Cordelette - How do you carry yours?
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Dom wrote: What's the link between the picture and the video? Edit: The Quote seems to be malfunctioning. The last question is from me (Dom) and not from Ray Pinpillage.I don't know, I just put up the DMM link. |
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harpo-the-climber wrote: Sorry for thread drift. I saw that video and am aware you aren't supposed to construct sling by knotting dyneema or spectra tape. However, I presume that there is no problem with using longer sewn dyneema/spectra slings as cordeletes by attaching them to two or three anchors and creating a master point by tying a figure 8 (or 9)? I have been doing this for a while with no problems.Dyneema should not be tied in a knot. It is probably OK for top rope anchors but it seems like a bad habit to get into. |
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knots are fine as long as there is rope in the system .... |
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Grosso Modo The DMM video shows that you should never tie your dyneema slings together using a knot. I've never seen anyone do this. Usually, dyneema slings are sewn together and I haven't seen dyneema slings sold without these ''sewn attachements''.
Cordelette on the other hand, is frequently tied together with a knot. (e.g. double fisherman's) In the picture, the sling has an overhand used to equalized both strands of the sling. It's not used to tie the sling together. You can clearly see the ''sewn part in the picture''. Don't know if this makes sense, but in a nutshell the video is apples and the picture is oranges. |
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Dom wrote:Grosso Modo The DMM video shows that you should never tie your dyneema slings together using a knot. I've never seen anyone do this. Usually, dyneema slings are sewn together and I haven't seen dyneema slings sold without these ''sewn attachements''. Cordelette on the other hand, is frequently tied together with a knot. (e.g. double fisherman's) In the picture, the sling has an overhand used to equalized both strands of the sling. It's not used to tie the sling together. You can clearly see the ''sewn part in the picture''. Don't know if this makes sense, but in a nutshell the video is apples and the picture is oranges.Not quite there killer. The knot is in a load absorbing section of the anchor. A knot in the dyneema cuts it by whatever % applicable. If for some god awful reason that master point were loaded beyond the decreased strength of the material with the knot in it, there would be problems. That's pretty basic stuff. Knot in dyneema, bad. Knot in dyneema at anchor, bad. Fall on anchor with knot in dyneema where the knot is used to form a master point and prevent extension, bad. |
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bearbreeder wrote:knots are fine as long as there is rope in the system .... the DMM video is very misunderstoodNot really. The DMM video represents a static fall onto knotted Dyneema and tied Dyneema slings. Regardless of the failure force it clearly shows what the friction of a knot does to Dyneema. If you watch closely you can see the slings melting at the knot well before they actually fail. DMM does not recommend knotting Dyneema or using it to construct your own slings. |
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Ray Pinpillage wrote: Not really. The DMM video represents a static fall onto knotted Dyneema and tied Dyneema slings. Regardless of the failure force it clearly shows what the friction of a knot does to Dyneema. If you watch closely you can see the slings melting at the knot well before they actually fail. DMM does not recommend knotting Dyneema or using it to construct your own slings.are you talking about a sewn sling with a knot in it, or tying knots connecting an open dyneema webbing? ... im talking about the former with rope in the system do you have a particular DMM reference where DMM does not recommend knotting their slings with a rope in the system??? to save us 20 pages of senseless arguments, ill just email DMM ;) |
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Ray Pinpillage wrote: Not really. The DMM video represents a static fall onto knotted Dyneema and tied Dyneema slings. Regardless of the failure force it clearly shows what the friction of a knot does to Dyneema. If you watch closely you can see the slings melting at the knot well before they actually fail. DMM does not recommend knotting Dyneema or using it to construct your own slings.How exactly does DMM expect you to use their 240cm dyneema slings then? As a giant loop only? |
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As stated before I do not think that the DMM video is applicable to normal dynemma use. As the runners are sewn there should not be a water knot that appears to easily slip. I feel that if you are using a triple shoulder length runner (240cm) to statically equalize a 2-3 piece anchor the master point knot should not be susceptible to this failure. |
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I use an 8 ft sewn nylon runner for sliding x on a three piece anchor. Maybe that's how? Or slinging a BFR? |
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Sam Stephens wrote:I use an 8 ft sewn nylon runner for sliding x on a three piece anchor. Maybe that's how? Or slinging a BFR?with or without limiter knots? Doesn't that have ridiculous extension potential? |
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bearbreeder wrote: are you talking about a sewn sling with a knot in it, or tying knots connecting an open dyneema webbing? ... im talking about the former with rope in the system do you have a particular DMM reference where DMM does not recommend knotting their slings with a rope in the system??? to save us 20 pages of senseless arguments, ill just email DMM ;)Please, let us(or at least me) know the response you get. |
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redlude97 wrote: with or without limiter knots? Doesn't that have ridiculous extension potential?Limiter knots on any suspect pieces. Just like using a 17 or 20ft cordelette to do a three piece sliding x really, except way lighter and less bulky. I got two of them made from 11/16 webbing. |
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Crossing wrote:When I carry mine, I coil it around my hand then wrap the remaining loop around the coil a few times and thread it through an individual strand of the coil and clip it. This pic might show it better.+1 Except that I quickly loop it back and forth a few times into a coil about 7-8 inches long. Quick to coil and uncoil, compact, and stays out of the way. |
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bearbreeder wrote: are you talking about a sewn sling with a knot in it, or tying knots connecting an open dyneema webbing? ... im talking about the former with rope in the system do you have a particular DMM reference where DMM does not recommend knotting their slings with a rope in the system??? to save us 20 pages of senseless arguments, ill just email DMM ;)What is the difference between a strand of Dyneema tied at the ends and sewn loop knotted in the middle? Assuming the force is the same you still have a knotted piece of Dyneema. In the pull tests the knots broke below their stated ratings and DMM recommended using only sewn sections. Here is an excerpt: "The accompanying video illustrates quite well how in certain knots the ends of the webbing simply pull through, rather than the sling dramatically breaking at the knot. Outside on the drop tower, in a dynamic situation using an 80 kg weight, a 60 cm sling tied with a triple fishermans survived a fall-factor 1 generating 16 kN on the load cell but failed at 14 kN in a fall-factor 2. This is likely to be because the dynamic loading causes a rapid build up of heat from energy dissipation within the knot. Using an 8 mm Dyneema® sling tied into the same length as an extended Dragon Cam sling (26 cm) it also failed a fall-factor 2. A sewn sling survived the same test. Although it is possible to achieve quite high strengths in slings tied together with specific knots, it is very hard to judge how they will behave when loaded, especially as the knot alters over time. Home-made tied Dyneema® slings lack the maintenance free and consistent high performance inherent in commercially sewn Dyneema® slings." Keep in mind that getting a 14Kn fall on toprope is all but impossible but you are still using knotted Dyneema. On lead with a rope I don't think you'd see a 14KN fall either but you're still reducing the strength of the sling. I'd like to hear their response too. I wonder if it isn't a bigger issue because reaching those forces doesn't really happen with the rope in the system? I have seen sewn Dyneema runners with a midway knot used to extend a belay device for a rap and a carabiner used at the end to act as a PAS while staging the rap. That would set up a static fall onto knotted Dyneema even though it is sewn. |
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im quite sure they dyneema sewn slings are fine to use as anchors with a masterpoint knot if there is rope in the system |
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I generally use a sliding x if using dyneema slings for an anchor. For |
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Apologies for multiple grammatical errors. Auto correct via I phone seems to be more of a hindrance than a help these days. |
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To save space, I carry it coiled up in my lower bowels. When I need it I just shit out the tip and pull it out like a tapeworm. |
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Ray Pinpillage wrote: What is the difference between a strand of Dyneema tied at the ends and sewn loop knotted in the middle? Assuming the force is the same you still have a knotted piece of Dyneema. In the pull tests the knots broke below their stated ratings and DMM recommended using only sewn sections. Here is an excerpt: "The accompanying video illustrates quite well how in certain knots the ends of the webbing simply pull through, rather than the sling dramatically breaking at the knot. Outside on the drop tower, in a dynamic situation using an 80 kg weight, a 60 cm sling tied with a triple fishermans survived a fall-factor 1 generating 16 kN on the load cell but failed at 14 kN in a fall-factor 2. This is likely to be because the dynamic loading causes a rapid build up of heat from energy dissipation within the knot. Using an 8 mm Dyneema® sling tied into the same length as an extended Dragon Cam sling (26 cm) it also failed a fall-factor 2. A sewn sling survived the same test. Although it is possible to achieve quite high strengths in slings tied together with specific knots, it is very hard to judge how they will behave when loaded, especially as the knot alters over time. Home-made tied Dyneema® slings lack the maintenance free and consistent high performance inherent in commercially sewn Dyneema® slings." Keep in mind that getting a 14Kn fall on toprope is all but impossible but you are still using knotted Dyneema. On lead with a rope I don't think you'd see a 14KN fall either but you're still reducing the strength of the sling. I'd like to hear their response too. I wonder if it isn't a bigger issue because reaching those forces doesn't really happen with the rope in the system? I have seen sewn Dyneema runners with a midway knot used to extend a belay device for a rap and a carabiner used at the end to act as a PAS while staging the rap. That would set up a static fall onto knotted Dyneema even though it is sewn.I think you are completely misinterpreting their results. The DMM testing is in regards to tying your own dyneema slings. With a triple fishermans the decrease in strength during the pull testing was reasonable. Most of the dyneema knots failed because the tails were able to completely pull through the knot. A fig8/overhand in a dyneema sling on the other hand doesn't have the same failure method. Dynamic drop testing isn't completely applicable either if there is rope/harness and a real person in the system. Yes knotting dyneema slings weakens them significantly but not based on the video provided. In use as a tether it makes more sense to avoid knotting such as in this more appropriate video dmmclimbing.com/knowledge/h… but again once a rope/harness/person are introduced, the knot becomes less of an issue. |