Why did I freeze my butt off with this UQ?

**andrewallan** · 01-27-2012, 04:34

Recently returned from NZ. My first experience sleeping in a HH, using a 3/4 length UQ that I thought I had designed very carefully, as per piccies.

It was probably 8-10C at night, and a bit breezy, but we were in the trees in a river valley. Each night I was cold from below. The UQ seemed to hang pretty well below my hammock, but I wonder whether having some airspace between the bottom of the hammock and the UQ was the reason I was cold.

I did have a night with the tarp strung high above the hammock, and then thought that maybe the tarp needed to be fitted closer to keep me warm. It made little difference. I was thinking that air movement around the hammock was keeping me cold.

In the end, we decided to sleep on our upturned Alpacka rafts, in the hammocks (for sandfly protection), and it was a lot cosier, although I was sleeping in all my clothes, inc Montbell exlight paka, and using both my quilt and UQ above. The rafts prooved palpably warmer underneath.

All this from someone who is able to sleep in the snow in a clothes in a BMW Cocoon parka in a sleeping bag with 500g of 550 loft down.

I was amazed at how cold the system was - ?any ideas to keep me warmer next time.

Andrew Allan

**FireInMyBones** · 01-27-2012, 04:43

Airspace between the UQ and hammock prevents proper warming and heat retention in the UQ. Sometimes this is called venting.

Is the UQ filled with down? There does not appear to be a lot of loft. From the pics, it looks like a summer quilt and not a lot of coverage.

**andrewallan** · 01-27-2012, 05:09

Yep, it's filled with about 150g of 900 loft down, and when flat, has a loft of about 4-5cm, so it looked toasty enough for what I was doing, which was summer useage (nb 8-10C, not F).

A

**Bubba** · 01-27-2012, 06:04

I'm no expert but it looks kind of narrrow especially at the one end. Maybe its not wide enough on that end to create a seal when hung and air is getting in that way.

**oldgringo** · 01-27-2012, 06:10

46*f, just to move things along.

**oldgringo** · 01-27-2012, 06:13

There's only one way to troubleshoot this. You need a crash test dummy...wife, gf, best bud, etc.

Put the dummy in the hammock, and fine tune your uq suspension. Done.

**gargoyle** · 01-27-2012, 06:15

I think your uq was a little thin (4-5cm =1-1 1/2 inches of loft).
Try adding a thin ccf pad or window reflector for an easy fix.
Most uq's have a loft of 3-4 inches (up to 10 cm) and a good fit. As mentioned, trapping the heat is the key, no matter what the loft is.
Wind will suck away the heat fast. A good tarp, set low to block any wind will help.
Experiment at home for a kit that works for expected temps.

**cfi on the fly** · 01-27-2012, 06:49

I'd like to see some picks if your alpacka in the hammock. Might have to to try that with mine!

**Bannerstone** · 01-27-2012, 07:24

At 46*F, I'm guessing that the quilt was probably doing well except in spots where it wasn't snugged up against you or where there might have been air leaks.

Get a helper like Oldgringo suggested, you'll be amazed at how little time it takes and how simply these problems can be solved. Testing invovles the helper running their hands between the UQ and the hammock looking for gaps then adjusting the suspension accordingly. When a gap is eliminated, you'll feel the difference in a matter of a few seconds.

David

**BillyBob58** · 01-27-2012, 10:10

Air getting under the hammock is almost certainly the problem. You will have to get it well snugged up against your back and with no leaks around the ends and edges. Like OG said, get some one in the hammock and experiment with the suspension and fit. Any draft can quickly make a 30F quilt into a 55F or even 65F quilt.

You can have it pretty snug and have a good fit on the edges and still have it gaping- not contacting your back- right in the middle. This is not as bad as an outright cold air leak/infusion under the hammock, but it does not help. Particularly with only ~ 2" loft being exposed to a breeze.

Finally, is this a differential cut quilt, with the outer shell bigger than the inner shell? If not, you might have it too snug, compressing the loft. With no dif cut, fit has to be pretty precise. Neither too loose nor too tight.

A thin pad in the hammock or a $3 space blanket between the hammock and quilt will give you a very noticeable boost.

http://www.jacksrbetter.com/UQ%20Installation.htm

Installing your under quilt for the first time is best done in the backyard with the help of a friend. Have one person get in the hammock and the other checking for air gaps and proper loft. The goal in attaching the quilt is to have it suspended beneath the hammock with no (or minimal) air gap between the hammock and the quilt AND minimal tension on the quilt. Tension on the quilt reduces the loft resulting in cold spots. Place one hand between the quilt and hammock to check for air gaps. Once the quilt is suspended so that any air gaps have been eliminated, using the other hand on the outside of the quilt check for full loft. If using a gathered end hammock, make adjustments in the suspension lines in small increments (1/2 inch increments) first on one end and then the other until the quilt is properly suspended with no air gaps and maximum loft. Once set, leave the suspension system in place so that the next time all you have to do is connect the corners of the quilt, draw the end cords, and make fine tuning adjustments.