Discussion Topic |
|
This thread has been locked |
Juan Maderita
Trad climber
"OBcean" San Diego, CA
|
|
|
Dec 21, 2015 - 11:52am PT
|
Matt M,
Well written. May I suggest that you avoid using the term "drop in anchor" to describe mussys or rams horns? This is a potentially dangerous misnomer if it catches on with climbers. A "drop-in anchor" is a specific type of concrete/masonry/stone fastener. Adequate for fastening artificial holds, but not for protection bolts or belay/rap anchors.
https://www.us.hilti.com/anchor-systems/flush-anchors/r67854
|
|
Rolfr
Trad climber
La Quinta and Penticton BC
|
|
|
Dec 22, 2015 - 04:31pm PT
|
I would disagree with this statement. Yes, with modern materials the chance of a single bolt failure, or any other link in the chain, is greatly diminished, but it can still happen. In the photo of your vertical setup the failure of the top bolt will shock load the other bolt. Do you really want that? Clearly, there is a way to have a vertical setup that won't shock load if there is a failure.
That doesn't make any sense, you load a single protection bolt with incredibly more force in a fall, than a three foot fall on a top rope if the anchour failed.
Also, I am not sure how the vertical setup doesn't twist the rope while the horizontal setup does.
Lowering on two right angle turns of the rope will ensure that it is kinked when you are done. Don't believe me? Go sacrifice an old rope and try it yourself
|
|
Studly
Trad climber
WA
|
|
|
Dec 22, 2015 - 04:41pm PT
|
Depending on how you feed the rope thru the belay device, its generally how the rope gets twisted. It should be fed straight in, and not from the side. I see many folks feeding a gri gri from the side, putting twists in the rope.
|
|
Dingus McGee
Social climber
Where Safety trumps Leaving No Trace
|
|
|
Dec 22, 2015 - 05:47pm PT
|
Studly is on the right track!
Kink, coils and curls in the rope most likely were there before lowering from the anchor.
How did they get there?
Poor Rope Management on the ground in the past by the owner/belayer of the rope.
|
|
wstmrnclmr
Trad climber
Bolinas, CA
|
|
|
Topic Author's Reply - Dec 22, 2015 - 05:53pm PT
|
Use an atc and have for years with no twist problems. I think studly and rolfr both on right track. Although many Mussy's laying against rock in the hills. Just haven't had problems before but what do I know. New to the convenience anchors....
|
|
bhilden
Trad climber
Mountain View, CA/Boulder, CO
|
|
|
Dec 22, 2015 - 06:16pm PT
|
I would disagree with this statement. Yes, with modern materials the chance of a single bolt failure, or any other link in the chain, is greatly diminished, but it can still happen. In the photo of your vertical setup the failure of the top bolt will shock load the other bolt. Do you really want that? Clearly, there is a way to have a vertical setup that won't shock load if there is a failure.
That doesn't make any sense, you load a single protection bolt with incredibly more force in a fall, than a three foot fall on a top rope if the anchour failed.
The bottom line is that bolts do fail. Hangers fail. A climber died in Owens Gorge this year because a bolt failed. Granted, bolts and hangers don't fail very often, but they do fail.
Maybe my use of the term "shock load" elicited some strong responses, but if you are going to drill two bolts and create an anchor why not do it in such a way that both bolts share equal load? You can do that either in a horizontal or vertical configuration. Your choice.
Why would you deliberately create an anchor where one bolt takes all the load and if that bolt fails an unnecessary(though maybe small) force will be applied to the second bolt? If you are going to do it. Do it as best as possible. If you really think that only one bolt is enough for an anchor then why even put in the second bolt?
|
|
JimT
climber
Munich
|
|
|
Dec 23, 2015 - 08:26am PT
|
Because we know that with modern bolts the chance of one failing is incredibly low and the chance of two succesively failing is non-existent.
Seperated bolts allow more placement possibilities, are cheaper and have a lower environmental impact.
My home climbing area, in common with much of Europe DOES only have single bolt lower-offs, no deaths have occured.
|
|
Greg Barnes
climber
|
|
|
Dec 23, 2015 - 08:45am PT
|
Europe may be ahead of the U.S. with bolt quality (loads of bomber glue-ins, etc), climbing standards, climber organizations, etc (ahem….metric system…ahem)…
BUT the non-redundant single point anchors are just dumb. Even before they get really worn down.
Euros have just gotten lucky so far (and maybe there's less random rockfall damaging anchors in Europe in general? Climber geologist study in the works…).
(Yes, I've climbed in Europe - Switzerland/France/Italy - and used a lot of single-point anchors).
|
|
JimT
climber
Munich
|
|
|
Dec 23, 2015 - 10:17am PT
|
The accident statistics show we are consistantly lucky!
|
|
|
SuperTopo on the Web
|
Let us know!