RRC Archives

Good reading:

http://www.southeastclimbing.com/faq/fa ... forces.htm

Gaar wrote:in the worst case senario is a 20kn impact force on the anchor system.

Gaar wrote:.....But remember thats the WORST CASE, and the beleyer is anchored....

Gaar wrote:We also know that the climbers knot will tighten absorbing some energy, their harness will stretch, their body will goosh, the anchor carabiners will stretch, the belayers harness will stretch, belay carabiner will stretch, the belay device will slip a little (as long as it's a plate type device) so it's hard to even get to 20 kN.

I'm not saying your going to get there, but plan for it

BJ wrote:I'm holding onto hope here that you'll explain your argument in greater detail, but statements like that aren't encouraging.

"The realationship of fall distance to rope out is the Fall Factor, which you determin by dividing the length of the fall by the amount of rope between you and your belayer"

I'm talking about plain weight. ~4500lbs=20kn



Karsten, Alan is a personal friend, I asked his persmission to use his name and reference, and am not throwing it around! I could say some things about Adam Fox if I wanted to but I'm not!

kdelap wrote:11kn on a toprope anchor is an extravagant amount of force that would be hard to attain.

I will consider this if you show numbers and can prove it! 11kn=2473lbs

But remeber in toproping if you pull down with 11kn on one side of the rope, the other gets the same, therefor the anchor gets 21kn.




Saxman
From your website
"A dynamic climbing rope must be designed to absorb enough energy so that the maximum force on an 80 kg. (180 lb.) climber in a factor 2 fall is not more than 12 kn. (2698 lb.). The maximum force on a top anchor could approach 19.9 kN or 4475 lbs."


God damn all I said was build the anchor to withstand 4496lbs and you'll be fine. Shit if you dont want to be safe fine with me, do whatever the fuck you want!

Ok so I haven't had the time to read Saxmans link but,

Gaar, I think that you will find that the names you are throwing around are about to be looked down upon in the international climbing community. As for Adam Fox, I do work for him, but haven't talked to him for days; (He has been out of the country). I am out west hanging out and skiing with a bunch of IFMGA guides that I threw the question out at again today. So one of them has done testing. The highest possible force you can get on a top rope anchor is around 7 kn in a real world scenario he stated. By all my calculations I can only get 10 kn. So I say 11.

But as for someone who is not sure if there anchor is strong enough, I always say add another piece. I am sure you probably teach something similar as well.

I don't know if I can get my hands on hard data, but if I can I will try to send you some.

Cheers!

To edit on.....This thread is hijacked


This should explane EVERYTHING very simply

Basic physics 101...
A weight (lbs) falling a specific distance (ft) gives you ft/lbs. of energy (THATS WITH NO STRETCH), I am aware of this.

Here ya go

1 In a 30ft climb with a fat ass 300lb client, using an 11mm gym rope, a gri-gri, and your 120lb belayer is anchored.

2 Your belayer cant keep up/ isnt paying attention/ blah blah....10ft of slack is introduced into the system.

3 Climber falls. 300lbsx10ft=3000lbs (WITH NOT STRETCH I KNOW)
Because this is a TR and newton says Every action has a equal and opposite reaction, it pulls on the belay with 3000lbs as well.

4 So 3000lbs on the climber side of things
3000lbs on the belayer side of things
= 6000lbs on the anchor or ~26-27kn

5 Okay so lets factor in strecth. Fuck for shits and giggles lets take out 50%
now we are back to 3000lbs or ~13-14kn on the anchor....

Now thats higher then 11kn and that was playing it safe with 50% stretch in the whole system!

Now a TR set-up is very different then lead climbing!

Karsten, pass along the numbers I just provided to your friends, and PM me, or post, their responce.

This has kind of gotten out of hand, and for that I apologize. Its just 20kn towards and anchor is very possible, ESPECIALLY in public guiding.

Please if you still have questions, review my last post, and PM me.. If reputable data can be provided to show other wise I will consider changing my stance.

You guys are silly.

Do you climb?

A S D F

Gaar,

I'll see what they say.

Odub

Not much this year... 1 day of rock, 2 days of ice, 3 days skiing off piste 2 on. I am hoping to get a few more in before the new year.

Ashtray

We obviously have nothing better to do.

Hope that covers it!

yeah its snowing here in zion, so walls are out of the question, mainly beer, herb, and slot car racing, oooo yeah SLOT CARS

Gaar wrote: Saxman
From your website
"A dynamic climbing rope must be designed to absorb enough energy so that the maximum force on an 80 kg. (180 lb.) climber in a factor 2 fall is not more than 12 kn. (2698 lb.). The maximum force on a top anchor could approach 19.9 kN or 4475 lbs."


God damn all I said was build the anchor to withstand 4496lbs and you'll be fine. Shit if you dont want to be safe fine with me, do whatever the fuck you want!

I couldn't find that part.