Just a short note before I go out again.
After much thought and experimentation, I have made some Bridge Hammocks using 2.8 mm Spyderline on the arc cuts instead of the 1/2" wide polyester tubular webbing.
- 2.8 mm Spyderline: 0.072 oz/foot.
- 1/2" polyester tubular webbing: 0.17 oz/ft
The webbing is 2.4 times heavier than the Spyderline for an equivalent breaking strength. Some of the 3 mm to 4 mm dyneema lines could be used to gain much greater breaking strengths.
A given length of the webbing occupies less volume than an equal length of the 2.8 mm Spyderline, but the Sypderline packs down to a smaller size because it folds back on itself better than the webbing.
I can stuff my Bridge Hammock made with the 2.8 mm Spyderline into a stuff sack 6" long by 3" diameter. Pretty small. My Bridge Hammock made with the webbing packs a larger than that.
The ratio of the dyneema lines to polyester webbing weights at greater breaking strengths would favor the dyneema line even more. For example, Samson 3 mm AS-78 has an average breaking strength of 2900 lbs and weighs 0.51 lbs/100' or 0.0816 lbs/ft. Compare that to the Strapworks 1" webbing rated at 3,500 lbs and weighs 0.39 oz/foot. A ratio of 4.78:1. A considerable weight savings. If even more strength was desired, the 5 mm AS-78 with a breaking strength of 5,400 lbs could be used. It weighs 0.16 oz/ft which gives a ratio of 2.44:1 with the Strapworks 1" polyester webbing, so the webbing is almost 2 1/2 times as heavy for less breaking strength.
The volume ratio would greatly favor the Dyneema line also. The ratio of the 3 mm AS-78 volume to the Strapworks 1" polyester webbing (2 mm thickness) for equal lengths is 1.8:1, i.e., the volume of the webbing is almost twice that of the dyneema line. The webbing is very stiff and would not pack well, where the dyneema line is very flexible and would pack down very well. Or the 5 mm AS-78 could be used. The volume ration is 0.65:1 favoring the webbing. The dyneema would still pack down smaller due to the stiffness of the webbing.
The Spyderline Bridge Hammock is 1.5 oz lighter than the equivalent Bridge Hammock using the webbing. Both hammocks use the identical fabric pattern and the finished sizes are identical. They use the same Spyderline suspension and 3/4" ID stainless steel rings in the suspension for accessories and spreader bars. In short, they are identical except for the Spyderline instead of the webbing.
The are of course, advantages and disadvantages to using the Spyderline versus the webbing.
- The fabric on the arc cut from the shoulder area to just above the feet any Bridge Hammock is under a LOT of stress as anybody who has used a Bridge Hammock can atest. The webbing on the arc cut serves as an anchor for zippers or Velcro. With the Spyderline, that anchor is gone. The Spyderline is too narrow to serve for sewing a zipper or Velcro to it. Sewing to the fabric is NOT advisable. Thus, any Bridge Hammock accessories that require the zipper or Velcro on the Arc cannot be used. This, of course, is not a problem for me since I don't use either.
- The Spyderline is more uncomfortable on the back and under the thighs when sitting crosswise in the Bridge Hammock for lounging. It isn't terribly uncomfortable, just more so than the webbing. Understandable since the forces are concentrated across the 2.8 mm ( approx. 1/8") width of the Spyderline instead of the 1/2" of the webbing. I don't find it so bad that I cannot sit crosswise though. But some might.
- less weight. Not lots of ounces, but even 1.5 oz helps when it doesn't detract elsewhere, as in my case.
- Packs smaller. Again not a whole lot smaller, but noticably and measurably smaller.
- The Spyderline is slightly less expensive than the webbing:
- Spyderline, 75' mini-spool, $23.75, $0.32/foot
- 1/2" polyester webbing from Sailrite: $0.35/foot
Not enough to make a big difference. But there are more suppliers for the Spyderline than the webbing.
- Also, if a higher rating on the arc cut load bearing material is desired without the weight penalty of stronger polyester webbing, 3.8 mm Spyderline or one of the 3 mm Dyneema lines like the Samson AS-78 or the Amsteel Blue will more than suffice for anybody. Many times lighter than any of the 1" polyester webbings available. There are more choices available using line rather than webbing.
Otherwise the two Bridge Hammocks (Spyderline vs. webbing) are identical in my use. The draft stoppers are interchangable between the two and the use of the draft stoppers is identical. Underqilts are interchangable bewtten the two and the useir use is identical.
The two Bridge Hammocks are totally identical in use and almost in appearance. A person has to look closely to see that the Spyderline cord is used instead of the webbing.
No time for pictures and no time to run out for film or get it developed. Sorry. Hoepfully when I get back in a few months.