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Alpine draws with rubber retainer AND knot


Original Post
Adam K · · Unknown Hometown · Joined Jan 2016 · Points: 40

Anybody have objections to this method of preparing alpine draws?

I'm aware of the danger of the sling unclipping when only using a rubber retainer (see video below), but in this method the overhand knot seems to eliminate that risk. With the knot in place, if one of the strands unclips itself then the biner is still attached to the large loop on the other side of the knot. Yes, the knot reduces the sling strength but it will still be stronger than the gear placement a lot of the time.

 


Discuss!

NateGfunk · · Unknown Hometown · Joined Apr 2013 · Points: 50

no, just no. 

Ryan Hill · · Oakland, CA · Joined Dec 2009 · Points: 30

http://dmmclimbing.com/knowledge/knotting-dyneema-vid/

Knots in Dyneema is a no-go.  

The retaining ring really isn't a useful addition to an alpine sling.  I would avoid using such a system.  Adding a knot to it is just adding to the issues.

Adam K · · Unknown Hometown · Joined Jan 2016 · Points: 40
NateGfunk wrote:

no, just no. 

Thanks for your reply but maybe explain why?

Beean · · Canmore, AB · Joined Feb 2014 · Points: 0

I've seen people do weirder stuff in the mountains.

Any reason to not just use the rubber retainer? You could look at your draw when you're racking up or placing it to make sure everything's all good.

Lena chita · · Cleveland, OH · Joined Mar 2011 · Points: 250
Adam K wrote:

Thanks for your reply but maybe explain why?

You are localizing the damage/rubbing spot with the knot. 

And and why would you want to do any of this in the first place? What problem/issue are you trying to address with your rubber gasket and a knot?

It is much easier to undo the tripled over sling one-handed if you don't need to look and think about which end you need to unclip 

Adam K · · Unknown Hometown · Joined Jan 2016 · Points: 40
Ryan Hill wrote:

http://dmmclimbing.com/knowledge/knotting-dyneema-vid/

Knots in Dyneema is a no-go.  

The retaining ring really isn't a useful addition to an alpine sling.  I would avoid using such a system.  Adding a knot to it is just adding to the issues.

That link addresses a knot to close a loop and not an inline knot, which does not have the same slipping issue.

To clarify, the reason I would want to use this type of system is to have one or two draws ready that are easy to extend in situations where I'm pumped or in a bad stance.. etc. Sometimes when you're in a rush and not careful then things get tangled or the biner falls off.

mpech · · Unknown Hometown · Joined Sep 2013 · Points: 6

looks like you are looking for a draw with a long dogbone.... just buy a few of those.

 One such example: 

http://www.metoliusclimbing.com/bravo_long_draws.html

 As others have pointed out, your knotting system localizes the wear on the dyneema sling to a single point. 

Kevin Mokracek · · Burbank · Joined Apr 2012 · Points: 200

The knot significantly reduces the breaking strength of the dynema.   I wouldn't do it on any piece of webbing that I might expect to take a fall onto or may receive a dynamic load.  

Healyje · · PDX · Joined Jan 2006 · Points: 290

In general it's probably best to refrain from trying to 'improve' upon the basics of what we do. 

The biners in alpine / trad draws are designed to be free and unrestrained, leave them that way.

anotherclimber · · Unknown Hometown · Joined Apr 2016 · Points: 70
Beean wrote:

I've seen people do weirder stuff in the mountains.

Any reason to not just use the rubber retainer? You could look at your draw when you're racking up or placing it to make sure everything's all good.

Watch the video that Adam K posted. I think the problem is that most people keep alpine draws tripled when not extended so it might be hard to check it's good. Plus if you are really pumped and tunnel visioning on a placement you might not check to see if one strand accidentally clipped into the carabiner and risk your life or injury.

anotherclimber · · Unknown Hometown · Joined Apr 2016 · Points: 70
Adam K wrote:

That link addresses a knot to close a loop and not an inline knot, which does not have the same slipping issue.

To clarify, the reason I would want to use this type of system is to have one or two draws ready that are easy to extend in situations where I'm pumped or in a bad stance.. etc. Sometimes when you're in a rush and not careful then things get tangled or the biner falls off.

I agree with you. But look at the link mentioned in the article that I posted below:

How to break nylon and dyneema slings

11mm dyneema sling with an overhand knot in them break at around half the strength of their full rating. Unfortunately they did not test the 8mm dyneema one which would have been interesting to compare. Now you probably figure no one is going to take a fall with that much force, but it's known that dyneema get weaker with age and use. 

Healyje · · PDX · Joined Jan 2006 · Points: 290

The 8mm dyneema slings are ultralight, throwaway consumables and shouldn't be used for more than three years as they lose strength each year and definitely shouldn't ever be knotted.

Kyle Tarry · · Portland, OR · Joined Mar 2015 · Points: 162
Kevin Mokracek wrote:

The knot ...I wouldn't do it on any piece of webbing that I might expect to take a fall onto or may receive a dynamic load.  

A knotted masterpoint is pretty standard when building any kind of equalized anchor...

Kevin Mokracek · · Burbank · Joined Apr 2012 · Points: 200
Kyle Tarry wrote:

A knotted masterpoint is pretty standard when building any kind of equalized anchor...

True but most master points are under a static load when used and there are usually two to four strands incorporated in the master point.   I knot my master points too but the OP is talking about knotting a alpine draw that could potentially take a large dynamic fall onto a single knotted dynema sling.   I would be much more comfortable using a nylon sling for the purpose The the OP intended.  

Healyje · · PDX · Joined Jan 2006 · Points: 290
Kyle Tarry wrote:

A knotted masterpoint is pretty standard when building any kind of equalized anchor...

But really doesn't have anything to do with the current discussion unless you're using skinny dyneema for your master point in which case you should reconsider.

Firestone · · California · Joined Nov 2015 · Points: 449

My biggest problem with the knot is you will be centralizing all the wear into one point. Unless you retie those knots every time you climb you might be very close to making the same mistake as the Skinner harness issue where he left a daisy hitched to the same point on his harness, centralizing the wear.

When you have a masterpoint in dyneema you have multiple dyneema strands, bringing the breaking strength back up. Also there is usually rope in the system which absorbs most of the impact from any falls.

goingUp · · over here · Joined Apr 2013 · Points: 40

+1 for Firestone

+1 for... well, all the other listed reasons on this thread not  to knot and gasket your alpine draws.

If you are looking to have a few runnser already extended for fast access, why not just keep a few slings with biners on em, over your shoulder while climbing?

Kyle Tarry · · Portland, OR · Joined Mar 2015 · Points: 162

Kevin Mokracek wrote:

True but most master points are under a static load when used and there are usually two to four strands incorporated in the master point.   I knot my master points too but the OP is talking about knotting a alpine draw that could potentially take a large dynamic fall onto a single knotted dynema sling.   I would be much more comfortable using a nylon sling for the purpose The the OP intended.  

Master points are under a static load when the follower is on them, but if the leader whips onto them it's a dynamic load.  Same with a short fall at the stance when connected with the rope or a tether.

I don't disagree that nylon might be a "better" choice by some measures, but I was simply replying to your comment about never tying a knot in webbing, which I think could be misconstrued.

Healyje wrote:

But really doesn't have anything to do with the current discussion 

I was responding to a comment specifically because I thought it could be misinterpreted/misinformation.

unless you're using skinny dyneema for your master point in which case you should reconsider.

A Google search for "ice climbing anchor" shows that many people use skinny dyneema slings on ice (just as an example: http://blog.alpineinstitute.com/2013/02/ice-anchors-part-i.html or https://www.petzl.com/US/en/Sport/News/2015-11-16/Tips-and-techniques-for-ice-climbing).  Petzl explicitly shows this technique in their video on how to make an ice climbing anchor.  I disagree that they should reconsider, and I don't see any reason that rock should be any different.

I also disagree with the general statement that knotting skinny dyneema is a bad thing due to the strength reduction.  A figure-of-8 knot (probably the most common knot for a knotted masterpoint) reduces strength to 14-21 kN in the DMM tests, and their test case (single loop being pulled apart) is a more harsh use case.  In other tests, the reduction can be as much as 50% (http://user.xmission.com/~tmoyer/testing/High_Strength_Cord.pdf).  In any case, given the use case of tying a masterpoint with multiple strands, and given the required minimum strength of the sling of 22 kN, this is still fine.

Now, skinny dyneema might not be the best choice for a workhorse anchor cord, primarily because of durability and longevity concerns, but the idea that it's a bad idea or unsafe is ridiculous.

Kevin Mokracek · · Burbank · Joined Apr 2012 · Points: 200

Bottom line is just don't do it.   There are a dozen reasons not to and no GOOD reason to do it.   Plenty of other options available. 

Healyje · · PDX · Joined Jan 2006 · Points: 290
Kyle Tarry wrote:

A Google search for "ice climbing anchor" shows that many people use skinny dyneema slings on ice (just as an example: http://blog.alpineinstitute.com/2013/02/ice-anchors-part-i.html or https://www.petzl.com/US/en/Sport/News/2015-11-16/Tips-and-techniques-for-ice-climbing).  Petzl explicitly shows this technique in their video on how to make an ice climbing anchor.  I disagree that they should reconsider, and I don't see any reason that rock should be any different.

Regardless of what Petzl shows, two wrongs don't make a right.

Kyle Tarry wrote:

I also disagree with the general statement that knotting skinny dyneema is a bad thing due to the strength reduction.  A figure-of-8 knot (probably the most common knot for a knotted masterpoint) reduces strength to 14-21 kN in the DMM tests, and their test case (single loop being pulled apart) is a more harsh use case.  In other tests, the reduction can be as much as 50% ( user.xmission.com/~tmoyer/t…).  In any case, given the use case of tying a masterpoint with multiple strands, and given the required minimum strength of the sling of 22 kN, this is still fine.

Except that 8mm skinny dyneema slings lose 3-4kn strength per year and, again, are designed strictly as ultralight consumables for alpine ascents and not for long-term use in rock climbing.

Kyle Tarry wrote:

Now, skinny dyneema might not be the best choice for a workhorse anchor cord, primarily because of durability and longevity concerns, but the idea that it's a bad idea or unsafe is ridiculous.

In the OP's use case it is both a bad idea and unsafe on multiple fronts.

Guideline #1: Don't be a jerk.

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