Newbie with a question
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Edward Zwibel
(YetiEddie) - MLife

Locale: Sunny San Diego
Newbie with a question on 08/30/2010 13:42:43 MDT Print View

How necessary is it to have a bivy over a down bag when tarp camping? I have a big SilTwinn tarp and groundsheet, primarily caming in southwest with occassional rain. Am I gonna ruin a down bag? If it does rain is it assumed the bag will get wet?

Never tarp'd. Gonna give it a go in a few weeks. Just dont want to ruin my kit.. or spend another couple hundred / add even more weight.

Thanks, and your patience in the newbie tolerance is appreciated.

Ed

Steven Hanlon
(asciibaron) - F

Locale: Mid Atlantic
bag cover on 08/30/2010 14:10:21 MDT Print View

if the down bag gets wet, you will be an unhappy camper. you might just need a sleeping bag cover, not a full blown bivy.

something like this

http://www.montbell.us/products/disp.php?p_id=2321027

if it rains, the down bag will get wet, no matter how you pack it away. Murphy likes camping with me it seems.

Edited by asciibaron on 08/30/2010 14:13:56 MDT.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Newbie with a question on 08/30/2010 14:11:42 MDT Print View

First, assess the risk of a light rain. Now assess the risk of a heavy rain. Now assess the risk of a 100-year storm.

If you use a sleeping bag under a well-pitched tarp, then it is very unlikely that vertical light rain is going to get the bag wet, at all. If you get hit with a heavy rain that blows underneath the tarp, then you are taking some risk of the bag getting slightly wet on the shell. If you get hit with the monster storm, then the tarp may blow away and everything gets drenched. You can take a couple of cups of water and throw that on your down bag shell, and it doesn't hurt much. You can wipe off a lot of the water. If you have wind-blown rain that is soaking the bag from underneath, then that is much worse. If that happens, you will spend a miserable night in a wet bag. That does not damage it permanently. If you dry a wet down bag in the sun, you will get most of the wetness out.

I have a SilShelter, and I've never gotten my down bag wet when it is under it.

--B.G.--

Edward Zwibel
(YetiEddie) - MLife

Locale: Sunny San Diego
Cover on 08/30/2010 14:23:05 MDT Print View

Thank you, I am making a ray way synth quilt right now which may just have to be my tarp companion. I cant justify another 125 bucks to the war dept. That should dry out well if the unexpected storm does rage. If its a 100 year storm, I'll snivel it out and crawl my way to safety when it passes! lol. Thanks

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Cover on 08/30/2010 17:08:28 MDT Print View

If you don't have a bivy sack, just take a super thin plastic painter's tarp. I buy one for about 69 cents and cut it into a piece just big enough to lay over my sleeping bag (for the event of horizontal rain).

When you pitch the tarp, think a lot about where the rain water will be puddling and go somewhere else.

If your sleeping bag gets hit with about ten drops of rain, then that is par for the course. If it is two cups of rain, then that will be a little damp, but you still get through the night.

--B.G.--

Art ...
(asandh) - F
Re: Re: Newbie with a question on 08/30/2010 17:36:28 MDT Print View

Or .........
you could just go camping with a lightweight Nemo Gogo and keep your down bag dry :-)

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: Newbie with a question on 08/30/2010 18:00:58 MDT Print View

Art, the original poster had stated that he didn't want to:

"or spend another couple hundred / add even more weight."

I once spent a very cold winter night up on Mount Rainier in a down bag. It had started as a new 4-pound down bag, and it had become a 20-pound wet sponge. After that, I learned real quickly how to keep my down bag dry. Funny how that works.

--B.G.--

Michael Ray
(topshot) - MLife

Locale: Midwest
Re: Re: Cover on 08/30/2010 20:00:40 MDT Print View

If you're taking some sort of raingear (DriDucks, poncho, etc) you can pull that over at least the bottom of your bag.

Mina Loomis
(elmvine) - MLife

Locale: Central Texas
tarps, no bivy on 08/30/2010 23:21:18 MDT Print View

I have several tarps and no bivy. A tarp is my favorite way to go, nice and light and, if it's not too stormy, open to the surroundings.

First tarp was a little flat no-name one my son left here after his JMT solo trip. Took it on 1 mountain trip, chilly and wet. Because it was small I had a hard time keeping the wind out and got cold but stayed dry.

Next one was a Kelty Noah's Tarp 9 x 9. Yes, heavy by BPL standards. Big enough for 2, a palace for 1. I spent whole stormy drenching nights under it, and more than one long pounding rainy afternoon curled up with a book and my sweetie, with our down bags nice and dry.

Later I started lightening up. Got an ID Silwing. Still room for 2, now 14 oz. or so. Catenary, easy to set up. More rainy trips. Texas has a reputation for being dry but it can pour. New Mexico in the mountains in the summer there is "monsoon season" when the rain seems never to stop. Wind in under the catenary edges made me cold, but once again, not wet.

The next NM trip, tried an ID 8 x 10. My sister and I shared it. Easier to batten down the edges against the wind. First night out, big storm, windblown hard rain. I had set it too high, and our bags were getting rained on at the foot end. I had to pull on a jacket and go out there in the middle of the night in the storm to reset the tarp down lower, foot end down to the ground, to keep the rain out. Sister slept through it all. In the morning our down bags needed some drying (fortunately we got a couple of hours of sun before the rain resumed) but the insulation was fine.

Nowadays when my husband is along on the trip we have been using that 8 x 10 to good effect. It is pretty easy to reshape if needed to keep a storm out, and there's lots of room under it. On our Wonderland trip I successfully set it closed against a storm one night, and we spent another afternoon napping under it in steady rain. The only wet bag we got was when my husband's Camelbak leaked inside his pack during the hiking day. Took a couple of nights of sleeping in it to dry that out with body heat. But not the tarp's fault.

When I am sheltering alone now I take my new toy, a Gatewood Cape. Nice because I can set it to the ground to keep wind out. Several rainy nights in it, no water on bag.

For a groundcloth I have some gg polycro. It lasts for several trips and is already cut the right size. As stated in a previous post, it is important to pick a spot where water will not run along the ground under the tarp.

I think maybe the tarp/bivy approach makes the most sense for folks who have the narrow solo tarps that do not extend out by much, and do not set all the way to the ground easily, or are not long enough to close off an end. Since I have had pretty good luck with the wider tarp and no-bivy approach, I haven't wanted to add the weight and expense of a bivy.

Although, I have a 14-year-old friend (in our Camp Fire backpacking group) who, on every trip, just brings an old generic waterproof bivy and no other shelter. He loves it.

Bottom line: Yes you can successfully use a lightweight tarp and a down bag without a bivy. In stormy weather this depends on careful setup and, sometimes, being willing to fiddle with it for a bit.

Edward Zwibel
(YetiEddie) - MLife

Locale: Sunny San Diego
Thanks on 08/31/2010 07:37:02 MDT Print View

I sincerely appreciate all the comments and I am going to likely get a bag cover if one comes up used here on the forums, till then I'll take my Contrail or Lunar Solo. You're most helpful!

Bob Bankhead
(wandering_bob) - MLife

Locale: Oregon, USA
Re: bag cover on 08/31/2010 09:50:57 MDT Print View

For comparison of similar products:

The Titanium Goat Ptarmigan Bivy (Intrepid top; silnylon bottom) weighs 5.8 oz and costs $90 (add $25 for a side zip)

The Montbell Sleeping Bag Cover is made of their Breez Dry-Tec fabric, weighs 6.3 oz and costs $125.

The MLD Superlite Bivy (Momentum top; silnylon bottom) weighs 6.9 oz and costs $155

Frank Deland
(rambler) - M

Locale: On the AT in VA
bivy and tarp on 08/31/2010 14:43:21 MDT Print View

Bivyis great for adding warmth or just as a ground cover. It is usually the end of the bag that gets wet, especially when sleeping on a slight downhill slope. The new bags dry very quickly, however, when the sun hits them during the last couple of Sierra hikes.

The bivy also helps keep ground dirt/dust off the bag.

Edited by rambler on 08/31/2010 14:44:41 MDT.

John Donewar
(Newton) - MLife

Locale: Southeastern Louisiana
Re: Newbie with a question on 08/31/2010 15:47:30 MDT Print View

Ed,

Go to Gossamer Gear's Site and watch Glen's setup video where he describes the "storm setup".

Face the foot end of your tarp into the prevailing wind when you set it up.

Lastly even though this may be very low tech it is also very low cost. What about a plastic trash bag over the foot end of your bag during a night of rain?

Anyone know where the lightest/durable trash bag of sufficient size can be found? ;-)

Party On,

Newton

Piper S.
(sbhikes) - F

Locale: Santa Barbara (Name: Diane)
Re: Newbie with a question on 08/31/2010 16:38:25 MDT Print View

If you are in the southwest, like I am, I would say the bivy is not necessary most of the time, but it's nice to have. I don't bring mine all the time.

Mina Loomis
(elmvine) - MLife

Locale: Central Texas
plastic bag on 08/31/2010 23:04:21 MDT Print View

"Lastly even though this may be very low tech it is also very low cost. What about a plastic trash bag over the foot end of your bag during a night of rain?"

I tried a plastic bag (my BPL pack liner) pulled over the foot of my sleeping bag once. Not to keep rain off--it wasn't raining that night--but to keep warmer, since it was cold and breezy under the tarp. In the morning the whole foot of my sleeping bag was wet with condensation!

Edited by elmvine on 08/31/2010 23:05:12 MDT.

John Donewar
(Newton) - MLife

Locale: Southeastern Louisiana
Re: plastic bag on 09/01/2010 04:54:22 MDT Print View

Mina,

The wisdom of experience is worth its weight in gold.

I would have thought that the "open" top of the plastic bag would have allowed the water vapor to escape. How large of a pack liner are we speaking about? Was there any "looseness" to the fit of the plastic bag's top opening around the foot of your sleeping bag?

Thanks for sharing your experience as we are all trying to give useable suggestions.

Party On,

Newton

Mina Loomis
(elmvine) - MLife

Locale: Central Texas
re: plastic bag on 09/01/2010 08:25:10 MDT Print View

Yes, it was pretty loose. As noted, it was one of the BPL pack liner bags, 13x10x30. Counting going around my sleeping bag volume, I think it came up to about knee level. Apparently air flow through the loose top edge was insufficient to prevent condensation.

It did do a nice job of blocking the breeze ("convection" heat loss) and I slept well after pulling the liner over my feet. And my sleeping bag aired out well in the morning. But if it had been raining, drying out would have been more difficult for sure!

I probably also draped a Precip rain jacket loosely over my torso to block the breeze there. I don't remember getting condensation in that area, but a jacket would have been even looser, not all the way around, and probably slipped off sometimes during the night.

You are right about experience. That is one reason I post infrequently on BPL, although I read it and learn a lot. When I do post, I want to be sure I can share a specific experience, since I am probably not experienced enough with different conditions to express valid generalities.

Michael Ray
(topshot) - MLife

Locale: Midwest
Re: Re: plastic bag on 09/01/2010 08:38:13 MDT Print View

I can see where you could have problems using a non-breathable bag (or is the BPL liner a breathable material?). FWIW, I didn't seem to have any problem doing the same with my DriDucks jacket (zipped and pulled over bag). It wasn't very cold (40-45F at night), but it also wasn't very windy. I decided to use it only because the foot of my bag would touch the tent I had made. So this was only 7 nights and they were nearly the same though some had rain as well.

John Donewar
(Newton) - MLife

Locale: Southeastern Louisiana
Re: re: plastic bag on 09/01/2010 11:44:29 MDT Print View

Mina,

Thanks for the detailed response to my question regarding the airflow. I wonder if a plastic bag with a larger opening held up at one point to the ridge line like a bug net would do the trick? ;-? Hmmmm.

Personally I use a Meteor Bivy that has a WPB nylon section on the lower footend portion of the bivy.

Homemade Meteor Bivy LS full length

The bottom is silnylon which also serves as my ground sheet and the upper portion is noseeum that serves as a bug net if necessary. The bug net can be zipped open and rolled back if it is not needed.

He is sewing his own quilt and I have had the "experience" of sewing my own and using a Meteor Bivy. ;-)

It can be made for approximately $50.00. I did it using materials from Quest Outfitters after downloading the patterns and instructions from Six Moon Designs .

Ed did mention;

>> I am going to likely get a bag cover if one comes up used here on the forums <<.

I don't know what his budget for a bag cover is but maybe the cost of materials for a bivy similar to mine is not out of the realm of possibility. I would gladly answer any questions he has regarding construction of a Meteor Bivy if he would choose to go this route.

Party On,

Newton

Edited by Newton on 09/01/2010 11:52:32 MDT.

Edward Zwibel
(YetiEddie) - MLife

Locale: Sunny San Diego
Thanks again! on 09/01/2010 13:29:32 MDT Print View

Thanks again all! And John thanks so much for that photo and illustration. I am going to buy that pattern and set about making one if the machine survives the quilt! Or the Ptmargin one looks neat also. I like the Meteor due to the open netting, the 2/3 bivy protection and roominess. Thanks so much. This forum has not disappointed!

Edited by YetiEddie on 09/01/2010 13:30:20 MDT.