Bivy and tarp question | High Sierra Topix  

Bivy and tarp question

Share your advice and personal experiences, post a gear review or ask any questions you may have pertaining to outdoor gear and equipment.
User avatar

Bivy and tarp question

Postby Wandering Daisy » Thu Jun 21, 2012 5:41 pm

Has anyone used the Six Moon Wild Oasis tarp or the Integral Designs Alpine bivy? In particular I am curious if the tarp is OK in high winds. Stability based on one trekking pole has me worried. The bivy has good reviews. (Yes, I am considering buying another bivy which will bring my collection to 4, but the two oldest are ready for the dump!).



User avatar
Wandering Daisy
Topix Junkie
 
Posts: 2608
Joined: Sun Jan 24, 2010 8:19 pm
Location: Fair Oaks CA (Sacramento area)
Experience: N/A

User avatar

Re: Bivy and tarp question

Postby Hobbes » Fri Jun 22, 2012 8:13 am

Wandering Daisy wrote:Has anyone used the Six Moon Wild Oasis tarp or the Integral Designs Alpine bivy?

My rant @ BPL:

I don't see the math (weight) nor functionality of a bivy.

First of all, a bivy bottom (used in lieu of a groundcloth), made out of some kind of WPB like silnylon, is almost by definition going to be heavier than window shrink wrap used with a floorless tarp.

By definition, I mean it has to be strong/heavy enough to sew, even @ 1.3oz yrd2. Compare this to really lightweight WP window shrink wrap, which has good puncture resistance, but almost even better, is so cheap ($2-3 for a 7x4) that it can be discarded after a trip.

Secondly, the incremental increase in tarp weight for a full coverage tarp (eg tapered/cat cut 10x8) vs bivy tarp (7x5) is nominal, especially considering you still have to take the same poles, guys, stakes, etc.

Third, coverage is a function of square footage. A 5x7 tarp will cover 35 sf, whereas a tapered/cat cut tarp, starting off @ 10x8 will come in the range of 65-70 sf - nearly 100% greater coverage/protection.

Fourth, if you're using a bag/quilt (either syn/down) built out of a quality DWR, like Teflon coated M50, in combination with a full coverage tarp, then you already have good splash resistance. That is, if any rain was to find its way in.

Fifth, using a quilt/down without an additional layer on top and/or a closed WP bottom (like sil) cuts down on condensation.

Sixth, using high quality insulation (eg 900FP down) will achieve much greater warmth with the addition of 2-4oz vs 4-6 oz of bivy material. If you want extra warmth or want to avoid drafts, simply make the quilt bigger and/or overstuffed. Either option will weigh less than a bivy.

The only advantage I see to using a bivy is the weight saved by using a poncho tarp vs carrying a stand-alone 5x7 bivy tarp. Yet, this 'advantage' also has a drawback - who really wants to hike in a poncho if it's raining? And do you bring along a wind shirt for marginal conditions?

I think many who have experimented with bivy tarp and/or poncho tarp combos have come full circle back to the tent concept, in terms of full coverage, but are simply using over-sized tarps to fill the 'tent' function. That's me.

Full thread:
http://www.backpackinglight.com/cgi-bin ... gination=1

More details:
My tarp is nothing more than Henry's original solo pulled out 6": 8'6x7'6x5' vs his 8'x7'x4'6.

http://www.tarptent.com/projects/tarpdesign.html

I added an 1.5' angled beak (2/3 coverage) in the front, to bring the length to 10'. The front is pitched at 38-40" high, while the rear is 24-26". I have the rear 2/3 covered - straight triangle - not angled beak. Like his, I have 12" guys on one side that allow me to pitch one side to the ground (the weather side), with the guy side slightly propped up to provide extra ventilation/room. I'm 6'1", and the tarp is big enough so that I don't touch any of the edges.

The whole thing weighs:
tarp + guys 11oz
(8) stakes 2.4
ground cover 1.4 (polycro or 'window shrink wrap' - Amazon link: http://www.amazon.com/gp/product/B000NH ... 03_s00_i00)

Simple tarps like these are by far & away the easiest things to make/sew. It only takes 6 yrds of material to make a 9' tarptent. (6 yrds = 18 feet; roll width is a around 5' wide, so you first sew two 9' sections together to get a 9'x10'. You can use the trimmings (ie 2.5' if you take it to 7.5' wide) for beaks, end covers, etc.

1st quality sil is around $10/yrd or $60 for this project.
User avatar
Hobbes
Topix Expert
 
Posts: 680
Joined: Wed Apr 27, 2011 8:09 am
Location: The OC
Experience: N/A

User avatar

Re: Bivy and tarp question

Postby AlmostThere » Fri Jun 22, 2012 9:23 am

I think it's pretty funny to post your rant at someone who has worn out more than one bivy. :mrgreen:
User avatar
AlmostThere
Topix Fanatic
 
Posts: 1762
Joined: Wed Jun 24, 2009 4:38 pm
Experience: N/A

User avatar

Re: Bivy and tarp question

Postby Wandering Daisy » Fri Jun 22, 2012 9:26 am

The "tarp" to use with a bivy does not have to have full coverage, rather it offers some head-area living space when it is raining. Many ACT through-hikers say that in wet condtions the tarp/bivy combination is the lightest and most weather-proof combination. It is OK to have your feet stick out so the tarp does not have to be large. I am only considering a tarp that sets up on trekking poles (which I take anyway) and a tarp that is more like a floorless tent. I have done tons of bivy backpacking and it has its advantages even though some UL tents nowadays are only half pound heavier. My current bivy is 1# 8 oz. and Goretex. The Integral Design bivy is 1# 1 oz. and E-vent (supposedly better). Bivy sacks, like all gear, have improved. My real question is, for a person who LIKES to use a bivy, is the 7oz weight savings and E-vent vs Goretex worth it? My old heavier bivy is perfectly functional. The tarp would be a addition, only to be used in wet conditions. I would not likely use it in the Sierra - rather it would allow me to more comfortably use the bivy in the Rockies, where it rains more often.

I am going to do a 36+ day trip in the Wind Rivers this summer. My one-person tent is now a Tarptent Moment. I am a bit leery of its weather-worthinness in intense thunderstorms, above timber and concerned about the condensation issues. Although not worn out the Tarptent has had lots of use. In the Rockies you can get a week+ of near freezing rainy weather so drying out the next morning is not an option and it is the cumulative days of dampness that I am worried about plus total tent failure. I am going to be in some remote locations where walking out if you have a tent failure is NOT an option. I am just looking into some other options.

I do understand your viewpoints on tarps and bivy. However I also am leery of UL tents in extreme condtions. A good alpine bivy is weatherproof - a tarp simply adds livability. And the Six Moons tarp has some mosquito netting at the bottom. I was just wondering if anyone had used it and if it really does keep out skeets.

Another problem I have had with my TarpTent, is that it takes a lot of space to set up. I would say that abotu 50% of the campsites I see and like will not work wtih the Tarptent. I find that I have to really look hard to find a spot.

My sleeping bag does have Dryloft outer shell, but it has been used so much I think most of the water resistance has worn off. It was encouraging, however, that when I washed the bag this spring it actually was difficult to get it totally soaked.

Or am I just getting old and parinoid? Worrying too much?
User avatar
Wandering Daisy
Topix Junkie
 
Posts: 2608
Joined: Sun Jan 24, 2010 8:19 pm
Location: Fair Oaks CA (Sacramento area)
Experience: N/A

User avatar

Re: Bivy and tarp question

Postby TRAUMAhead » Sat Jun 23, 2012 11:22 am

Wandering Daisy wrote:Has anyone used the Six Moon Wild Oasis tarp or the Integral Designs Alpine bivy? In particular I am curious if the tarp is OK in high winds. Stability based on one trekking pole has me worried. The bivy has good reviews. (Yes, I am considering buying another bivy which will bring my collection to 4, but the two oldest are ready for the dump!).
I'd consider something like a MLD Duomid (http://www.mountainlaureldesigns.com/sh ... cts_id=105) or MLD Trailstar (http://www.mountainlaureldesigns.com/sh ... cts_id=102) for wind. You can get perimeter netting added to the Duomid.

I switched to to a tarp (HMG Echo I and beak, http://www.hyperlitemountaingear.com/echo-i-tarp.html & http://www.hyperlitemountaingear.com/echo-i-beak.html) just to try it out tarping, haven't gotten to use it on any backpacking trips yet though. The Echo I is also on the heavier side for Cuben Fiber, 12oz for both in separate stuff sacks, but I liked the modular aspect of it. Still need to pick up a bivy too but my Jeep is taking all my backpacking funds. :retard:
“The word adventure has gotten overused. For me, when everything goes wrong - that’s when adventure starts.” - Yvon Chouinard
User avatar
TRAUMAhead
Topix Acquainted
 
Posts: 60
Joined: Tue Apr 19, 2011 10:44 pm
Location: Bakersfield, CA
Experience: N/A

User avatar

Re: Bivy and tarp question

Postby Wandering Daisy » Sat Jun 23, 2012 12:33 pm

I looked at the Mountain Laurel website and they have some impressive stuff. But, their wait times are too long for my needs. My fault for not getting my act together sooner! I simply need something before they would be able to get it made and sent to me.

There are twp types of "bivies" - mountaineering quality complete bivy that has a hood system that allows you to weather a storm without a tarp, albeit in claustrophobic conditions. A few are basic but most have hoop/pole hood systems. The basic ones are lighter. Then there are bivies that really are sleeping bag covers - the hood system is more like a sleeping bag with a cinch-tightening. These are intended for use with tarps or in a tent. Since I have not used these I am not sure they would work well enough in the event of a tent or tarp failure. They should keep the condensation that drips off my TarpTent roof off my sleeping bag, which really may be all I need. In some ways having all these choices is frustrating!

When you buy a bivy you have to decide which type of bivy meets your needs. And if you have never used a bivy I suggest you borrow one and try it before buying a bivy. Many people do not sleep well in a bivy. I am not trying to "sell" others on using a bivy. I am just trying to sort out the quality of what is available. There are so many untested products out there nowadays that one has to be careful.
User avatar
Wandering Daisy
Topix Junkie
 
Posts: 2608
Joined: Sun Jan 24, 2010 8:19 pm
Location: Fair Oaks CA (Sacramento area)
Experience: N/A

User avatar

Re: Bivy and tarp question

Postby TRAUMAhead » Sat Jun 23, 2012 1:15 pm

I've used some pretty slim sleeping bags in the past and I'm using a quilt right now, so I think I'll be okay. Basically considering 2 companies right now, sleeping bag cover/UL bivy style, Katabatic Gear Bristlecone bivy at about 7oz, $150 (Sil floor), and Virga Outdoors bivy at about 5oz, around $200 (Cuben Fiber floor). As long as it isn't raining or snowing, I don't see a problem with the bivy by itself.

I'm mainly a fair weather, weekend warrior, summer Sierra backpacker so an eVent/Goretex bivy is overkill. Hell, most of the time you don't even need to setup your shelter.
“The word adventure has gotten overused. For me, when everything goes wrong - that’s when adventure starts.” - Yvon Chouinard
User avatar
TRAUMAhead
Topix Acquainted
 
Posts: 60
Joined: Tue Apr 19, 2011 10:44 pm
Location: Bakersfield, CA
Experience: N/A

User avatar

Re: Bivy and tarp question

Postby Wandering Daisy » Sat Jun 23, 2012 3:24 pm

If the bivy has a waterproof not-breathable (sil-nylon) bottom, you have to perfect the art of rolling over in your sleeping bag without rolling over the bivy. If you get the underside up on a bivy you will get condensation. My alpine bivy has four small loops on corners. I take tent pegs and peg down the corners. This seems to keep the bivy flat on the ground when I roll around. I've done a 16-day trip plus several 8-10 day trips in the Sierra using only the bivy. Perfectly adequate for the Sierra. My pack fits horizontal inside as a pillow. Still room for shoes and ditty bag at the very head of the bivy. My bivy does not have a side zipper and I do not find that a problem. A small tarp at the head would be nice for getting in and out in the rain and allow you to have your head out in a rain. For your situation I think the UL bivys (sleeping bag covers) should be just fine.
User avatar
Wandering Daisy
Topix Junkie
 
Posts: 2608
Joined: Sun Jan 24, 2010 8:19 pm
Location: Fair Oaks CA (Sacramento area)
Experience: N/A

User avatar

Re: Bivy and tarp question

Postby sparky » Sun Jun 24, 2012 8:25 pm

Bear Paw designs has a couple 2 pole tarps that might interest you.
There is a million ways to be human, all are worthwhile.

True happiness is the absence of striving for happiness.
-Chuang Tzu.
User avatar
sparky
Topix Expert
 
Posts: 880
Joined: Tue Jul 20, 2010 10:01 am
Experience: N/A

User avatar

Re: Bivy and tarp question

Postby Chris B » Fri Jul 06, 2012 3:40 pm

Wandering Daisy,

After spending years backpacking in the rainy and windy UK i thought I would try and save a bit of weight and try the bivy and tarp options and to be honest I just don't get it. Tarps, OK if it doesn't rain or get windy ie. when you can just sleep on under the stars anyway. On to bivys, maybe I had bad gear or just sweat a lot but I always had major condensation issues even during dry nights. Sleeping or trying to sleep on a rainy night in a bivy is no fun at all. Basically bivys are OK as a last resort but not a practical sleeping system.

If you want to keep it light look at the Big Anges Fly Creek UL series, the one man version weighs about 2lbs and is far more robust than it feels. You can carry a pole repair sleeve if you are worried about breakage and even if you have catastrophic failure you can always wrap the remains around your sleeping bag and it would be better than a bivy sac! If you are really concerned about tent failure just carry an emergency bivy just in case.
User avatar
Chris B
Topix Novice
 
Posts: 13
Joined: Wed Aug 10, 2011 1:23 pm
Experience: N/A


Return to Outdoor Gear Topix



Who is online

Users browsing this forum: No registered users and 3 guests