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Climber injured in bluies after 30m fall 2/Jan/13 21-Jan-2013 At 11:23:10 PM jrc

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Thanks for that Olbert and i do appreciate your response.

Thanks also for the wikipedia reference where i found i did at least get the FF calc correct; and as P noted, the elongation of the rope is not relevant as the FF is the pre stress calculation.

As i indicated in my note, my force calculations were an approximation, i admit, for simplicity, and were given primarily for relative purposes but also to show there are severe forces able to be generated even in 'small' falls.

Re the force calc; the energy in the fall would be mgh, this energy being absorbed by the stretching rope and resulting in a force along the distance it stretched,(which would be proportional to the length of rope deployed, not the length of rope itself (as i wrongly calculated giving rise to the mgh / r calc where it should have been mgh / (r x%elongation) (assuming linear elongation in the foregoing)-sorry for the confusion).

With the scenario of the slack in the belay i was trying to see if there was a way you could get the FF above 2 which i always thought was some sort of sensible limit. I did not assume rational belayer behaviour - ie yes he could sit there with a metre of slack in the system and yes i agree that is dumb. Thanks for picking that up

Happy to discuss further ! I'll be in the bar of the Imperial at 6pm on Sunday 27th.