Bivvy bag/bivvy cover recommendation needed.

[WanderingWanderer]

Dear all, I need some advice about bivvy bag as I plan on buying one.

Being lightweight backpacker my considerations are that the said bivvy should be:
-as lightweight and simple as possible
-waterproof and breathable

Choice of one product among all these available may cause problem especially for someone like me with no bivvy experience as this will be my first bivvy sack, hence my question.

Are there any bivvys worth buying that beside the forementioned characteristics do have the heat reflecting layer inside to improve it's overall warmth?

Your sincerely, Jarek.

 

[Teepee]

You'll struggle to find anything simpler or lighter than this; http://www.mountainlaureldesigns.com/shop/product_info.php?products_id=173

If that's too spendy, I'd recommend going for a Rab (they have just taken over production of Integral Designs excellent bivy range).

I've been highly impressed with my Event bivy. Fully enclosed, it's breathable enough allow my down insulation to stay dry over extended trips.

 

[Midnitehound]

If you want to have breathable and waterproof you need to go for Goretex. A bivi bag will add a season to your sleeping bag because it produces a microclimate, is windproof, allows water vapour to escape and obviously because it is another layer.

A heat reflecting layer would be Aluminium/Mylar and would stop the breathability and therefore induce major dampness. This would be far more counterproductive than the advantage of some reflected heat. It is best to only have separate reflective material below you so as to insulate you from the floor and reflect body heat back to you. This in addition to a good sleep mat. If you want reflective material above you it needs to be at tarp level rather than bag level so it doesn't interfere with breathability. It is dampness that can rapidly drop your temperature.

You can mod a reinforced Aluminium foil picnic blanket with or as a light tarp to put a reflective surface above you. This will be cheap, warmer, extremely light and hopefully relatively spark resistant. The same can be used as a reflector behind a fire, this was highly effective at the latest Prepper meet I went to in the Forest of Dean, I highly recommend it.

If you want value for money then go with a MOD Goretex bag that is Super Grade or Grade 1. The newer ones are DPM, the Green ones can be showing their age if used. The MTP ones are pricey for the same job. A MOD bag is a good first bag or even last bag. If money is no object then you can throw hundreds at new posh commercial ones that can be lighter, have zips and are little more breathable. I've always found the MOD ones do the job and are very good value.

 

[Teepee]

Heat reflective layers are made of other materials too, not just Mylar There are plenty of breathable heat reflective fabrics on the market, some of them made into bivy bags.

Gore-Tex is not the only waterproof breathable fabric, it doesn't have to be Gore-Tex. There is equal or better on the market.

 

[ADz-1983]

This entirely depends on if you want a bivy as just a bag protection or a full shelter. For just bag protection you could grab a Borah Bivvy which is like the MLD Superlight but less expensive. If it's for full shelter I have heard good things about the Rab Ridge Master as it's side entry and great quality.

To me personally I do not see the appeal of a bivvy as a shelter other then the small footprint it needs so good for mountains but for anything else it's just not really practical. You can go much lighter and get much more room by going for a silnylon or cuben tarp/tent. Have you looked into the MLD Trailstar or Duomid?

 

[WanderingWanderer]

Thank you for input!

RAB seems to make "Survival zone" bivy - pretty simple and lightweight, made of pertex (allegedly waterproof), I'd improve it with side closure and voila. That's the one in the lead right now, thanks!

Midnitehound, I was also considering military bivvys, especially US Modular Sleep System bivvy in "woodland" camouflage but those surplus bivvys have one disadvantage - the weight, which puts them aside in the competition.

Teepee could you elaborate on those heat reflective and breathable materials and bivvys made of these that you've mentioned?

ADz-1983, thanks for tarp suggestion, but we'd learned that they do not work very well - time to put up a bedding and to pack it back is the factor.

 

[Johnnyboy1971]

Any military kit is going to be weighty, it's designed to be used and abused.
What climate are you going to be camping in? Is it cold and wet? Cold and dry or wet and humid. Just some more considerations to think about.

Just one thing to add is that the more openings like side zips are potential weakness for both strength and water ingress.

 

[Teepee]

The survival zone bivi is a coated Pertex, not bad but not as breathable as a lot on the market. I've a bivy made from it-it's OK in summer but winter gives it issues with condensation. It doesn't hold a candle to my Event bag, nor does my issue Gore-Tex bag but then doesn't cost anywhere near as much. Good bivvy bags are spendy.

Here's an example of a reflective breathable bivy; http://www.ebay.co.uk/itm/like/1113...1=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0 Ok for emergency and occasional use but not something to use regularly. My Rab Event bag appears to have a reflective coating too although it isn't advertised as such. I know a few of the other brands have aluminized their membrane too.

It's rare I'll bivvy without a tarp. Fine in settled weather with light winds and no rain but when it's howling, the cover a little tarp provides for cooking under or getting changed is golden. Sun shading too ( I think I remember what that means...)
A little micro tarp is very quick to pitch and even quicker to take down.

You could always look at a hooped bivy for even more coverage. More like a tent than a bivvy bag. Rab Ridge raider for example. At 1100g though, a microtarp provides better storm protection, more space and lighter weight.

 

[Midnitehound]

Thank you for input!

RAB seems to make "Survival zone" bivy - pretty simple and lightweight, made of pertex (allegedly waterproof), I'd improve it with side closure and voila. That's the one in the lead right now, thanks!

Midnitehound, I was also considering military bivvys, especially US Modular Sleep System bivvy in "woodland" camouflage but those surplus bivvys have one disadvantage - the weight, which puts them aside in the competition.

Teepee could you elaborate on those heat reflective and breathable materials and bivvys made of these that you've mentioned?

ADz-1983, thanks for tarp suggestion, but we'd learned that they do not work very well - time to put up a bedding and to pack it back is the factor.

I did wonder whether you were wanting to go with a cheap basic bivi as this is your first but if you have some money to throw at it then yes there are lighter alternatives made from goretex by another name fabrics i.e. breathable but waterproof. Some of these other fabrics are worse, as good or better depending upon your priorities. My Goretex MOD DPM bag is <770g and cost me £20. You pay a lot to reduce that by a few grams particularly if you want performance e.g. eVent fabric. Reflexion fabric by Sympatex is a heat reflective breathable fabric but then breathability is dependent upon humidity as well of course.

I understood pertex was windproof and showerproof but not waterproof in the same vein as Goretex or the like. It is a case of looking at the Hydrostatic Head and whether you may end up sleeping on a curly dog i.e. a poodle. Goretex is 20k HH minimum when new I seem to remember. It makes a big difference whether the water is touching you or you are touching the water! The thinner lighter Pertex style bags don't have an HH anywhere near as good as Goretex and are usually proofed by a less durable reappliable coating rather than being intrinsic. If you end up sleeping in a wet ditch with a lower HH bag then don't be surprised by water seeping in due to the increased HP created by your body weight. It depends what the bottom layer is made from of course.

I have the GB MOD bags and an Amerkin GI US MSS bag. The US DOD bag is excellent but keep in mind that a zip is a weakness for waterproofness, no floating kit across a river with it or prostrating in a K9.

 

[Ahjno]

Have a look at the Alpkit Hunka

 

[R3XXY]

http://www.snugpak.com/military/special-forces-bivvi-bag-2109

Ridiculously light and compact, breathable, well made. Can be found cheaper than on the Snugpak website elsewhere.

 

[weekender]

Have a look at the Alpkit Hunka

Beach lover has just put a Hunka XL up for sale.
No connection etc


Sent from somewhere?

 

[Shewie]

Goretex FLO2 fabric is good for bivvies, Terra Nova use it in their top end bags. It breathes much better than regular Goretex such as the army bags.

Extremes in temperature have a lot to do with it too, on the coldest nights you're going to condensation inside as warm air from your body cools on the outer shell and condenses, I've woken up with small puddles in my army bivvy a few times.

The most breathable bivvy I've used is the MLD Superlight, it's by no means waterproof but if you use a decent shelter above you then they're great. They trap a bit of heat and keep drips and wind blown mist off you.

For regular bushy type camping with a tarp and bivvy you won't go far wrong with an Alpkit Hunka, Rab Survival etc, if you don't mind a bit of extra weight go for the British or US army Goretex or mvp bivvies, but do expect condensation in cold weather.

 

[Simon.C.Hubbard]

Sorry for the noob question, but thinking of getting a tarp/hammock combo I'm assuming. Bivvy bag is unnecessary for the setup?

 

[WanderingWanderer]

Dear all,

thank you for your informative replies.

Lynch me but having considered all cons and pros of civvie marketed bivvys I've gone back to the original idea of military bivy cover... The civilian made ones seemed to lack the needed durability in the same time being very pricey. The only advantage which was low weight was not enough to turn the odds into favour of civvie covers.

But thanks again for input, and have a great time in great outdoors!

Your sincerely, Jarek.