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Double-length Sling as Sport/TR Anchor


Original Post
Josh Gates · · Unknown Hometown · Joined Mar 2017 · Points: 0

Any issues with using a (nylon or dyneema) double-length sling (sliding x with limiters) for a two-bolt anchor, either on TR (where there's no issue with rope or biners running over an edge, so no static line build needed)? I usually use a quad or a sliding x with limiters made from 7 mm cord, but the slings are more compact, and I'm curious.

jg

Brad Johnson · · Charlotte, NC · Joined Jul 2017 · Points: 0

I use a 18mm Nylon all the time to set up top rope anchors.  Hasn't killed me yet. 

Jack C. · · Calgary, AB · Joined Mar 2013 · Points: 325

Generally you don't want to knot dyneema.  For nylon it's a-okay and with a TR setup neither will likely kill you but I wouldn't be stoked if I saw a partner do it.  Tying a double length with two limiter knots and a sliding x is isn't something I ever do.  I'd just do an overhand/double-overhand/figure-8/ double figure-8 in the middle.  One less knot to tie.

John Wilder · · Las Vegas, NV · Joined Feb 2004 · Points: 1,535

Sure. Used to do this before I got lazy and just use draws. 

I still occasionally use this method if I'm running an all day tr. 


Scott and Sara · · Unknown Hometown · Joined May 2017 · Points: 0

You could just clip the ends of the sling to the anchors and tie an overhand/figure 8 in the direction of tension and use lockers all around. Simple, efficient. strong and redundant.

Erroneous Publicus · · Unknown Hometown · Joined Jun 2010 · Points: 5
Scott and Sara wrote:

You could just clip the ends of the sling to the anchors and tie an overhand/figure 8 in the direction of tension and use lockers all around. Simple, efficient. strong and redundant.

You don't need to use lockers all around.  It's also no issue to tie a knot in Dynema.  Reduces the failure strength, but not enough to matter in a top rope scenario. 

Zach Raney · · Leadville, CO · Joined Aug 2014 · Points: 0

+ 1 for double nylon with a fig 8 or overhand masterpoint, cordalette quads ain’t bad for TR

John Wilder · · Las Vegas, NV · Joined Feb 2004 · Points: 1,535
Jack C. wrote:

Generally you don't want to knot dyneema.  For nylon it's a-okay and with a TR setup neither will likely kill you but I wouldn't be stoked if I saw a partner do it.  Tying a double length with two limiter knots and a sliding x is isn't something I ever do.  I'd just do an overhand/double-overhand/figure-8/ double figure-8 in the middle.  One less knot to tie.

Uh, what? There's no reason not to tie a knot in a sling made of dyneema. 

Now if you cut a sling made of dyneema and tie it back together, that kind of knot is bad, as dyneema doesn't have enough friction to hold. 

Jack C. · · Calgary, AB · Joined Mar 2013 · Points: 325
John Wilder wrote:

Uh, what? There's no reason not to tie a knot in a sling made of dyneema. 

Now if you cut a sling made of dyneema and tie it back together, that kind of knot is bad, as dyneema doesn't have enough friction to hold. 

C'mon we've all heard it said.  Don't act like I just made something up.  Somebody like me has to be around to perpetuate internet rumors after all.

John Wilder · · Las Vegas, NV · Joined Feb 2004 · Points: 1,535
Jack C. wrote:

C'mon we've all heard it said.  Don't act like I just made something up.  Somebody like me has to be around to perpetuate internet rumors after all.

Nope. Never heard of that one. 

Tapawingo Markey · · Unknown Hometown · Joined Feb 2012 · Points: 75

Any reason you don’t want to use two draws? 

Kyle Taylor · · Atlanta Ga · Joined Sep 2017 · Points: 0

My TR anchor, I've used it several times. All lockers,  sling doubled up with the "x", no knots however.

Lee Green · · Edmonton, Alberta · Joined Nov 2011 · Points: 50
Kyle Taylor · · Atlanta Ga · Joined Sep 2017 · Points: 0
Lee Green wrote:

Like the clove hitch at the biners at the anchor point!

Jack C. · · Calgary, AB · Joined Mar 2013 · Points: 325
John Wilder wrote:

Nope. Never heard of that one. 

Really? Wow that is quite surprising to me! I've heard that loads of times. I guess I just climb with a bunch of midwestern idiots.  Oh wait a second I don't have to guess.  I know I do: I'm one of 'em.

eli poss · · Durango, Co · Joined May 2014 · Points: 442
Jack C. wrote:

Really? Wow that is quite surprising to me! I've heard that loads of times. I guess I just climb with a bunch of midwestern idiots.  Oh wait a second I don't have to guess.  I know I do: I'm one of 'em.

Yes knots in dyneema can reduce the strength up to 50%. However, you to think things through rather than just spouting blanket statements such as "never knot dyneema". Unless you're using unacceptably worn dyneema slings, you shouldn't ever get anywhere near breaking strength from a top rope, even with the lowest strength efficiency knot.

Kyle Taylor wrote:

My TR anchor, I've used it several times. All lockers,  sling doubled up with the "x", no knots however.

Please don't do this. If any strand cuts you're fucked. Even if it's not running over any sharp edges, it can still get cut. Many rodents have quite the taste for nylon and falling rocks, even small ones, can easily slice a sling.


And to the OP: There really no good reason to use the sliding x even with limiter knots. Either use a quad or tie a masterpoint 

Kyle Taylor · · Atlanta Ga · Joined Sep 2017 · Points: 0
eli poss wrote:Please don't do this. If any strand cuts you're fucked. Even if it's not running over any sharp edges, it can still get cut. Many rodents have quite the taste for nylon and falling rocks, even small ones, can easily slice a sling.


And to the OP: There really no good reason to use the sliding x even with limiter knots. Either use a quad or tie a masterpoint 

Could you show me an example of what you think is best? 

Thx!

alexd81 · · Unknown Hometown · Joined Oct 2016 · Points: 20
Kyle Taylor wrote:

Could you show me an example of what you think is best? 

Thx!

What's best is situational, but a sliding X on one sling is not an anchor because it lacks redundancy for arguably the most vulnerable part of the anchor: the sling. Soft goods do wear and can suffer cuts. Dyneema in particular has been shown to weaken from being handled and knotted. A sliding X can be used as part of an anchor, but by itself it is not sufficient. If you are going to use a sliding X type anchor, use two slings so that you are not dependent on a single strand of webbing. 

Josh Gates · · Unknown Hometown · Joined Mar 2017 · Points: 0
Lee Green wrote:

What happens here when the sling fails or when an anchor fails? Seems like it'll all just fall apart, especially since that clove's not being tightened at all.

alexd81 · · Unknown Hometown · Joined Oct 2016 · Points: 20
Josh Gates wrote:

What happens here when the sling fails or when an anchor fails? Seems like it'll all just fall apart, especially since that clove's not being tightened at all.

Depends on where the sling fails, but a clove that has been tightened by load will probably hold unless the cut is right at the knot. But that question is what keeps me from using the setup. I don’t think a hitch gives you the same level of redundancy as a knot. But who knows.  Seeing some pull testing would be nice.

The other issue with it is that you can only really have one carabiner at the master point. Not practical for many scenarios.  


baldclimber · · Ottawa, Ontario, Canada · Joined Jul 2015 · Points: 0
eli poss wrote: Please don't do this. If any strand cuts you're fucked. Even if it's not running over any sharp edges, it can still get cut. Many rodents have quite the taste for nylon and falling rocks, even small ones, can easily slice a sling.

And to the OP: There really no good reason to use the sliding x even with limiter knots. Either use a quad or tie a masterpoint 



Kyle Taylor wrote:


Could you show me an example of what you think is best? 


Evolve your thinking past what is "best" or "best practice".  Know and understand what you're trying to accomplish instead.  Eli gave you two options.

Two bomber bolts: they're redundant.  Sling with sliding-X: no redundancy to gain pointless equalization on two bomber bolts.  Slings have been cut by rockfall http://publications.americanalpineclub.org/articles/13201213756/Rockfall-Anchor-Chopped

Guideline #1: Don't be a jerk.

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