Bivy Sack

[Mental-Miles]

After seeing Paul handling his thermarest and sleeping bag in a bivysack at www.Grenzsteintrophy.de I am planing to get a bivysack myself ... but which one?
Of course I am looking for a light one, breathy (Goretex?), waterproof (Goretex), durable floor layer to protect the thermarest, a comfortable entry and some space for gear to be stored. Any suggestions which one to take?

Thanks for answers in advance

[sherpaxc]

I wish I could help you.  I got a Montbell Dry Tech bivy from some recommendations on here and used it on the CT this summer.  Thank goodness I had a tarp, because it was NOT waterproof AT ALL.  I guess the flip side is good though in that I had zero condensation issues. 

3 of us had the same bivy, one guy was going to sleep under the stars and some rain moved in.  It pretty much soaked him through quick.  REALLY disappointed in it.

[Mental-Miles]

Dear Sherpaxc,

yes, that seems to be the point: In the end, most bivysacks seems to be like old bike panniers in the pre-Ortlieb-times : "some kind of water resistant, but never water proof", so why should one buy an expensive/fancy one?

An other point is: Only some of the webpages of the companies are mentioning if the Bivysack will contain the sleeping pad inside ... Does anyone has got the necessary size in inch/cm to compare?

So here is the result of my investigation so far:
- The most light:
MLD SUPERLIGHT BIVY (Neo Air compatibel) 156 g http://www.mountainlaureldesigns.com/shop/product_info.php?cPath=22&products_id=30
Titanium Goat Ptarmigan Bivy 165 g  http://www.trailblaze-trekking.com/titanium-goat-ptarmigan-bivy.html
montbell B-DRTC.U.L. SLEEPING BAG COVER  http://www.montbell.us/products/disp.php?cat_id=104&p_id=2321027

Mid-weight, but "tuffer":
Alpkit Hunka (Neo Air compatibel)  http://www.alpkit.com/shop/cart.php?target=product&product_id=16312&category_id=253
oware BivyLargeLongSidezip http://shop.bivysack.com/product.sc?productId=47&categoryId=2
RAB Alpine Lite Bivi 420 g. http://rab.uk.com/products/equipment/bivis/alpine-lite-bivi.html
MSR AC Bivy http://cascadedesigns.com/msr/tents/essential-series/acbivy/product

Regular gear weight ratio:
Mountain Equipment Borealis Bivi 550 g. http://www.mountain-equipment.co.uk/the_gear/tents_+_shelters/bivis/borealis_bivi---365/

Allmost a tent-version:
Black Diamond http://www.blackdiamondequipment.com/de-de/shop/mountain/shelters/spotlight-bivy/
Outdoor Research Highland Bivy http://www.outdoorresearch.com/en/or-gear/accessories/shelter/highland-bivy.html

The most lite tent:
Nemo Gogo Elite http://www.nemoequipment.com/nemo2011-gogoelite

So, does anybody know, which of these are really waterproof?

[bmike-vt]

for about the same weight as the nemo and the blackdiamond (and other typical brands, i would guess), you can move into a tarptent. and you don't have to carry a tarp in addition to the bivy, assuming you need it to cover your head.

waterproof, more room for gear, better ventilation.
i picked up an REI minimalist bivy on sale, found it too tight with my 30d down bag and insulated pad.
then went for the tarptent contrail. a few minutes to setup (easier, for me, than a tarp).

i certainly see the advantages of the bivy, no doubt. and would likely use one if i lived out west. lots of bugs here in the east, and i like having the mesh off my face with room to stretch out.

[samh]

If you want your bivy sack to be truly waterproof you will need to purchase one that is comprised of either Goretex or eVent fabric.  These materials are relatively heavy per sq. meter of fabric so the overall weight of a waterproof/breathable bivy will often be as heavy, or heavier than the weight of an ultralight tarp.

For instance, compare these two options:

Integral Designs South Col Bivy which has a mfg listed weight of 22 oz and MSRP of $260.00.
http://www.integraldesigns.com/product_detail.cfm?id=693&CFID=1894524&CFTOKEN=43394557

Gossamer Gear Spinn Twinn spinnaker tarp which has a mfg listed weight of 8.6 oz and MSRP of $175.00.
http://gossamergear.com/shelters/shelters/spinntwinn-tarp.html


The volume of space needed for these two options is very similar, both offer full protection from rain yet the tarp system will be extremely more breathable and protect you from the constant threat of wetting out from condensation inside your bivy sack.  The downside to tarp use is it lacks wind protection.  To counter that a non waterproof bivy sack can be added to your gear list with a weight penalty of around 7 or 8 ounces, another $150 and a half liter of volume. 

[sherpaxc]

I agree with ya'll.  That's why I had decided to just keep my Montbell bivy.  It had zero condinsation and when used with a tarp it was very effective at cutting the wind.  Not a roomy bivy by any stretch, and I have to use my pad outside of the bivy, but that's no biggie to me.

It's uber light and will really stuff into a compact size.  I use it in conjuction with an 8x10 tarp.  I love all the protected room I have under a tarp. 

[Adam Alphabet]

In a similar search for a water proof breathable bivy sack a few years ago I ended up with an Integral designs all eVent overbag. I ended up selling it after minimal use because of the large volume and heavy weight, around 18oz. The thing was huge, super long, wide, built spacious for winter use. The eVent is exceptionally breathable I can't say anything about goretex bivys as I've never used one. If I were getting a waterproof breathable bivy though, eVent would be my only choice. They are hard to impossible to find commercially. Mountain laurel designs used to make an alpine bivy that had an all event top, I think it weighed in around 10 to 12oz. If you're using a down bag I would stay away from something like the MSR e bivy or anything else with a silnylon top. backpackinglight.com has tonnes of threads talking about bivy's you'll find info there.

While the ID bivy was an interesting experiment For nearly the same weight I always go to my trusty first gen TiGoat bivy and ID poncho tarp (5x8). If there's no rain expected I just sleep bivy out, it's not water proof at all, great breathability though. If inclement weather is in the forecast I set up the tarp as well. I have been caught being lazy and not setting up the tarp led to waking up in the night to pitch. Not the worst if you've practiced various pitches in the backyard when you're bored. I've also been soaked because I didn't hear the rain with my ear plugs in.

I've learned to sew in the mean time, now if anyone knows where I can get some 3 layer eVent or the like I've got a project planned that will fulfill my dream of a light weight water proof bivy. Anyone??

[Area54]

Terra Nova make a great little tarptent:

http://www.backpackinglight.com.au/prod919.htm

[sigma7]

I'm using an Exped Bivy Bag (the eVent only version) since more then two years. Reliable, but heavy.


-- sigma7

[bartspedden]

I've got the titanium goat bivy and used it on the CTR this summer. It is NOT waterproof and it's meant to be used in conjunction with a tarp. I sold my waterproof bivy (goretex with 2 poles) to get the titanium goat bivy because of the weight.  It was a 10+ year old Moonstone that kept me dry and warm on many trips over the years.  But for bikepacking, the 3lbs was more than I was willing to carry.  The titanium goat bivy weighs in at about 5oz. so there's lots of options for waterproofing and still saving lots of weight.  Tarps, UL tents, tarptents, whatever you can think of.

I guess for me it just comes down to weight.  It seems that there's a non-waterprood bivy + tarp'ish solution that offers more room at less weight than a waterproof bivy.

[sherpaxc]

So my question is, if one were to use some time of scotch guard or whatever on a non waterproof bivy, is it going to mess up the fabric or anything?

[JReeves]

I completely agree Bartspedden.  My "tent" that I've used with great luck is the GoLite Shangri-La 1 used in conjunction with two short aluminum poles that break down and fit in my frame bag.  The Shangri-La itself will fit in with my Big Agnes Air Core Insulated, in the stuff sack included with the pad.  The complete system weight 24 ounces, and is really compact.  So to see some of the options for a bivy that weighs 20+ ounces is confusing to me...  For that kind of weight and size, I wouldn't trade the Shangri-La.  It gives more space and is completely waterproof, with room to store your gear, and even cook inside of in a pinch if it were to be raining outside.  I also own the Nest that turns it into a double-wall, bugproof tent with tub floor for another 16oz.
With that said, I recently picked up an MSR E-bivy($59) to add to my collection of gear.  I'm planning on using this for many of my trips.  It weighs less than 9 ounces and is smaller than a can of soda.  The weight and size was a huge selling point for me, as was the ease of use.  I found that after riding 80+ miles in a day, even the 3 minutes it takes to set up my "tent" can seem like a pain.  For the most part, I "plan" on the weather being nice during any excursions, so it's really just a safety measure to take it along should the weather turn nasty.  I also plan on building/buying an ultra-light tarp to use on occasion.  These days you can find 5'x8' sil-nylon tarps for under 6 ounces, and really compact.  I think having the pieces to put together a sleep system to suit any conditions is a nice way to go, and if done right, can be put together really light, and for a good price...

[s8tannorm]

RAB from the UK make various eVent bivvy bags. I've been using an Assault for a couple of years and it's been fine although big and a little heavy. Some of their Alpine eVent bags should fit what you're looking for without a weight penalty.

[bartspedden]

So my question is, if one were to use some time of scotch guard or whatever on a non waterproof bivy, is it going to mess up the fabric or anything?

I would give the manufacturer a call and ask them.  Typically, waterproof materials do have some type of "beeding" finish (i.e. DWR, etc.) that needs to be re-applied with time.  The manufacturer will be able to guide you towards which one they prefer.  Over the years I've never had a reason to not follow their recommendations. If their is no recommendation let me know what the material is and I'll do a little research.

[JayP]

goals, comfort level, time spent sleeping, wieght, waterproofness all have impact on which bivy and they all have there spot...i have a half dozen different bivies but seem to grab the same one all the time now a days.

personally i carry a bivy on all my treks but hardly ever use it. occasionally i will pull it out to use as a ground cloth for my pad. also on occasion i will just tuck my feet into the end of it to keep them warm.

the Montbell Gore bivy is the one i use and it IS waterproof, trust me been there. it does come in 2 sizes if your looking for a bit more room, winter/summer. the winter fits my -20 bag no problem, the summer size is just big enough to do the job. my style of traveling doesnt promote a lot of sleep so for a few hours it is perfect. i have been wet out on the inside due to condensation but have also learned there is a certain temperature to use it and not use it. for me, if it is raining i probably am not going to sleep....and if my trip is more casual and i do plan to get a normal nights sleep regarless of weather i will bring a tarp tent.

choose your gear to the stlyle you are traveling.
hope that helps.

[mmeiser]

I completely agree Bartspedden.  My "tent" that I've used with great luck is the GoLite Shangri-La 1 used in conjunction with two short aluminum poles that break down and fit in my frame bag.  The Shangri-La itself will fit in with my Big Agnes Air Core Insulated, in the stuff sack included with the pad.  The complete system weight 24 ounces, and is really compact.  So to see some of the options for a bivy that weighs 20+ ounces is confusing to me...  For that kind of weight and size, I wouldn't trade the Shangri-La.  It gives more space and is completely waterproof, with room to store your gear, and even cook inside of in a pinch if it were to be raining outside.  I also own the Nest that turns it into a double-wall, bugproof tent with tub floor for another 16oz.

Have a shangrila 3, trimmed down to 1lb 4.5oz. Tremendous room. Don't carry a pole. Sometimes I improvise one with a branch and my knife, but often simply pitch a line around a tree and pitch it in various tarp configurations.

When it's buggy I carry a "bug bivy" which is simply a sea-to-summit bug net sewn to a bit of ground cloth to keep out the creepy crawlies.

I never thought I could use something as small as an SL 1, but my experiences with the SL3 made me realize it may well be the lightest and most versatile UL solution around.

Most of the time one would use the SL1 as a tarp... just a single line off a tree... or one's bike. And it has plenty of room. Especially if you open up the wings a little. However when things get mean (i.e. snow storms, cold, strong winds) it can be pinned completely down on all sides.

What's more, it's a-symetrical design not only works well for pitching off a tree or your bike, but also with a bug bivy.

I just hope when I get around to getting one I can trim off 5-6 ounces of extra web belts, platic clips for an internal bug net, silly poles for vents on the ridgeline and a bunch of other crap like the SL-3 that I can cut out.  Still trying to figure out why they put hooks for the bug net on the tent... and not on the bug net itself. All that stuff really ads up... not just in weight, but pack size... which is more important to me then weight.

But right now... I'm going to spend my time playing with the golite poncho tarp until it gets to cold to use it. Then I'll be using it with my OR aurora bivy, then I'll go back to my SL3.

BTW, some thoughts on my OR Aurora bivy... it is a little heavier then some of those mentioned here, but it is completely 100% waterproof. Indeed I've slept in puddles in it and stayed dry and comfortable. I do worry thought that like an older otlieb waterproof panier that it'll loose that edge. But then.. everything wears out eventually.

I have found that as people have mentioned here that most bivy's will compress a down quilt causing cold spots if it's not plenty big enough for the sleeping pad you're using.  I found this out after extensive use with a big agnes insulated air core mat and a down sleeping bag on my trip last january down the eastern divide. I ended up sleeping on top of it most of the time and just using it as a ground cloth. A bit disappointing.

I am planning this winter on experimenting with various other tricks including putting sleeping pads under my bivy and just using thinner insulated mats.  We shall see.

[ollie.olsson]

I did my military service in the Northern Parts of Sweden, and we had to use http://en.carinthia.positionierung.at/products/tents/bivy-tent-tour this bag. Minus the pole.

We slept in it down to -30 degrees Celsius (the sleeping bag could handle -40). We ALWAYS had condensation issues, no matter what. However, dried VERY quickly, even at those temperatures. Just need some sun and wind, and you're sorted.

[anth]

I picked up a marmot alpinist bivy this year and am planning on using it for the ctr next summer. Used it for some other trips and climbs already and pretty impressed. Picked mine up on sale for a bit over $100, about 15oz, packs to a bit bigger than my fist, and plenty of room for a 30deg bag, thermarest, and more space for gear inside. Haven't had to test it in a downpour yet but the nights I did use it got very little to no condensation with my face exposed. Its got a big flap you could lay over you face and not zip while still keeping water out (although you might get a bit of condensation that way). I believe its made from marmots waterproof membrane strata fabric. Seems pretty durable for a light bivy. Plus its bright orange! Dont know if people didnt know about this one but Im a far more experienced climber than bikepacker so I got it with that in mind as well.
cheers
anthony

[bartspedden]

Anth, like you, my mountaineering/climbing backgorund is richer then my mountain biking background, but I'm working hard to change that  I used a moonstone gore-tex bivy for about 10 of the last 15 years and finally sold it.  For me it came down to weight and functionality (more on this later). At 15oz, the marmot is pretty sweet option though! My moonstone was almost 3lbs, but I did buy it in 1992 and it had two poles.

This is just a personal preference, but I like the ability to change in/out of wet clothes without getting my base layers wet and a breathable bivy/tarp seems to be an option that foots the bill here. And at a combined weight of 9.2 oz for 4 stakes, titanium goat bivy, and a cuben fiber tarp it seems to be a better weight-to-functionality ratio for me.   The tarptent Moment is another option that I keep coming back to for some reason.  I know it's 30oz, so it's more then 3 times heavier, but it's ease of setup is amazing and it does offer better protection if needed.  I guess the thing that will keep me from going the moment route is the fact that I know I don't need it, even if I want it.  The downside of the tarp is increased setup/breakdown time and more difficult camp site selection. Not that it's "hard" to set up the tarp, but in comparison to the moment there is more work for setting up a tarp. Here, the bivy wins hands down, just roll it out and jump in! I guess that's why I like the tarp option with a breathable bivy, I only have to set up the tarp if it's raining. Otherwise I just use the bivy.

Does anyone use a tarp in combination with a waterproof bivy? I can see the benefit for changing clothes and eating/cooking.

[MilesGear]

As a mountaineer and search and rescue I use a bivy a lot.  I'm usually about treeline and like not having to rig a tarp.  Just throw down the bivy and get inside.  After several bivy sacks I decided to make one that was big enough for gear and to get dressed inside.  After people saw me testing prototypes it turned into a cottage industry.  This is waterproof / breathable and no condensation.

MilesGear Uber Bivy
http://www.milesgear.com/UberBivy.html 

Dave