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Offset
climber
seattle
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Mar 17, 2009 - 03:44am PT
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why is the pro traxion even being mentioned? i mean, i know...but i can still ask right. it was miss-used and cannot be asked to perform if being asked the wrong way.
if someone ties into the rope the wrong way (even if is Looks almost right) - is the particular rope they used brought up? never!
could these people have set up a roll block wrong? probably so.
it's a tragedy, a shame and will impact some folks big time... but i hardly see this as a protraxion issue.
imo...
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Caveman
climber
Cumberland Plateau
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Mar 17, 2009 - 07:18am PT
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Lets see if I've got this right........
1 Don't use protraxion
2 Don't use any ascender with 'teeth'
3 Don't hang your butt on anything with a cam
4 Don't listen to rock climbers when it comes to ascending or descending ropes!
Forget about 1 2 and 3. 4 is the ticket.
Petzl jumars lol
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tom woods
Gym climber
Bishop, CA
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Mar 17, 2009 - 10:58am PT
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The mistake on the traxion led to a 15 foot fall, isn't necessarily enough to kill you.
This isn't a traxion only failure, the guy had a back up knot that caught. It was the combination of the jugs and the traxion.
The jugs had to catch a bigger force then they can catch, and cut the rope.
Now I'm all worried about those darn jugs. Say you're climbing in a party of three, so one guy is jugging a free line. Say it's an over hanging climb so you attach your jugs to the free line and rather then lower out you decide to jump of the ledge for shits and giggles. If there's stretch or worse, slack, you could put some force on those jugs.
What sort of shock load does it take to generate 5KN?
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JLP
Social climber
The internet
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Mar 17, 2009 - 11:06am PT
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I recall details of this from an earlier report.
The haul rope he was using was very thin - 9mm or so (PMI?).
Correct me if I'm wrong.
9mm is just too thin. Walls beat the sh#t out of haul lines. The toothed ascender/hauler type devices don't help. Also, the thinner the rope, the smaller the surface area the teeth are spread across, making things even worse.
Interesting fail mode on the device, for sure. I don't like the design of that thing. Doesn't seem to constrain the pulley axle very well.
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Fishy
climber
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Mar 17, 2009 - 11:16am PT
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Lots of talk about the fall factors and static lines as if "static line" can only be one thing.
There are HUGE variations in the elasticity of static lines. Some are made only of nylon, to ensure that they have a little stretch. Some are thicker, others are thinner, different weaves, sheaths etc etc.
I remember seeing some numbers which showed that the elongation of a few static lines tested fell around 10-20% of the climbing ropes used in the comparison - this would correspond with fall factors being in the region of 5-10x higher using a quick rule of thumb.
But these numbers are only fuzzy recollections - the only way to know for sure is to look up how stretchy YOUR specific rope is.
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ontheedgeandscaredtodeath
Trad climber
San Francisco, Ca
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Mar 17, 2009 - 12:57pm PT
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Wall climbing in the continental U.S. is probably the only variation of climbing where time and weight are not an issue. It seems like almost every (non-storm) accident on walls involves either some kind of jugging mistake or leap frogging pieces, often resulting from an effort to save time or weight.
To me, jugging a loaded haul line off of a hauling device just seems unnecessary and intuitively wrong, regardless of what the engineering says. Weird things happen when systems get jolted.
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Caveman
climber
Cumberland Plateau
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Mar 17, 2009 - 02:22pm PT
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Some here don't like the Petzl ascenders so now you have the BD N-force ascenders. Wonder if they are 'YOSAR approved'?
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Mr_T
Trad climber
The 7th Pin Scar on Serentiy Crack
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Mar 17, 2009 - 02:40pm PT
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[I use a 8mm static for hauling, I'm not anti-static line.]
The question this: a climber + bag fell ~15' onto a static line (unknown diameter - 9mm?) and the line cut. The age and condition of the line are unknown. The weight of the climber is unknown. How much force was on the ascender when it cut and was it within the 5kN failure range specified by the manufacturer?
Any engineering types out there? A static line has between %10 to %20 of the working elongation of a dynamic. A 10.5 dynamic runs in the %5-%8 range. So for a static estimate %15 of %6 - we'll round it up to %1 working elongation.
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Mr_T
Trad climber
The 7th Pin Scar on Serentiy Crack
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Mar 17, 2009 - 02:48pm PT
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Also a question for WBraun types - has a climber ever cut a dynamic rope by falling onto ascenders. Not ascenders popped off (I've read of this several times), but the rope cut. Has this ever happened?
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tolman_paul
Trad climber
Anchorage, AK
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Mar 17, 2009 - 03:05pm PT
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ontheedgeandscaredtodeath,
I don't know why you think wall climbing has no constraints on speed and weight. Hard aid climbing can be very time consuming, but I don't know anyone that intentially takes extra weight or extra time on a wall. It's all a balance, the longer you plan to take the more food and water you take, which means more weight to hall, which means more time on the wall.
I think you'll find most successful teams carry as little gear as possible and climb as fast as possible. Yes, progress is upwards (or downwards) of an order of magnitude slower than the speed ascents, but still every bit of gear taken needs to be hauled that 3000'.
To me the real issue is many folks have little appreciation for the potential downfalls of their shortcuts. Jugging may seem relatively safe, but when you add in factors that decrease the safety factor, reportedly a thin line, added weight of pig, jug line being held by an ascender type deviced and then a 15 foot fall, a failure was pretty much and very sadly guranteed.
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Nefarius
Big Wall climber
Fresno
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Mar 17, 2009 - 03:14pm PT
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"but I don't know anyone that intentially takes extra weight or extra time on a wall."
hahaha Don't get out much, do ya! There's Pete, for starters! He's pretty much the poster boy of that mentality! lol
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Mr_T
Trad climber
The 7th Pin Scar on Serentiy Crack
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Mar 17, 2009 - 03:40pm PT
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I don't know who this is, but they do seem concerned about haul bag weight.
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Caveman
climber
Cumberland Plateau
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Mar 17, 2009 - 04:08pm PT
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Must be Canucks. Those dudes always put a high priority in fine brews!
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Hardman Knott
Gym climber
Muir Woods National Monument, Mill Valley, Ca
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Mar 17, 2009 - 04:15pm PT
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Gotta love hauling your own firewood...
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ontheedgeandscaredtodeath
Trad climber
San Francisco, Ca
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Mar 17, 2009 - 04:29pm PT
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All I know is that I've been pi$$ed I did not bring enough beer on a wall climb and have discussed the necessity of each piece of gear before starting an alpine route. On walls, I just don't get what's to be gained by doing things like jummaring loaded 9 mils.
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Mr_T
Trad climber
The 7th Pin Scar on Serentiy Crack
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Mar 17, 2009 - 05:11pm PT
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How much force for how big a fall?
Equate the work done by the fall to the work done stopping the fall.
F is force on the ascender
m * g * fall_distance = F * stop_distance
But really, your body absorbs some force:
m * g * fall_distance = F * stop_distance + body_absorption * stop_distance
F = m * g * fall_distance / (stop distance) - body_absorption
stop_distance = rope_out * working_elongation
F = m * g * fall_distance / (rope out * working elongation) - body_absorb
In this case (5m fall, 50m of rope out).
F = 70 * 10 * 5 / (50 * 0.01) - body_absorp = 7000kN - what your body absorbs
So, yeah, I'd guess he got around 4kN on a 9mm static that was already absorbing a dropped haul bag.
My guess is that rope elongation and body absorption are non-linear, so you don't cut a rope in a 1' bounce. Above 30' (ie your body doesn't absorb a fall too well and won't absorb energy) expect a cut line. It all depends on how well your body absorbs a fall. A block of granite bolted to an ascender that falls 1m should cut the line (for those of you who do such things).
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Lambone
Ice climber
Ashland, Or
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Mar 17, 2009 - 05:19pm PT
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jugging a haulrope off a protrax is a really bad idea. this sucks.
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JuanDeFuca
Big Wall climber
Stoney Point
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Mar 17, 2009 - 05:25pm PT
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Can one still buy the yellow jumars?
I have Gibbs but if Werner thinks they are crap I need something else.
Juan
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Studly
Trad climber
WA
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Mar 17, 2009 - 05:29pm PT
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There's got to be allot of other climbers out there who jug a protraxion with the haul bag free hanging. 3 person parties and soloists. The protraxion didnt fail, it was the jumars that cut the rope.
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Lambone
Ice climber
Ashland, Or
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Mar 17, 2009 - 05:33pm PT
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yeah but the cam in a pro-trax is essentially the same as the cams in the jumars that cut the rope. still a bad idea. even if the pully doesn't fail, it can't be good for the rope. Plus isn't it scary to know the skinny chord your life is dangeling on is getting crushed by a sharped toothed cam? No thanks...
the smarter way is to hang the load off a klimheist knot munter muled to the anchor just below the pully. that way the hauling device isn't loaded. Once the jugger is up you can cut the load release knot to weight the hauler.
thanks to werner for that beta.
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