Yes, getting into this DIY compulsion one of the things I didn't figure I'd ever need to make myself was a tarp. Then came the new Dave Womble model with doors, and now yours with an integrated bugnet....
packs. That's it, I'm drawing the line. I will buy a pack, not make a pack.
(wonder how long that will last...)
Grizz
Originally Posted by dblhmmck
Sounds good Grizz, and like yourself, I don't know where this DIY obsession will end. I am amazed that we are all finding so many fascinating approaches to check out, especially when our explorations appear to be going in parrallel.I'll be making silnylon end-caps, and will sew them in. These will drop from the spreader bar level down to the edge of the fabric. At the bow end I am wider, which means that a lot of the fabric spread is used to make the "floor" beneath me. At the stern end we have only my comparatively narrow feet, and so the "floor" of the hammock is narrower. The shape of the edge of the fabric is therefore pretty different at the two ends. To accommodate this I'll use a flatter shape for the endcap (an ellipse) at the bow end, and a narrower shape at the stern (a parabola). Given a 36" spread over a 60" body, the height difference is noticable---an ellipse is 20" high while a parabola is 27.5" high. All other things being equal, that means that the floor of the hammock will tend to slope down, if the ends are hung at the same level. I could fool around with the body cut (dblhmmk does this), but I'm not sure right now what I'd do, and I think I can raise the stern end a little through the suspension if that's what I end up wanting to do.
Anyway, you mentioned hammock body shapes, and yes, I have tried out a few variations. But I want to say, I have gone back to a tapered rectangle for my hammock body shape. The primary reason for me is, the material that extends out laterally beyond my suspension lines makes a better attachment place for a zipper. It also helps a bent knee stay contained inside when the hammock is cut shallow.The zipper problem is only MOSTLY alleviated, while problematic areas still remain at the two ends closest to the lateral support lines. I am addressing this by installing two sepparate zippers; one verticle around the shoulder, one horizontal that doesn't need to extend much beyond the knees.
End caps for my hammock are now very different at the head and foot. I have a very low spreader bar at the head, and I find the end forms a very shallow parabola.
Onto this hammock body and end caps, I've sewn my tarptent-like hammock top. Drawing attached:hammock4.jpg
I have been making some changes in the first prototype of the bridge hammock. I think that I have found the size and shape of the hammock body that will work. Material for the body is Walmart 3oz nylon. I have not ordered the material yet for the final version.
I plan to make an under quilt for the hammock. However, I would like to have a pocket under the hammock body for a pad. I was thinking of using two layers of 1.1 oz. nylon for the body. That would make hammock body 2.2 oz/yd. That would not be much more weight that the 1.9 oz fabric.
I am concerned that this will not work. If the two layers are the same, then the load on the body of the hammock would be shared by both layers. If I put the pad in then I think that the bottom layer will carry most if not all of the load.
I went out and used a 5/16 pad for the measurements. Distance from support webbing to the other side of the support webbing at the hips was 33.25 inches with me in the hammock. I then placed the pad between the tape measure and the hammock body and measured 33.75 inches.
That made about one half inch difference in fabric width. As of now I have not thought of a way to share the loading on the fabric with and without a pad.
Comments?
Yea walking bear I'm not sure of the 1.1 for the body, even if you double it.
I think it's a personal decision but I just don't think the stuff gives you much of a buffer for failure. You could make the bottom layer 1.9 and the inside 1.1 to save weight. I have fumbled with the idea of 1.9 with a silk inner lining.
Personally, I really don't like the pad in the hammock with me. Yes it's better in a double hammock, but I still prefer having it come from beneath and cinched up.
As always, these are personal decisions.
Scott
"Man is a stream whose source is hidden." RWE
I noodled around the idea of a double layered bridge a while ago, but dropped it once I saw an idea Scott had for an adjustable underbody.
It is so dang easy to take a rectangle of 1.1 fabric and suspend it beneath the bridge, pulled up at the corners, and put a pad in there first. For a pad that doesn't compress, you just bring the fabric up flush. You can drop a quilt down there also, now you need to be more careful about compression, but Scott worked out (and I adopted) an adjustable undernetting that you can raise and lower easily while you're in the hammock.
You pay a weight cost over the 2 layer 1.1 oz approach, but gain a lot in flexibility.
But you know all that already. So, taking the 2 layer path as a given, I don't see why the bridge should be fundamentally different from another hammock w.r.t. the two layers sharing the load, with the pad inside, or not. I would guess, as you are, that you'd want to cut the outer shell a little larger.
BTW, these hip measurements must be when you're using the side pull-outs, yes?
Grizz
No side tie outs. It was from the support webbing down under the hammock and back up to the other side. Straight accross would be much less. I was wanting to see what the difference in width of the fabric would be.BTW, these hip measurements must be when you're using the side pull-outs, yes?
Grizz
Got it. Went past that part of the post too quickly. I should have
recognized the scale of the numbers...take a foot off each side of a 5' wide piece of fabric and you get about 3'.
it's been a long day, with a couple of long stupifying meetings (predictable from my many posts today).
thank goodness for wireless, and a general acceptance of multi-tasking in meetings.
Grizz
I plan to make an under quilt for the bridge hammock. My current thinking is that I will use insulation between two layers of 1.1 oz nylon. I plan to cut the bottom layer several inches larger than the top layer of fabric. I will then quilt the two layers and the batting. I think that I can then tighten up the under quilt so that the top layer is tight without compressing the insulation because the bottom layer of fabric will not be pulled by the quilt suspension. When needed a pad could be placed between the under quilt and the hammock.
I'm retired so ended all of those meetings.However, the church has a few for me.
I made a hammock with 1.1 nylon body. To compensate and give additional strength, I sewed 4 straps of 1" grossgrain ribbon across the width. One was at the height of my neck, one at the waist, one just under the butt (about 13" lower than the waist), the final one was placed at the knees. I felt like the middle two would be especially beneficial since it is the area of greatest weight (and stress when entering or exiting). I admit I don't know as much about fabric strength as much as some folks around here, particularly Warbonnetguy, but I thought I'd throw out the suggestion. Any thoughts from the engineers in the group?
These photos show the black support straps This one from the inside.
Last edited by dblhmmck; 10-02-2007 at 19:17.
Walking Bear,
I'd say that its not entirely necessary to share the load with and without the pad... even using 1.1oz fabric... I weigh about 180 (up and down a bit either way from there.) With 1.9 I can put my hand down and lift my body weight against the fabric of my hammock to shift my body position. Thats pretty serious point loading. As an example the spinnaker cloth (.75oz) that I was looking at has tear strengths on the order of 40-50 lbs per inch. Thats pretty strong. You can probably get an idea of the strength of the fabric you want to use by cutting a strip say 1" wide and loading it until it tears/breaks or stretches so much you consider it "unsafe". That would give you the lb/in number, to be safe use half or a third that in your working out if you think you need the extra support.
Personally with my climate I can't really imagine ever wanting to use a camping hammock uninsulated in some way. Lounging ones, maybe... But if I plan to sleep overnight in it, it'll need something on the bottom.
I'd just cut the half inch differential and I'd be surprised if the top layer doesn't stretch to make contact with the bottom layer when there's no pad.
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