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Re: [paulraphael] Proposed Anchor Rigging:
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paulraphael
May 20, 2007, 4:16 PM
Views: 22577
Registered: Feb 6, 2004
Posts: 670
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I tried a couple of different vertical configurations to see if there would be any issues. With angles approaching zero degrees, the movement of the strands when load angle changes is minimal. There's only a lot of motion if the anchor is pulled off axis by 30 degrees or more (as in a big pendulum fall). Friction of the strands over each other was minimal.
I tried putting a deliberate twist in the middle strand to see if this would cause binding. One out of the three times i dropped a weight onto the anchor (off axis, in a pendulum type fall) the strands bound, causing the load to be distributed to only two of the arms. I couldn't get this to happen when the anchor was set up properly (no twists).
So this is something to look out for, especially when the arms are parallel or nearly so.
The other issue in a vertical crack is extension. In the example in the attached picture, if the top or bottom piece were to blow, the extension would be under thee inches (the bottom piece is close to the power point, the top piece is tied off with a limiter knot). If the middle piece blows, extension will be 8-1/2 inches. I'd be ok with this, but if your placements were such that the lower piece and the middle piece were more than a couple of feet apart, you'd want to bring the arm lengths closer together by using different length runners.
(This post was edited by paulraphael on May 20, 2007, 4:17 PM)
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vertical_acr.jpg
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Post edited by paulraphael
() on May 20, 2007, 4:17 PM
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