Improper top rope belay revisited

8:57 a.m. on April 13, 2010 (EDT)
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This is a follow up to a thread posted 9/5/09 by Solojourneys, regarding solo top roping. reference: http://www.trailspace.com/forums/climbing/topics/60204.html

I felt compelled to revive this thread because several of the postings therein described basically unsafe belay set up concepts, and wish to warn others why these belays are considered suboptimal, especially considering a bolted top rope anchor should offer ideal bomber pro, compared to most trad belay situations.

Solojourney describes a set up he alleges to be redundant, which is kinda true, but it falls considerably short if evaluated using SRENE (Solid, Redundant, Equalized, Non-Extending) criteria to construct anchors. To begin with, whenever Solo’s rope is weighted only one half of the system will be bearing weight, placing all that weight on just one of the two anchor bolts at any time. Thus no effort is made to equalize the burden among both anchors. Since the most common failure mode of anchors is the stone or a device's placement within the stone – not the equipment per se – Solo’s set up fails to provide security from the biggest liability of any belay set up.

Furthermore since the twin rope lengths are not joined together down-line from their attachment to the anchor bolts no provision is made to limit extention (the free fall that results when one anchor fails, before the other anchor receives the load on the other rope). If the bolts have any distance between them the shock loading of the back up rope can be as severe as that which caused the first anchor to fail, not exactly a desireable circumstance. Both of these issues can be mitigated somewhat if Solo takes the effort to unite both rope lengths with a figure eight below the bolts, preferably such that the angle between the rope lengths leading to the bolts form an acute angle of less than 40 degrees.

Lastly as Bill alludes in his comments to Solo, the self belay devices he describes do not allow the rope to feed through the device when engaged, thus any fall will create some level of shock when the rope is loaded thusly; he is better off using a Trango Cinch or similar device that permits some slippage of the rope through the device when initially shock loaded by a fall.

The variation of this top rope scheme described in the same thread by Tokyo Bill has all the liabilities of the system used by Solo; additionally the back up system (the rope with intermittent figure eight tie-ins, makes shock loading the back up rope a certainty. Worse, depending of the distance between these figure eight tie-ins, this set up possibly will result in a significant - up to factor-1 fall - something that should be avoided if possible.
Ed

8:58 a.m. on April 13, 2010 (EDT)
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Well, I disagree with various aspects of your analysis. Rather than waste time with that, however, let me ask this:

What is your preferred rig?

I'm always happy to learn something new.

- Bill

8:59 a.m. on April 13, 2010 (EDT)
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Hey whomeworry,
Ah, having read more carefully, I guess you're concerned first about the "one clove hitch on each anchor point" idea suggested by Solojourneys. I'll agree with you that this isn't optimal. I generally rig an eqalized anchor and attach my rope to it with a figure eight on a bight clipped to the anchor's power point, and this is what I'd recommend. Will that take of your first issue, or is there more to it?

Your second point seems to be the recommendation of a Trango Cinch (or similar) because it has a built in "dynamic" component to its autolock function. Sounds nice; but what does Trango say about it? I actually e-mailed them, and I'll let you know if I hear anything.

In truth, however, I'm relying on the shock absorbing capacity of my dynamic rope when I TR solo, just like I am when I climb with a partner. The idea that my rig would be inadequate at the low loads created when TR soloing in the absence of the extra margin provided by a "dynamic" autolock function suggests that I would be equally at risk climbing on top rope with a partner who belayed me with a gri-gri (which also has no built in dynamic component to its catch). If I believed the protection system was really that delicate, I'd probably quit climbing; but I think this is just not the case.

Finally, the same point applies to the backup on the second strand. This is obviously intended to be the lifesaver in the event of a total failure of the device or the first strand. With that said, I take falls of various factors on dynamic ropes all the time; and I trust my ropes to hold them. That trust doesn't go away just because I'm climbing without a partner. I therefore have full confidence in this backup. Rope jumping and a variety of other extreme uses of ropes suggest that they'll stand up to the contemplated loads just fine, absent a sharp edge, friction burn-through or other critical failure.

Anyway, fun to think about. I'm looking forward to hearing your ideas.
- Bill

9:00 a.m. on April 13, 2010 (EDT)
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You are correct, Bill, that the major concern was Solo's failure to equalize force distributed between bolts with a power point. One last comment on that topic: If one incorporated a cordelette to tie in the anchor points, there a debate in choice of materials. One camp argues in favor of the high tensile chords versus traditional nylon webbing or chord, claiming the high tensile materials offer higher static load capacity. Those favoring traditional nylon products claim the stretchy properties of nylon provide additional dynamic response to shock loading, enhancing better distribution of forces among anchor points, thus outweigh any benefit of higher load bearing capacity of spectra/Dyneema chording and similar high tensile products A study presented at the 2000 International Technical Rescue Symposium, conducted by a team that included Tom Moyer, and Chris Harmston (who was the QC manager at BD during that time) debunked several assumptions about high-tensile chord and concluded nylon was the preferred material for anchor systems. (reference: http://www.xmissiom.com/~tmoyer/testing

Regarding my concerns about the design of your backup (second rope system); they are twofold. First off, no self belay system is as dynamic as being belayed by a second. When you state you rely on the dynamic properties of your rope while soloing, just like when you climb with a partner, you overlook the important dynamic properties of having a partner's body break your fall. A dynamic belay device partially compensates for lack of a second to catch your fall.

Regardless, using the set up you describe, the fall is borne only on the length of rope extending between you and the anchor, while a fall belayed by a partner from below spreads the dynamics of the fall over a longer section of rope, including the length that runs from you to the anchor, as well as the length leading back down to the belay stance. In fact the principle safety feature of any system is the rope's capacity to stretch when loaded; reducing shock to the unknown qualities of your system (reliability of rock and anchor placements) thus any rigging solution should consider maximizing the length of rope that absorbs a given fall as a primary safety feature. (The caveat here, being a situation that results in you bouncing at the end of a fall.) In any case, self belaying a solo top rope climber using the set up you describe has significantly less dynamic properties than a top rope belayed by a second, regardless what belay device the second may be utilizing.

The second concern is your system incorporates some redundancy (using the tag end of the rope as a second rope with intermittent figure 8 loops) that provides only modest additional pro, when instead incorporating the tag end of the rope into the primary pro would offer a safer system. As you pointed out, the rope is the most bomber piece of equipment in any system, provided one follows decorum pertaining to care and retirement of equipment. In fact the rare rope failures that do occur are primarily caused by routing over sharps, and other lead errors. Hardware is the second most reliable element, again assuming proper care of your gear. It is the rock, the craftmanship of whoever set the bolts, and the condition of the bolts, that are the weakest links in top rope systems. Far and away the most likely failure mode of your primary belay system is the anchors or rock. Thus your backup system will not provide significant additional safety, since it only protects against failu
re of the relative bomber first rope and belay device, yet still relies on the same suspect anchor points. At that, the design of your back up with specific reliance on intermittent tie ins along the second rope will shock load the anchors more than the primary belay rope ever would, substantially increasing the potential for failure of that system too.

My preference (I don't solo top rope for several reasons) would be a dynamic equalized, anchor station, utilizing nylon webbing or a cordelette, tied as a quad rig with limiting knots (reference http://www.rockclimbing.com/cgi-bin/forum/gforum.cgi?post=2315817 ) with two or more inverted, opposing bineers, one of which should have a locking gate, linking the power point to the rope. I would attach my harness to the sharp end of the rope with a figure eight. I would thread the tag end of the through a gri-gri or Trango Cinch, which is also attached to my harness via a cord of sufficient length to eliminate the sharp end of the rope accidentally actuating the belay device's trigger. While no redundancy exists for failure of any specific element other than the use of two bolts, this set up observes safety is best obtained by reducing stress on the anchor system. (To this end one can use a basic equalette in favor of a quad if more dynamic properties are desired in the anchor station set up.)

What this set up takes advantage of is utilizing twice the rope length and a dynamic belay device, thus minimizing shock load to the bolts and rock should a fall occur, as compared to the setups you and Solo describe. Note I did not describe knoting the tag end of the rope, to prevent belaying off the rope end, because I assume I can reach the ground in less than one pitch from the tope rope station.
Ed

1:56 p.m. on April 13, 2010 (EDT)
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...Your second point seems to be the recommendation of a Trango Cinch (or similar) because it has a built in "dynamic" component to its autolock function. Sounds nice; but what does Trango say about it? I actually e-mailed them, and I'll let you know if I hear anything.
....

TBill,

I can tell you what Trango (and Petzl) have to say about self-belay with the Cinch (and Grigri and other similar devices). I have had several conversations with Mal about safe practices with various pieces of climbing gear - his and other companies as well.

With respect to the Cinch, Mal says very emphatically, "DON'T!!!" The basic reason is that, contrary to "popular wisdom", the Cinch is not an automatic belay device, nor is it "dynamic". In similar conversations with the Petzl folks, they say the same thing about the Grigri. Even with a belayer operating the device, climbers have been dropped to the ground. According to both, this has happened way too often in gyms, where both are used extensively. With a belayer, the problem is almost always operator error. Remember, this is from the manufacturers, not from my personal opinions.

Mal pointed out to me one problem that has happened with both the Cinch and Grigri when used as a self-belay device. If the backup knot is too close to the device (i.e. not enough rope to allow run), the knot can hit the device in such a way as to pop the side plate off. He also pointed out several other ways in which a self-belay with such devices can fail. The Cinch, Grigri, and similar devices are excellent and safe when used for the purposes and in the way in which they were designed. But they are all too often misused, and the operators complacent.

There are only two devices readily available which were designed as self-belay, solo devices - the Silent Partner and the Soloist (and for aid, the Soloist Aid). The Soloist and Soloist Aid will not hold inverted falls (and say that right on the device). A lot of people consider the Silent Partner to be too bulky, though I have found that a significant problem only for off-widths. The SP also does not hold well in icey conditions.

Sometimes ascenders with teeth are suggested. However they (and even a lot of "clamping" devices) have been known to actually shred or cut the rope when force is suddenly applied in a fall.

One of the problems with the "clove hitch on every piece of pro" approach is that all falls become factor 2 falls. This is hard on the rope, to say the least.

Frankly, I do not believe this is an appropriate topic for Trailspace. You can only learn safe rope-soloing with an experienced mentor. Reading about it, especially on the Internet, does not convey the information correctly, and tends to lead less experienced people to think they understand it and can just go right out to the cliffs and do long multipitch routes.

3:11 a.m. on April 14, 2010 (EDT)
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Bill,

Great post, as usual. Thanks for that input on the Cinch and other devices. (My e-mail to trango's customer service address bounced for some reason (incorrect address, it said, but I got the address off trango's site), so unless I can find another way to contact them, your information may be the best we get.

I agree with you that rope soloing (even TR solo, which is the only type I do) is not a skill that should be learned on the internet. Maybe that was whomeworry's principal thought - before I distracted him with specifics: that it is probably better not to follow Internet advice on topics where you're betting your life.

I'm comfortable with my system; but I'll take an experienced partner on the other end of the rope every single time, if I have the choice.

whomeworry,

Thanks for the thorough feedback. Much appreciated.

I have to admit that I'm not sure that I understand your recommended system, especially how you are attaching the rope to your anchor's power point and what you mean by "sharp end" and "tag end" in the context of a TR solo, but I'll keep thinking about it.

- Bill

10:13 a.m. on April 17, 2010 (EDT)
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Bill S:
Thanks for advising better devices for solo climbing/belaying. I like the concept of the Silent Partner device, albeit ice is probably an issue. Your comments got me curious, and I want to get back to the source that originally recommend I use the Cinch in similar circumstances. I don’t rope climb solo, top rope solo, nor for that matter top rope tied into bolts. So Cal destinations near my home receive heavy traffic, thus I learned to consider all bolts suspect.

I normally belay using simple (KISS) set ups like Figure-8s, or locking biners. I learned of the Cinch on an Alaskan trip a few years ago, including two guides (acquaintances of one of one of the other climbers), who suggested using the Cinch on fixed ropes along portions of the route leading up to the ridgeline. This portion of the route encountered 40o+ slopes of snow, ice crusts, verglas, and some steeper rock nearing vertical. We all were concerned we pass through portions of this route quickly, to minimize exposure to slides along some sections, as well as maximizing productivity while weather permitted. Your comments compelled me to do some research; I discovered in fact several other aspects of how we used the Cinch were not per the manufacturer’s recommended practices. Looking back, I wonder why the guides suggested using the Cinch in the first place, over ascenders or other hardware. If I can get back to these folks, I will follow up with their comments.

Tokyo Bill:
Sharp end of the rope is the climbing end; the tag end is the other end.
Respecting Bill’s request that we avoid technical discussions that could confuse, thus lead others to injury, I will limit further comments of this topic, stating you should contact equipment manufactures, or the one of the guide service that originally provided your instruction, per rope set up for solo climbing.
Ed

August 21, 2014
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