I added it to the hood area, 3" to the mesh and 3" to the nylon hood; that way I still only used two yards of the top material.

I also made a side zip using one continuous zipper. It was a pain, but I think it was worth it. Rather than try to make the zipper do a 100 degree turn, I added a small triangle to the mesh, turning the zipper twice in smaller angles. It works quite well.

Hood end with my Sub Kilo and Z-lite.

Foot end. I also made the corners 10" high because I have size 14 feet.

Opened up.

Close up of the curve in the zipper. Someone with better sewing skills could've done much better.

Final weight: 6.7 oz without trimming the seam allowances. I haven't decided yet if I want to go back and add stitching to make them lay flat.

Thanks to Jamie for making the pattern, and thanks to everyone for posting their bivys. The discussion and pictures helped me a lot.

Jeff

[James Stewart]

Laurie, under 4 oz. is impressive! Did you use two separate zippers? Any better photos?

[Conner D]

I made my own. This was one of the first myog projects of mine that I have been pleased with. The fit is great. I will post pics this weekend when I get to use it. It weighs 5.4 oz with sil seconds from owfinc (used them for everything), .9 oz ripstop breathable, .9 oz noseeum netting, and a cont. coil sipper.

[Laurie Gibson]

James,

I used two zippers; the side zipper is 24" length. The photo shows where the two closed zippers meet. Except for the side zipper, the construction of this project is very straight-forward. I'm not sure I'd go to the trouble to add the side zipper next time, as it was hard for me to do perfectly neatly.

It is LytW8 for sure. I will use a polycryo ground sheet under the thin cuben floor though. Dirty ground sheet stored in outside mesh pocket of backpack; clean bivy inside the pack.

[Dave Holst]

I have read the thread a few times and ordered my material. I was just wondering, as it got a little confusing, is the current pattern design compatible with a thick pad like the neoair or will I still need to add a little bit of extra height? I'm just using the regular size pad. Took me a while to get my material from thru-hiker to aus so dont want to balls it up if i can avoid it. Cheers.

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