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This makes no sense . . .


tpcollins

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I found an article online where a girth knot can reduce the the strength of a sling with a lost nearly 50% - one should use a carabiner instead. I have Metolius Daisy Chain made of 11mm Dyneema rated at 4950#. I would have preferred to use a girth hitch to tie it into the belay loop on my Petzl Aspir harness. Would I still be at risk if I were only to fall a maximum of just 2' with it? I have trouble understanding how the smaller diameter of a carabiner will maintain more strength over the girth hitch. Thanks

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Many folks girth hitch their Daisy to the harness, despite designers warnings. Bottom line is you should never fall onto your personal anchor. Even 2' could be horrible. This can be mitigated several ways. If multi-pitching, anchor into the rope via clove hitch. The rope is designed to absorb dynamic force. another option is the Purcell prusik for a personal anchor. This will also absorb dynamic force, albeit much less than a climbing rope... Hope that is helpful...

 

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Using an online fall force calculator for a 150 lb person equaled a 15kN force for a 2' static fall above an anchor. It should make sense that something going over a tigher bend would reduce its strength. Thus the warning.

 

It's totally situation dependent. Most scenarios would not have you loading your tether like that. Using your belay loop is fine as long as you periodically check the nylon and move the knot around every so often. Tethers should really only be used as a quick way to stabilze yourself at the anchor. If there is a situation where the leader or belay could generate a high fall factor, use the rope to tether in as well.

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this makes no sense...

 

 

Thanks for the replies. I'm planning to use both a Prussic knot and a Ropeman 1 on a Bluewater 7/16" Assautline as my lifeline to arrest a maximum of a 2' fall. I may have to practice a bit while standing on terra firm - thanks.

 

IMG_0895_zpsf72ceb0a.jpg

 

shudder to hear the story behind the use of this. money says that it is a bad idea. a very bad idea.

 

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You're going to damage your innards if you fall on static gear. If your goal is to rope solo then look up some ways to do that. There are some experienced folks on this board who can help. If your goal is to connect yourself to an anchor or fixed line then just use the rope. KISS

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worried about the loss of strength due to girth hitching but planning on this? wrong priorities.

 

I hope this is just a self belay of a fixed line. If so, there are much better devices to use, ones that would slide up smoothly therefore not generating that "max 2ft" fall potential. like a micro traxion or this http://www.kong.it/doc/Kong_Back-Up.pdf

 

Heck even a unmodified gri gri works better.

 

 

even so, use a dynamic rope to mitigate any small fall onto the rope.

 

Edited by genepires
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what is this for again? I must have missed something

 

Actually I'm switching from a typical "safety harness" used for deer hunting to a Petzl Aspir climbing harness (and the Voltige shoulder harness) while hunting from a tree stand. At my age, I'm afraid of leg trauma associated with hanging from a harness for any length of time ,that is tethered from the rear and facing me away from the tree. I'm under the impression that a rock climbing harness would increase my ability to get back to the stand or the climbing sticks. I will always be connected to the 7/16" Assaultline as I leave the ground, and once on stand, I would adjust the Prussic so that the Metolius Daisy Chain is taut either going under my armpit to the lifeline behind me or over my shoulder. My goal is to limit my fall to about 18"-24" total.

 

I could add a Petzl ASAP Absorber if additional cushion is necessary. Thanks.

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I believe Yates sells a adjustable daisy chain that has a built in load limiter.

 

so the static line is fixed to above the tree stand?

 

you have some kind of ladder to get up to the stand?

 

Cavers have extrensive methods and tools for ascending fixed static ropes.

 

 

 

try reading this about short static falls, which you are exposed to with this system.

http://www.rockandice.com/lates-news/the-dangers-of-short-static-falls

 

It really would not be hard or expensive to put some dynamic components in your system. If you are worried about the damage from sitting in a harness for a while, then you should really be concerned about static falls.

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At the stand: Yates adjustable daisy (very adjustable - rated load limit: 300 lbs) clipped to the anchor backed up by a short length of dynamic rope attached to the anchor via a clove hitch (pretty adjustable) to a locking biner at the anchor power point. Clip the loose end of the dynamic rope into the anchor with a figure 8 on a bight, and tie in to your harness (threaded just like your belay loop) with a rewoven figure 8. The Yates is girth hitched to your belay loop.

 

 

It's unclear how you're ascending the rope. That's the other part to think about.

 

 

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