Prusik loops

[Tommy_B]

Plus, if a very specific set of conditions are met, you could clip into the wrong part and it pulls itself out

[peds]

6 hours ago, Tommy_B said:

Plus, if a very specific set of conditions are met, you could clip into the wrong part and it pulls itself out

... no it can't.

 

It's a closed loop, there's no free end for it to pull out...

[Tommy_B]

Yes it can. Unless we're talking about different knots in which case I apologise. 

A sliding double fisherman's knot has the 2 opposing knots in "the middle" and 2 loops on either side so it looks like a bow tie. If the carabiner is clipped into the opposite side, it can pull through.

The reason I know this,  is from teaching students to climb and watching someone tie this very knot and then having to demonstrate to them what can go wrong.