Insultex Bridge Hammock

[TeeDee]

I finished my Insultex Bridge Hammock today.

For those that missed my post elsewhere, this is one of my Bridge Hammocks with 3 layers:

1. Bridge Fabric
2. 3 layers of Insultex
3. 1.1 DWR nylon ripstop

I had sewn layers 2 and 3 yesterday. Today I finished sewing 2 and 3 to 1. Installed the cords on the arcs, tied the cords the proper length for the suspension triangles, installed the Bridge Pillow and hung the hammock.

I'm liking this idea of integrating the Insultex into the Bridge Hammock more and more.

Observations:

1. CBS - we experienced Cold Butt Syndrome. I'm not too sure if this is because I didn't allow sufficient width for layers 2 and 3 above or if this is just plain CBS. Under the butt, the Insultex was pulled tight. I hadn't allowed sufficient width of the Insultex over and above the Bridge Hammock fabric proper. I had allowed 3" extra. On the next version I'll increase that to maybe 6" or 9".
2. Immediate warmth elsewhere - other than the CBS, we felt immediate warmth under the torso and the legs. Under the torso, the Insultex was also pulled tighter than I would have liked, but not as tight as under the butt. Even so, the warmth was immediate and very evident.
3. No adjustment - with the Insultex integrated into the Bridge Hammock itself, it is the ultimate in no adjustment under quilts - hang the Bridge and the under quilt is also hung - just part of the hammock.
4. go to ground - this occurred to us today. If we had to go to ground and it was very cold, we could use the Bridge Hammock as a supplemental top quilt. That would add 3 layers of Insultex to the insulation. Try that with any other hammock.
5. replaces 3 items with a single item. The Insultex integrated into the Bridge replaces a regular Bridge Hammock, the under quilt and a Dri Ducks weather shield with just the Insultex hammock. The completed Insultex hammock weighs 25.55 oz. That includes the Bridge Hammock and the suspension cords and excludes the bug netting and the SLS and tree huggers. 25.55 oz replaces:
   
   1. Regular Bridge Hammock: 12.30 oz
   2. Down under quilt: 21.75 oz
   3. Dri Ducks Poncho weather shield: 8.75 oz
   
   Replacing 42.80 oz with 25.55 oz, for a weight savings of 17.25 oz. Over a Lb.
   
   With the Insultex, the Dri Ducks poncho weather shield is not needed. Of course, with a regular, separate Insultex under quilt, the Dri Ducks would not be needed either. So just by replacing a down under quilt with the Insultex, we drop 8.75 oz. A regular, separate 3 layer Insultex under quilt, I estimate would weigh approximately 15 oz to 16 oz. By integrat6ing the Insultex under quilt into the Bridge itself, we save the weight of a second 1.1 DWR ripstop cover and the arc cords. Above and beyond the weight savings is the sheer convenience of use - zero adjustment.
6. reduced bulk - the Insultex Bridge Hammock is about the same bulk as the compressed down under quilt. Thus, bulk is saved on a separate Bridge Hammock and the Dri Ducks poncho weather shield. The Insultex Bridge Hammock is not compressed, simply folded. This makes packing simpler and saves time over compressing the down under quilt. The Insultex Bridge Hammock could probably be compressed slightly by sitting on it once folded, but the bulk savings would be minimal. One of my Bridge Hammocks, when folded for packing is slightly smaller than the typical Nalgene bottle. So that amount of bulk is saved.

Increasing the width of the Insultex will increase the weight, but only marginally.

All of this assumes, of course, that the Insultex insulation performance proves out to be sufficient.

[animalcontrol]

I finished my Insultex Bridge Hammock today.

For those that missed my post elsewhere, this is one of my Bridge Hammocks with 3 layers:

1. Bridge Fabric
2. 3 layers of Insultex
3. 1.1 DWR nylon ripstop

I had sewn layers 2 and 3 yesterday. Today I finished sewing 2 and 3 to 1. Installed the cords on the arcs, tied the cords the proper length for the suspension triangles, installed the Bridge Pillow and hung the hammock.

I'm liking this idea of integrating the Insultex into the Bridge Hammock more and more.

Observations:

1. CBS - we experienced Cold Butt Syndrome. I'm not too sure if this is because I didn't allow sufficient width for layers 2 and 3 above or if this is just plain CBS. Under the butt, the Insultex was pulled tight. I hadn't allowed sufficient width of the Insultex over and above the Bridge Hammock fabric proper. I had allowed 3" extra. On the next version I'll increase that to maybe 6" or 9".
2. Immediate warmth elsewhere - other than the CBS, we felt immediate warmth under the torso and the legs. Under the torso, the Insultex was also pulled tighter than I would have liked, but not as tight as under the butt. Even so, the warmth was immediate and very evident.
3. No adjustment - with the Insultex integrated into the Bridge Hammock itself, it is the ultimate in no adjustment under quilts - hang the Bridge and the under quilt is also hung - just part of the hammock.
4. go to ground - this occurred to us today. If we had to go to ground and it was very cold, we could use the Bridge Hammock as a supplemental top quilt. That would add 3 layers of Insultex to the insulation. Try that with any other hammock.
5. replaces 3 items with a single item. The Insultex integrated into the Bridge replaces a regular Bridge Hammock, the under quilt and a Dri Ducks weather shield with just the Insultex hammock. The completed Insultex hammock weighs 25.55 oz. That includes the Bridge Hammock and the suspension cords and excludes the bug netting and the SLS and tree huggers. 25.55 oz replaces:
   
   1. Regular Bridge Hammock: 12.30 oz
   2. Down under quilt: 21.75 oz
   3. Dri Ducks Poncho weather shield: 8.75 oz
   
   Replacing 42.80 oz with 25.55 oz, for a weight savings of 17.25 oz. Over a Lb.
   
   With the Insultex, the Dri Ducks poncho weather shield is needed. Of course, with a regular, separate Insultex under quilt, the Dri Ducks would not be needed either. So just by replacing a down under quilt with the Insultex, we drop 8.75 oz. A regular, separate 3 layer Insultex under quilt, I estimate would weigh approximately 15 oz to 16 oz. By integrat6ing the Insultex under quilt into the Bridge itself, we save the weight of a second 1.1 DWR ripstop cover and the arc cords. Above and beyond the weight savings is the sheer convenience of use - zero adjustment.
6. reduced bulk - the Insultex Bridge Hammock is about the same bulk as the compressed down under quilt. Thus, bulk is saved on a separate Bridge Hammock and the Dri Ducks poncho weather shield. The Insultex Bridge Hammock is not compressed, simply folded. This makes packing simpler and saves time over compressing the down under quilt. The Insultex Bridge Hammock could probably be compressed slightly by sitting on it once folded, but the bulk savings would be minimal. One of my Bridge Hammocks, when folded for packing is slightly smaller than the typical Nalgene bottle. So that amount of bulk is saved.

Increasing the width of the Insultex will increase the weight, but only marginally.

All of this assumes, of course, that the Insultex insulation performance proves out to be sufficient.

-what temp did you expirence CBS?
-what is your down uq temp rating?
-I'm still confused about 1 layer of Insultex and 3 layers? is this bridge 1 layer+2 layers scrim or 3 layers of insultex+6 layers scrim? I know this has been covered, I'm just slow i guess
-purpose of your DriDuck poncho referenced above? An incorporated Insultex insulation cannot be used as rain gear so I'm struggling on why your including it here. I'm assuming you find it necessary for UQ protection...

The numbers still look good depending on actual/proven temp ranges...weather is getting nice enough to make testing harder...

[ref103]

we need details. I've thought of a bridge hammock but not too much. this rekindles my thoughts of a bridge. if i'm getting this right you made a sewn in double layer hammock with 3 layers of insultex built in. did you just sew the insultex and nylon at the perimeter of the hammock?

[TeeDee]

-what temp did you expirence CBS?

I did some extensive temperature measurements on CBS previously. Measured temps using one of those IR devices from Harbor Freight. We've experienced CBS at temps from the 30s to the 70s. The measured temperatures of the Bridge fabric directly under the butt came out consistently in the 70s and 80s. I couldn't find a good external cause of CBS and so I'm of the opinion that CBS is physiological in origin.

-what is your down uq temp rating?

The measured loft is 5" to 5.5". That is the loft when laying flat on the floor. I've measured the loft when hanging under the Bridge at 6". I think that is a false measurement though since the down is pulling the outer shell material away from the inner shell material. I think the floor measurement of loft is the more accurate.

I've seen charts that rate 5" of down at -40*F. I think I remember one article somewhere that gave a formula for computing the rating the military uses for temperature rating from the loft of down. From memory, I think that 4" came out to -20*F (that's strictly from memory and so highly undependable). I've not been able to find that article again on the web. I've seen a reference once to a chart that Thru-hiker posted on loft and temperature rating and I think his chart pegged 4" of down loft at either 0*F or -20*F, cannot remember which. Another chart indicates a rating of -40*F for 5.2" of loft.

-I'm still confused about 1 layer of Insultex and 3 layers? is this bridge 1 layer+2 layers scrim or 3 layers of insultex+6
layers scrim? I know this has been covered, I'm just slow i guess

The Insultex as we got it is 3 layers quilted together. The 3 layers are in order:

1. scrim - this is a thin material of some sort
2. inside material - don't really know what this material is
3. scrim - this is a thin material of some sort

layers 1 and 3 are the same material I think.

All 3 of these layers constitute a single layer of Insultex as we got it.

So the Insultex Bridge is 3 layers of the above 3 layers. More confused now - right.

-purpose of your DriDuck poncho referenced above? An incorporated Insultex insulation cannot be used as rain gear so I'm struggling on why your including it here. I'm assuming you find it necessary for UQ protection...

The Dri Ducks poncho serves as poncho in a pinch, but it's main use for me is protection of the down under quilt from rain blown under the tarp. I'm paranoid about keeping my down dry, really dry. One bad experience is all it took for me to become paranoid about down and water - either liquid water or vapor that can condense in the down. So for me, protecting the down under quilt from water is essential. If I could bailout of a hike in a day or less, I could be more relaxed about down and water.

Since the Insultex itself is impervious to water, I'm hoping that it's insulation properties are not ruined by water like down's is. Also, that then the Insultex needs only minimal protection from water (liquid or vapor) to be usable. I'm hopeful that since the Insultex is a synthetic insulation, that like Climashield or other synthetics, when wet, body heat can dry it out. I'm more hopeful for this aspect than for Climashield and other synthetic insulations, because of the thinness. The thinness of the material means that it holds less water (experience to date seems to indicate that it the amount of water held in the material is negligible or, for all practical purposes, zero) and hence dries out even faster than Climashield. My experience with the Insultex poncho to date in light and drenching rains indicate that water does not influence it's properties.

The numbers still look good depending on actual/proven temp ranges...weather is getting nice enough to make testing harder...

Agreed - actual experience in actual weather trumps all else. I'm trying to stay optimistic without being overly so

[TeeDee]

we need details. I've thought of a bridge hammock but not too much. this rekindles my thoughts of a bridge. if i'm getting this right you made a sewn in double layer hammock with 3 layers of insultex built in. did you just sew the insultex and nylon at the perimeter of the hammock?

Have to go right now - will reply in more detail later.

[TeeDee]

we need details. I've thought of a bridge hammock but not too much. this rekindles my thoughts of a bridge. if i'm getting this right you made a sewn in double layer hammock with 3 layers of insultex built in. did you just sew the insultex and nylon at the perimeter of the hammock?

Short answer - yes.

I first sewed the Insultex layers to the 1.1 ripstop on the ends only. That kept those layers together.

Then when I sewed the bridge end hems, I put the Insultex and 1.1 ripstop under the hem and sewed the hem. That took care of the ends.

I then hemed the arcs and did the same there. Since the arc portion of the Insultex and 1.1 ripstop weren't sewn together, it was slower going and more tedious.

I think on the next version, I will sew the Insultex and 1.1 ripstop together on the entire perimeter. That keeps them together and then sewing the hems on the Bridge are easier.

note that since the Insultex and 1.1 ripstop are wider, much wider than the Bidge, you need to put tucks in the Insultex/1.1 ripstop on the ends.

Note: when sewing the Insultex and 1.1 ripstop, have the ripstop on the top and the Insultex on the bottom so that the feed dogs on the sewing machine are feeding the Insultex. If you have the 1.1 ripstop on the bottom, things slip around a lot.

[Dutch]

This is a very good way of having an insulated bridge vs. using down with all the baffles. I like it, does it come in purple?

[TeeDee]

This is a very good way of having an insulated bridge vs. using down with all the baffles. I like it, does it come in purple?

Shucks - I used all of my deep purple 1.1 ripstop up on the down quilts.

I'm still working on getting the tension out of the Insultex layers.

My first thought was that simply making the Insultex layers even wider would work. It might, but I think I would have get un-necessarily wide to ease the tension.

I've investigated where the tension is coming from and it's due to the middle dipping down more than the arc depth. I cut the arcs 6" deep. But when hung the bottom of the arcs is almost 13" below the corners. That means that the corners are pulling the middle of the Insultex layers up. You can see this effect with the 1.1 ripstop and Insultex being pulled above the arc at the mid-point.

I think that making the ends much wider and leaving the middle the same width I currently have, might solve the problem.

I think I may pull all the stitches, add to the end width on the 1.1 ripstop and put the whole thing back together and see how that works.

I was running out of fabric, so I made the Insultex Bridge by taking apart an older Bridge that was too wide and cutting it down to our current dimensions. Now I can see that I'll have to take it apart again .

[GrizzlyAdams]

...
I've investigated where the tension is coming from and it's due to the middle dipping down more than the arc depth. I cut the arcs 6" deep. But when hung the bottom of the arcs is almost 13" below the corners....

I've seen this phenomena also (the arc depth being significantly larger than the cut depth). Helps some to pull the hammock ends farther apart. At least when I have, the arc depth is no longer 12" on a cut 6".

I agree with the analysis in any case. Insultex compresses, it compresses most at the butt because of the afore-mentioned factors.

I've been thinking about turning my Insultex poncho into a fitted UQ, observed this same problem (based on past reported experiences). I'm thinking that if the edges near the center were tucked some to create more of a bathtub shape in the butt area, that might help.

Only one way to find out...

Grizz

[dblhmmck]

TeeDee,

Thanks for sharing your findings. You certainly seem to be on a roll with your gear production/innovations.

Thanks also for arranging the group buy on the Insultex. I am incorprating mine in a bridge design also.

I have been making a new double bridge (not simply a double layer, but another two person bridge). I am using the insultex as supplemental bottom insulation with open and closed cel foam pads. The insultex is permanently sewn to the bridge as you have done, but only in certain areas. I am using it in a pad pocket for the legs and butt, the insultex extends up to the waist. A closed cel foam removable pad is used under the legs, and 3/4 length inflatible pad 1 1/2" thick (REI Lite-Core) under the upper body. Overlap of insultex and inflatible pad is from the waist to the upper thighs. Overlap of 3/8" closed cel pad is from the upper thighs to the feet. I have also sewn in side insulation of insultex and 3/8 closed cel pad from the upper thigh to the shoulders. I have used a double layer of the insultex in each area.

On the sides, the 3/8" closed cel pad is sandwiched between the two layers of insultex with a single layer 1.1 nylon. Under the legs the 3/8" pad is on top of the double layer of insultex. This pad sleeve has mosquito mesh sewn over the insultex and a layer of 1.1 nylon is sewn along three edges to form the pad sleeve. I hope to do a test hang (using only two trees!) this week-end.