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stevep
Jun 4, 2004, 4:28 AM
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Maybe it's just semantics Robert, but I'll stick with my original assertion, that saying "the GriGri failed" is a poor choice of words. It implies that the GriGri did not act as designed when used properly. As far as I can tell from the accident report, the GriGri behaved properly. There was no definite conclusion on the accident report, only a possible scenario about a piece of rock getting sucked in (and one that they were not able to duplicate in testing).
Granted there are possible failure modes with a GriGri (threading backwards), and I'll agree with you on the inattentiveness problem. But these things happening still wouldn't mean the GriGri failed. It means the person using it failed. If someone put a rope through an ATC, but failed to put it through the locking biner, you wouldn't say the ATC failed would you?
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rescueman
Jun 4, 2004, 3:50 PM
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In reply to: Rapell backups a recipe for disaster? Bullsh!t.
What's Bullsh!t is that you didn't read my post. I was responding specifically to pneumoped's post about placing a prussik above the rappel device, and I suggested the safer alternative of an autoblock below the rappel device, which has become the standard for a rappel backup.
In reply to: About the tendancy of a panicky falling rapeller to grab the prussik, I guess if you are going to panic in a fall then you should not be climbing anyway
This is an insult to the extremely experienced vertical cavers (who are the real experts in rappeling) who have lost their lives because of this automatic panic response that every human being is susceptible to.
We know from vehicle accident studies that it takes the conscious mind about a second to respond in an emergency. In a motor vehicle, that means you're already through an intersection before you can hit the brake. On rappel, with your hand on the overhead prusik (where you will not experience rope burn until the prusik melts) it means you'll be travelling 22 mph downward and will have dropped 16' before you can even react.
So let's be very clear: a prussik above the rappel device has been demonstrated to be both inconvenient and potentially deadly. A friction hitch (typically autoblock) below the rappel device has become the accepted standard for safe, efficient, and easy rappel backups. The only caveat is that the lower friction hitch cannot be allowed to reach the rappel device or it will either jamb the device or be rendered ineffective.
- Robert
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rescueman
Jun 4, 2004, 4:09 PM
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In reply to: As far as I can tell from the accident report, the GriGri behaved properly. There was no definite conclusion on the accident report
In reply to: If someone put a rope through an ATC, but failed to put it through the locking biner, you wouldn't say the ATC failed would you?
Your example is obviously a case of "operator error". The accident report did indicate that the climbers were careful in their use of the Grigri, including a ground pad to protect it from the gravel. There was no clear "operator error" in this case - the Grigri was used as intended (or at least not in any way that was specifically prohibited by the manufacturer).
My contention is that it was the design of the Grigri which made it possible, under these circumstances, for the tiny piece of gravel to both get sucked into the device and to get lodged in such a way that it would tear the rope.
There are other ascending and rappelling devices on the market that might have similar problems.
This is NOT a critique of Petzl. I have great respect for their product line. It is a problem associated with devices with internal parts which cannot be inspected during use.
And my further contention is that the more complicated we make our gear the more likely will there be an unexpected failure mode.
KISS - keep it simple and safe.
- Robert
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csoles
Jun 4, 2004, 4:46 PM
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In reply to: In reply to: As far as I can tell from the accident report, the GriGri behaved properly. There was no definite conclusion on the accident report The accident report was very thorough and very professional. It's authors were careful not to state a definite conclusion, but the overwhelming amount of evidence (including the scratch on the cam) indicated beyond any reasonable doubt that the rope tearing was due to a sharp crystaline rock embedded in the cam.
Stevep is right. This was operator error, not a failure of the device. If the GriGri had been rigged up off the ground, nothing could have been sucked in. Had a tube type device been used with that rig, a rock could still get inside and lodged without notice since the belayer usually stands away and isn't looking inside. Rigging any belay device next to the ground is a bad practice, period.
I don't recall any climber fatatilities from a prusik above (citations?), though there were some cavers lost decades ago. An autoblock below also has some real problems that users must be aware of or face serious consequences.
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stevep
Jun 4, 2004, 4:50 PM
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Robert, maybe you and I read different versions of the accident report, but it very clearly states that no one of the possible failure scenarios was preferred over any other, and that despite many tests, they were never able to get a foreign object in the GriGri to damage the core. If we want to talk about keeping it simple, it seems to me that the simplest explanation is that an external edge caused the ultimate failure, as ropes do get cut by rock edges, both in the real world and in the lab.
Certainly its possible that the foreign debris in the GriGri did cause this accident, but my reading of the report is that this is far from proven, and as such, its not responsible to title the post "GriGri failed".
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killclimbz
Jun 4, 2004, 4:52 PM
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In reply to: The accident report was very thorough and very professional. It's authors were careful not to state a definite conclusion, but the overwhelming amount of evidence (including the scratch on the cam) indicated beyond any reasonable doubt that the rope tearing was due to a sharp crystaline rock embedded in the cam.
It seems to me that they were unable to replicate this accident in any of the scenarios. I do not think that this proves beyond a reasonable doubt as to how this happened. I agree that this seems to be the most likely scenario. I also think that a similar scenario could happen with a belay device. I also agree that the opening statement about Gri Gri failure is misleading. Will I watch out for this scenario when using a Gri Gri and or belay plate? You bet. Sometimes you can just do everything right and it still goes wrong. Maybe with a belay plate it would have been easier to tell that something was wrong and would have been able to do something about it before it became catastrophic. I don't know. What I do know is a climbing brother was lost and I am saddened by it. My condolences.
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overlord
Jun 4, 2004, 4:58 PM
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the question presents itself:
In reply to: on the edge of the cliff on a piece of canvas being used as edge protection
why did the grigri lie on the floor??? or am i not understanding correctly. i alwas belay with grigri "from hand" becasue i hate the feel it has when its attatched to the anchor.
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alpnclmbr1
Jun 4, 2004, 5:22 PM
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In reply to: the question presents itself: In reply to: on the edge of the cliff on a piece of canvas being used as edge protection why did the grigri lie on the floor??? or am i not understanding correctly. i alwas belay with grigri "from hand" becasue i hate the feel it has when its attatched to the anchor.
This is one thing that I understand least about the sar report. They apparently think that this anchor configuration is reasonable and appropriate. (given the response in the thread so do most of us?)
I think it is nuts and I would never use that set up and I have never seen anyone use that set up with any kind of belay device.
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sandstone
Jun 4, 2004, 5:28 PM
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Since the concern (in this sub-discussion) is that the rappel rope could be cut by route cleaning debris falling into the Gri-Gri, pneumoped was absolutely correct in suggesting that the backup should be placed above the Gri-Gri. A backup placed below the Gri-Gri is useless if the rope is severed by debris in the Gri-Gri.
On "normal" rappels (just rappelling, not cleaning a route) I don't think debris in the device is much of a concern -- just take the normal precautions to keep loose things away from the device.
My take on the accident is that it was freak occurence, and may never happen again -- but who knows? This unfortunate fatality has made it clear to me that a severed rope is something I need to consider when I am cleaning a route and generating a lot of debris.
Rescueman was also correct, normally the best placement for a rappel backup is below the device. This is well documented. I gave up on "above the device" rappel backups more than 20 years ago based on reports of multiple fatalities due to associated failures or problems.
I'll continue to use my Gri-Gri for rapping down to clean routes. It's the right tool for the job. The only thing that will change will be my backups, from now on I'm going to use knots on a second rope. A backup above the Gri-Gri might be OK, but for me it'll be a second rope.
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rescueman
Jun 4, 2004, 6:10 PM
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In reply to: Robert, maybe you and I read different versions of the accident report, but it very clearly states that no one of the possible failure scenarios was preferred over any other ... and as such, its not responsible to title the post "GriGri failed".
Do you own stock in Petzl?
There is only one version of the accident report written by Midwest Technical Training Associates on August 21, 1999.
http://www.esssar.org/...ts/Public_Report.pdf
The only unresolved question was whether the debris in the Grigri or the rock edge caused the final failure of the core after the debris in the Grigri caused extensive sheath damage and exposure of the core:
3.4 UNRESOLVED QUESTIONS
…the investigators are unable to definitively determine how the core was ultimately severed once the sheath was damaged and the core bundles exposed.
The conclusions were very clear and stated as a likelihood only because there was no way to conclusively "prove" that this scenerio occured (they use the term "likely" in the same way that a laywer is required to use the term "alleged" when describing criminal action):
3.5 FINAL CONCLUSIONS
…At some point a foreign object was likely introduced into the Grigri… the debris was likely introduced during normal climbing activities… the object in question was probably no more than a centimeter in diameter with one or more small, very sharp edges… After less than 7 feet of rope traveled through the Grigri, the debris became trapped and a sharp edge began to tear the rope's sheath… At several points along this sheath damage the rope's core was exposed… Nearly immediately the rope parted.
You'll notice, however, that in this recommendation, the design problems of the Grigri are stated as "facts":
4.1 RECOMMENDATIONS TO THE CLIMBING COMMUNITY
4.1.4 Use of the Pezl Grigri
Due to the facts that a) foreign objects can become introduced into the Grigri unbeknown to the belayer, b) this debris can cause damage to the rope, and c) the Grigri is very hard to handle when oriented horizontally, the investigators recommend that Petzl consider cautionary statements in its literature regarding poor handling characteristics and inability to clear debris when the device is used at or near a horizontal orientation.
- Robert
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rescueman
Jun 4, 2004, 6:23 PM
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In reply to: Since the concern (in this sub-discussion) is that the rappel rope could be cut by route cleaning debris falling into the Gri-Gri, pneumoped was absolutely correct in suggesting that the backup should be placed above the Gri-Gri. A backup placed below the Gri-Gri is useless if the rope is severed by debris in the Gri-Gri.
If your Grigri severed your rope on rappel (and I agree that this is a very unlikely scenario), a prussik above the device will do you no good. The spring from rope stretch will pull the cut end through the prussik before it can stop your descent.
In reply to: from now on I'm going to use knots on a second rope. A backup above the Gri-Gri might be OK, but for me it'll be a second rope.
This is the safest method for working on rope. It is the standard required by IRATA and SPRAT, the two professional organizations that set safe practices for international and US rope access work. And the most commonly used backup device is the Petzl Shunt.
- Robert
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sandstone
Jun 4, 2004, 7:58 PM
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Recueman wrote:
In reply to: If your Grigri severed your rope on rappel (and I agree that this is a very unlikely scenario), a prussik above the device will do you no good. The spring from rope stretch will pull the cut end through the prussik before it can stop your descent.
Rescueman, you state that last sentence as a definitive fact. Can you provide references to back that up?
I'm not trying to make you look bad, I'm just trying to separate the wheat from the chaff in this discussion.
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stevep
Jun 4, 2004, 8:08 PM
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No I don't own stock in Petzl. I do think they are a good company that makes many good products, including the GriGri. The GriGri has definite limitations, as do all other products from any company. As was pointed out above, debris trapped on the rope could get sucked into a tube type belay device and cause sheath damage. The report stated that the Grigri was generally very good at clearing such debris. Lesson here should be watch for debris stuck to your rope, not that the "GriGri failed"
As far as the other points made in the report:
"poor handling characteristics and inability to clear debris when the device is used at or near a horizontal orientation". This is incorrect use of the GriGri, and not recommended in Petzl's literature. I can't think of any photos or drawings I've seen in Petzl's literature that show GriGri's being used in anything other than a vertical orientation. Again, all I'm trying to get across is that the phrase "GriGri fails" is misleading, given that this implies a mechanical failure when used correctly. Maybe Petzl does need to be a little more clear that a horizontal orientation close to the ground is a bad thing, but I don't think it qualifies as a device failure.
"More than one individual commented that, in the investigations they had conducted, they found that only very small sharp edges are required to
severely damage or sever an unpadded rope under certain conditions. This lends some credence to the scenarios in which a sharp edge located a short distance from the GriGri severed the exposed core. No Symposium attendee refuted any of the investigators' findings or conclusions, nor did they prefer one scenario over another." I guess we can read what we want from different points in the SAR report, but this section says to me that a possible, if not likely, ultimate cause of the rope severing was a sharp edge in the environment, not inside the GriGri. Further this says that a large cross-section of industry experts did not favor a scenario in which the GriGri was the cause of failure (or any other scenario).
All that said, I want to make it clear that outside of the technical discussion we are having here, this was a very unfortunate accident, I am very sorry for all involved, and that I am not trying to assign blame to any one person or thing.
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rescueman
Jun 4, 2004, 9:50 PM
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In reply to: Recueman wrote: In reply to: If your Grigri severed your rope on rappel, a prussik above the device will do you no good. The spring from rope stretch will pull the cut end through the prussik before it can stop your descent. Rescueman, you state that last sentence as a definitive fact. Can you provide references to back that up?
References to what? My statement was a statement of the obvious to anyone who has any on-rope experience. If you've ever cut a loaded rope, you would know that it flies up like a rubber band (which is what it is designed to be).
A prusik, like any other friction device, does not stop the load instantaneously - there is always slippage since it has to be maintained in a loosened state in order to allow descent and tightens up enough to grab only after sufficient acceleration and friction (there is lots of documentation for this, but primarily for rescue loads - 450-600 lbs)
The only way a prusik could possibly catch you in such a scenario is if it was far enough above you on the rope that, after enough rope fed through on its rebound to seize the prusik, there was still some rope left before the prusik slipped off the cut end. But this would require that it be out of reach during rappel - an impossible scenario.
- Robert
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rescueman
Jun 4, 2004, 10:17 PM
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In reply to: "GriGri fails" is misleading, given that this implies a mechanical failure when used correctly.
No, not necessarily. A mechanical failure is one mode of failure. A functional failure due to its inherent design is another mode of failure. The function of the Grigri is to allow safe lowering, rappelling, and belaying. If it fails to perform as expected because of its design, then it has failed. And there have been many cases of functional failure, most of which are warned against in the Petzl technical bulletin that comes with the device.
See: http://www.thebmc.co.uk/.../articles/grigri.pdf
In reply to: I guess we can read what we want from different points in the SAR report, but this section says to me that a possible, if not likely, ultimate cause of the rope severing was a sharp edge in the environment, not inside the GriGri. Further this says that a large cross-section of industry experts did not favor a scenario in which the GriGri was the cause of failure (or any other scenario).
You're focusing only on "ultimate failure". The more important point is that the ultimate failure was secondary to the tearing of the sheath and would not have occured without that primary defect. The investigative report makes it clear that the use of the Grigri in a horizontal orientation (which is not mentioned in the warnings issued by the manufacturer) prevented it from clearing the debris which caused extensive sheath damage, exposing the cord and allowing the core to be cut (by whatever cause).
- Robert
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sandstone
Jun 5, 2004, 4:01 AM
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Rescueman wrote:
In reply to: References to what? My statement was a statement of the obvious to anyone who has any on-rope experience. If you've ever cut a loaded rope, you would know that it flies up like a rubber band (which is what it is designed to be).
References such as published test studies, or even your own tests. You made your statement as if it were a fact, I'm just asking you to back that up.
You say your statement is something that should be obvious to anyone who has any on-rope experience. My on-rope experience is small compared to some, it only goes back about 30 years, but your statement did not strike me as an obvious fact.
In reply to: A prusik, like any other friction device, does not stop the load instantaneously - there is always slippage since it has to be maintained in a loosened state in order to allow descent and tightens up enough to grab only after sufficient acceleration and friction (there is lots of documentation for this....
I'd like to read that documentation. Which titles are you talking about? If you've got the page numbers and everything, please post them.
In reply to: The only way a prusik could possibly catch you in such a scenario is if it was far enough above you on the rope that, after enough rope fed through on its rebound to seize the prusik, there was still some rope left before the prusik slipped off the cut end. But this would require that it be out of reach during rappel - an impossible scenario.
An impossible scenario huh?
We seem to be heavy on opinion and light on fact in this discussion, so I did my own test. Remember what we're talking about is a backup for a theoretical rope cut by debris in a Gri-Gri during a rappel (while cleaning a new route). The load would be body weight, and the load would be applied very quickly to the prusik if the rope were cut.
I positioned an 11mm rope, with the end about 6ft off the ground. I climbed up a step ladder and got on rappel near the end of the rope with an ATC, and rigged a prusik backup (6mm cord) above the ATC. The prusik sling was only about 18 inches long, it was very easy to reach. I hung a separate rope and tied into it with a figure 8 knot -- this was to keep me from hitting the ground if the prusik failed. Sounds like a lot of work, but I have a tall climbing wall in the warehouse with ropes already on it.
I rappelled (free hanging) to the end of the line (I mean I was holding the very last inch of the rope right against the ATC), then I let go. The prusik caught me. I caught me quick. It looked like the prusik didn't slip at all, because the rope would still easily reach the ATC.
I tried it again, this time pulling the prusik knot down real close to the ATC before I let go, so there was maximum slack in the prusik line. It caught me just fine. I tried it again, this time I loosened the prusik knot AND pulled it down close to the ATC. It caught me. I tried my best to make the prusik fail, but was unsuccessful -- it caught me every time.
I wanted to better simulate a rope being cut, i.e. a more sudden loading of the prusik (I wondered if those last few inches of rope sliding through the ATC were giving the prusik time to grab). I rigged a quick release mechanism by passing the rap rope straight through one of the slots of the ATC, then I clamped a pair of ViseGrip pliers onto the end of the rope. The rope was not rigged in rappel mode, it ran straight down through one slot of the ATC, and the full load was held only by the ViseGrip jammed agaist the bottom of the ATC. I flipped the lever on the ViseGrip to release it, and the prusik caught me. I tried it a few more times, and the prusik caught me every time.
I'm not endorsing an "above the device" prusik backup for rappelling (there are better ways to backup a rappel).
Rescueman, none of us can know everything, and none of us should try to. We should just try to help each other out with what we do know. Things that we are uncertain of, or that we cannot substantiate, should be stated as an opinion only. It's very clear in my mind that some of the things you are saying are just plain b_llsh_t. If we were discussing Barbie dolls in this forum, the difference between opinion and fact wouldn't matter, but it does matter here.
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rescueman
Jun 5, 2004, 1:00 PM
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In reply to: I'd like to read that documentation.
As I indicated, the test results are for rescue loads, typically falling 3 meters in a facter .3 fall. There are no tests that I'm aware of for single body weight because it is not necessary to set standards for personal recreation as it is for formal rescue activities - and for professional rope access, prusiks are not considered reliable.
For instance, according to Trango: "there is no agreed upon standard for testing belay devices. The UIAA, the CE, and the ASTM cannot agree on a common method."
The UK Health and Safety Executive study of personal protective equipment concluded about prusiks:
http://www.hse.gov.uk/...df/2001/crr01364.pdf
"Prusik knots clearly work. Some are better suited to holding large loads while others are more suitable when an easy release is required. The combination of main rope and prusik rope is critical to how the knot will behave. Even with the limited variety tested, significant differences are seen between the combinations. Great experience would be required to predict the behaviour of any combination. It would be more realistic to adopt one knot and rope combination, and experience its behaviour until its performance in different situations can be assured. For most situations, in rope access, a device would be available which would perform in a predictable fashion. Prusik knots are probably best suited to non-PPE applications such as hauling and suspending equipment."
For rescue loads, the test report most commonly referenced is:
http://www.pushdtp.com/trm/art/be.html showing single prusik slippage of between 20" and 38" before stopping the load. Other similar tests show similar results.
In reply to: We seem to be heavy on opinion and light on fact in this discussion, so I did my own test. Remember what we're talking about is a backup for a theoretical rope cut by debris in a Gri-Gri during a rappel (while cleaning a new route). I rappelled (free hanging) to the end of the line (I mean I was holding the very last inch of the rope right against the ATC), then I let go. The prusik caught me.
Your informal "test" in no way approximates what would happen in the event we're describing. How much rope were you hanging on? That determines the amount of stretch and hence spring energy in the rope after parting - there is an enormous difference between 20' and 100'. What was you velocity during rappel when the rope was "cut"? Sounds like zero according to your description.
What you performed seems to be a static test, not replicating the dynamic effects of both rappel velocity and rope rebound. Your methodology was seriously flawed.
If you feel that this anecdotal "evidence" of the security of a prusik backup is sufficient for you to rely on it, then (and this is my opinion) I suspect your 30 years of rope experience might come to a crashing conclusion.
In reply to: Rescueman, none of us can know everything, and none of us should try to. Things that we are uncertain of, or that we cannot substantiate, should be stated as an opinion only.
I beg to differ. Climbers can afford the luxury of opinions. As a climbing and rope rescue instructor who makes part of my living training fire/rescue squads and industrial rescue teams, I have a professional and legal responsibility to try to know everything available in the field. Part of that responsibility is to be clear about what is a personal preference or opinion and what is offered as substantive fact based upon my own experience, judgement and years of reading virtually everything published in the field.
- Robert
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csoles
Jun 5, 2004, 3:09 PM
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In reply to: A functional failure due to its inherent design is another mode of failure. The function of the Grigri is to allow safe lowering, rappelling, and belaying. If it fails to perform as expected because of its design, then it has failed.
A product is not defective when used improperly, as in this case. Since you have read everything, please show a reference that recommends using the device horizontal or any device on the ground. Warning sheets cannot forsee all possible misuses and tacking on more labels just means fewer people will read them. Since the root cause was a rigging error, placing fault on the device is a disservice because it prevents people from learning from the tragedy.
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sandstone
Jun 6, 2004, 6:13 PM
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Rescueman wrote:
In reply to: There are no tests that I'm aware of for single body weight...
I've never seen any either, that's why I asked you for them.
If you have an opinion, that's cool, share it -- but clearly state it as an opinion. Before you state something as a fact, you should be prepared to back it up.
To state something as fact when it's only an opinion is irresponsible -- you can get somebody hurt that way.
In reply to: Your informal "test" in no way approximates what would happen in the event we're describing. How much rope were you hanging on? That determines the amount of stretch and hence spring energy in the rope after parting - there is an enormous difference between 20' and 100'. What was you velocity during rappel when the rope was "cut"? Sounds like zero according to your description.
Rescueman, review the original discussion thread, and review this sub-thread. In the original post about the accident the climber had been lowered only a short distance, and his velocity was zero (they had stopped lowering him before the rope parted). This sub-thread is about the possibility of a rope being severed by debris while cleaning a route on rappel (a very slow stop-and-go process).
Maybe you can clean out cracks and pockets while zipping down the rope at high speed, but I am a mere mortal -- I have to go much slower. For me it typically involves rappelling a foot or two, locking off the Gri-Gri, digging and brushing, then dropping down another foot or two, repeat ad nauseum. It's about the only time I use my Gri-Gri, because it is so good at this type of stop and go rappell (and it by default is pre-rigged as half of an ascending system if I need to go back up the rope).
My personal test was not controlled or highly scientific -- I did not offer it as such did I? I did accurately post my procedure and my results. My test did approximate the conditions of cleaning a route on rappel. I stopped short of sacrificing a rope for the test, but I did simulate a quick parting of the rope at the device.
I had about 40 feet of rope out, btw.
In reply to: What you performed seems to be a static test, not replicating the dynamic effects of both rappel velocity and rope rebound. Your methodology was seriously flawed.
Go back and read the description of my test. When I pulled the prusik down near the ATC I had about an 18 inch dynamic drop, with 40 feet of stretched rope to rebound.
You proclaim that my test methodology was "seriously flawed". That smells to me like another opinion that has been stated as fact. Please explain in detail the "serious flaws".
In reply to: If you feel that this anecdotal "evidence" of the security of a prusik backup is sufficient for you to rely on it, then (and this is my opinion) I suspect your 30 years of rope experience might come to a crashing conclusion.
How are you getting the notion that I plan to rely on a prusik backup? You're not getting that idea from anything I've posted. Don't get so emotional man, keep your cool and read what I actually said. If you do you'll see that I specifically and clearly stated (in two posts no less) that I do not advocate an "above the device" prusik backup for rappelling.
After Pneumoped made his post about considering a prusik backup above the Gri-Gri, you went off on a rant, eventually proclaiming that it was "impossible" for such a prusik to catch if the rope was severed in the device. That smelled like b_llsh_t to me, and lacking published test references (and not wanting to post a useless opinion with no data to back it up) I did my own test. That test convinced me that your proclamation of "fact" was indeed 100% USDA Approved B_ullsh_t.
I still don't advocate an "above the device" prusik backup. I also don't advocate posting opinions and half-truths as facts in a climbing forum -- because doing so could get someone hurt.
Go back and read my original post in this thread. I expressed my gratitude for the original poster sharing his experiences. It had made me think about the possibility of route cleaning debris severing my rap rope in the Gri-Gri (making my backup knots below the Gri-Gri completely ineffective).
I posted my original message so other people who are cleaning routes would get a "heads up", and maybe re-think their backup strategy as I did. My goal was just to try to help out some folks. Rescueman, I have no idea what your goal is.
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sandstone
Jun 6, 2004, 9:04 PM
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In reply to: Climbers can afford the luxury of opinions. As a climbing and rope rescue instructor who makes part of my living training fire/rescue squads and industrial rescue teams, I have a professional and legal responsibility to try to know everything available in the field.
If you cross the line into the hubris of thinking that you actually do know everything about a subject, you are fooling only yourself.
In reply to: Part of that responsibility is to be clear about what is a personal preference or opinion and what is offered as substantive fact based upon my own experience, judgement and years of reading virtually everything published in the field.
Oh give me break, and get down off the high horse while you're at it.
In this very thread you have made proclamations of "fact" that have been clearly shown to be nothing more than personal opinions and bad assumptions.
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stickclipper
Jun 6, 2004, 9:51 PM
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In reply to: I posted my original message so other people who are cleaning routes would get a "heads up", and maybe re-think their backup strategy as I did. My goal was just to try to help out some folks. Rescueman, I have no idea what your goal is.
Wow!
Sandstone, your posts were a clear demonstration of experience, logic, and an open mind. I hope you continue to post on this site.
Thank you for going through the time to do that test; I've never been an advocate for above the device rappell back ups, but I'd always wondered if they would lock up quickly enough.
Rescueman, you're an arrogant azzhole.
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stickclipper
Jun 6, 2004, 10:02 PM
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I just read Sandstone's test and Rescueman's response one more time...
and, man, that is great stuff! I don't know if I've ever seen someone so thoroughly (and scientifically!) shot down.
Rescueman, learn to READ! I can't wait to see how you respond, as you are so obviously in the wrong. In fact, I wouldn't be surprised if you never posted again!
Dude, I can almost sense your feathers ruffling as you read this, thinking "What? I'm trained in rescue! I'm a professional. Who are these nobodies to shoot me down? How dare they actually ask me for explanations of the things I say? They should accept it as gospel! I'm RESCUEMAN!"
I'm sure you have knowledge, but I'm equally sure you have neither an open mind nor critical reading skills.
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unabonger
Jun 7, 2004, 1:49 AM
Post #48 of 118
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What are some problems with rappel backups done on the "above the device" side of the rope? I assume by "above" you mean the loaded side of the rope?
I've heard this before and usually have used a bachman knot (I think that's the name...) off my legloops on the non loaded side of the rope, but I haven't heard a cogent discussion of the reasons.
UB
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dirtineye
Jun 7, 2004, 2:53 AM
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Registered: Mar 29, 2003
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In reply to: In reply to: Rapell backups a recipe for disaster? Bullsh!t. What's Bullsh!t is that you didn't read my post. I was responding specifically to pneumoped's post about placing a prussik above the rappel device, and I suggested the safer alternative of an autoblock below the rappel device, which has become the standard for a rappel backup. In reply to: About the tendancy of a panicky falling rapeller to grab the prussik, I guess if you are going to panic in a fall then you should not be climbing anyway This is an insult to the extremely experienced vertical cavers (who are the real experts in rappeling) who have lost their lives because of this automatic panic response that every human being is susceptible to. We know from vehicle accident studies that it takes the conscious mind about a second to respond in an emergency. In a motor vehicle, that means you're already through an intersection before you can hit the brake. On rappel, with your hand on the overhead prusik (where you will not experience rope burn until the prusik melts) it means you'll be travelling 22 mph downward and will have dropped 16' before you can even react. So let's be very clear: a prussik above the rappel device has been demonstrated to be both inconvenient and potentially deadly. A friction hitch (typically autoblock) below the rappel device has become the accepted standard for safe, efficient, and easy rappel backups. The only caveat is that the lower friction hitch cannot be allowed to reach the rappel device or it will either jamb the device or be rendered ineffective. - Robert
NO, I read your post.
And like a lot of your other posts, you sound like an idiot.
If it is insulting to sauy that panicking in a fall will get you killed, I'm GUILTY, but the panickers are probably dead or serioiusly injured.
YOur analogy about moteor vehicle accidents just shows yo uare an ever greater idiot, because a climber can train for falling and react much faster and more correctly than an untrained person can.
Get a clue.
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rescueman
Jun 7, 2004, 3:18 AM
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In reply to: I just read Sandstone's test and Rescueman's response one more time...and, man, that is great stuff! I don't know if I've ever seen someone so thoroughly (and scientifically!) shot down.
If you, or anyone else on this forum, accepts sandstone's "experiment" as scientific (when even he acknowledges that it isn't) then all you've proven is that you're willing to accept whatever coincides with your own misperceptions and choose to argue , like sandstone, against whatever contradicts your preconceived notions and limited experience.
At least sandstone was willing to test his hypothesis, albeit under conditions which give his conclusions a very limited scope of applicability. And what's most peculiar, is that sandstone is going to such great lengths to "prove" the reliability of a technique that he very specifically doesn't recommend.
In reply to: I can't wait to see how you respond, as you are so obviously in the wrong. In fact, I wouldn't be surprised if you never posted again!
What's the point of continuing to offer my knowledge, insights and experience when the most vocal on this forum are the ones least interested in learning?
Those who can offer no more than insults and profanity in place of honest dialogue and discussion are not worth my time.
- Robert
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