Webbing based recessed bar bridge

[Peabody]

Hi all,
I’ve just finished my webbing based recessed bar bridge hammock based on the Ariel by Grizz. I used double layer Hexon from Dutch (1.6 outer and 1.0 inner layer). The webbing is Dutch’s Spider 1.5 - I used a binding foot to attach it to the edge before turning it in and sewing like a BIC/Hiking Dad design.
I used a soldering iron to cut out the two layers at once. I attached them to a piece of sheetrock with some thumb tacks. This made cutting the fabric much easier and had the added benefit of melting the two layers together. The dimensions were the same as Grizz’s Ariel except the width, which was exactly 2 inches wider to account for the rolled edge. The two illustrations were taken from Grizz’s engineering the Grizz Bridge Ariel video.
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I had to round the 4 corners where the cat curve ends to allow for binding with the webbing. I also cut some reinforcement patches from 300d pack material for the corners and attached it with seam grip adhesive, making those corners extremely strong. Here’s some pics of the rounded corners and the reinforment along with my spreader bar recepticals made from spider 1.5.
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Here’s the completed hammock with dog bones attached. I made the suspension legs of the triangle to be 32” with 36” spreader bars (21.5” dog bones with 10.5” distance to webbing loop from spreader bar attachment)
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Here’s me enjoying the fruits of my labor - thumbs up!
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Thanks to Just Bill, Grizz, WV, and others for helping me out with some great advice!

[FJRpilot]

Great job! That a really unique solution for the spreader bar attachments. Very creative. Did you leave one end open so you could slide in a pad?


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[Peabody]

Thanks FJRPilot, I read your ariel bridge for a bigger guy thread a few times. HF is such an awesome resource.

The spreader bar attachment was a little too time consuming. When I do another bridge, I’ll probably make it a hybrid with the connection point of the amsteel and webbing at the point where the spreader bars connect. This will save the effort of fabricating a spreader bar receptical as I can just larks head the amsteel to the webbing with the spreader tip in between.

Yes, I hemmed the outer layer separately. So I can slide a pad between the layers. I actually like a pad with a two layer bridge because 1. I find it comfortable and 2. It gives me a go to ground option in a pinch.
I made the 1.6 the outer layer because if I use a thick pad, the support from the inner layer is basically eliminated, so I wanted a strong outer layer.

[tightwad]

I love the solution of using the sheetrock and push pins!

[GrizzlyAdams]

Nice new approach to the corner. I spent more effort, more ways, with different approaches to the recessed corner. Cut-outs of various kinds, re-enforcements, always the pain point of the design. Given the delicacies of spliced cord lengths which Just Bill in another thread has described most ably, the next thing I'd try resembles what you described. I'd see if I could do webbing on the sides with loops, have an opening to that loop resembling what I did with my reported Ariel build, and cord from there with a larks head. You pick up weight obviously using webbing rather than cord, but the build will definitely be more straightforward

[Peabody]

Thanks Tightwad and Grizz!

Grizz, I’ve actually already designed the template for the hybrid you described. With Dutch’s new spider 1.5, the weight is only 1.5gm/ft, basically eliminating the weight penalty - but it’s a little pricey. I’ve gotta wait the mandatory 1 month wife-approved waiting period to start my new plan though.

[Just Bill]

Nice new approach to the corner. I spent more effort, more ways, with different approaches to the recessed corner. Cut-outs of various kinds, re-enforcements, always the pain point of the design. Given the delicacies of spliced cord lengths which Just Bill in another thread has described most ably, the next thing I'd try resembles what you described. I'd see if I could do webbing on the sides with loops, have an opening to that loop resembling what I did with my reported Ariel build, and cord from there with a larks head. You pick up weight obviously using webbing rather than cord, but the build will definitely be more straightforward

Thanks Tightwad and Grizz!

Grizz, IÂ’ve actually already designed the template for the hybrid you described. With DutchÂ’s new spider 1.5, the weight is only 1.5gm/ft, basically eliminating the weight penalty - but itÂ’s a little pricey. IÂ’ve gotta wait the mandatory 1 month wife-approved waiting period to start my new plan though.

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If one is willing to do a double layer as Peabody has just done.. this might hold up better. But essentially this is the webbing edge to dogbone hybrid.
However you can see the lines of force developing here. Could it be cleaner, probably. Do I know how... I might.

Peabody's reinforcement patch may be good as well but one issue with reinforcing a corner is then you move the force to the edge of the patch and that can tear out too.

As I mentioned elsewhere; the absolute lightest is usually where I start. So some of this can easily be solved if you're willing to simply employ heavier fabric and underload it.
Using 1.0 robic to hold 200 lbs without blowing out at the corner or the middle is a different conversation than using double 1.7 fabric to hold the same 200lbs. So to an extent that is a simple solution.

Peabody- one issue with rounding the corner is that while it does improve your ability to turn the corner... it also reduces material in that corner. If you are familiar with gusseted crotch or articulated knees used in active/hiking pants you'll find that the solution to high stress and/or binding areas is to add material. (similar to the way Grizz added triangles to this joint) So using some micro darts/pleats would ultimately be the better way to both turn the corner and provide relief without introducing more seams. Grizz and WV likely remember the bridge that was made via a series of pleats only... neat idea. The mildly unfortunate problem with this solution for a recessed bar bridge is that you are 'turning the wrong way' in adding the pleats, so working this extra material into the pattern and having it lie properly once pleated is an issue. The articulated knee solution works for the knee cap side, not the back of the knee side basically.

The general problem with all webbing based bridges is that you fix the body to each stitch of the suspension. With the channel suspension over amsteel the whole bridge is able to float, contort, twist, and move to accommodate the stress as you change positions. This not only makes a lighter stronger bridge, but also a more comfortable one as it can deform to your individual shape. So I would strongly encourage you to try one in this style before you go too far down the rabbit hole. If nothing else so you'll have a point of reference to compare once your spousal imposed probationary period has expired.

Grizz- I still think you had the right idea with your ideas regarding using webbing/grosgrain to build the channel to speed things up. That was pretty well the immediate response from every sewing contractor who has ever looked at this style of bridge. Though I still feel you still have the problem of matching the stretch of dissimilar materials. Plus the button hole.

In that regard I might agree with Peabody in pointing to Dutch's new wonder webbing. These woven UHMWPE products seem ideal though the button hole remains an open question. I haven't gotten quite far enough to confirm but I suspect the Kevlar is 'out'. Once cut it seems the only clean way to stop it from unraveling is to fold it back upon itself and sew it off. It also distorts too much with the loose weave and I can't picture how you could slit the button hole without it unraveling overtime.

However the UHMWPE seems to strike a balance between the ultra tight weave of the standard webbing/grosgrain and the excessively open Kevlar. It is heat seal-able at the ends and should take a button hole. It seems that it would be flexible enough to both fold and turn the corners; while staying flexible enough to move with the fabric as it moves under load and position changes.

But getting it in a 3" width is not currently an option, and likely a pricey experiment to commission if the mill could even do it. And of course going to that size may produce more stability for the manufacturer, which in turn could create a tighter weave and defeat the point.

To me the only true difficulty in the project is the channels and attaching them to the body. That is by far the largest labor component once you get past the splicing, and the easiest to mess up.
I do understand the initial frustration of the splicing... but that is a problem easily solved once past the hump and really not a huge hunk of labor or a valid reason not to build the bridges.

[Peabody]

Bill,
I definitely see your point about stress lines in the illustration you gave. I wonder though how the corner of the material was cut before binding:A591B8A8-5093-432B-8167-1F0829BB0CA9.jpg
Sorry for the crude drawing. It seems that the top illustration would be stronger as the transition in the fabric would be smoother.
Also, is the channel is part of the body or separately attached? It seems it would also be a less stressful transition for the hammock body if it were part of the body. I guess I’m asking if it stands to reason that fewer corners = stronger construction.
Webbing based bridges like the Ridgerunner are proven, but that’s a bar end design. I do think I got lucky with my recently competed bridge, but the corners were really time conuming to fabricate.
The trial and error is kinda fun though- just wish it were less expensive.

[Just Bill]

The channel is added after: So if I follow, your sketches don't apply. You would be introducing more points of failure with no clean way to finish them.
The body looks more or less like the Ariel (I do my ends differently).

You roll hem the straight portion of each end first with no backing.
Then you roll web the cat cut portion with your webbing or grosgrain of choice.
Then the half inch webbing goes over that on each side before being tacked down. (as opposed to outside only as Brandon does.)
Finally you sew on the channels to each end with a minor recess off each corner. so you have room to add the dogbone, get the pole in, and then feed the dogbone through the channels.

End bar bridge with extensions but with no seams in the body. State of the art 4-5 years ago, lol.
Technically that's a dumbed down way to build an Faux Ariel. (sorry Grizz, I am not familiar enough with The Tempest to come up with something witty to name it).

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Hopefully that attachment works-

Rolled webbing end bar bridges work because they remain end bar bridges. If you look the RR has the same lines of force and tension on the material.
In this photo you can literally see them running from the occupant's butt to each pole tip.
Credit where credit is due; Brandon found a material that balances weight, structure, and strength to integrate it into his design.
His design also has some subtle engineering features that I will not comment on but at the end of the day it remains an end bar bridge.

As you recess the bar though;
You shorten bar to bar distance.
You increase the depth of curve relative to the length of curve.
You ramp up the stress as a result.
This is before you go nuts and really crank on the curve depth to pop the center of the bridge.

You also introduce a load condition not possible on an end bar bridge- loading directly under the bar. The actual line of tension is a few inches towards the center... not directly under the bar itself. Which is roughly where the bedspace begins. With the RR it's actually nearly impossible to lay with your head close to the bar so you never 'cross over' this line of tension allowing the fabric to better distribute it. Your head really doesn't want to go much past the saddle bags (for a visual reference), nor is the bridge designed to take it there.

The Ariel handles this by reducing the extension to either side somewhat. With roughly 9" of bedspace to either side of the bar for the most part you're laying your neck on the line of force and your relatively light melon just beyond it. About the same on the foot side where the ridge is just under your ankle and your heels are about the only weight 'out there'. Even this little bit though can cause wear. You can feel this line of tension formed where the body changes from rigid and then loosens as you cross it. On your bridge this spot should be about 3" or so to the center from a spot directly plumb to your bar. The 'natural pillow' effect some describe.

If you follow this to further extremes; The issues become more apparent.
My original micro had a bar to bar distance as small as 4' with 3' of body flying out beyond the bar on the foot side.
My current premium bridges allow the user to go roughly 20" beyond the bars.
While I don't advertise it or suggest it; you can actually sit on the edge of my bridge between the bar and the tree as well.
I do show that someone about my size can actually curl up in a ball and sleep in the very end of my bigger bridges directly under the bar as well.

If you looked from the side and thought of the pole tip as the center of a clock:
An end bar bridge takes the main line of force at about 4:00. For the most part this is a single line of tension that dissipates into the fabric.
While slightly off of the main rolled webbing edge- it is fairly parallel with the suspension.

An Ariel takes the force mostly from 4:00, with an allowance for a bit of force to be applied from 4:00 to roughly 5:30. (A primary load and a secondary load)
With the channel design, this also allows forces to transfer back to the suspension indirectly at various angles.

My premium bridges allow you to apply force from 3:30 to roughly 8:00 with the primary load allowed to arrive from any direction, and additional secondary loads to travel through as well.
While that is a concept that is difficult to explain to even hyper bridge nerds... here's a simple visual way to show what I mean.



That's a fun trick but what I did not show is that I can step over the bar with one foot on each side of the bar or even both feet on the far side as well.
Though liability concerns and outright silliness of it prevented me from filming that.

This is not an easy thing to follow. I'm no genius, just a carpenter. I do test exceptionally high in 3d spacial intelligence and that's basically what I do for a living. (model things in my head and then build them).
Bridges are along the lines of some of the insane oragami things you see. It's just a 2d sheet of paper (fabric) that you have to turn into an incredibly complicated curved shape that is also structural. Unlike oragami though you cannot(normally) fold or crease your way there but avoid any folds creases or wrinkles.

The pleated bridge was a notable exception wherin 3d space was created from 2d by folding and then relying on fabrics properties of reforming smooth shapes.
To an extent that's what the channel suspension does for you that the more rigid webbing edges cannot.

All that said- we are talking the limits of what can be done and very extreme examples.

Bic's bridge and WV's take complicated things and make them doable... that in itself is it's own level of genius.

Grizz distilled very complicated stuff into fairly complicated stuff so that enough people can follow it without diluting it too much. That's a bit why I discourage messing with it... you're getting a really high level design that few people in the world could have designed from scratch that solves problems that you might not even realize you have. It's like buying a Tesla... high price of entry but once you have it who really cares how it works.

Me- I just talk to much.

[TrailSlug]

Nice job on the hammock.