help with underquilt design

**stevebo** · 07-24-2009, 12:44

Hey guys, I would like to make a 3/4 underquilt and am not sure about the design. I have some leftover insulation I bought a couple of years ago when I made a synthetic insulated rayway quilt. I also have some breathable liteweight ripstop from walmart. I would like to make a 3/4 length quilt for my diy speer hammock. My question is, what shape do I make the underquilt ? Im not worried about a suspension for the quilt. (My diy speer has a special adjustable double bottom, big enough to hold an underquilt ) Ive made 2 rayway quilts in the past 4 years, so Im definitely capable of making an underquilt, but wasnt sure about the shape----any suggestions? Also, Im not sure how much insulation I have, and how thick the quilt will end up being. Is there any way to boost the efficiancy of the insulation, with out adding more loft?

**sclittlefield** · 07-24-2009, 12:54

Originally Posted by stevebo

Also, Im not sure how much insulation I have, and how thick the quilt will end up being. Is there any way to boost the efficiancy of the insulation, with out adding more loft?

I can't comment much on the shape of your underquilt. Though I am sure a rectangle would work, there may very well be a better way.

On the insulation boosting - I think about the only thing you can do to boost your warmth without adding more insulation would be to use a space blanket. That and wear warmer clothing to bed.

**stevebo** · 07-24-2009, 18:25

One question, do you put the space blanket on top of the underquilt, or on the bottom? I saw your plans for your diy hammock pad---do you have any condensation problems? Bythe way, I enjoyed your blog----the over under hammock is a pretty neat idea! I dont keep track of the time I spend camping or working on gear, but im sure I spend alot more time actually building gear than actually using it!

**Merganser** · 07-24-2009, 18:50

If you put the underquilt between two layers of a double bottom hammock I would expect it to be compressed, that would make it less effective.

I just finished a UQ, with a differential cut to boot. I made measurements on the underside of the hammock, to the center from each side at one foot intervals (use pins or clothes pins to mark a grid on the hammock before hanging). I used one dart on each side of center and made the darts combined take up 1/2 the difference between the of the measurments (max width of the UQ) and the width of the measurements. The remaining excess is gathered. I just finished this and have not put it to any serious tests but it seems to have worked out wonderfully.

Here's what the pattern looked like with the darts I described.
IMG_9654.jpg

Here is the finished quilt laid out
IMG_9740.jpg

and on my hammock
IMG_9745.jpg

**Take-a-knee** · 07-24-2009, 18:57

That looks like a fine piece of gear, Elaborate on it if you would please, fabric, insulation, weight, etc. What hammock is that?

**jbo_c** · 07-24-2009, 21:23

I agree. Looks well done.

What kind of insulation?

Jbo

**Merganser** · 07-24-2009, 23:59

Originally Posted by Take-a-knee

That looks like a fine piece of gear, Elaborate on it if you would please, fabric, insulation, weight, etc. What hammock is that?

The shell is 1.1oz ripstop from ThruHiker. The insulation is Climashield, two layers of Combat. The shell and insulation are differential cut. The UQ weights 28oz.

I posted more information about the UQ on this thread...
http://www.hammockforums.net/forum/s...ead.php?t=8822

The hammock is a DIY, sort of my take on a Blakbird, a Bluebird if you will. Here are a couple more picks of that.
IMG_9547a.jpg

IMG_9549.jpg

IMG_9550.jpg

IMG_9552a.jpg

**psyculman** · 07-25-2009, 05:05

Marganser,

That's a very good looking uq. Could you tell me the numbers? Like, the length, width of your cardboard template, and the length and width of those darts? I have seen other patterns, but, none with the end darts. I don't need a diagram.

Thanks

**Merganser** · 07-25-2009, 09:14

Originally Posted by psyculman

Marganser,
Could you tell me the numbers? Like, the length, width of your cardboard template, and the length and width of those darts? .

I got the idea for the end darts from UQs like the JRB that are simply rectangular and get their shape from being gathered at the ends, just like the hammock body they are trying to hug. I knew the Climashield I wanted to use wasn't going to bunch up as well as down so I decided to make darts in the end. I figured out pretty quickly that getting the darts exactly right so there were no air gaps with UQ totally flat would be impossible. So what I did was make the darts take up 50% of the fabric that would be gathered at each end.

Everything is based on a single pattern I made to correspond with the inside layer of the shell. The darts on each end are a little different, close though and I almost averaged the darts. The darts are customized for my hammock, which has tie out points that are a little different than either a Hennessy or Blackbird (Blackbird would be closest). My hammock also has a 132in body. I'm happy to share my numbers but I would encourage measuring your own or at least checking mine against your hammock to be sure they will work for you.

The pattern is based on an 84x42 in rectangle. The darts are positioned so that there is an equal mount of space between each dart and the edges. I cut my pattern from landscaping fabric and added a seam allowance (1/2in, should have gone 5/8) but marked the finished outline with a sharpie. The dart width measurements I will list from the head end to the foot end as if you were looking down at the inside shell, which is how I made my pattern. They are at 1ft intervals and form straight Vs.

ft-left-right
0--5----7
1--1----5
2-------3
3-------1
4--0.5---
5--2.5---
6--4.5--1.5
7--6.5--6

The form is cut to match the finish size of the inside shell, so 84x42 minus the darts. This is where those lines on the pattern representing the finished measurements were handy. I stuck pins through the pattern and into the card board, 3 per dart, and marked them with a sharpie before removing the pattern. Then just connected the dots. Also, be sure to tape it together the right way. It's easier to do the "outside" of the darts first, just make sure that you're taping on the "outside" of the cardboard too or your form will be a mirror image of what it should be.

You want the cardboard rather distressed or the form will have a very unnatural shape. If I were starting over (someday I'm sure I will) I would cut it out first and the roll it both ways before taping it together, beating it up after its taped was awkward and I had to retape a bit. Also the duct tape didn't stick as well as I thought it would. Not sure if packing tape would have been better. I taped bits of lath on each corner for legs to get it up a bit so fabric/insulation could hang over the edge. Lots of trouble with the tape there, a cable tie through the cardboard to keep the legs from pulling away from the cardboard would probably address that issue.

The inside shell is cut from the pattern with the seam allowances. The insulation was cut just a little oversize for each layer and trimmed up later, after the darts were in for both layers. I trimmed close to the finish size, using the form as my guide and parallel to the floor.

The outer shell dimensions I measured with a tape from the inner shell over the insulation, just like the fabric would be. Taken this way the measurements included the seam allowances. The outer shell finished size turned out to be 87.5x46. I used the same pattern for the darts. I centered it between the ends and repositioned it side to side so the distance between each dart and the end was he same. I just extended the darts to the end.