New Borah eVent bivy – 12.5 oz!

"Thoughts?" Let's get a few into the hands of a few BPLers to get the Paul Harvey's The Rest of the Story, but based on specs, pics, and cost, this is a game changer. I'm away from home so I'll need to take a few measurements to see if I can fit my Xtherm, sleeping bag, and yours truly in one without compressing the down. I suspect that I'll need to size up though but that'd be true with a competitor as well.

Between my time on the PCT (sleeping semi cowboy in my Borah splash bivy) and the fact that most of my trips year round are shorter trips targeted at mild weather, I've been really thinking about getting a proper WP bivy. I've always been stopped by either weight or price, so this is a really impressive looking piece. Not sure it's going to find its way into the gear quiver this year, but it is really, really tempting.

if you're sleeping in the rain, eVent is good if you just want wind and splash protection, or mist/dew, then eVent is not breathable enough and too heavy with a 0.7 oz/yd2 fabric like M50, the bivy could be half the weight?

Sounds like a great deal. I don't have any experience with eVent for bivies, but i've heard good things about it for that use. One of my main issues with eVent or any conventional WPB tech, is the issue of DWR, and how not durable almost all of these are, and once the DWR fails, the fabric and system becomes much less breathable (especially with nylon outer fabrics, because it swells some with moisture absorption). There are two main ways around this issue, which manufacturers and companies have not yet, to my knowledge, even tried. Treating the outer face material with silicone encapsulation ala EPIC type process, or using woven polypropylene (or polyethylene) fiber fabric as the outer face. Most of us know polypropylene is used in things like Dri Ducks, Frogg Togs, etc, and polyethylene is used in tyveks and the like, but this is the non woven forms of PP and PE. Thin, non woven forms of any polymer type material is much weaker and less durable than the woven, fiber forms. Doesn't matter if you're talking about polyester (mylar), nylons, or even UHMW-PE. PP fiber is fairly comparable to cheaper, more common forms polyester fibers as to tensile strength, abrasion resistance, etc. It's main lack is it handles UV exposure worse than even nylon, but there are ways around this, such as adding carbon to the polymer in it's liquid state (they also do similar with UHMW-PE plastics). PP is used extensively in the carpet industry–it's considered to be fairly durable in such applications and to have good abrasion resistance (because it's so much lighter per volume than other synthetics, even nylon, you can use larger, thicker fibers to increase durability). So hopefully someday manufacturers and company designers will wise up and use better outer fabrics or DWR for these membrane type WPB tech. But with the DWR industry being so big and profitable (and so consumable), it might discourage such changes.

Bummer! I just got the old version about a month ago, and I haven't even used it yet! That new closure system looks way easier to use.

My one and only experience with Bivys is the USGI GTX bivy that I used in the military. I've slept through several torrential downpours in it and did not have any water get through. Any moisture experienced was due to me breathing into the sleep system instead of sleeping on my side and breathing out. Even when used in less than ideal conditions, I didn't have any issues with it wetting out or the DWR wearing off. I know far less about fabric and fabric treatment than you but just mentioning all this to note that it can be done. So I can say the USGI system is good to go albeit heavy at 2.5lbs by BPL standards. How will eVent hold up under these conditions? Dunno but I'm willing to roll the dice. From a weight perspective, compared to a cuben fiber 8×11 tarp, bivys don't make much sense. From an ease of use/deployment perspective, they start to shine. Don't have to worry about stacking ballast on stakes that don't have a good purchase in the ground, all you need is a roughly 7'x3' piece of real estate to set up shop, don't have to worry about your shelter blowing down, etc. But, once you decide that you want to pair a bivy like this with a tarp, the M90/Apex tarps look like a much better option. Not sure that anyone was debating this.

The DWR on a bivy should last a lot longer than DWR on a jacket or the like. Unless you're using it as a stand alone shelter and subjecting it to significant rain. If it's exposed to direct rain hits, would wear off the DWR much faster than if only occasionally lightly splashed. So it depends on the use. If you use a small tarp in conjunction, should last awhile. I just wish companies would use more truly durable DWR's for rain protection purposes (since such solutions are already there).

ArcturusBear1 wrote: "If it's exposed to direct rain hits, would wear off the DWR much faster than if only occasionally lightly splashed." I don't get that. Washing with detergents, and exposing the DWR to friction and dirt and UV exposure would effect the DWR over time, but I doubt that direct rain would do much, unless it has a high acid content.

Rain can hit with fairly high force (relatively speaking). Depends on how strongly bonded the DWR is to the surface. If hundreds and thousands of high velocity rain drops hit the same area constantly over a longer period of time, the force friction alone can wear it down. How much and how fast exactly, i don't know. I haven't read any specific studies on this alone. Wash cycles (with just water) simulating friction and water effects are the most commonly used way of measuring approximate wear of DWR's. I suppose one could test this by a hose and seeing how long it takes for the fabric to wet out. If you got plenty of water, go for it. I'm on a small well, so likely not to test this. The highest bonding DWR is being phased out (because of pollution/potential health issues), and other options (Nikwax, cheap silicone sprays, etc) aren't near as good to begin with anyways. But all those other factors that you mentioned would speed it up greatly. I guess "durable" means different things to different people. :) Personally i consider durable for near the life of the garment or piece, and that is achievable now in different ways. But until consumers start demanding change or better DWR's by voting with our wallets, then things likely won't change and we'll keep having to buy consumable DWR products and reproofing our gear.

Yeah, Jerry- I have a splash bivy now (actually with the fabric combo you mentioned). I'd be using this as a standalone shelter for short trips where I'm comfortable that I won't need to hide out in prolonged rain. 12.5oz shelter weight ain't bad and I actually like sleeping in bivies.

This looks like the perfect replacement for my 32 ounce Integral Designs bivy. Is the size enough for a 3 inch pad and a 20 degree bag?

I think I'm gonna try this out to replace my "older" snowy side bivy. I have the all E-vent snowy side bivy which I have no problem using or carrying, even though it weighs in at about 26 ounces. This one is claiming to be in at 12.5 ounces, no its not all e-vent, but I will give it a go this winter and see how I like it.

Can someone help me understand why a bivy is preferable to a tarp or a lightweight tent like the Solplex? It seems like a much different experience to save roughly 3 ounces. Is it just the weight savings that make it appealing, or is there something particularly enjoyable about a bivy?

walk all day..throw down bivy and go to sleep. Simple. I think you either love it or hate it. wake up in morning..fast and easy to break camp. Its also lower profile then a tent. If its nice out, just sleep on top of it under the stars (cowboy camp). I also carry a MLD cuben grace solo tarp in case of rain and I want someplace dry to sit and relax. For me, part of it is the weight but honestly most of it is for the simplicity, time spent setting up/breaking down camp and site selection. Its definitely not for everyone, happens to work well for me though. I would never go back.

half the time I sleep with no tarp – when it's not going to rain – then a bivy is good because it protects from dew/frost, wind, damp ground if it's raining I use floorles tarp – bivy protects from damp ground, rain splash, wind

In addition to what Joe and Jerry mentioned, I think a WP bivy's small footprint makes it desirable. Say you want to camp on a granite ledge with a great view, and no place to pitch/stake a tarp, a WP bivy lets you do that and not worry if an unforecasted storm pops up.

>Is it just the weight savings that make it appealing, or is there something particularly enjoyable about a bivy? Sometimes a tent just won’t do and it can’t be explained by weight or bulk or anything like that. http://imgur.com/QejWegS

in addition, if you use snow caves, trenches, etc- a eVENT bivy is the cat’s a$$! :)

Just ordered one in black. Can't wait.

Interesting bivy offering. Two comments: Their web page says: "High Quality sil/PU coated waterproof bottom" Sil/PU ??? Silicone / Polyurethane??? Er… which is it? I don't think PU will stick to Silicone Or is this a typo??? Also… I did not see a mention of it being seam sealed. If you have to seam seal it that could add an oz to the 12.5. And if the inside of the floor is slippery, then adding some seam sealer grid lines to the floor to prevent slipping of your back down to the foot section could add another oz. billy

One side of the fabric is coated with silicone, and the other side is coated with polyurethane. Edit for slight correction, the following is from Ripstop by the Roll (assuming it's the same material): "This fabric is coated with a silicone/PU layer on one side, then a multi-pass PU coating on the other to create a highly waterproof/non-breathable fabric." It may be the same waterproof fabric from Ripstop by the Roll that is called "Silpoly PU4000" that Richard Nisley tested to very good results. Not only does it have a high initial HH, but after wear it maintains a fairly high HH. PU coating is apparently better for applications where more pressure will be applied to the fabric over water. If it is the same material, it would be excellent for a bivy bottom. Should last a long time and be waterproof a long time. I have some in camo that i haven't used yet, but plan to use for bivies. PU can be taped btw, which is the nice thing about having one side with a PU coating.

Where on the Borah Gear website do they state they are using SilPoly? I don't see it They simply say: "High Quality sil/PU coated waterproof bottom" Many silnylons (especially the high quality, high HH ones) use a Silicone-PU blend. See MLD's website, for example: http://www.mountainlaureldesigns.com/fabric.php Edit: and Billy, there's no way seam-sealing a bivy would take 1 oz of seam-sealant. Nor would adding silicone-stripes on the bottom (something totally unnecessary, IMO) add an additional 1 oz.

They don't, but it may be the same material. It also may not be. It would be a plus if it was.