Posted: Thu Dec 11, 2003 5:03 pm
I'm not that courteousCrankmas wrote:does your engineering friend give a good reach around?
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Posted: Thu Dec 11, 2003 6:08 pm
Check out http://www.climbtennessee.com/train/fall.html for a calculate it yourself guide.
Posted: Thu Dec 11, 2003 6:58 pm
So explain to me how you come up with the figure that the force is almost doubled at the last piece of pro. It seems to me that it would be less than half on a dynamic belay.
The scenario that I proposed was ; rope tied at anchors,climber climbs to the full stretch of the rope (60meters above the anchors). Pitches off and falls 120 meters. The maximum amount of force exerted in the system will be 6.81 kn.
Now, if you add dynamic components to the system then you reduce the shock forces(i.e. kilo newtons)
Am I right or wrong? Because from what you are saying. A dynamic anchor will have more force imposed on it than a static anchor.........doesn't sound right to me.
The scenario that I proposed was ; rope tied at anchors,climber climbs to the full stretch of the rope (60meters above the anchors). Pitches off and falls 120 meters. The maximum amount of force exerted in the system will be 6.81 kn.
Now, if you add dynamic components to the system then you reduce the shock forces(i.e. kilo newtons)
Am I right or wrong? Because from what you are saying. A dynamic anchor will have more force imposed on it than a static anchor.........doesn't sound right to me.
Posted: Thu Dec 11, 2003 7:27 pm
why do people worry about this shit? Can someone tell me a story of a rope breaking in a normal fall(nothing sharp cutting the rope) at the Red River Gorge?
Posted: Thu Dec 11, 2003 8:03 pm
dirt - you are correct in your scenario there is no force doubling at the anchors because the rope is not being redirected by a peice of pro. That is what creates the pulley effect and the doubling of forces.
what dynamic components can you factor in on a factor 2 fall directly onto the anchor? knots tightening and your body deforming, but that is about all I can think of. Not as signigicant as when you have an actual belayer and they are being pulled.
what dynamic components can you factor in on a factor 2 fall directly onto the anchor? knots tightening and your body deforming, but that is about all I can think of. Not as signigicant as when you have an actual belayer and they are being pulled.
Posted: Thu Dec 11, 2003 11:12 pm
Dirt, tell your friend to use my 3 year old, fraid to hell rope in his scenerio.
Posted: Fri Dec 12, 2003 12:09 am
at what point would the knot blow? using a figure-8 or a bowline..
Posted: Fri Dec 12, 2003 12:56 am
well the whole point behind the figure 8 knot is that it tightens on itself. The rope itself would snap leaving the "still tied knot" trailing
behind you into Hell!
behind you into Hell!
Posted: Fri Dec 12, 2003 1:02 am
right, but the knot lessens the integrity of the rope. both keep around 70% of the rope strength (i believe).. but would it, as it tightens down on itself, shear the rope as it goes or would the rope just snap at that point?
Posted: Fri Dec 12, 2003 2:14 am
the rope would break where the standing end (closest to your harness) enters the knot.