Bivy on east coast

FROM RYAN'S LOST COAST JOURNAL, APRIL, 2004 – "Being wet had taken its toll. These were the wettest and stormiest conditions I've ever used the Quantum Arc X – Quantum Vapr Bivy – SpinPoncho combo. This night, I would boil some tea and then crawl into bed for a few hours in the evening. I wore wet polypro long johns (I kept my sopping Cloudveil Prospector pants out of the bag tonight, although I'd worn them wet to bed the previous night), a mostly wet Smartwool long sleeve zip-T, and a fairly damp Cocoon Pullover to bed. My only dry clothing that I wore to bed was my fleece socks, which stayed dry under the poncho, inserted into the shoulder straps of the (Gossamer Gear) G5 (Backpack) as padding. After my two hour nap, I woke up and everything inside was really wet – the bivy was a condensation station like I've never seen, and my down bag was getting soggy. Now here's the surprising part. By morning, all was pretty dry. Clothing was dry, bag had restored some loft, and there was no condensation in the bivy. This was one of the more remarkable observations I've ever seen in the backcountry, and gave me a whole new level of confidence of dealing with down in wet conditions. The key, I think: reasonably warm night time temperatures (48-52 degrees; note that outside humidity was 100%) and ultrabreathable shell fabric on both the bag and bivy: Pertex Quantum. This observation made the entire trip worthwhile."

Look up threads on dew point.

Well if you didn't sound experienced I'd say it was too much bag/insulation for the temp you were sleeping in…you overheated, perspired, became cold, bag wet out.

But since you are accustomed to the temps in the same bag – I'm not so sure.

i believe a bivy would have helped keep the dampness out. was there any insulation between you and the ground. wind chill could be a factor. just a light breeze and a little dampness could create a chill. some times i'll just do a couple of sit ups or leg lifts right in my bag to get the blood flowing and body temperature up to warm up my bag, if i wake up and only need a few more hours of sleep, maybe have a snack if at all handy. get a meal in me as soon as i wake up, dry the bag out in the morning if needed

During March through early May – in the mornings, all horizontal surfaces are covered with really large water droplets. Each drop is about 3/8" / 10mm in diameter and 3/16" / 3 mm in height.

I'm not sure my bag ever had DWR coating (it's an older bag, and I never tried cowboy camping before), or if the coating is just worn off (the bag has been washed a dozen times).

The temperature rating on the bag (which use as a quilt in those temperatures) is usually fine in these conditions under my tarp, and I used the same pad I always use (a BA insulated air core). I also ate well, had a snickers and some water before bed, and wasn't unusually tired/sore – so my heat output should have been fine. When I woke up chilly and damp, I just put on a fleece jacket, and tucked my legs into a 100 wt fleece shirt, and slept fine the rest of the night.

But when I woke up in the morning, the insulation in the sleeping bag was definitely damp. The insulation was dampest near the outside by a wide margin.

A bivy with a good DWR might fix it, and be nicer to use than my groundsheet under my tarp (I move around a lot so I need to put gear near my feet to keep them on the groundsheet since the ground is always damp and sometimes muddy).

But if a bivy would just make the situation worse on the east coast where we always have heavy condensation, I'd rather skip the expense of buying one :)

I have had no luck with bivies on the East Coast. In fact, I have given up on them due to condensation.

I had great luck with Event bivies when used in the winter in New York, NH, and PA, but at any other time I found bivies added to condensation.

In spring and fall I often used an Equinox Ultralight bivy with a silnylon floor and DWR coated nylon top, and the floor was ALWAYS covered in condensation in the morning.

Depending on the humidity and temperature, there would also be condensation on the underside of the nylon top, though always much less than the coated floor. I liked the bivy due to protection from insects and such when my bag was not fully zipped, but if I did it again I would get a bag cover without a waterproof fabric anywhere. Still, the bivy did not mitigate condensation on or in my bag.

if you use a bivy, get one that you can stake down and whose top you can somehow hang from a vertical support, thus creating a mini-tent. The condensation will stay on the bivy top and it'll not damp your bag unless both surfaces get in touch