Dirtyoldman
06-01-2003, 06:28
After a lot of reading and thought I concluded that an underquilt was the best way to insulate a hammock so I started some experimentation.
The first problem was to find the correct shape/pattern to make the quilt. I used some cheap polyester material and 1 inch foam for the test and was very pleased with the results. No more pad inside to deal with and no cold spots to worry about.
Using what I learned from my prototype I converted a cheap sleeping bag into a underquilt as follows...
(READ ALL THE INSTRUCTIONS AND MAKE A SCRAP VERSION FIRST)
determine and mark both vertical and horizontal center lines. these are used as a referance for all other markings.
along top and bottom sew a single line about one inch in.
for a 4x9 ul asym the quilt needs to be 47" wide or so. from the longwise centerline mark each side 23". sew a single line here to trap the insulation and cut the excess off leaving a one inch margin (24)
after both sides are done you should have a 48 " wide piece with the zipper removed and about 1 inch of loose material all the way around.
The next step is to make 2 v shaped cuts on each end to gather the ends together. (it is easier to make a v now and cut it out with the foot end then try to install one later.)
mark a line 9 inches inside of each of the longwise lines sewn earlier or 13 " from the longwise centerline. It should run from the bottom or top edge inward for 30 inches parallel to the longwise centerline. on this line mark a point 24 inches from the outer edge of the bag.
for each of the four lines fold the piece in half and flatten best possible. At the outer edge mark 4 " from the seam just formed. Using a straight edge create a triangle and mark/sew. cut off the excess material and finish joint with a cap piece or oversewing.
at the head end along the longwise centerline make a similar v cut stopping 12 inches from the shortways centerline. Use the same 4" width for this longer triangle.
If I have explained this correctly you should see a distinct football shaped curve present with one cut obviously missing.
On the original I cut a slit 6 inches off the center and ran down the footend longwise centerline. Then I sewed the end tips together so it worked just like the opening on the Hennessy. It worked fine except I could figure out an easy way to finish and reinforce the inside end of the cut.
For this prototype I marked, sewed and cut away half of the left side at an angle so the quilt can be pushed aside again leaving a one inch margin. I started the cut at the outer edge 12 inches from the shortwise centerline and ran it down and in to a point 24 inches from the shortwise centerline on the longwise centerline. This left a 12 inch end peice where I normally would park my feet. The exact cut has not been determined and needs to be experimented with yet.
As you may have noticed there are only two things left to do. Install a system to fasten the quilt to the hammock and finish the outer seams.
For mine I sewed loops on my hammock spaced 12 inches apart along the joint between the netting and the botton. Along the edge of the quilt I sewed loops of 3/4" elastic arranged to fall inbetween the loops on the hammock and attached the quilt to the hammock by running shock cord though each loop running along the side and tying the ends off to the main hammock support ropes. I also knotted the shock cord at the ends of the quilt so that it could be pulled tight. Safety pins could be used instead of sewing loops If your squeemish about sewing the hammock itself.
You could also use elastic and clips for attachment but I havent tried this arrangement. You may need to make the quilt an inch or two narrower to allow the elastic some stretch room.
Once you have determined how your going to attach the quilt finish all outer seams and inspect.
The original bag for this try was a 20 dollar el-cheapo with 3 lbs of hollow fiber fill and had a starting weight of 3 lbs 12 oz. The finished weight for mine was 1 lb 8 oz. and should be suitible down to 30 degrees (maybe). A better bag may have yeilded improved results but I havent had to confidence yet to chop up an expensive one to test. It may be possible to Use this with a mummy bag or a down bag but I would try the elcheapo version first.
Notes:
more then one quilt can be used at one time to increase tempature rating.
The bag I used was 75" long but length doesnt seem to affect the overall fit that much. For other sized hammocks the size of the triangles can be increased to tighten the fit or elastic installed at the head end.
On mine I had intended to add a space blanket inside of the bag and removed the stitching used to stabilise the insulation. After I was halfway done I realised I had forgot to put the blanket in....DOH!
The first problem was to find the correct shape/pattern to make the quilt. I used some cheap polyester material and 1 inch foam for the test and was very pleased with the results. No more pad inside to deal with and no cold spots to worry about.
Using what I learned from my prototype I converted a cheap sleeping bag into a underquilt as follows...
(READ ALL THE INSTRUCTIONS AND MAKE A SCRAP VERSION FIRST)
determine and mark both vertical and horizontal center lines. these are used as a referance for all other markings.
along top and bottom sew a single line about one inch in.
for a 4x9 ul asym the quilt needs to be 47" wide or so. from the longwise centerline mark each side 23". sew a single line here to trap the insulation and cut the excess off leaving a one inch margin (24)
after both sides are done you should have a 48 " wide piece with the zipper removed and about 1 inch of loose material all the way around.
The next step is to make 2 v shaped cuts on each end to gather the ends together. (it is easier to make a v now and cut it out with the foot end then try to install one later.)
mark a line 9 inches inside of each of the longwise lines sewn earlier or 13 " from the longwise centerline. It should run from the bottom or top edge inward for 30 inches parallel to the longwise centerline. on this line mark a point 24 inches from the outer edge of the bag.
for each of the four lines fold the piece in half and flatten best possible. At the outer edge mark 4 " from the seam just formed. Using a straight edge create a triangle and mark/sew. cut off the excess material and finish joint with a cap piece or oversewing.
at the head end along the longwise centerline make a similar v cut stopping 12 inches from the shortways centerline. Use the same 4" width for this longer triangle.
If I have explained this correctly you should see a distinct football shaped curve present with one cut obviously missing.
On the original I cut a slit 6 inches off the center and ran down the footend longwise centerline. Then I sewed the end tips together so it worked just like the opening on the Hennessy. It worked fine except I could figure out an easy way to finish and reinforce the inside end of the cut.
For this prototype I marked, sewed and cut away half of the left side at an angle so the quilt can be pushed aside again leaving a one inch margin. I started the cut at the outer edge 12 inches from the shortwise centerline and ran it down and in to a point 24 inches from the shortwise centerline on the longwise centerline. This left a 12 inch end peice where I normally would park my feet. The exact cut has not been determined and needs to be experimented with yet.
As you may have noticed there are only two things left to do. Install a system to fasten the quilt to the hammock and finish the outer seams.
For mine I sewed loops on my hammock spaced 12 inches apart along the joint between the netting and the botton. Along the edge of the quilt I sewed loops of 3/4" elastic arranged to fall inbetween the loops on the hammock and attached the quilt to the hammock by running shock cord though each loop running along the side and tying the ends off to the main hammock support ropes. I also knotted the shock cord at the ends of the quilt so that it could be pulled tight. Safety pins could be used instead of sewing loops If your squeemish about sewing the hammock itself.
You could also use elastic and clips for attachment but I havent tried this arrangement. You may need to make the quilt an inch or two narrower to allow the elastic some stretch room.
Once you have determined how your going to attach the quilt finish all outer seams and inspect.
The original bag for this try was a 20 dollar el-cheapo with 3 lbs of hollow fiber fill and had a starting weight of 3 lbs 12 oz. The finished weight for mine was 1 lb 8 oz. and should be suitible down to 30 degrees (maybe). A better bag may have yeilded improved results but I havent had to confidence yet to chop up an expensive one to test. It may be possible to Use this with a mummy bag or a down bag but I would try the elcheapo version first.
Notes:
more then one quilt can be used at one time to increase tempature rating.
The bag I used was 75" long but length doesnt seem to affect the overall fit that much. For other sized hammocks the size of the triangles can be increased to tighten the fit or elastic installed at the head end.
On mine I had intended to add a space blanket inside of the bag and removed the stitching used to stabilise the insulation. After I was halfway done I realised I had forgot to put the blanket in....DOH!