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Cordelette - How do you carry yours?
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By Ray Pinpillage
From West Egg
Sep 21, 2012
Middle
bearbreeder wrote:
knots are fine as long as there is rope in the system .... the DMM video is very misunderstood


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.

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By bearbreeder
Sep 21, 2012
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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By redlude97
Sep 21, 2012
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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By Scott Krankkala
Sep 21, 2012
Climbing Trail Creek
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.

As far as racking I just hold the bar tack in my hand, wrap around my palm several times, wrap around the coil, and pull an end through the loop and pull tight. Easy to rack, easy to unrack, and low profile.

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By Sam Stephens
Sep 21, 2012
Top half of Melifluous
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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By redlude97
Sep 21, 2012
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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By johnthethird
Sep 21, 2012
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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By Sam Stephens
Sep 21, 2012
Top half of Melifluous
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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By Nick Nystrom
From Pittsburgh, PA
Sep 21, 2012
The start of pitch 3 of Ecstasy
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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By Ray Pinpillage
From West Egg
Sep 21, 2012
Middle
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 fisherman’s 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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By bearbreeder
Sep 21, 2012
im quite sure they dyneema sewn slings are fine to use as anchors with a masterpoint knot if there is rope in the system

otherwise they wouldnt sell it in 240/400 cm lengths ... but who knows maybe DMM has a special no knot sling while BD, Metolius and all the other manufacturers think its fine

well see what they say after the weekend

petzl has the same take i do on "knotted slings" for setting up raps . which incidentally DOESNT have a rope in the system ...

from rockclimbing.com/cgi-bin/forum...

Absolutely, Petzl is concerned regarding a fall on any static lanyard onto an anchor whether you have an overhand knot in the lanyard or not.

I first want to point out that you should never put yourself in position for any type of fall when positioned directly into the anchor. if you do need to move while at a belay you should avoid a fall factor 1 or greater due to the impact forces you can generate. This information accompanies all of our lanyard technical notices and is also found online, petzl.com/...t/C06-FIN-ANNEAU.... (Third panel down--RG)

As a suggestion, when multi pitch climbing Petzl recommends an overhand knot in the middle of a 120cm lanyard girth hitched through the double tie-in points to assist the climber by extending the rappel device off of the belay loop and at the same time allowing you to still be connected into the anchor, petzl.com/...ing_Catalog-2012.... (page 18 and page 19).

Keep in mind regarding the DMM tests that these tests were performed with a static mass falling vertically off of a static anchor point and completely free of any obstruction once in flight. These labs tests are accurate and a great learning tool but when in the field and when you introduce a harness and the human body into the system the impact forces will be decreased because of the stretch of the harness, rope, and body of the climber, etc.


there are a lot of ways to kill yourself climbing, i find it quite hilarious personally that the people who have come up to me in real life and try to tell me that my PAS aint safe or some other intrawebs killer thing ... dont wear helmets, which is probably one of the best things to do if you want be "safe"

people go mad cow on the intrawebs over dyneema knots, top rope anchors, and other little things when what is going to kill you will be more mundane stuff ... but youd think that PAS/knots/etc are killing climbers left right and centre ;)

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By Jacob Krenn
Sep 21, 2012
Jacob Krenn working his way up the Incredible Hulk...
I generally use a sliding x if using dyneema slings for an anchor. For
top rope setups, long trad routes, or a wall, I use
a dynamic Titan cordelette tied in a web-o-lette fashion, it may weigh a hair more, but can be stored in a compact fashion and gives you a peace of mind that using any readily debatable anchor method doesn't. I also tie in directly with the rope via a clove hitch for those that assume I use a PAS and am a gumby for using a Titan cord as an anchor cordelette. Just my preference thats all. If you am your partner agree on an anchoring system or style it's clearly good enough for the people who may depend on it.

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By Jacob Krenn
Sep 21, 2012
Jacob Krenn working his way up the Incredible Hulk...
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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By Colonel Mustard
From Reno, NV
Sep 21, 2012
Colonel Mustard
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.

I find that this technique saves precious space on my harness and doesn't throw off my equilibrium.

That's my two cents. Your results may vary.

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By redlude97
Sep 21, 2012
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 fisherman’s 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/how-...
but again once a rope/harness/person are introduced, the knot becomes less of an issue.

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By slk
From Reno, NV
Sep 21, 2012
me
Colonel Mustard wrote:
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. I find that this technique saves precious space on my harness and doesn't throw off my equilibrium. That's my two cents. Your results may vary.


This is disgusting. I feel sorry for your partner. Clipping into a hazardous situation. The shame, oh the shame.

You are all idiots. Is that offensive? Especially...

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By Ray Pinpillage
From West Egg
Sep 21, 2012
Middle
bearbreeder wrote:
im quite sure they dyneema sewn slings are fine to use as anchors with a masterpoint knot if there is rope in the system otherwise they wouldnt sell it in 240/400 cm lengths ... but who knows maybe DMM has a special no knot sling while BD, Metolius and all the other manufacturers think its fine well see what they say after the weekend petzl has the same take i do on "knotted slings" for setting up raps . which incidentally DOESNT have a rope in the system ... from rockclimbing.com/cgi-bin/forum... Absolutely, Petzl is concerned regarding a fall on any static lanyard onto an anchor whether you have an overhand knot in the lanyard or not. I first want to point out that you should never put yourself in position for any type of fall when positioned directly into the anchor. if you do need to move while at a belay you should avoid a fall factor 1 or greater due to the impact forces you can generate. This information accompanies all of our lanyard technical notices and is also found online, petzl.com/...t/C06-FIN-ANNEAU.... (Third panel down--RG) As a suggestion, when multi pitch climbing Petzl recommends an overhand knot in the middle of a 120cm lanyard girth hitched through the double tie-in points to assist the climber by extending the rappel device off of the belay loop and at the same time allowing you to still be connected into the anchor, petzl.com/...ing_Catalog-2012.... (page 18 and page 19). Keep in mind regarding the DMM tests that these tests were performed with a static mass falling vertically off of a static anchor point and completely free of any obstruction once in flight. These labs tests are accurate and a great learning tool but when in the field and when you introduce a harness and the human body into the system the impact forces will be decreased because of the stretch of the harness, rope, and body of the climber, etc. there are a lot of ways to kill yourself climbing, i find it quite hilarious personally that the people who have come up to me in real life and try to tell me that my PAS aint safe or some other intrawebs killer thing ... dont wear helmets, which is probably one of the best things to do if you want be "safe" people go mad cow on the intrawebs over dyneema knots, top rope anchors, and other little things when what is going to kill you will be more mundane stuff ... but youd think that PAS/knots/etc are killing climbers left right and centre ;)


This is the internet, if we can't make up hypothetical situations what are we left with? :)

I don't know anyone who's ever had a fall onto a static sling while free climbing.

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By EvanH
From Boone, NC
Sep 30, 2012
If you're going to quote the article, you should quote the most important part. The conclusion is as follows:

"Overall, we should stress that we strongly recommend that you do not construct your own Dyneema® slings by tying lengths of loose Dyneema® tape together."

The tests run by DMM are only indicative of slings created by knotting the ends of the Dyneema together to form a continuous loop.

The question that we're discussing here is one of load direction. Tying limiter knots (ie knots within a closed loop sling system) create loading through the knot, whereas tying a triple fisherman's to form a closed loop creates loading against the knot and can result in severe loss of strength in a low-friction material.

Think of it this way:

A triple fisherman's knot relies on friction to hold the loop. A limiter overhand does not require friction in the system to hold the loop together. I'll concede that tying a limiter knot when extending a rappel device could be an issue, but in that instance you have the sewn termination to back up your knot.

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