Bridge Hammock

[Mule]

The picture that HC4U pointed to is the commercial version, with one of the Jacks of "Jacks R Better" fame modeling the lounging capability.

After a weekend with HC4U, me, Hooch and Cerberus, I knew you'd get hooked on the DIY thing. A guy that can make concert quality musical instruments is going to make production quality DIY hammocking gear. I for one am looking forward to seeing what you come up with.

All-Mule already has a name for his DIY bridge :



Grizz

Griz, that is funny and I will call it such b flat!

[Walking Bear]

The bridge hammock tread has been quiet for a few days. I thought I would bump it a little.

I have started working on bridge hammock version 3. Maybe if I keep making changes, I can get to a higher version number that Gizz.

It is a double hammock again similar to the to the last one. I wanted to make it wider than the last one. The middle is about 36" wide and about 56" at the ends. Its about 86" long when finished.

I moved the spreader bar supports down 12' from the end of the rings. This will allow for a longer side to the triangle of the suspension and puts them closer to the shoulders. When that is done then the fabric at the end of the hammock hangs lower that the rest of the hammock when the hammock is occupied.
I placed a dart in the bottom of the hammock in the head end that is 12' long and 3.5 inches wide. That took out about 7" of fabric in the very end of the hammock. That helped a great deal in raising the floor in the end of the hammock. Probably could get by without any pillow without much difficulty.

I put chalk marks on the seam in the dart in the photo so it would show up better.
I have used 2" wide webbing loops to hold the trekking poles as spreaders. The tip end has a piece of tubing with a hole in one side for the tip to go into. The handle end is a loop of the 2" webbing sewn to the hammock webbing on one side. The other side is sewn to a second piece of webbing that is sewn to the hammock webbing with a gap for the handle to go through.

Next step is end caps and suspension system and netting.

[GrizzlyAdams]

The bridge hammock tread has been quiet for a few days. I thought I would bump it a little.

I have started working on bridge hammock version 3. Maybe if I keep making changes, I can get to a higher version number that Gizz.

sorry, this is funny. I just came inside after putting up my v0.3 for the first time. I'm not counting the grey prototype in the release series. However I count it, this is the 5th bridge hammock I've made. Not like there's competition for a record or anything..

It is a double hammock again similar to the to the last one. I wanted to make it wider than the last one. The middle is about 36" wide and about 56" at the ends. Its about 86" long when finished.

I thought the double hammock idea you had was cool. My original intention for this next one was to make it into a double as well. But, as I put hammocking fabric on my Christmas list, my wife rather pointedly asked me if I would refrain from buying further fabric until Christmas (and my birthday, which comes a week and a half later) had past. I agreed.

So the materials I had at hand for v0.3 are 1.9 oz rip-stop, the same as I used for v0.1 and v0.2. I could have made a double body with that, but was concerned about weight. I have a pile of black silnylon, courtesy of Cannibal, and figured I could use that for an underbody.....but its sil and I need to be concerned about condensation. I figured I'd be better off making a 2nd body from the sil that would clip onto the ring corners. That way when there is something between the bodies, there is also a bit of air coming from the top. At least in theory. If needed, I can create more of a gap between hammock bodies by hanging the outer body lower. Anyway, the main body is 1.9 oz chocolate colored ripstop, and the outer body is black sil.

I found with v0.2 that the recessed spreader bar created significant complications when making a bug net, and making the hammock sock. Those things are Just Plain Easier if the spreaders are outside the body of the hammock. When I lay in v0.2 I lay with the recessed spreader just a little beyond my head. I figured that if I made a hammock with the spreaders on the outside, but with narrower fabric, I'd get the same effect more or less.

My motivation for v0.3 was simplicity and symmetry. Everything else I make for the bridge is easier that way.
My intention was to cut a 6" symmetric parabola on each side of a 51" wide and 82" long piece of fabric. I'd measured 48" width under the head spreader of v0.2 , and 51" allow for the 3" you lose rolling the webbing. Somehow I goofed and cut 53" wide---I think I measured the cut from the short side of the roll and mis-remembered with roll width---any way it's 2 inches wider than intended. And as a consequence of this and that the spreader is a little farther beyond my head, not as flat from side-to-side as is v0.2. I won't do anything about this (e.g. lengthen the spreader bar) until I use it a few nights. Tonight will be the first.

I've got no endcaps, and 30 mph winds outside! I got my hammock sock on, the head end is kinda funky because it was made for the recessed v0.2 spreader. It will be easy to adapt that though.

I'll make more of a report later. I just guess Walking Bear and I are in sync!

I moved the spreader bar supports down 12' from the end of the rings. This will allow for a longer side to the triangle of the suspension and puts them closer to the shoulders. When that is done then the fabric at the end of the hammock hangs lower that the rest of the hammock when the hammock is occupied.
I placed a dart in the bottom of the hammock in the head end that is 12' long and 3.5 inches wide. That took out about 7" of fabric in the very end of the hammock. That helped a great deal in raising the floor in the end of the hammock. Probably could get by without any pillow without much difficulty.

The no pillow thing is very slick. If it weren't for the hassles of bugnet and hammocks, I'd have stuck with the recessed bar.


Thanks for the update Walking Bear!

Grizz

[GrizzlyAdams]

I revised my bridge for a few reasons
a) the asymmetry of v0.2 kept getting in the way of simple add-ons for the hammock. In particular the recessed spreader bar made it a lot harder to fit a bugnet and to fit a hammock sock up near the head. A result of the recessed bar being a last minute modification to an already cut body was that the hammock was narrower under the head spreader than under the foot spreader, which mean that the floor of the hammock wasn't level if the ridgeline was level. Correctable, but it got to be a bother.
b) Something....not at all sure what but I suspected it was related to the sloping floor somehow, made it so that after a night in the hammock I'd have a persistent sore spot on my left knee, at least if I spent any significant time on my back. It would go away after a day or so. Still, Not Good.
c) It was too long. While it is handy to have space to drop a quilt or fleece in an area above my head, it made the hammock longer, with ramifications on tarp coverage.
d) The underbody I cut for quilts did that part fine, but was not dimensioned to really hold layers of padding well between itself and the hammock body. A side affect of not really thinking through its own dimensions when I made it, mostly.

So I resolved to address these with a version that was narrower to start with (to get the benefit of a recessed speader bar) but shorter (to get the benefit of a recessed spreader bar), symmetric, and with a closely fitted underbody.
For reasons outlined in yesterday's post I ended up making a sil underbody.
Finished dimensions : 51" wide at the head and foot, 39" wide at the center, 80" long.



v0.3's first night out was a dozy. Low temps hit 19 degrees F. Average wind was 12 mph, with gusts to 30 mph. I got the hammock sock from v0.2 over it, but it didn't fasten well at the head end. I sorta needed to be oriented that way because that's where the tab for the zipped up zipper resides. I was getting blasts of cold air over my face periodically through the night.

One of the objectives for the evening was to try out an insulation scheme. A couple of weeks ago I bought some insul-brite fabric (with the mylar reflection, but breathable) and am trying to see how it can be useful. It's not thick enough to stand on its own, so I figured I'd put it on top of a 1/8" GossamerGear Thinlight pad (2 of them actually, 20" wide, side-by-side), and put on top of that a Thermarest Prolite 4.



The thermarest works well into single digits on the ground, so I'm trying to see if it can be used above ground. But it's narrow. It needs to be between me and the insul-brite, in order that my body heat can warm its air cells. So the idea was to see if the Thinlite and insul-brite work as insulating "walls" for where I touch the hammock not on the Thermarest.

I slept in insulating clothing as per my habit, in a cold weather sleeping bag, and did fine if I ignore the blasts of arctic air straight from Saskatchewan that blew in through the gaps of the hammock sock.

But that underbody is sil. Have I lost my mind?

I thought that if there were air at the edges and ends then perhaps I could get away with it. The HH supershelter uses sil downstairs, after all.

Here's the gap between hammock bodies, when I'm sitting in the hammock. There's air.



It's actually a bit tighter when I'm laying down (had to sit up to take the picture).

This morning there was frozen condensation on the inside of the sil at the footend, beyond where the thinlite pad extended (but the insul-brite pad did extend). There was no discernible condensation on the thermarest or the pads beneath it. There was however frozen condensation on the top side of the thinlite pad covered by insul-brite, but not covered by the thermarest (e.g., the walls).



In thinking this through, I think that if the underbody was not sil I may not have had condensation at the foot. However, the material of the underbody shouldn't affect the location of condensation pictured above---it would have happened there if the underbody had been DWR 1.1 oz.

So the take-home message for me from last night was
a) no sore left knee!
b) Fix the hammock sock head end to fit v0.3
c) it wasn't completely crazy to use sil as the underbody. The jury is still out on that though.
d) I should try using wing pads with a Speer SPE (which I have) and put that between the hammock bodies.

well I have a day job to attend to...

Grizz

[kohburn]

so do you have plans (measurements mostly) that would help another DIYer to duplicate your results?

[GrizzlyAdams]

so do you have plans (measurements mostly) that would help another DIYer to duplicate your results?

there's The Guide, although that's dated.

To make what I just did you start with 53" x 82" of 1.9 oz ripstop.
You hem the short ends (I've allowed for an inch, probably too much.
You cut a parabola 6" deep on the long sides. The Guide gives a table you can scale to give waypoints on the cut. The Guide describes also rolling the webbing into the cut edges and sewing. You put SMC rings on the webbing, snug up against the end of the hammock.

I'll have to write up how to use hiking poles as spreader bars.

It's a start for you.

Grizz

[Jazilla]

Grizz, weight of v0.3?

[GrizzlyAdams]

Grizz, weight of v0.3?

Without the underbody (or still to be added endcaps) the walk into the woods, hang it up, and have a nap weight is 21.5 oz.
Add the underbody to get to 27.3 oz.

Here's how I get to those numbers
2 6' long pieces of 1" wide OWC camo webbing to anchor to tree,
+ 2 nanowire biners (can lower weight with Dutch gizmos, and do,
but those are someplace else right now) 4.8 oz

"top" suspension line : 2 SMC rings and cord between them measuring distance between endpoints where the hammock connects, lines from rings to biners at tree 2.9 oz

hammock body, including corner rings and webbing on them for securing hiking pole head, caps for hiking pole tip, suspension lines, HRM twice with four holes in her head (to connect to SMC rings on ridgeline) 13.8 oz

underbody and minibiners for attaching 5.8 oz.

I've not added in the weight of extra dowels in my hiking poles. They are semi-permanent. I'll be putting endcaps in, this will add perhaps 1 oz.

I'll re-weigh after adding end-caps (with a built-in pocket I think), and
weigh the hammock sock after I've made the mod needed for v0.3.


Grizz

[hangnout]

To make what I just did you start with 53" x 82" of 1.9 oz ripstop.
You hem the short ends (I've allowed for an inch, probably too much.
You cut a parabola 6" deep on the long sides. The Guide gives a table you can scale to give waypoints on the cut. The Guide describes also rolling the webbing into the cut edges and sewing. You put SMC rings on the webbing, snug up against the end of the hammock.

So the narrow part of the hammock is about 38"? I think I have decided to jump into this project and will probably have some "dumb" questions

[GrizzlyAdams]

So the narrow part of the hammock is about 38"? I think I have decided to jump into this project and will probably have some "dumb" questions

Your figuring follows the right principle. Before rolling the webbing the narrow part is 53-12=41 inches. The webbing roll takes up 1.5" (but the last 0.5" of that is webbing, which "counts" as far as width), so I'd call it 39" wide.

ask whatever. No such thing as a dumb question.

Grizz