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Rudmin


Nov 9, 2009, 7:27 PM
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Re: [dingus] An anchor to analyze [In reply to]
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I think everyone can agree that it is more likely than not safe enough, but not great. Anybody have any idea what the level of risk of the anchor failing under climbing use is? I would be pretty sure that the chance of failure is less than 20% over the course of a day's use, but maybe higher than 1%

What amount of risk does each little "mistake" add? Like a biner on biner connection coming unclipped? Probably 1/100 chance of that happening. A gate being forced open + having enough force to break the open gated biner? Probably almost nil when top roping kids.


altelis


Nov 9, 2009, 7:43 PM
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Re: [Rudmin] An anchor to analyze [In reply to]
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Rudmin wrote:
I think everyone can agree that it is more likely than not safe enough, but not great. Anybody have any idea what the level of risk of the anchor failing under climbing use is? I would be pretty sure that the chance of failure is less than 20% over the course of a day's use, but maybe higher than 1%

What amount of risk does each little "mistake" add? Like a biner on biner connection coming unclipped? Probably 1/100 chance of that happening. A gate being forced open + having enough force to break the open gated biner? Probably almost nil when top roping kids.

And were you aware that you have a 6/45 chance that some random person on the webz will "cite" made up statics 85.7% of the time, every time?


reno


Nov 9, 2009, 7:50 PM
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Re: [altelis] An anchor to analyze [In reply to]
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altelis wrote:
Rudmin wrote:
I think everyone can agree that it is more likely than not safe enough, but not great. Anybody have any idea what the level of risk of the anchor failing under climbing use is? I would be pretty sure that the chance of failure is less than 20% over the course of a day's use, but maybe higher than 1%

What amount of risk does each little "mistake" add? Like a biner on biner connection coming unclipped? Probably 1/100 chance of that happening. A gate being forced open + having enough force to break the open gated biner? Probably almost nil when top roping kids.

And were you aware that you have a 6/45 chance that some random person on the webz will "cite" made up statics 85.7% of the time, every time?

The funny statistics reference notwithstanding, the other question to ask is "What percentage of risk am I, personally, willing to accept?"

Trite though it may sound, a 10% risk of total failure might be acceptable to one person, and 10 times too high for another. 20% is too high for you... I'm OK taking the 1 in 5 chance.

Each... his own... something like that.


dugl33


Nov 9, 2009, 8:02 PM
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Re: [Rudmin] An anchor to analyze [In reply to]
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In my opinion, odds of failure would be very low if we are assuming the pieces are solid.

My failure scenario would be as follows.

Dad is taking his kids to fat camp, but pulls off to toprope a scruffy bluff at New Jack City. Dad notices a hot sport climber in prana shorts and sports bra, and fails to notice his rather jumbo child has moved upward developing seven feet of slack. The kid has also wandered to the right a bit. Kid breaks a hold, pops off, and all the load goes to the rigid stem friend at the top. The rock, despite looking good, is loose and friable, and the cam pulls. The load drops to the nut, shock loading it, and it pulls. Finally the load swings to the .75 old school camalot, which, despite its apparantly bomber appearance, also pulls, with no apparent benefit from the load already reduced by the failure of the upper pieces.

Or, the kid just manages to unclip the rope when arriving at the top, and peels to the desert dust-pile, amid the beer cans and shotgun shells.

(Of course, my own anchor set-up would look like it was straight from the AMGA guidebook)


kylekienitz


Nov 9, 2009, 8:23 PM
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Re: [dingus] An anchor to analyze [In reply to]
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dingus wrote:
kylekienitz wrote:
dingus wrote:
kylekienitz wrote:
In effect it is a two piece anchor with a backup.

Otherwise known as a 3-piece anchor.

DMT

Well, yeah that's true. However, usually when I think of a three piece anchor all three pieces play a role in absorbing the load.

That is an illusion I assure you.

DMT

HAHA Well thank you Dingus, I feel greatly assured.


kylekienitz


Nov 9, 2009, 8:34 PM
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Re: [reno] An anchor to analyze [In reply to]
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reno wrote:
"What percentage of risk am I, personally, willing to accept?"

Personally I don't see much reason to risk it for TR. If you have the means to make a bomber anchor, why not? Multipitch- sure things might get a bit dicey, you might have to get a bit creative with the anchors, the risk factor might rise. Not because you don't know how to make good anchors, but because the situation demands it. TR, not much demand for risk there... most of the time anyway.


reno


Nov 9, 2009, 8:41 PM
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Re: [kylekienitz] An anchor to analyze [In reply to]
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kylekienitz wrote:
reno wrote:
"What percentage of risk am I, personally, willing to accept?"

Personally I don't see much reason to risk it for TR.

That's the rub, though... Risk WHAT?

Would you accept a TR anchor with a 1% chance of total failure? A 2% chance? 3? Where is your line?

That's the question. There is no answer that fits all.


kylekienitz


Nov 9, 2009, 8:54 PM
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Re: [reno] An anchor to analyze [In reply to]
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reno wrote:
kylekienitz wrote:
reno wrote:
"What percentage of risk am I, personally, willing to accept?"

Personally I don't see much reason to risk it for TR.

That's the rub, though... Risk WHAT?

Would you accept a TR anchor with a 1% chance of total failure? A 2% chance? 3? Where is your line?

That's the question. There is no answer that fits all.

It is strange to really think about it in percentages like that. It gives me the shivers.

I'll just go back to my 'safe as possible in the particular situation' ideal.


(This post was edited by kylekienitz on Nov 9, 2009, 8:55 PM)


jt512


Nov 9, 2009, 9:00 PM
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Re: [reno] An anchor to analyze [In reply to]
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reno wrote:
kylekienitz wrote:
reno wrote:
"What percentage of risk am I, personally, willing to accept?"

Personally I don't see much reason to risk it for TR.

That's the rub, though... Risk WHAT?

Would you accept a TR anchor with a 1% chance of total failure? A 2% chance? 3? Where is your line?

That's the question. There is no answer that fits all.

While risk is a personal matter, you guys are off of what is rationally acceptable by several orders of magnitude. It would be insane to accept a 1% chance of a TR anchor failure. That would more-or-less guarantee that practically every climber who TRs on a regular basis would die or be critically injured due to TR failure during his TR career. For comparison, sport parachutes have a failure rate of about 1/1000, and you carry two of them; so your chances of dying on any given jump are on the order of one chance in 1 million.

Jay


bennydh


Nov 9, 2009, 9:16 PM
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Re: [kylekienitz] An anchor to analyze [In reply to]
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kylekienitz wrote:
reno wrote:
kylekienitz wrote:
reno wrote:
"What percentage of risk am I, personally, willing to accept?"

Personally I don't see much reason to risk it for TR.

That's the rub, though... Risk WHAT?

Would you accept a TR anchor with a 1% chance of total failure? A 2% chance? 3? Where is your line?

That's the question. There is no answer that fits all.

It is strange to really think about it in percentages like that. It gives me the shivers.

I'll just go back to my 'safe as possible in the particular situation' ideal.

Percentages whaaaa? All this thinking inside the box with narrow minded logic. Why not try to will the safety margins in your favor. If you will the send to happen, and your sending chi is centered, you eliminate all risk.

...and what does it mean to fail anyway... death maybe, but death is a new beginning; you can come back as an eagle... or a dragon!


Partner robdotcalm


Nov 9, 2009, 9:27 PM
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Re: [jt512] An anchor to analyze [In reply to]
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jt512 wrote:
While risk is a personal matter, you guys are off of what is rationally acceptable by several orders of magnitude. It would be insane to accept a 1% chance of a TR anchor failure. That would more-or-less guarantee that practically every climber who TRs on a regular basis would die or be critically injured due to TR failure during his TR career. For comparison, sport parachutes have a failure rate of about 1/1000, and you carry two of them; so your chances of dying on any given jump are on the order of one chance in 1 million.

Jay

That assumes the failure of the second parachute is independent of the failure of the first? Is this the case? I've seen videos of one parachute not deploying properly and when the 2nd parachute is opened it entangled with the first. That's why I'm asking the question.

Cheers,
Rob.calm


kylekienitz


Nov 9, 2009, 9:28 PM
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Re: [bennydh] An anchor to analyze [In reply to]
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Obviously percentages are bogus, considering the huge gray areas concerning rock quality, equipment, and the hundreds of things outside our control. Who knows how high they get? I bet we have all, in certain situations, operated under 'risk percentages' much higher than anyone would be comfortable with if it was expressed as a number.

Kind of one of those 'how close have you come to dying how many times' kind of questions. Kind of creepy to think about, most of the time we don't.


Rudmin


Nov 9, 2009, 9:39 PM
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Re: [dugl33] An anchor to analyze [In reply to]
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dugl33 wrote:
In my opinion, odds of failure would be very low if we are assuming the pieces are solid.

My failure scenario would be as follows.

Dad is taking his kids to fat camp, but pulls off to toprope a scruffy bluff at New Jack City. Dad notices a hot sport climber in prana shorts and sports bra, and fails to notice his rather jumbo child has moved upward developing seven feet of slack. The kid has also wandered to the right a bit. Kid breaks a hold, pops off, and all the load goes to the rigid stem friend at the top. The rock, despite looking good, is loose and friable, and the cam pulls. The load drops to the nut, shock loading it, and it pulls. Finally the load swings to the .75 old school camalot, which, despite its apparantly bomber appearance, also pulls, with no apparent benefit from the load already reduced by the failure of the upper pieces.

Or, the kid just manages to unclip the rope when arriving at the top, and peels to the desert dust-pile, amid the beer cans and shotgun shells.

(Of course, my own anchor set-up would look like it was straight from the AMGA guidebook)

What would be much more feasible than each piece consecutively blowing out is that the climber gets to the top, stands up above the anchor with the ropes tight and then sits back down. The rope pulls across both gates and unclips itself. Even that would be a hard move to pull off, but it only needs one thing to go wrong.


curt


Nov 9, 2009, 9:58 PM
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Re: [johnwesely] An anchor to analyze [In reply to]
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johnwesely wrote:
justroberto wrote:
budman wrote:
Metal to Metal?
Aluminum biners get loaded over small-profiled metal hangers worldwide countless times a day without incident. Why would this be any worse?

Because two biners clipped together have a tendency to unclip themselves.

I hate that and keep telling them to not do that.

Curt


curt


Nov 9, 2009, 10:11 PM
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Re: [jt512] An anchor to analyze [In reply to]
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It's ugly for sure, but, assuming the rock is good, the only real issue I would have (as others have pointed out) is with the two MP biners not being opposed.

Curt


jt512


Nov 9, 2009, 10:24 PM
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Re: [robdotcalm] An anchor to analyze [In reply to]
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robdotcalm wrote:
jt512 wrote:
While risk is a personal matter, you guys are off of what is rationally acceptable by several orders of magnitude. It would be insane to accept a 1% chance of a TR anchor failure. That would more-or-less guarantee that practically every climber who TRs on a regular basis would die or be critically injured due to TR failure during his TR career. For comparison, sport parachutes have a failure rate of about 1/1000, and you carry two of them; so your chances of dying on any given jump are on the order of one chance in 1 million.

Jay

That assumes the failure of the second parachute is independent of the failure of the first? Is this the case? I've seen videos of one parachute not deploying properly and when the 2nd parachute is opened it entangled with the first. That's why I'm asking the question.

The first parachute is supposed to be jettisoned before the reserve is deployed. With some systems this is automatic; with others, it must be done manually. Either way, if there is a failure to jettison the first chute, then failure of the reserve, due to entanglement with the main parachute, is almost guaranteed.

Jay


johnwesely


Nov 10, 2009, 5:32 AM
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Re: [jt512] An anchor to analyze [In reply to]
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jt512 wrote:
While risk is a personal matter, you guys are off of what is rationally acceptable by several orders of magnitude. It would be insane to accept a 1% chance of a TR anchor failure. That would more-or-less guarantee that practically every climber who TRs on a regular basis would die or be critically injured due to TR failure during his TR career.
Jay

I think you are forgetting that top ropers are a radical bunch who like to live life on the edge.


hansundfritz


Nov 10, 2009, 6:09 AM
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Re: [bennydh] An anchor to analyze [In reply to]
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bennydh wrote:
...and what does it mean to fail anyway... death maybe, but death is a new beginning; you can come back as an eagle... or a dragon!

Sounds like something a belayer should never shout up as encouragement to the cruxed-out leader.


LostinMaine


Nov 10, 2009, 6:12 AM
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Re: [jt512] An anchor to analyze [In reply to]
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My first rule of anchor building is always sound placement of individual anchor pieces. We can't really tell that from the photos, but they look sound enough.

Years ago, people didn't always equalize anchors, but catastrophic failures were rare because the individual placements were sound, or high FF falls were rare. It is only recently that we have gotten caught up in the SRENE analysis technique (which isn't a bad thing). There is a reason that the "S" comes first.

Opposite and opposed 'biners would be quite helpful for this setup, though.

So Jay, did the anchor take falls and lowering? Was anyone hurt by this setup?


kappydane


Nov 10, 2009, 6:18 AM
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Re: [reno] An anchor to analyze [In reply to]
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In the situation, the size of the kids and how the anchor were tested would seem relevant. If the kids are small and you are a normal sized adult and you load tested the anchor with your body weight, the risk goes way down. If an anchor can hold a jump loaded 170lb adult, I would trust a 70lb kid climbing on it on top rope.


kachoong


Nov 10, 2009, 6:36 AM
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Re: [dugl33] An anchor to analyze [In reply to]
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dugl33 wrote:
4.) gear is old -- old style .75 camalot, rigid stem friend.

dugl33 wrote:
Finally the load swings to the .75 old school camalot, which, despite its apparantly bomber appearance, also pulls, with no apparent benefit from the load already reduced by the failure of the upper pieces.

Why you hatez on the U-stem? Whyz? I have one and use it in anchors.


madscientist


Nov 10, 2009, 6:43 AM
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Re: [jt512] An anchor to analyze [In reply to]
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One of the reasons this anchor is "bad" is that it can be easily improved considerably with the gear already there. Reverse the anchor biners and clip the nut to the lower draw. Reverse the biner clipped to the nut. No more gear (possibly less since you might remove some biners), better equalized, and should take less than a minute.

I personally have climbed an anchors like this, but this one is just too easy to make much better.


Partner j_ung


Nov 10, 2009, 7:47 AM
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It's not a certain death sentence, but they guy who built it is running more on luck than skill.


qtm


Nov 10, 2009, 9:34 AM
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Re: [j_ung] An anchor to analyze [In reply to]
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Looks like if the forged friend fails, that biner is going to fall across the gate of the other and unclip the "backup".

Would have been simple to clip the backup to the draw holding the rope.


johnwesely


Nov 10, 2009, 9:45 AM
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Re: [hansundfritz] An anchor to analyze [In reply to]
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hansundfritz wrote:
bennydh wrote:
...and what does it mean to fail anyway... death maybe, but death is a new beginning; you can come back as an eagle... or a dragon!

Sounds like something a belayer should never shout up as encouragement to the cruxed-out leader.

I was climbing an R/X rated route once, and about half way up, my belayer yelled up, "If you fall here you are seriously going to die". I yelled back down, "I know that, but thanks for breaking my concentration". He knew from the outset that there was no pro on the route.

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