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Re: [sungam] double figure eight for anchor?:
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CelticGuy
Jun 22, 2014, 6:57 PM
Views: 9270
Registered: Aug 27, 2013
Posts: 9
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A double figure-8 basically has 2 bights that are through the end of a figure-8. The 2 bights are a serial single rope and as a result if one gets cut both of them fail. Tie one and pull one of the loops and you'll see what the issue is. This has been documented by Craig Luebben in his anchors and trad climbing books. Bunny Ears are just a glorified American Death Triangle IMO. A death triangle with a cinch that can fail.
Tie an overhand on the bight (on each of those bights - aka bunny ears) and you're bomber. This removes the automatic equalization but why would you want a dynamic equalizing point if you're tied into the anchor with your rope anyway ?
So here's the issue I really see. If for some reason a bight gets chewed up and fails, basically any load will cause the bight to slip through the end of the 8 and hence the second bight will come un-tied. Doing an overhand on each stops this from happening. It's a really simple thing to do and adds extra insurance. Worth it for the extra minute IMO.
I know, you're gonna say, but it's your master rope and it shouldn't fail. I agree BUT a master rope with a tight bend puts way more stress on the rope than a pull in a straight line. Yes, it's unlikely to fail. But why not just be a little bit safer ??? It's costs nothing.
BTW, if you look up carabiner sawing through a rope, you will understand my paranoia. The example was with a carabiner that had been used in a quick-draw and hooked into the hanger. The quickdraw was reversed and the metal chafing on the 'hanger' side was then used by the rope side and it cut through the rope very quickly. If you're pumped or not paying attention you may be using a dodgy 'biner at your anchor!
Yeah, yeah, I'm being very paranoid. maybe a regular bunny-ears has a 1:10,000 chance of failure. Tie overhands and it now has a 1:(10,000)^2 failure or 1:100,000,000. For an extra minute isn't this worth it ?
FYI
http://dmmclimbing.com/...tential-rope-damage/
(This post was edited by CelticGuy on Jun 22, 2014, 7:26 PM)
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Edit Log:
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Post edited by CelticGuy
() on Jun 22, 2014, 7:02 PM
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Post edited by CelticGuy
() on Jun 22, 2014, 7:04 PM
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Post edited by CelticGuy
() on Jun 22, 2014, 7:08 PM
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Post edited by CelticGuy
() on Jun 22, 2014, 7:10 PM
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Post edited by CelticGuy
() on Jun 22, 2014, 7:16 PM
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Post edited by CelticGuy
() on Jun 22, 2014, 7:19 PM
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Post edited by CelticGuy
() on Jun 22, 2014, 7:26 PM
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