Although I tend to approach testing in a more conservative manner, there is something to be said for your gonzo approach! Now I cannot wait for the weekend and my testing session.
Thanks for the input.
Jim
Although I tend to approach testing in a more conservative manner, there is something to be said for your gonzo approach! Now I cannot wait for the weekend and my testing session.
Thanks for the input.
Jim
Fulfillment is living a life that makes the lives of others worth living.
DIY is addicting and fulfilling!
"If guns kill people, then pencils mispell words, cars cause people to drink and drive, and spoons made Rosie O'donnell fat."
It is with great humbleness that I respond to this thread. I have been splicing rigging and climbing ropes for arborists and tree climbers around the world for about a decade now. I consider myself to be quite well versed in the whats, hows, and whys of many of the ropes available today.
I have been hammock-camping since about 1999, but I am new to this forum and have been astounded by the wealth of information to be had here. I know my rig is about to undergo a major overhaul that will probably cut the weight by about 70%!!!
That said, I think the 6-8" whoopie bury is mega overkill. If you're talking about 7/64" Amsteel, that's got to be around 4,000 pound breaking strength and you guys aren't even putting 10% of that load into it (good safety margin, though).
I haven't tested it (but rest assured I will tomorrow), but has anyone tried going down to like a 2" bury? Just sitting here thinking about it, I think even 2" would be WAY more than you would have to worry about.
I understand that dyneema/spectra is very slippery, but I think given the application the generous 10:1 up to 15:1 safety margin most of y'all are runnin, I'm sure you could save a gram and shorten the bury.
There is obviously no harm at all in having extra buried. I post this mostly as a learning opportunity. Either for you or for me!
love
nick
you're probably right!! I'd say that with most of us and diffinately with me, that we've all hit the ground for one reason or another and if by putting that little extra (ok I made my whoopies with about a 10" bury) length in there for the bury makes us feel safer..... But please, by all means go out in your back yard and test it with a 2" bury And don't forget to take pictures!! Make sure you bounce and flip and flop around a bit in the hammock too. That's what I was doing when I had a bowline knot (in amsteel) let go.
I do want to hear how your testing goes...
TinaLouise
Nice to hear from a new poster, especially one who has professional knowlege of splicing. I am at work today, and I plan on running some simple tests. Wish I had a strain guage, but will have to settle for lifting some known weights.
Jim
Nick - Glad to have an experienced splicer contributing here and hope to get some tips from you but I have to disagree with what your wrote.
7/64" Amsteel Blue is rated by Samson to a avg. strength of 1600# and a min. strength of 1400#. Rope is rated without a safety factor applied.
Samson's instructions state a whoopie sing derates the rope to 60% but I checked with them and they've been doing some testing that shows the number is better, with the line retaining about 80% of its strength.
http://www.hammockforums.net/forum/s...ad.php?t=12319
In the end we're dealing with about a 5:1 safety margin. Possibly lower because we apply the rope in ways that create a very small bend radius. Still plenty safe IMHO,
Hope this isn't coming off as confrontational, just trying to keep everyone informed and safe.
Knotty
"Don't speak unless it improves the silence." -proverb
DIY Gathered End Hammock
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Stretch-Side "Knotty Mod"
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Nick,
Welcome, and thanks for sharing your experience. I hope you'll go ahead with the tests of a 2" bury (why not start with 6" an work down?), but I second Knotty's concerns. When it comes to whoopie slings, of course, the questions is not failure but slippage. We have become used to using ways of increasing the tension on the constricting rope for UCRs, but maybe we should investigate ways of doing the same thing for whoopies. It would be nice to have the option of a shorter hammock-to-tree distance. When you test, put something soft under the hammock. Thanks.
Splicing line is just too much fun. Ideas start popping into your head. Enjoy.
Bat
Bat
Beginning my NOBO trip on the AT on 2/28/12.
It is recommended that you don't knot dyneema and other high-mod lines. What it boils down to is that they are just too slippery to hold a knot. Tina, we're gonna have to teach you how to splice an eye in the end of that amsteel!
I'm trying to find a good article that really illustrates the point, but most high-mod lines will slip-out and very low loads (10%ish).
Have you modified your knot?
Time to switch to a splice!
love
nick
Totally agree about the no nots in dyneema/amsteel. I read where Brion Toss did some testing and found knots slipping at as little as 10% of rated load, like you wrote.
I think the reason a lot of people have gotten by with knots is because some knots hold the slippery stuff better than others and generally we're not pushing the limits of the rope.
I've had pretty good luck with a double fisherman's knot but just noticed that even the Wikipedia page for the knot talks about using the triple version in dyneema. Stick to splicing whenever possible.
http://en.wikipedia.org/wiki/Double_fisherman's_knot
"Dyneema/Spectra's very high lubricity leads to poor knot holding ability, and has led to the recommendation to use the triple fisherman's knot rather than the traditional double fisherman's knot] in 6mm Dyneema core cord to avoid a particular failure mechanism of the double fisherman's, where first the sheath fails at the knot, then the core slips through."
Knotty
"Don't speak unless it improves the silence." -proverb
DIY Gathered End Hammock
DIY Stretch-Side Hammock
Stretch-Side "Knotty Mod"
DIY Bugnet
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