UKC

Hello,

Does anybody know more about this knot:
http://www.climerware.com/f8x.shtml

Is it safe? Is it indeed easier to undo?

Cheers,
Michel

In reply to michel4388:

I've used it for TRing in indoor walls. I actually think that it's harder to undo than a normal fig 8 - it's just quicker to tie.

CCW

In reply to michel4388: This was highlighted a few years ago by the instructional staff at glenmore lodge - they tested it and found that when the loop was subjected to loading in different directions (like might happen when operating a semi-direct belay)at the same time that the knot loosened.

In reply to michel4388:

Use a Bowline - the king of knots.

Bob

In reply to michel4388: The danger is that you still leave too little tail. You have to allow enough tail for the knot to invert down the rope at least 3 times, which is what it will do if shock loaded from the side. The bonus of adding a stopper knot is that it almost certainly generates enough tail.

In reply to michel4388: use a double bowline if you want to make it easy to undo

In reply to cmordaunt:
Hmm. I was taught that the fig 8 doesn't need a stopper knot, and I've heard this advice repeated many times. Is it wrong then? I was shown the knot described here as an easy way of keeping the tail out of the way, and virtually eliminating the chance of accidentally clipping the tail instead of th live rope. And a positive side effect being that the knot was easier to undo after weighting.

Slightly concerned I might have been using dangerous techniques for the last 15 years...

In reply to Simon Caldwell:

It's the old EDK thing again. I've never heard of a fig 8 inverting when used for tying in, even if the central rope loop has got something else clipped into it that might pull it open. I've only ever heard of this happening in an abseiling situation.
This advice that it doesn't need a stopper knot because it tightens on itself when loaded correctly (i.e. not in the EDK pulling open situation) has been going around for a long time. As I'm sure you are aware (but others may not be), this is generally qualified by saying there should be a long tail to allow for slippage.

However I suppose it's a theoretical possibility that it could invert especially if members of the group go away and use the knot in unexpected scenarios. There's a tendency for some people to try and keep advice for beginners as simple and as foolproof as possible. Insisting on a stopper knot on all occasions would cater for the EDK possibility so it covers the instructor for all eventualities.

In reply to Alison Stockwell:

I read somewhere that the minimum length of tail for fig.8 is 1 cm for each mm of rope thickness, eg. an 11cm tail for an 11mm thick rope.

In reply to michel4388:

One of the insturctors used them at a wall I worked on and after a session with adults they were a complete nightmare to undo, as opposed the ones I tied with a standard stopper knot.

In reply to Simon Caldwell:

I was taught that a fig. 8 doesn't need a stopper knot as longer as you have at least 6 inches of tail, and I never tie one when I climb. That said, when I teach tying-in I always make people tie it because it is a good way of ensuring they have enough tail, there is no way anyone can tie a stopper knot with less than about 8 inches of rope.

That say again, in theory tying extra knots in your rope will weaken it, increase sheath slippage. Though, I doubt in reality it makes a noticable difference.

In reply to michel4388:

I use it all the time as I like the fact that the tail comes back towards me rather than parallel with the live rope. I wouldn't say its noticeably easier to untie after a lob, mind.

In reply to Removed User:

Trouble is you don't want 6-8 inches of tail just hanging about, so makes sense to tie it of just for neatness. I've heard there is an arguement for it on long multi pitch climbs where you could end very tired and end up clipping into the wrong when abseiling, but making sure the stopper knot is flush with the fig 8 (which isn't often done) should solve this.

In reply to michel4388: It may increase the radius at the first-loaded bight, and, hence, improve the load tolerance overall, but I prefer the siple overhand knot which I fidn is a useful indicator that the end of the rope has not migrated into the knot.

In reply to michel4388: don't clip the tail into the belay instead.....keep that loop free for clipping belay device etc..

In reply to michel4388: I have seen a fig 8 invert 3 times when loaded from the side, same situation you could easily have in a belay setup. I therefore will always use a stopper to give me enough tail and I will always use it completely flush with the other knot to prevent accidental clip in. I never ab or climb without checking my harness and my tie-in knot - thats good practice and should solve any problems.