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Re: Gri Gri Test
Posted: Tue Sep 28, 2010 2:53 pm
by caribe
robert birchell wrote:This is NOT in anyway a suggestion to belay with no hand on the brake end
of the rope.
You can't use the click-up (previous forum), now it looks like your grigri procedure is also defective. You need to talk to someone who knows what they are doing. Belaying is serious stuff.
Re: Gri Gri Test
Posted: Tue Sep 28, 2010 2:58 pm
by caribe
Artsay wrote:Seems simple but it does take a little bit of figuring out to get it to work right. Totally worth the effort though.
Michelle I love the attitude that allows one to approximate perfection with time. You have been climbing for quite a while now and you are still open to learning. I am with that vibe
Re: Gri Gri Test
Posted: Tue Sep 28, 2010 5:45 pm
by robert birchell
caribe wrote:robert birchell wrote:This is NOT in anyway a suggestion to belay with no hand on the brake end
of the rope.
You can't use the click-up (previous forum), now it looks like your grigri procedure is also defective. You need to talk to someone who knows what they are doing. Belaying is serious stuff.
Well, you got one thing right....Belaying is serious stuff.
Re: Gri Gri Test
Posted: Tue Sep 28, 2010 7:30 pm
by caribe
robert birchell wrote:It was very difficult to measure but was not much.
Do it again. Tie a small string tightly to the rope at the very top of the grigri. To measure the amount of slippage, measure the difference between the new position of the string and the top of the grigri after the fall. Metric units are preferred.
- Pay out a measured amount of slack. Repeat the fall 10 times each as a function of the measured amount of paid out slack. Plot a chart of slippage vs. climbing-relevant, paid out slack with error bars at each point. Be careful so your climber doesn't deck.
- Annotate the chart with wind speed and wind direction, barometric pressure, dew point, number of draws that the rope passed through, type, thickness and age of rope and weights of climber and belayer. You should probably report the static coefficient of friction of the rope also.
Re: Gri Gri Test
Posted: Tue Sep 28, 2010 7:42 pm
by bcombs
Re: Gri Gri Test
Posted: Wed Sep 29, 2010 3:09 pm
by Saxman
caribe wrote:robert birchell wrote:It was very difficult to measure but was not much.
Do it again. Tie a small string tightly to the rope at the very top of the grigri. To measure the amount of slippage, measure the difference between the new position of the string and the top of the grigri after the fall. Metric units are preferred.
- Pay out a measured amount of slack. Repeat the fall 10 times each as a function of the measured amount of paid out slack. Plot a chart of slippage vs. climbing-relevant, paid out slack with error bars at each point. Be careful so your climber doesn't deck.
- Annotate the chart with wind speed and wind direction, barometric pressure, dew point, number of draws that the rope passed through, type, thickness and age of rope and weights of climber and belayer. You should probably report the static coefficient of friction of the rope also.
You forgot to add to let the rope rest at least 30 mins between each attempt or to use 10 ropes from the same batch.