yep, i might have to edit if when i publish this is wonky
imagine the tree is above and out of site....that end of the tether is attached, and i'm focusing on the 'biner and friction hitch (i'm using a distel hitch here)
this is with a figure 8 on a bight tied at the end of your tether and clipped to your 'biner, you should see that if the thinner cords break then this loop still catches on your 'biner which is holding your bridge.....in this configuration you would fall a few feet though before that loop caught you
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here i'm showing how when at height you can double over that slack in your mainline between friction hitch (prusik, etc) and loop clipped on 'biner.....if you double it over like that then you can tie knots shown next...doubled over stuff you'll tie with is to the right
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here's just 2 simple overhands tied in that doubled over slack....this is not the best knot to use....but it is quick and easy....i would do this for 2 reasons 1. take up slack for the sake of not having extra tether flipping around and 2. so that if my friction hitch fails then the amount of slack i have to fall before the figure 8 on a bight grabs me is less....less slack is good
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here's where you can tie another loop in that slack and then clip it to your 'biner...this is accomplishing the same thing as that end loop i talked about in first photo....but it is just making a closer one
i used a simple overhand for demonstration here, but if i was serious about that method, then i would practice and use an alpine butterfly
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