Under-Pad for double duty?

[HighMiler]

Just got back from a trip where I changed from sleeping on the ground to sleeping in my Traveler hammock. I had planned to sleep on the ground, using my 3/4-length Thermarest and down quilt in my bivy sack throughout, but decided to try sleeping in the 11-oz. hammock I'd brought along for comfort, reading chair, hanging out, etc.

After learning how taut to pitch the hammock, I plunked my entire bivy unit into it. The waterproof coating on the bivy bottom kept the T-rest pad in place and provided a bug-net head covering. Sleeping with a quilt gave me no issues about getting unzipped, etc.

But sleeping on my side, I found my knees getting cold when they compressed my quilt against the side of the hammock, so now I truly understand the rationale behind an underquilt. The unit worked good until we got above timberline, and I went back to sleeping on the ground -- which I was set up for anyway.

I worked out an underquilt using a down-filled quilted couch throw as soon as I got home in prep for my next outing. Now I'm thinking about an underpad of thinnish ensolite foam or such that could be doubled or tripled underneath as a ground pad. Like to be adaptable without having to carry the added weight of a dedicated ground pad

Any thoughts?

[Bushwalker]

One popular method with some snow campers/X-Country skiers/mountaineers is to use a thin high-density foam mat underneath their regular self-inflating sleeping mats to add that extra layer of insulation...

There are some heavy-duty extra-high-density (yellow) foam sleeping mats (like the "Karrimat" from the English 'Karrimor' company, that I have one of here - and that I think may be currently out of production, as I couldn't see them on their website last time I looked..), that are both much warmer and lighter than the more common and much cheaper (blue) PVA foam mats..

[I believe the Karrimats might be made from that same type of "EVA" foam that those 'Thermarest' Z-fold and Ridgeline models are ???].

[HighMiler]

I, too, have a yellow Karrimat. When I was guiding on snow/glaciers, we slept direct on such mats, and the white ensolite eqivalents -- mostly about 3/8" thick. We shaped the snow underneath like one would a sandy bed with scooped-out holes for hips and shoulders. When I had a second pad or air mattress, even a T-rest and such, my thin pad went in-between me and the air-filled pad/mattress to break the convection zone. Always slept warm.

My search is for a thin mat minimum about 48" by 66" that will conform to my hammock's cocoon shape and then could be doubled underneath one when forced to sleep on the ground.

A friend gave me a sheet of white closed-cell foam about half the size I need that was used to pack his new LCD television. I'm going to look for a source of this material. Packing material should be pretty inexpensive, right?

[Reality]

I would certainly use a thin pad if I didn't have an under-quilt/blanket.

However, I've found that using pads in a hammock changes the feel of what I like about the hammock. I'd rather have just the conforming fabric than the more rigid or fixed nature of the pad.

I may be mis-reading... Are you wanting to use a pad under your hammock like an under-quilt (rather than in the hammock)? If so, you'll likely have some issues with it conforming (keeping out drafts).

The foam fabric that is used to wrap televisions and such may not offer much on the ground.

I suppose you don't want the added weight of carrying an inflatable mat or ccf pad that may not be used much. You may be able to circumvent this in your trip planning stage.

Reality

[HighMiler]

You got it! I want to wrap the outside of my hammock with a thin foam barrier.

Would love to have a 9-ounce T-Rest Neoair or somesuch, but on a fixed income - - - And your other point about not carrying extra weight is right on, too. I'd rather not carry my 21-ounce T-Rest pad in addition.

Maybe I will wait and see what Santa Claus brings.

And, bottom line, the foam may not conform properly to keep out drafts -- that's why I was seeking input before getting too crazy here. If I could carry that 9-ounce Neoair plus my underquilt I could be very adaptable.

[HighMiler]

Did a couple of test overnighters in my Mozzie Traveler. First morning it was 33 degrees at wakeup; Second AM was 27 degrees by the river below our home.
I rigged a "Sportsmans Blanket" under the hammock to create a double layer, provide a wind shell, and, hopefully, reflect back a bit of body heat. Used the same 3-pound down quilt both nights.
First night I slid some white 1/4" thick closed-cell foam sheets in place between the two layers where I figured my hips and shoulders would be. Woke up to find I had moved off the insulating pad and those pressure points were cold. I had a third sheet of this packing material and some duct tape, so at about 3 AM, I taped the three pieces together and slid them back in, slept until daylight with no more "cold" spots, but felt I slept a bit chilly -- I was kind of stiff and sore.
Second night I used one of those 72" x 24" egg-crate foam pads between the two layers. Slept through the night, woke feeling comfortable even though it was colder. This pad weighs 22 oz. where the 1/4" thick pads total 13 oz. Warmer, but adds to the load.
Couple of thing to remember: Basically, thicker is warmer and: If you don't have fuel in the furnace, you aren't going to generate heat. A high-calorie bedtime snack -- or even a quick "midnight snack" -- helps enormously.

[GGervin]

Gossamer Gear is offering a "Thinlite" pad 1/4" thick and 39" wide, advertized as good for hammocks or split in half for "two standard 1/4" pads." Folded instead of split, that might be the very pad you are looking for - hammock duty and ground duty. I have a 1/8" thick GG Thinlite, and it's pretty good for added ground insulation with very low weight and a very reasonable price.

[Reality]

The Thinlight is a great pad, GGervin. And that's a good idea for this application.

Reality

[PBF Support]