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General Climbing Discussion

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Worn lower-offs 17-May-2012 At 4:46:33 PM Olbert

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On 17/05/2012 Winston Smith wrote:
>Mikl,
>
>Dumb question: Why this configuration which only loads one ring? The second
>ring is presumably the back-up but only in a shock-loading situation if
>the first failed.
>

I'll field this one.
Firstly, a problem with most set ups is that both rings/shackles/chains/biners are worn. In this setup only one item is being worn - the d-shackle, this means its easier to replace, maintain and assess.

As an added bonus, with this setup, you can leave the d-shackle to significantly more before replacing it. Theoretically (though you wouldn't do this in practice) you could leave the d-shackle until it fails because the backup u-bolt should be as strong as it was when it was first placed. In the case where both anchors wear at the same rate (as in the original post) you would have to replace both anchors fairly conservatively as if one fails the other is just as likely to fail, and so could easily lead to a total and catastrophic failure.

The second ring is a back up. It should remain basically as new for a very long time, much longer than the set up shown in the original post where both rings have considerable wear.

You imply there will be significant shockload on the second ring if the first were to fail. This is not the case. Shockloading is when an abnormally large force is suddenly applied in the event of a failure, however, in this case the rope (which presumably is dynamic) lowers the peak impact force to a reasonable level.