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  1. #21
    Syb's Avatar
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    Tim is correct, thanks for the clarification and sorry for any confusion folks. The channel I sew would NOT be strong enough to support someone as I use the same method as Knotty's.
    Syb
    Enjoy the elevation

  2. #22
    MAD777's Avatar
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    All is well. No confusion on Syb's method after he explained that the channel was 1/2". I knew he was talking about a Warbonnet style end.
    Mike
    "Life is a Project!"

  3. #23
    WV's Avatar
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    Quote Originally Posted by DemostiX View Post
    Several interesting things here.

    First, we can be very wrong about materials. If nylon, channels, and contemporary polyester thread were not strong enough, we would not see commercial vendors making hammocks with them. There is no reason to expect intuition about which are strong and strong to what. For example, I couldn't believe that so much rope was being carried on rope until I read about sailing usage, and further that Dyneema (tm) and similar can have no better chafe guard than more of the same, it is that chafe resistant.

    Second, I'll bet there is no predictability on the way the nylon fabric find will behave under the kind of load we apply, and our loads in particular. We don't know what we have, beyond one or two parameters. You need only to look at stretch vs % load curves for rope of different materials to see that. This accounts for such variation in experience, for example of discomfort with the edge. The more reason, I think, and a very strong reason to be able to adjust what you've made to your needs.

    Third, I would much appreciate learning more what you've learned from your multiple whoopie strings along the edge that allow you to shape the effective arc of the end channel and tune your bed.
    Good points. My guess that multiple channels wouldn't be strong enough by themselves was just a guess. It didn't take into consideration the materials that might be used.

    The way I reinforce my edges so I can attach smaller lines is to put a 1/4" hem in the edge, just folded under once, then fold the material (typically 1.9 oz. ripstop) over about 2". I stitch the edge down with a single line of stitches, spaced as far apart as the PTI permits. If I have borrowed my wife's machine I use a zig-zag stitch. Then I cover the folded edge with a 2" wide piece of stronger material, such as Dyneema reinforced pack cloth and sew it down with two rows of stitching about 3/8" apart. This leaves a channel about 1/2" wide that's formed by the ripstop covered with the pack cloth. Then I sew in a zig zag pattern (not a z-z stitch) from the edge of the channel out to the edge of the doubled ripstop and back, spacing the peaks of the triangles about 3" apart. All of this is intended to put multiple lines of stitching reinforcing the channel with the needle holes as far apart as possible, and some of the stitching (the large zigzag) oriented to give maximum strength to the forces that the lines exert on the fabric. The I run a larger cord - either 5 mm utility cord or 7/64" amsteel - through the channel and fasten the ends somehow (depends on individual hammock design). Then I put holes through the channel next to the larger cord with a small soldering iron. These holes are spaced every 3" near the zigzag peaks.
    Then I add the small cords. These have been hollow-braid lines, either 130 lb. Spectra, 120 lb. Kevlar, or 150 lb. Dacron. They go around the heavier cord in the channel twice and are spliced with a locked Brummel at one end and a whoopie sling at the other. (I'm not suggesting that any sane person would follow my example. It's a lot of work to make 30 or 40 miniature whoopie slings.) Here's a picture of a way of using a bungee at the edge of a gathered end hammock (untested - it was just something I suggested to Knotty). You could simplify tests of an adjustable hammock by cutting out a corner of the hammock fabric - maybe 12" x 24", reinforcing the 12" edge and the corner, and using just 4 small cords spaced 3" apart. The first one would go where the green bungee is shown in this picture. (In fact you could use a bungee for the edge cord - it pulls tight enough to keep the edge up when you're lying in the hammock, but it stretches so you can sit comfortably without the fabric cutting into your legs. I use bungees for the edge cords of my adjustable hammocks.)]

    Now, what have I learned? Lots, but adjusting the whoopies is something to be done carefully, with the assistance of someone to lie in the hammock while you work. There's lots of getting up and lying down to be done. Enlist an assistant - I've tried bags of dog food, but a live body is best (a person, not a dog - tried that, too.)

    Feel free to use these methods for your experiments, but please post any results (good or bad) so others can benefit. Also ask questions if they come up. I'm happy to help if I can.

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