is this a safe top rope anchor?

the "super 8" not is not redundant know as one stand connects the two loops.

nerds

see the diagram on page 125 of Rock Climbing Anchors by Craig Luebben. You can probably find it on google books if you don't own it. here

As others have said the 8 and clove are fine for tying into pro/trees but I would double up on the 8s for a master point.

Turner wrote:the "super 8" not is not redundant know as one stand connects the two loops.

I agree - either loop goes and the other loop will pull thru. Not really any better than a single figure 8.

Aleksei,

I think your anchor is safe. As many have pointed out adding redundancy at the master point would make it safer. I agree.

Greg D wrote:Keep in mind dynamic rope stretches. It will rub every time you weight and unweight the anchor. If you are only taking a few runs on it, no big deal. But if many people will be taking laps you should protect points that rub.

I agree. The constant weighting and unweighting will cause stretch and contraction. When this happens over edges or sharp blemishes in the rock it can quickly develop core shots (or worse.) If the anchor is free hanging that won't be problematic. Otherwise I would suggest using a short section of static rope, cordelette, or webbing, all of which have less dynamic properties than the rope. If it is what you have, it will be fine, just pad it well.

Have fun

DrunkenHaymitch wrote:see the diagram on page 125 of Rock Climbing Anchors by Craig Luebben.

Excellent recommendation.

Greg D wrote:Keep in mind dynamic rope stretches. It will rub every time you weight and unweight the anchor.

So does static rope. People think that static rope doesn't stretch at all. It does, but not as much as dynamic rope. For static elongation, static rope is <6% and dynamic rope is <10%.

There's not going to be a whole lot of difference in an anchor made of short lengths of rope. In either case, pad sharp edges and you'll be fine.

Larry S wrote: I agree - either loop goes and the other loop will pull thru. Not really any better than a single figure 8.

agreed
The only thing you really gain from the super-8 in this configuration is that it is easier to untie.
Over the years I have seen a few toprope anchors get damaged by rubbing on the rock and it was always part of the knot that was frayed. The super-8 gains nothing in terms of protecting from this.

If you look back at the original link you posted: chockstone.org/TechTips/Bun…
It shows using the super-8 to connect to two bolts. The context there is, setting up a fixed line, or using your rope to create a multipitch anchor. These are very different applications then a toprope master-point. A master-point for a toprope anchor is left unsupervised while you climb and moves around way to much, especially when using dynamic rope.

Could someone demonstrate how the super 8 is no more redundant than the OP's figure 8? I've read arguments on both sides, but can't visualize it.

Steve Davis wrote:Could someone demonstrate how the super 8 is no more redundant than the OP's figure 8? I've read arguments on both sides, but can't visualize it.

Get yourself a piece of cheap cord/string and tie a super eight in it, next cut one of the loops, then pull on the loop as if it were the master-point. You will notice that both loops fail.

The BHK won't do this. Another knot that won't fail this way, uses less rope, and is easier to untie after loading than almost any other knot is the Bowline on a bight. youtube.com/watch?v=mh-WhlT…

MTKirk wrote: Another knot that won't fail this way, uses less rope, and is easier to untie after loading than almost any other knot is the Bowline on a bight

Ummm, hello. Same problem as super eight.

Greg D wrote: Ummm, hello. Same problem as super eight.

yeah, what Greg said is correct because again, the integrity of those two loops is dependent on that single initial bight. If any of those '4' strands fails, the whole thing goes.

Dan Allard wrote: yeah, what Greg said is correct because again, the integrity of those two loops is dependent on that single initial bight. If any of those '4' strands fails, the whole thing goes.

Can anyone show a documented case of a Super-8 or a bowline on a bight anchor failing because the "fold over" bight failed?

I'm in serious doubt it ever has so I'd put this in the category of "technically possible but practically impossible".

Yes, the super eight failed.

MTKirk wrote: Get yourself a piece of cheap cord/string and tie a super eight in it, next cut one of the loops, then pull on the loop as if it were the master-point. You will notice that both loops fail. The BHK won't do this. Another knot that won't fail this way, uses less rope, and is easier to untie after loading than almost any other knot is the Bowline on a bight. youtube.com/watch?v=mh-WhlT…

Steve Davis wrote:Yes, the super eight failed.

Site your documentation.

Hey Aleksei!

You've received some good feedback mixed with some quintessential hilarious MP offshoots. To add my own perspective, I'll start with a reminder that a key feature of climbing is not taking risk, but managing it.

You can climb on this anchor many times and probably not die, especially if it's not rubbing over any edges. If you take home one message from all of this forum, take home the BHK - know it's out there and know it would make your system a little bit better (a LOT better if the master point was around anything sharp, and a good thing to do as a default).

You are wise to practice this in your apartment, and I'm sure you are reading up a bit, but remember that it would be especially wise to connect with someone who has a good deal of experience and shares your level of acceptable risk (a hard thing to judge - how is an aspiring outdoors climber to judge the experience, level-headedness, and quality of instruction of an experienced climber... but that's a topic for another MP discussion). Fiendishly devour the classic textbooks - "Freedom of the Hills", "The Mountaineering Handbook", and "Rock Climbing Anchors" to get your self-education, but remember there is no substitute for climbing with an experienced sensei when it comes to becoming fluent with these skills and thinking about all the contingencies as you're building an anchor on the cliff. MP has a lot of wise people who can give you a lot of good feedback, but it also has a lot of people who may not think like mere mortals and would tell you they'd take a whipper on a girth hitch around a dead log, and so I wouldn't recommend a dear friend try crowdsourcing something as high-stakes as anchor-building skills. One big, major step towards managing risk in climbing is finding a sensei you can trust, and climbing with them again, and again, and again.

Otherwise, your anchor looks good. I would take a whipper on that ;-D.

I did just as MTKirk suggested. I tied a piece of twine into a super eight, cut one of the loops, and weighted the other (with my finger). One of the cut strands pulled through the knot and the remaining loop failed.

Edited for tone.

johnnyrig wrote:So when you cut one loop of the two "bunny ears", looks like the remaining loop, and how it's threaded through the rest of the 8 is similar in form to the finish of a bowline. Which is secure, generally, if you remember to finish it. Pull tests showing evidence of failure? Personal experience?

some of you are gonna freak out at whats on the AAI blog about anchors ;)

alpineinstitute.blogspot.ca…