Parallelogram Hammock

[geneaut]

My advice is get some 'beater' fabric to test ideas on. Make a rectangular hammock from your Hex70.

[hiroshima1320]

That's exactly what I did. I'm glad I didn't ruin some $10+ a yard material. At $10.50 for 7 yards of material, I feel the knowledge was worth the price. I'm not entirely sure where the problem is, but I think I'll buy some more "beater fabric" as you so eloquently put it, and make a regular rectangular hammock. I'll try to get the exact same material so t my testing is a little more precise. I'm thinking about doing another trial version that is a half bridge, with the spreader bar at the head end. It may be a horrible failure, but we'll see.

[wa4chq]

As always I had floppy side edges by the feet and shoulders.
My first idea was Knotty mods but then I remembered something I have tried before (idea i got from Xtrekker) bar tack the edges over the ridgeline. First I tried it with a safety pin and it did the job.
]

Have you tried just whipping the ends and pulling the floppiness out? I whipped mine and don't notice a real problem with floppiness.

[wa4chq]

OK, yesterday afternoon I set up the PH and tried it with the UQ. Because of the angle of the lay, it does not feel as good as with my other reg. cut hammock. I made some adjustments to the UQ suspension and got it a little better but didn't have much time to work with it. The first thing I noticed was the UQ caused the dreaded calf ridge syndrome. After making small adjustments, the c.r. was reduced but the area down by my feet were in a floppy mess. Up by my right shoulder, the UQ was high and falling over me a bit....that part I didn't mind as much as the foot problem. Sorry, no pictures. I'm thinking that a pad may work better, esp. if it's full length....
Neil

I solved the UQ/calf ridge problem...my 3/4 UQ needed to be moved closer to the head end of the hammock, placing the foot end of the UQ more under my butt then across the back of the calf's.

[Snowball]

Have you tried just whipping the ends and pulling the floppiness out? I whipped mine and don't notice a real problem with floppiness.

No, i don't use the whipping method always channels. I have tried to shorten the edges by doing a mod on the channel ends but not on the Parallelogram hammocks i have made.

[wa4chq]

The PH was the first time I used whipped ends. I like it.

Sent from my XT1031 using Tapatalk

[LowTekk]

*Eyes pop from their sockets*

Start-Screaming.jpg

I just started on here and you guys are designing a hammock with everything but a Flux Capacitor! Before we know it we'll all get zapped to a parallel universe where we string our trees to hammocks with rocks and the clouds are made of ripstop nylon... *rocks in the corner and whimpers* where's my woobie?

Seriously though, you guys just tied my brain in knots, but man oh man, do I wanna know how this experiment turns out! Subscribing to this one!

[wa4chq]

Hey Lowtekk.....I still enjoy this hammock. I've opted to use a SRL but not the one shown in the picture. I'm now using a UCR for the RL. I've made a few minor adjustments to the whipping to reduce some of the fabric flop...I don't use or need a knotty mod with this hammock. I think a real test would be to make a regular hammock the same length and width and whip the ends and see how it feels along side this one. My other diy is regular cut but longer and has gathered ends and a knotty mod....
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[WillUpnDown]

I've been fiddling around with the idea of a parallelogram hammock. My early results are similar to what Meckelangelo reported at the beginning of this thread. (I was unaware of this whole discussion until just a couple of days ago.) He did some really good work. None of the really great stuff starts out a success.

Initial test results from my parallelogram hammock experiment.
Fabric 1.9 ounce ripstop 72” wide 1” seam. Angle offset 20° (2.2’ by simple trig. I did find that using two side measurements are easier than using angles. Meckelangelo used a 30" baseline.)
Test set-up: I laid out the fabric on what I call my sail-loft tables. Using one edge of the fabric as a straight edge I confirmed that Ripstop by the Roll makes nice 90° cuts, and I measured for my diagonal. My goal was a right-orientation lay, meaning laying face up my right arm is at the edge--I think this follows the convention here.
I then divided the line into 12 steps (6.5") to use on a spreader-rig I didn't use. I did use these marks to WWW fold the fabric for whipping.
First test. Fabric 13’ from whipping knot to whipping knot. This makes a huge hammock.
I think my suspension was about 30°. No ridgeline. What I noticed immediately is
1. a large wall of fabric rises on the opposite side of the lay (to my left). There’s a lot of loose fabric along the edges near my head and feet. A Knotty Mod would be perfect to constrain this, but I don't think it would modify the tension.
2. My lay angle looked very steep. Maybe 25-35° off axis. (Angles are notoriously difficult to visually eye-ball close to the same plane).
3. A really nice flat lay was very easy to achieve.
4. It is possible to lay opposite, but it seemed like my left (outside) arm just wanted to flop out. The fabric seemed a lot shorter head to foot. I was able to make it work....but it was fussy and not at all practical.
Next test.
I improved my whipping and connections. And I shortened the length between whips to 10’. This is based on the wide spread reporting that 11 foot hammocks are very comfortable. I figure 10 feet would amplify any problems. I think it did.
This time my hang was inside in my living room, my suspension angle was closer to 45° ( For safety I didn’t want to get too high off the ground. I realize that every element was something I’d done, the whoopee-slings, soft shackle, whipping, even the screw eyes...)
1. I got what seemed like a good lay, but there was a torque from the steep fabric on one side. I shifted around and this went away.
2. I don't know enough to know if I had a calf ridge, etc... Could I fall asleep in it? Maybe. Yesterday's 13' length--absolutely.
Result. Maybe hammocks should have a dead-center spot marked. Then users can either butt-aim for it, or butt-aim for the off-center spot that results in the most consistently comfortable lay for them.
2. Problems were amplified as predicted. Slight changes had significant results mostly negative.
3. Trying all four lays, the right-lay (as designed) from both directions and the left or opposite lays. Oddly the second right lay didn’t seem to work. The opposite lays had the arm flopping out problem.
4. Slight moves would put pressure on my shoulder or feet.
Results
1. I don’t know enough to be able to consistently repeat a result. Hammocks are surprisingly complex. This is being aware of what I don't know.
2. I do think that parallelogram hammocks raise a lot of interesting possibilities. The initial hypothesis is: A rectangular hammock has a ‘natural straight lay’ perpendicular to the axis. For practical reasons users compromise with a diagonal lay and this can work just fine. By shifting the fabric with the parallelogram cut, this will shift the ‘natural straight lay’ by the same angle as the cut: In my test 20°. This should allow for a diagonal lay that is flatter than is possible with a rectangular hammock.
This last point is simple geometry. However, it applies for a line, not for a plane. A rectangular hammock will have a flat lay for a plane, but shifting the sides to a parallelogram introduces torque (pressure) which is experienced on the feet and shoulders. Slight changes of lay angle increase or decrease this.
3. For the 10’ variation a Knotty Mod should be about 4’ long. Also if parallelogram hammocks prove to be useful, than the ‘wall’ opposite the lay (for me to my left side) would be a great place for gear pockets--or a window.

For future: Hammocks can be absolutely fool proof, the flexible and comfortable Mayan hammock is a perfect example. Or they can be tricky: Most are in someway a compromise, especially short hammocks and possibly other non-standard designs. The thread on Hammock Forums on Parallelogram hammocks I thought was full of dismissive comments. I think there’s a lot of really good thinking in the community, it’s why I’m so interested. Hammocks can be a real puzzle. (I loved those weeks I simply could not grasp the footbox or the Knotty Mod, knowing that eventually it would click and it would be nearly impossible remembering what it was like to not get it. It can really help future learning to understand how that light bulb eventually goes off. I will stay as dumb as a brick until I get it.)
There’s a reason we have the hammocks that we have, but there’s no reason we can’t develop hammocks that are like sleeping weightless in space and weigh less than a pound.
For now I think I’ll give this experiment a rest. Get more experience, go camping--there's snow out there! What am I doing in Los Angeles? I also need to finish my professional work..... (No money no hammock camping. It’s probably more like ‘no money, only hammock camping...’)
We have the hammocks that we have is because the basic design is so simple, the physics are incredibly favorable to the task, and they generally work pretty good. Making them better or just different, I think we all agree is a lot of fun.
Will

[Ragabash]

Just a thought, but could the difference in lay simply be (or at least in part because of) a width difference? Let me explain.

Take a 14 foot piece of fabric and say it's 5' wide (for easy math) cut it on a 30 degree diagonal, and the end "width" when you sew a channel is (5/sqr(3))*2 feet, or over 5'9". The length would now be just over 11 feet (before sewing the channel). Even if fabric cut and force coefficients and flux capacitors had nothing to do with it (I'm sure there is something else going on), and it was for all intents and purposes a rectangle, that width change would significantly change the feel of the lay and shoulder squeeze.