Do you trust one bolt?

J. Albers wrote: I don't. I think that Fixe setup is pretty darn stupid (I'm referring to the picture that Brian posted). Why the F would you take what would be a redundant anchor and then make it non-redundant by clipping the chain into the rap ring and thereby forcing the climber to rappel off of one piece of gear. Yes, I understand that those rap rings are truck, won't ever break, blah blah. That does not change the fact that you have created a non-redundant anchor. Is it really that hard to simply thread the rope through the chain and the ring separately? Of course not. I simply don't understand the upside to this setup other than exchanging redundancy for a marginally cleaner setup. I've had to rap off of plenty of junk anchors in the mountains and that's fine, but when you have the choice, why not make it is safe and redundant as possible. ...and to Jim from Germany. The bolting and anchor setups in the Frankenjura are not what I hope to see here in the States. Many of the routes that I did had plenty of ground fall potential and on top of that, you had to rap off of a single glue-in. Not exactly ideal in my book. However, I will admit that most of Europe seems to be heading towards using SS hardware at all times, and I wish American bolters would emulate this.

I get what you're saying. Mostly I like that they are oriented slightly apart and vertical instead of next to each other horizontally. The obvious advantage being decreased angles and if the rock is dubious being far apart. It would also save some chain for whomever is installing the anchor being that there's only chain on one bolt. A single link on the other bolt would be ideal for redundency. Pull them together, clip or thread and go.

Jim Titt wrote: Vertical bolt placement has no connection with the strength since by definition all parts of the anchor are strong enough. The reason for vertical alignment of two seperate bolts or rings is to reduce friction and twisting of the rope. With inline chainsets the normal recommendation is to fit them at a 30° angle from vertical if possible as they become easier to multiple clip without the upper karabiner(s) interfering with anything lower.

This is incorrect. The angle absolutely changes the overall strength of the anchor. Go do a search on the American Triangle and you will understand why the angle between the bolts is important.

Brian in SLC wrote: One rappel ring, one rappel carabiner, one rappel device, one harness, one rope. Which do you think the weakest link is? Besides the climber...ha ha.

What is the weakest link?

Definitely my feeble arms and reptilian brain...(grin).

That said, read my response to DannyUncanny above. In short, I understand that there are parts of the system that will always lack redundancy. Fine. But why would you remove redundancy when it is super easy and simple to include it? It just doesn't make sense to me.

fat cow wrote: I get what you're saying. Mostly I like that they are oriented slightly apart and vertical instead of next to each other horizontally. The obvious advantage being decreased angles and if the rock is dubious being far apart. It would also save some chain for whomever is installing the anchor being that there's only chain on one bolt. A single link on the other bolt would be ideal for redundency. Pull them together, clip and go.

Agreed. I think the vertical setup is ideal if you simply add a quicklink to the end of the chain and simply leave it flush with the lower bolt rap ring. This way, you get all of the advantages you mentioned, plus the anchor is 100% redundant. Easy, simple, done.

I love J. Albers constructive criticism. Sounds like you're a "bolt" expert who has taken to many philosophy 103 logic courses.

I'm just curious, have you ever replaced any bolts and inspected an old quarter incher? I find it funny you have your panties up in a bunch about the euro style vertical chain placements redundancy flaw when they're brand new expansion bolts.

Get back to me on the rating of a single fatty rappel ring, and let me know if you're still worried.

Too duh loo.

As for the actual topic, rappelling off one bolt is just scary, even if it's bomber. I've had to rap off a single bolt twice. Once was when I was replacing an anchor and the drill battery died, and another was in Zion when the last pitch had a single bolt.

Thanks for all the opinions.

If Bob D' placed the bolt, I'd hang off of just one.

don't worry slim... you are too slim to pull that bolt out, carry on.

I'm fine clipping to a single bolt when rapping.

J. Albers wrote: This is incorrect. The angle absolutely changes the overall strength of the anchor. Go do a search on the American Triangle and you will understand why the angle between the bolts is important.

No, my statement is correct.

While I could do a search on the American Death Triangle it is easier for me to open the file on my computer since I´d guess I´ve one of the largest amounts of test data on the ADT in the world.
Some years ago we were commisioned to do the testing on various ADT scenarios and naturally the two-point, horizontally orientated abseil/lower-off was included, we ran quite a few different geometries through right up to the 120° included angle which in real life is virtually impossible to achieve abseiling.
To break a bolt conforming to EN959 with a 120° ADT you require a radial load in excess of 25kN and to achieve this with an ADT you need to impose a force on the central point (the abseiler) of 30.12 kN.
In reality most if not all manufacturers make their equipment a bit stronger than the requirements of EN959 and for the chainset shown the manufacturers conservatively give 30kN for the hanger and a 10mm wedge bolt holds ca 38kN so to break the hanger (the weak point) we need a load of over 36kN.

Since these forces will destroy all the rest of the equipment in the system (abseil device, karabiner, harness etc), possibly the rope and naturally the abseiler themselves clearly my statement that all parts of the anchor are strong enough is true.

Using normal climbing rope it is impossible to maintain an ADT with 120° included angle anyway and we were unable to ever achieve the minimum rated strength required for the bolt before rope failure.

Inline chainsets to a single attatchment point are more versatile for installation, use less material and resources, cheaper, have lower friction, reduce twisting and are the system of choice for 99% of applications. No known case of failure has ever been reported and they are accepted as standard fitment in European climbing walls.

i trust a single bolt ... i try not to trust the rock the single bolt is in if i can help it ...

the bolt itself does not fail ... the rock or the poor installation of the bolt may fail ...

the question is how much do you trust the rock or the person who put the bolt iin ...

bearbreeder wrote:the question is how much do you trust the rock or the person who put the bolt iin ...

+1

however, out of principle i even would usually back up a single bolt that 'I' place.

Jim Titt wrote: Inline chainsets to a single attatchment point are more versatile for installation, use less material and resources, cheaper, have lower friction, reduce twisting and are the system of choice for 99% of applications.

They're also simple.

Mine aren't cheaper. All stainless. Between the bolts and the anchor, that system runs me around 37 bucks per set.

Another thing I like about that set up, is, if folks want to siege TR off it, they're more likely to back it up. You can run the rope through the ring, add a draw, positioned to take the weight, and, TR all day. Last person up, no matter how experienced, takes the draw off and doesn't have to worry about threading the rope: just lower off. Easy, safe.

Easy to add a biner, rapide, rapide and ring if you don't like the single ring.

Jim, 'preciate your info! Thanks.

Brian in SLC wrote: All stainless.

Thanks for investing in the SS hardware. I really wish the rest of the community would do the same.

Jim Titt wrote: No, my statement is correct. While I could do a search on the American Death Triangle it is easier for me to open the file on my computer since I´d guess I´ve one of the largest amounts of test data on the ADT in the world. Some years ago we were commisioned to do the testing on various ADT scenarios and naturally the two-point, horizontally orientated abseil/lower-off was included, we ran quite a few different geometries through right up to the 120° included angle which in real life is virtually impossible to achieve abseiling. To break a bolt conforming to EN959 with a 120° ADT you require a radial load in excess of 25kN and to achieve this with an ADT you need to impose a force on the central point (the abseiler) of 30.12 kN. In reality most if not all manufacturers make their equipment a bit stronger than the requirements of EN959 and for the chainset shown the manufacturers conservatively give 30kN for the hanger and a 10mm wedge bolt holds ca 38kN so to break the hanger (the weak point) we need a load of over 36kN. Since these forces will destroy all the rest of the equipment in the system (abseil device, karabiner, harness etc), possibly the rope and naturally the abseiler themselves clearly my statement that all parts of the anchor are strong enough is true. Using normal climbing rope it is impossible to maintain an ADT with 120° included angle anyway and we were unable to ever achieve the minimum rated strength required for the bolt before rope failure. Inline chainsets to a single attatchment point are more versatile for installation, use less material and resources, cheaper, have lower friction, reduce twisting and are the system of choice for 99% of applications. No known case of failure has ever been reported and they are accepted as standard fitment in European climbing walls.

At this point, this is a semantic argument, but considering it has started...oh well.

I think you are missing the point of what I am saying. First, your argument that the angle of the bolts does not in general make any practical difference in the anchor strength is correct. By the time you have applied enough force to break bolts out of the rock at any angle, you are likely going to have other failures in the system (the rope, the harness, etc.). However, this does not change the fact that the overall strength of the setup is decreased as you increase the angle between the bolts. You don't need test data to verify this....all you need is an undergraduate physics text book. In fact, I bet I can walk into my office and get any number of introductory physics students to draw a free body diagram describing why bolts placed vertically produce a stronger anchor setup than bolts placed horizontally.

Now in my mind, neither of the arguments above are to be taken as 100% accurate. Why? Because both arguments are predicated upon having perfect bolt installation, good rock, zero bolt corrosion, etc. In reality, many of these types of complications, while controlled for by a careful bolter, can never be completely dismissed. Everyone makes mistakes, including experienced bolters. Moreover, no manufacturing process is perfect either; thus there will inevitably be faulty hardware floating around that looks fine, but doesn't meet spec. IMHO, these are the reasons to include two bolts in an anchor, and to not rely on a single rap ring when designing and implementing an anchor setup. In short, why introduce additional potential weak links into your anchor system when you can easily avoid it? You can provide me with all of the lab test data in the world, but it won't convince me that the conditions of actual bolts in the real world will necessarily meet the standards that you find in a controlled lab test environment.

There, my idiotic rant is over. Back to grading.

I can see different points of view here, but I definitely agree with J Albers the most on this issue. It is kind of silly to arbitrarily make a would-be perfect anchor less redundant by having only 1 ring (regardless of the ring strength).

My preferred set up for rap stations are the vertically oriented bolts, but I usually make the whole system redundant, either with chain or (usually) cable, but always 2 rings or fixed biners. With shared (and hanging) belay/rap stations I like to place them horizontally for the sake of reducing the clutter caused by two or more climbers suspended from the single point on a horizontal plane.

I know that there are a few things that we as climbers have to depend on soley, but some the ones that were stated eariler are actually quite easily and commonly avoided.

For example: Redundancy for a poor belayer is a gri gri. Redundancy for harnesses are the multiple attachments (that's why we don't tie into just the belay loop). Redundancy for ropes can be doubles. Also, it's easy to add another rap loop and/or biner to a harness if redundancy is desired there. Plus, if either one of those failed, at least I have a hold of the rope which could be considered as redundancy on slab - I know it probably wouldn't matter on anything steeper than that, but it does give me peace of mind.

I think the point is that it's better to err on the side of caution when it's so easy to set it up that way.

But to answer the original question, yes, I rap from single bolts fairly often, but they are usually mine. If one did fail, at least I could "live" with it being my own doing.

Just my 2 cents...

bearbreeder wrote:i trust a single bolt ... i try not to trust the rock the single bolt is in if i can help it ... the bolt itself does not fail ... the rock or the poor installation of the bolt may fail ... the question is how much do you trust the rock or the person who put the bolt iin ...

bolts can and do deteriorate over time. i broke an old buttonhead just clipping a draw into it. i know the person who placed it, and they are competent. it was probably a good installation when they put it in in the mid 80's. it looked like the shaft had a small pit or some other material defect, and then rust chewed away at it over time.

also, i'm not a fan of the vertically oriented or diagonally oriented anchor set ups. with the horizontal setup you just put 2 same-length draws in and you're done. with the vertical setups you end up horsing around extending, shortening, wrapping the sling around the biner few times, etc. just unnecessarily complicates things for when you want to set up a TR, or when you are rapping.

While I have never actually used one of those inline anchors, I'd have no trouble trusting one. The anchor *is* redundant, except for the rap ring, but that burly ring isn't going anywhere.

And yes, if the circumstances required it I'd rap off a single bolt. I frequently only clip into one bolt at the anchor anyways (yes I'm gonna die, but I haven't yet). Now, if I was climbing on some forgotten sandstone line in the middle of nowhere that had manky rusted out spinners on it, I'd back it up, but usually the anchors are super bomber.

Are the chains on Scarface in IC still tearing up the rock from blowing in the wind. The vertical arrangement looks like a good solution to that problem.

I'll do just about anything to avoid rapping off of a single bolt..

awesome rappel anchor we left on the wigwam dome for those without a 70 (and don't care to walk off)