Review: OR Advanced Bivy Sack

Joined
Feb 21, 2001
Messages
158
This bivy is a 3-layer JGI 1.1 oz. Gore-Tex fabric upper section for maximum vapor transport, 1.7 oz. taffeta, complete with bombproof Hydroseal-200 coated floors, and every seam completely taped with Gore-Seam tape for total water-proofness.

Length = 90 inches,
Width at Shoulders = 25 inches,
Foot Width = 21 inches,
Pole Height = 19 inches.
Weight 31 ounces.

The sack is MADE IN U.S.A.
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The "go lighter bug" has bitten me. (Not to the extent that my five day pack weighs sub 14 pounds, but it has bitten me none the less.) I read magazine articles, surfed the web, browsed bookshelves, talked to experienced backpacker and mountaineering friends and trailmates, and decided that my stuff weighed too much to lug most of the time through the Rockies. I let it sink in for about a year. Earlier in the season I gathered my gear, stood over it, and began to ponder which of my necessary, recommended, and too often expensive gear was in direct conflict with my quest to go lighter.

My TFN tent, weighing in at approximately six and a half pounds packed, stuck out immediately. It's a great tent, don't get me wrong. It has served me well, and still will on occasion no doubt. Especially when my wife ventures out with me. ;) It is just that I couldn't help but think that I could replace it with a lighter alternative, saving at least a couple of pounds.

So I began researching smaller, lighter tents. I scaled back and sized down, shaving ounces here and there. There are some great lightweight tent options out there, but I though as long as I'm looking into light weight tents, I should look into the lightest weight shelters available. Which eventually brought me to bivy sacks... Looking at biviy sacks, I eventually found the OR Advanced Bivy. Actually, it found me first, thanks to a guy on a trail earlier in the Rockies. He was nestled between two boulders just off the trail, in a place no tent could have hoped to have fit. I stopped, chatted, then moved further along in search of a local better suited for pitching my shelter. A made a mental note to check into it after the trip.

I checked. I asked. I borrowed. I considered the weight savings: a whopping 70%! (Not to mention the space savings. The sack takes up little space in my pack, and its generously sized stuff sack allows for fast stuffing.) I couldn't move off of that fact. My 6.5 lbs TNF tent or a 1.9 lbs bivy? Easy! The 1.9 lbs bivy. I was hooked. (The Advanced Bivy weighs 1.5 lbs without poles and bug net, incidentally. There are lighter sacks out there. I compared features and decided that a few ounces of weight was worth the clamshell. See next paragraph.)

The OR Advanced Bivy is destinquished from other bivies on the market by it's clever clamshell opening. This opening is achieved by using two poles, and allowes the top (including the bug net) to range from closed to approximately 90 degrees. Ever used a bivy that lays on your face or barely above it? I have. Ugh. Never again. Nice evening? Open her all the way up and stare at the stars. Storming out? Close her up and stay dry. WARNING: You should never close a bivy all the way. Always leave a couple of inches open to promote air flow. The design allows for this. You will still remain dry. "Breathable" is a relative term, after all.

(I had my wife hose me down in my backyard. I know I'll never encounter rain like that in the mountains. I zipped up, left a few inches open, and stayed dry. Untill she shoved the hose in the opening, but that's not exactly a design flaw. ;) Trust me, I got her back.)

As with any bivy sack, space is limited, and about the only thing that you can do in it is sleep. I'm 6 feet tall and weight about 195 pounds. I can fit a sleeping pad, a four season bag, and a few necessities inside and sleep comfortably. Tossers and turners probably will not claim the same. Changing clothes can be tricky. Practice before your first use. Actually, practice before you buy, if you can. A friend of mine loves the concept, but hates the reality. It isn't for everyone. If more space is something you crave, or "need," then step up in weight and size to a one man tent. You heard it here: Claustrophobes and clumsy folk beware!

(Actually, I find that if I string a tarp or poncho over my head things are quite comfortable, should I need a more "tent like" experience.)

OR gear has a reputation of being bomb proof. OR bivies, and the Advanced Bivy in particular, have been around for years, and I have yet to have heard or read about one wearing out. For that matter I haven't heard mention of any of their gear wearing out in less than reasonable timelines.

Setup is easy. You simply roll it out, slide in the poles, and add your pad, bag, and body. The pad is held in place by two velcro straps inside. A nice touch, but I'm not convinced that they are necessary. You should be done in at least half of the time it takes to set up the average free standing tent.

The drawbacks? They're expensive. (Expense is relative. What's technical rainwear cost these days?) Space is limited, as I've already mentioned. Your gear, but for a few small essentials, will remain outside. You wouldn't want to weather a lengthy storm in one. (A properly strung tarp largely mitigates the last two, imo.)

So, if you have been thinking about saving the significant space and weight that a bivy sack affords, and aren't detered by needing more space, place the OR Advanced Bivy on your short list of possible purchases.

Erik
 
I've used a bivibag for a long time; the whole British Army now for the last ten years.

Hooped bivi's (tunnel tent sort) are the most comfortable; the Ritz of bivi's. They allow some air circulation without compromising the concept. Air movement lets the Goretex work.

Try to rid the bivi of any condensation from your sleep/damp clothes produced overnight before packing it away. Same goes for your sleeping bag. Just a good airing will do.

Use a poncho/tarp for all your administration (bungee all the corners to give a fast set up). You can change socks, change clothes, check your map and cook under a tarp but not a bivi. At night use the tarp above the bivi to add even more protection and it allows the Goretex to work in the very wet.

Set the bivi out on a dry piece of ground with drainage. Waking in the worning in a stream formed from the night's rain is not nice. Lying in water defeats the Goretex system.

Be careful where you sleep as vehicles can't see you. Bivi's are also no protection from rock falls or broken trees and branches.
Use a thermal bed role, thermarest, to stop the chill from the ground.

A bivi bag can be used as a river crossing floatation bag, survival bag or even a body bag. For hyperthermia treatment climb in with a hot woman.

For pure freedom they are the biz. I've slept well in some wild storms in one.
 
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