How much are Dyneema/nylon weaved slings affected by knots?
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So I'm sure most everyone has seen the DMM video about breaking dyneema slings. This was done with the DMM brand slings that are almost all dyneema, except for the outside colored part. It was nice to see that the sewn runner held a factor 2 fall. |
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All soft goods are affected by knots. 25-60% as an approximate number depending on the knot and material. Sewn slings are rated at 22kN. Even with a 60% reduction in strength after knotting most sling are still strong enough for most any situation. But, even if you tie a double, triple, over, under figure 19 knot, you're gonna die. |
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Here is a link to see some testing on slings, both dyneema and nylon. I was surprised how they fail. I only watched the video. |
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do you have a rope in the system? ... if so dont worry about it if the sling is in good condition |
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Thanks for the input guys. Bearbreeder, yes there is a rope in the system. I do a lot of multi pitch trad and multi pitch sport climbing so I'm looking for material to use as a cord/webolette. It seems like there are a million different opinions. Right now I usually use the blue water titan spectra/nylon mixed weave sling on most climbs that are around 4 or 5 pitches or less. Any longer and I usually bring the mammut 8mm dyneema slings. |
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spirg wrote:What do you guys use for multi pitch trad anchors?The rope, usually. There are many, many, many threads on this. |
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spirg wrote:Even if I tie the cordeltte into a figure 8 knot, or figure 27 for greg d, apparently I will still die. On a serious note, I know there is a reduction in strength but as you said with the rope in the system it shouldn't be a worry. What do you guys use for multi pitch trad anchors?Honestly how much has anyone read on anchor failure due to the cord material? I can't recall any. They've all been failure of the gear / rock or placement. |
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spirg wrote:Thanks for the input guys. Bearbreeder, yes there is a rope in the system. I do a lot of multi pitch trad and multi pitch sport climbing so I'm looking for material to use as a cord/webolette. It seems like there are a million different opinions. Right now I usually use the blue water titan spectra/nylon mixed weave sling on most climbs that are around 4 or 5 pitches or less. Any longer and I usually bring the mammut 8mm dyneema slings. Even if I tie the cordeltte into a figure 8 knot, or figure 27 for greg d, apparently I will still die. On a serious note, I know there is a reduction in strength but as you said with the rope in the system it shouldn't be a worry. What do you guys use for multi pitch trad anchors?depends on the situation ... if im block leading ill use a cordelette or long dyneema or nylon slings ... if its swap leading, sometimes ill use the rope what you use is up to you as long as its "safe" and it works efficiently ... everybody climbs differently ... the nice thing about cord and nylon webbing though is that for more adventurous multi, you can use it as bail tat, etc .... without cutting up those $$$ dyneema slings |
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Scott McMahon wrote: Honestly how much has anyone read on anchor failure due to the cord material? I can't recall any. They've all been failure of the gear / rock or placement.Well its conclusive. A guy who has been climbing a year or two has never heard of it happening so it MUST be impossible. |
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Derek Huff wrote: Well its conclusive. A guy who has been climbing a year or two has never heard of it happening so it MUST be impossible.Yeah you're right...funny how I've been a member of this website alone for 6 years. Please feel free to share your wealth of knowledge of anchor cord failure OUTSIDE of a lab. And it's conclusive...you've been here for 9 days and you are making friends all over. Thanks for all your awesome contributions. |