Help with Bivy

Matt, I have found the bivy/tarp setup to be the lightest, storm worthy setups around. I'd say the only watchout is in warm buggy weather. I can't speak to using a poncho liner to sleep in, but I can speak to the pieces that make up a traditional bivy/tarp as a shelter/sleep sytem.

Component #1 = Tarp
The simplest is a 5'x8' tarp made of silnylon (i.e. intergral designs siltarp). It will weigh around 7 oz. Other options include poncho tarps, cat cut tarps, etc and tarps made of spinnaker or cuben fiber to save weight. You will want to add some line (Kelty trip tease) and 8 titamium stakes.

Component #2 = bivy
A cover to your sleeping bag with a waterproof bottom and a breathable, but water resistant top. I'd recommend one that zips and has at least a small bug window. Examples are Mountain Laurel Designs Super Light Bivy and Titanium Goat Ptarmigan Bivy. The bivy will typically go right on the ground. The bivy will weigh around 7 oz

Component # 3 = sleeping pad
This pad usually resides inside the bivy. The most basic pads are closed cell foam like those sold by Gossemaer Gear. Other options include a range of self inflating pads to down filled mattresses (heavier but more comfortable). A closed cell pad can weigh as little as 2 oz to as much as 12 oz depending on thickness and length.

Component # 4 = sleeping bag or quilt.
This bag goes inside the bivy on top of the pad. For 30 degree camping there are some great options, but some of the the better are probably a WM Summerlight or a Marmot Hydrogen. If you are into quilts a Golite Ultra 20 is another great option. This type of sleeping bag will weigh under 1.5 lbs.

This setup will weigh around 3 lbs total for shelter, pad, and bag. It will keep you comfortable in a wide range of conditions. Here is a picture of what this system might look like.

ID 5×8 Siltarp+line+stakes, MLD Superlight Bivy, Golite Ultra 20 Quilt (inside bivy), GG Thinlight Pad (inside bivy). Total weight is 2.3 lbs and has kept me warm to 20 degrees.

I went into these details to give you an idea of what a basic system looks like, is used, and weighs. Is this the type of system you are thinking about? If not provide a few more details on each piece you are considering.

Jamie

Unless you are a VERY warm sleeper you are going to get cold. Doubling up the liner on top of will help some, but I don't think you will be happy.

A bivy is similar to a windbreaker-type layer….some warmth is added but it is not significant.

You will need your sleeping bag to be comfortable, or perhaps your poncho liner will work with your warm layer clothing system.

What layers do you carry?

(Great job on taking your kid, btw!!!!)