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Chockstone Forum - Gear Lust / Lost & Found

Rave About Your Rack Please do not post retail SPAM.

Author
Bivy bags — do they work?
TimP
2-May-2016
11:59:42 AM
Anyone use bivy bags?
I got myself a secondhand one that looks hardly used. It's a supper light Outdoor Research bag, probably an older model. Quite a nice design and I got the hang of sleeping in it a on a few trial nights. So on Saturday, with a forecast for rain, I set up to see how waterproof it is.
We got about 20mm over an hour in a cracking storm. Quite exciting as I was up a tree in my back yard testing out my home-made portaledge as well — the idea that this would be my big-wall sleeping setup.
Anyway the bivy held out for a while but then began to weep water inside. I thought it might have been internal condensation wicking water through but it just got damper inside till it started soaking into my sleeping bag and thermarest
After the storm passed about 4am I finally gave up and retreated inside to my warm & dry bed.
So my question is do bivy bags work and I just need to get a better one. Or don't they work in full-on weather (a big ask from a single lightweight shell) and I should aim for another setup.
Jayford4321
2-May-2016
12:40:31 PM
Bivy bags R great and I use one regularly.
Gotta B careful about the model material an seam sealing if necessary.
Also gotta B careful about the application as some R more robust than others an U can get away with lighter weight models 4 alpine use.

Try an work out where the water wicked in, eg waz it a taped seam, or waz it the entry flap? Cos some models with X tha chest entry require sleeping more upright 2 shed the storm from wickin ya zip.
If it waz a side entry, didja sleep with it as tha low spot in a pool of gathering water?
If a taped seam, then apply seam sealer liberally. This means even more than Ed does when he greases up anticipating fun.
johnpitcairn
2-May-2016
12:57:00 PM
I remember the reviews of some of those OR bivy bags (helium?) mentioning waterproofing not being one of the strong points. A bit like the helium jackets maybe?
widewetandslippery
2-May-2016
5:08:31 PM
As nutball said they all differ.

Lots are made for extra protection in tarp camping, dry alpine use. The more maritime ones are way heavier. The US models are often the former.

miguel75
3-May-2016
10:33:26 AM
I have the BD big wall bivy (the long version) and have used it happily in a downpour multiple times. When new it had sealed seams though I liberally applied my own seam seal as well and haven't had any discernable leaks to date. In saying that I do experience condensation at the foot end if I'm in a warmer rain storm.

I really like the zip across the shoulders and the delrin(?) rod/fly setup as I don't like the bivy touching my face when I'm sleeping...

All is all it's an awesome bivy
OozeDumbHopeless
3-May-2016
12:05:30 PM
I have a gortex one that is fantastic. Drier than any tent.
simey
3-May-2016
9:35:18 PM
I've owned two bivy sacks... the first one was great and I did a lot of ski trips using it alone. My current one is shit and is useless at keeping my sleeping bag dry, even when used inside a tent where it touches the walls.

phillipivan
3-May-2016
9:40:46 PM
Mikey, the only downside to your bivvy bag is that it's not really much smaller or lighter than a lightweight tent, especially if you multiply by two people. Which means you would probably only use it on the occasions when there is a good reason not to use a tent like on a wall, or when you can't be arsed spending three minutes to setup up a tent.

IdratherbeclimbingM9
4-May-2016
8:42:50 AM
On 2/05/2016 TimP wrote:
>Anyone use bivy bags?
>I got myself a secondhand one that looks hardly used. It's a supper light
>Outdoor Research bag, probably an older model. Quite a nice design and
>I got the hang of sleeping in it a on a few trial nights. So on Saturday,
>with a forecast for rain, I set up to see how waterproof it is.
>We got about 20mm over an hour in a cracking storm. Quite exciting as
>I was up a tree in my back yard testing out my home-made portaledge as
>well — the idea that this would be my big-wall sleeping setup.
>Anyway the bivy held out for a while but then began to weep water inside.
>I thought it might have been internal condensation wicking water through
>but it just got damper inside till it started soaking into my sleeping
>bag and thermarest
>After the storm passed about 4am I finally gave up and retreated inside
>to my warm & dry bed.
>So my question is do bivy bags work and I just need to get a better one.
>Or don't they work in full-on weather (a big ask from a single lightweight
>shell) and I should aim for another setup.

I have two bivy bags.

After making do with inferior substitutes for many years, I purchased my first decent one (full goretex), in the mid-‘80s and it is still my most often used, even after over 30 years of good service.
It’s a J&H brand (Aussie company based in Queanbeyan, but I don't know if they still make them?), olive green coloured, slim-line style design (tapered footbox, and not a lot of wriggle room elsewhere), as I mainly use a mummy-style sleeping bag with it. The whole bivy turns with the sleeping bag if I turn in my sleep.
It has a horizontal across-the-chest entry slot with a small rainflap, plus an internal mossie net within the slot that is separately zippered. It has extra length above the head for minor storage of clothing, but no mechanism for holding the fabric off your face, other than careful arrangement of such items that aren’t used as a pillow.

The only time it has ever leaked was after the internal seam sealing tape came adrift on this slot for about 10 cm in one particular spot, due that design creates stress points on it’s ends while entering/exiting. I re-glued it with seam sealer and it has been fine since.
It gets used very regularly and I've found that it handles all manner of wet weather very well, however if one is camping out in wet weather for an extended period (say 3+ days in foul weather or a week of consistent light rain), then one eventually ends up with a damp sleeping bag, mainly due to entering and leaving the bag during such conditions, and minimal opportunity to dry things out in the meantime!
Under certain conditions condensation within it can be an issue, particularly the foot-box area, as the wide strip of mosquito netting adequately vents the upper half.
It is this bag that I use during my Buffalo North Wall pursuits, and for lightweight summer trips.

I decided to purchase another bivy bag after I was almost run-over by a large 4WD vehicle one night as I lay sleeping within it at an obscure part of Gunnimeroo campsite in the Warrumbungles one climbing trip. I thought I was off the beaten track, but the 4WD was doing a lap of the area and didn’t see me…

The next bivy bag I bought is a full goretex Macpac brand, bright yellow in colour, roomier style bag, with a side entry slot, a hooped hood, bug mesh, and also a separate ventilation port. Being a hooped and roomier bag it is slightly heavier/bulkier though this trade off for the comfort it gives isn’t much, and it has proved to be a better option for trips (particularly motorcycling), when extended wet weather is a high likelihood of being encountered.
I find the side entry facility to be a lot easier (quicker) to use when the weather is bad and over-all this results in my gear staying drier longer.
Over-all I think the Macpac one would stand up to bad weather better than the J&H one, but I use the J&H one more because it is lighter, packs up smaller, and if the weather is going to be truly 'off' then I take a tent these days, so my Macpac one is the in-betweener.

Some of my mates have cheaper style bivy bags incorporating nylon bases, etc, and on trips that we have done together they have been adequate to start with, but not as good as mine proved to be, as the longer trips went on; … this particularly the case when condensation within them was involved.
Theirs didn't leak, but saying that, we haven't encountered a really good downpour at the same time, on those trips.

Re
>So my question is do bivy bags work and I just need to get a better one. Or don't they work in full-on weather (a big ask from a single lightweight shell) and I should aim for another setup.
Assuming it isn't a base result of the material it is constructed of, do as gnaguts suggests and find the leak point and seam seal it.
Serious walling entails having a fly* for the portaledge...
;-)


Re M75 / pi, and;
>BD big wall bivy
I observed one in use by my wall climbing partner on one Buffalo sojourn. It didn't rain that trip, though they appear well made. I particularly liked the feature it has for allowing your climbing rope to attach to the bag without water ingress, so that you can remain tethered comfortably while sleeping.


* Post edit.
A lightweight adequate substitute for short term use, can be improvised from the large plastic bag that double mattresses come wrapped in. Check the bins at back of your local furniture store!
grangrump
4-May-2016
4:16:35 PM
On 4/05/2016 IdratherbeclimbingM9 wrote:
>A lightweight adequate substitute for short term use, can be improvised
>from the large plastic bag that double mattresses come wrapped in. Check
>the bins at back of your local furniture store!
Have done this. Waterproof (but condensation) and heavier and bulkier than you might think!
RNM
4-May-2016
4:36:45 PM
The BD (formerly Bibler?) bivy bags are awesome. About USD$225 I think from memory. The best investment for wall climbing. We have used ours big wall climbing (about 30 days total?) and since then for random camping and they have held up really well - no holes, no leaks.

Favourite night on the Salathe was at Heart Ledges. Massive tropical style down pour. Water running down the rock. Turns out Heart Ledges slope into the wall, so we ended up in a little lake. Was like being in a water bed, as the bits of the bag that weren't weighted down were floating. We could peer out and watch others having epics above - head torches swinging in the dark stormy weather, yells and at one stage something went whistling and flapping by - I will never forget that sound of impending doom. In the morning there was a mass exodus off the wall as people went down to dry out sleeping bags etc. We grinned and headed up with the wall to ourselves!

They have a rated loop that is seam sealed - you clip the outside to the anchor and the inside one to you.

Never liked sleeping in a harness, so just took one inch webbing and tied that around my waist at night.

Anyway... get one.
OozeDumbHopeless
5-May-2016
8:24:45 AM
"not really much smaller or lighter than a lightweight tent"

500 gram tents?
dalai
5-May-2016
9:11:42 AM
Yes.

Hikelighter
widewetandslippery
5-May-2016
9:19:51 AM
On 5/05/2016 OozeDumbHopeless wrote:
>"not really much smaller or lighter than a lightweight tent"
>
>500 gram tents?

I wouldnt use a tent under 1000g, normally 700g.

A 300 to 400g shelter with a light bivy works realy weĺl

And dont cost too much
dalai
5-May-2016
5:17:31 PM
My Big Agnes Fly Creek UL1 weighs ~940g packed... Great little tent.
widewetandslippery
5-May-2016
5:25:15 PM
I used a tarptent rainbow 700g? for a prtdavey/south coast track walk recently. Awesome.

There are 16 messages in this topic.

 

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