The Cowboy String Theory Lightweight Bridge Hammock w/ Integrated Net

[kitsapcowboy]

More than a year ago, I made my first DIY bridge hammock, because I thought the available vendor options weren't quite right for me, and I was inspired by the elegant lightweight ones GrizzlyAdams had developed; I found out I really liked bridge hammocks and some of the advantages they can confer to your overall backpacking loadout at certain tines of year...

https://www.hammockforums.net/forum/...rizz-Inspired)

Then I tried to push the envelope and build a simple, trailworthy ultralight (6-ounce!) bridge hammock, which taught me a lot and turned out really well...

http://hammockforums.net/forum/showt...-Beta-Version)

After a couple of builds of both the Rope Bridge and Web Slinger DIY designs, I came upon my current DIY bridge hammock design, which adds an ultralight integrated stowaway N550 bug net (similar to Derek Hansen's HUG bug net, but built-in like on a Dutch Half Wit) and combines what I consider to be some of the very best features of both the Rope Bridge and the Web Slinger -- in terms of both construction and performance -- and comes in at a very svelte 9.5 ounces! Made with lightweight, low-stretch RBTR ROBIC 1.0 fabric, it's good for hangers up to at least 200. I call it the "String Theory", owing to its Dyneema cord suspension and the fact that when I started cutting and stitching it I had only a vague notion of how I wanted to evolve the design from previous iternations. I pretty much engineered the whole integrated bug net thing on the fly (thereby violating one of my most fervently held design principles), but I was very happy with how it turned out.

Here is my result...




Type: Single-layer lightweight end-bar bridge camping hammock with integrated bug net and Amsteel suspension
Materials: 1.0 RBTR ROBIC XL ripstop nylon, 0.5 oz RBTR N550 mesh, 2.25" poly grosgrain ribbon, 7/64" Amsteel Blue, Mara 70 poly thread
Dimensions: 80" long, 48" arc length at head/foot, 32" wide at center, 36" spreader bars at head/foot
Weight: Hammock only approx. 7 oz; hammock w/ integrated net 9.5 oz (270 grams); hammock w/ net and Dutch spreader bars approx 19 oz

The basic shape and construction of the bridge hammock body on the String Theory is very much the same as my original Rope Bridge, completely symmetrical along both axes, albeit built from much lighter fabric. The 7/64" Amsteel suspension is contiguous with the dog bones of the suspension triangles at each end of the hammock, so three pieces precision-spliced together run 145" apex to apex on each long side.

Amsteel is relatively light and relatively inexpensive compared to the other common bridge hammock suspension components one might choose; it is also fairly easy to splice. However, it does require a strong channel to affix it to the body of the hammock. In his various bridge hammock engineering videos (including the one for the GrizzBridge Ariel), Grizz shows some fairly elaborate methods for creating a folded and layered lightweight nylon channel to enclose the cord suspension. When I created my Rope Bridge I substituted a simple channel of wide grosgrain ribbon folded around the Amsteel and triple stitched, adding some weight to gain expedient construction of this critical structural component, as well as some long-term trailworthiness. I used a narrower 2.25" ribbon on the String Theory to reduce the weight penalty of the ribbon channel by 25% with little disadvantage over my previous method.

The end caps are the same quick and dirty parabolic shape as on my previous bridge hammocks, but they have been simplified to a single layer of the same fabric as the hammock body. A retention loop for the bug net and an additional loop for a pillow tether, both made from gutted paracord, were sewn into the seam for added functionality.

The bug net is permanently attached to the head end cap and suspended from a self-adjusting ridge line (SARL), another feature that came about during the evolution of the Rope Bridge. With a double-strand shock cord section at the end, attached via larkshead knot to one of two terminal fixed eyes, the 1.75mm Dyneema SARL automatically adjusts from 126" to 133", staying taut when the hammock is unloaded, when the occupant is sitting in the center, or when the occupant is fully supine in line with ridge line. The 54" long bug net's head end apex is suspended by one shock cord Prusik loop and its centroid is suspended from from a second Prusik using a length of of shock cord with a cord lock run through a well-reinforced grosgrain patch. Mitten books allow for quick deployment and removal of the net from the ridge line. This system lets you adjust the position, height, and drape of the net good enclosure while accommodating various positions (for lounging, sleeping, or reading) while occupying the hammock. There is plenty of space within the net, which stays well up off one's face while still sealing well at the draped edges to keep biting insects at bay. The net rolls up out of the way and secures at the head with the same mitten hook that fastens it to the ridge line.




Entry and exit from the netted hammock is really easy... Because of the ridge line supports and corner anchors at the ends of the head-end spreader bar, the "no-fly" zone underneath the net can be easily maintained while hammock is empty, and your adjustments to net position are conveniently maintained when you flip it up to get in and out...




Just as actual string theory in the realm of quantum physics is criticized because it fails to provide satisfactory answers under certain conditions, it should of course be noted that this lightweight integrated-net bridge hammock is not a one-size-fits-all solution to hammock camping; however, its design -- or elements of it -- may resonate with some members of this community looking for the same advantages and features I was seeking when I built it, and so it is presented here.

One final note: a grateful tip of the hat to GrizzlyAdams for pioneering and popularizing the use of Dyneema cord for bridge hammock suspension. His valuable work over the last decade has helped put this interesting class of hammocks in reach of DIYers looking for something different from a typical gathered-end model that compares favorably in weight, packed size, and comfort at a reasonable cost for the project.

This prototype is now on the way to a friend down south for some summertime field tests, and another String Theory hammock is in the works for use later in the year. This is a design I will continue to enjoy using and updating in the future...

More to come. Please feel free to comment or query below. Thanks for reading this project report.

[Edited to add: Photo links fixed.]

[rweb82]

It seems like half of your posts the pictures won't load for me. Dang it! I want to see this thing. Is there a trick to getting them to load?

Sent from my Pixel XL using Tapatalk

[Otter1]

The WOW doesn't stop coming from you, does it??? Great hammock.

[kitsapcowboy]

This DIY project report was submitted to this forum for ENTERTAINMENT PURPOSES ONLY. Use any methods, ideas, or inspirations contained herein strictly AT YOUR OWN RISK. I accept no responsibility whatsoever for any injury or harm that befalls others owing to information presented here, and I accept no responsibility for any errors the post contains.

I do not in any way advocate that others should do anything I have presented here; this thread is strictly DOCUMENTATION OF FACT. Readers beware.

There is a lot of great information on Hammock Forums available from members with much more substantial experience, better ideas, and better methods than mine. SEEK IT OUT.

Thank you for your attention.

[kitsapcowboy]

The WOW doesn't stop coming from you, does it??? Great hammock.

Many thanks, Otter

It seems like half of your posts the pictures won't load for me. Dang it! I want to see this thing. Is there a trick to getting them to load?

Hmmm... Don't know. They show up fine for me. I hope it works out for you eventually...

[TallPaul]

How are you suspended?
I see what looks like a 4x4 at an angle on one side.

And bridges don’t work for me but kudos on pushing the envelope. Great looking design.

[kitsapcowboy]

How are you suspended? I see what looks like a 4x4 at an angle on one side.

That's the typically overbuilt swingset support attached to my daughter's elevated playhouse. It's part of a 14-foot tall cement- and metal-reinforced A-frame play structure, and I think it's sturdier than my house...

And bridges don’t work for me but kudos on pushing the envelope. Great looking design.

Thank you very much.

[ObdewlaX]

Impressive... really!

Throw an ultralight tarp in with that & it'd be a gram weenie or ultralight/light backpacker's wet dream! What am I saying? It is! Looking forward to hearing how the field trials go & a write up.

Did I mention, impressive?

[kitsapcowboy]

Impressive... really! Throw an ultralight tarp in with that & it'd be a gram weenie or ultralight/light backpacker's wet dream! What am I saying? It is! Looking forward to hearing how the field trials go & a write up. Did I mention, impressive?

Many thanks.

I've spent a total of 12 nights in this prototype. I'm 6'2" and 175 lbs. I've settled on this bilaterally symmetrical shape as the ideal shape for me in a bridge hammock. With a finished waist 32" wide at the midpoint, there's room to move around or side sleep. The 3:4 spreader-to-fabric ratio at each end, I get a hammock that virtually eliminates shoulder squeeze without being too tippy. I get plenty of space down by my feet without feeling cramped at the head end, so I don't feel compelled to investigate the use of either a shorter foot spreader or a wider head spreader, and I don't need to differentiate which pole goes where. The String Theory in the very supportive 1.0 oz ROBIC is sufficiently firm to be about as comfortable as my original midweight Rope Bridge with virtually the same dimensions, and the fabric shows no degradation at the critical points along the edge where it is sewn to the grosgrain channel, in the corners and at the midpoints of the cat-cuts on each side.

Seated in a transverse fashion biased toward one edge, the String Theory is also pretty comfortable for lounging with reasonable back support, when pitched at a proper sit height. The grosgrain provides suffiecient buffer from the Amsteel behind the knees when using the hammock as a chair with your feet on the ground.

[HandyRandy]

I really like how you solved so many of the problems that come with typical bridges! It’s lightweight. It’s easier to setup with the symmetrical shape. It has a ridgeline. It can be used in chair mode. Less shoulder squeeze, more foot room. I love it.

So do you like to lay with your head opposite the netted end when you don’t plan on using it?

Suggestions:
Use internally spliced shock cord for the ridgeline so it’s more structural. Or do it like Jeff Myers demonstrated.
https://youtu.be/dVVpA_AJb5M
https://youtu.be/RQCqE4HiL40

Maybe use some velcro on the net and body around the elbow to help spread it out further down.

Make the hammock fabric double layer by the head end, so that the netting could be stored between the two layers. This should also provide you with a nice storage pocket for lots of other items when the net is deployed.

Add extra padding in the middle of the arc on one side for a more comfortable for chair mode. Then add a saddle bag on the opposite side that can be flipped inward, which could serve as a pillow pocket to hold your pillow in the perfect spot. Since your arcs are centered, this should work out well. You’d have yourself a hammock that excels in chair mode!

Use carbon fiber spreader poles to match the lightweight design of the body.

Are you going to sell your older bridges?