How would you join SRT rope ??

[Cave_Troll]

Double fishermen's are pigs to undo. hence why some people choose to put a reef knot in the middle. this however, makes the whole "knot" assembly longer and a bit harder to pass.
The above "alpine butterfly with a double fish in the loop" is secure, easier to undo and includes a safety loop to clip in to .

 

[Geoff R]

Thanks Martin; and it keeps the knot short to pass. 

One observation; is it possible that people used to tying Alpine Butterfly knots (which I am) could end up having an inherently safer method joining two ropes under stress using Cave-Troll's method above (thanks Cave-Troll), compared to the Capuchin/Half Double Fishermans solution which relies in effect on no mistake being made tying the final portion correctly.

One having two knots that would need to go wrong, the other having one knot. 
Obviously this is an academic point as I would hope the caver likely to be involved doing any of this for a group would be totally fluent in all possible knotting methods !

just a thought .... 

 

[darkplaces]

hmm thats rather neat cave_troll....

 

[Dep]

Thanks Martin; and it keeps the knot short to pass. 

One observation; is it possible that people used to tying Alpine Butterfly knots (which I am) could end up having an inherently safer method joining two ropes under stress using Cave-Troll's method above (thanks Cave-Troll), compared to the Capuchin/Half Double Fishermans solution which relies in effect on no mistake being made tying the final portion correctly.

One having two knots that would need to go wrong, the other having one knot. 
Obviously this is an academic point as I would hope the caver likely to be involved doing any of this for a group would be totally fluent in all possible knotting methods !

just a thought .... 

Indeed - the point at which this becomes important is when you are dangling at the end of a rope wanting to tie another one on.

I would always opt to use the knot I am most comfortable with - as long as it is secure and can be tied/untied in a matter of seconds it'll do. If I'm dangling down a shaft and someone else is shouting down at me that the manual purists recommend an XYZ knot for its incremental advantage in a special situation, then I am likely to tell them to f**k off as it really isn't that important.

 

[JB]

JB if Ive understood your posting correctly, a Capuchin is a half double fishermans tied on a bight and is easily distinguished as the resulting loop cannot slip closed (unlike its similar Barrel knot)
(If this is correct, this was my intended 2nd idea to start this thread)

Yep - that's what exactly what I mean. Sorry, didn't read your first post carefully enough.

 

[Paul_L]

I love the alpine with a double fish in loop as its easy to untie, but its significantly weaker at 53% than the reef with double fish at 65%.

 

[paul]

I love the alpine with a double fish in loop as its easy to untie, but its significantly weaker at 53% than the reef with double fish at 65%.

53% or 65% who cares? If you end up getting close to exceeding either, you would be in bits anyway...

 

[paul]

hmm thats rather neat cave_troll....

Yes it is. But when you are dangling on the end of a rope with some nasty drop beneath you, the less fiddly it is to join two ropes the better. Poking your second rope through the central "tunnel" and tying the half-double-fishermans is quite easy...

 

[Cave_Troll]

i thought someone would come up with a "strength" objection to using an AB.
if you're that worried about it , i assume you don't use ABs to make the Y hang at the tope of the rope?

 

[martinr]

Double fishermen's are pigs to undo. hence why some people choose to put a reef knot in the middle. this however, makes the whole "knot" assembly longer and a bit harder to pass.
The above "alpine butterfly with a double fish in the loop" is secure, easier to undo and includes a safety loop to clip in to .

Looks interesting. Assuming you have abseiled down and reached the stopper knot in your rope (you dont say what knot you use for this), how do you then add the additional rope and tie this knot?

 

[Downer]

Looks interesting. Assuming you have abseiled down and reached the stopper knot in your rope (you dont say what knot you use for this), how do you then add the additional rope and tie this knot?

What's this question about, Martin? Wouldn't you just lock off hard a metre or so above the stopper and haul up the end of the rope to tie it? I think I'd prefer to leave the stopper on until the AB was complete though. And put a jammer or two on the rope just in case, being a nervy sort! But I bet you meant something completely different.

 

[Paul_L]

i thought someone would come up with a "strength" objection to using an AB.
if you're that worried about it , i assume you don't use ABs to make the Y hang at the tope of the rope?

loop loaded AB's are actually 67% it's only when rope loaded they are a weaker knot.
Fig 8 would be preferred at 70% but even that can be badly tied and drop to 55-60% of rope strength.

Maybe i'm being too anal, but i always prefer to use the strongest knot when dangling myself (and especially others!) from it.

 

[Paul_L]

I love the alpine with a double fish in loop as its easy to untie, but its significantly weaker at 53% than the reef with double fish at 65%.

53% or 65% who cares? If you end up getting close to exceeding either, you would be in bits anyway...

You are right, and maybe I am an anal rigger, but as he old saying goes, better safe than sorry...

 

[martinr]

Looks interesting. Assuming you have abseiled down and reached the stopper knot in your rope (you dont say what knot you use for this), how do you then add the additional rope and tie this knot?

What's this question about, Martin? Wouldn't you just lock off hard a metre or so above the stopper and haul up the end of the rope to tie it? I think I'd prefer to leave the stopper on until the AB was complete though. And put a jammer or two on the rope just in case, being a nervy sort! But I bet you meant something completely different.

No hidden agenda, just trying to visualise how cave trolls method would work. Am I right in thinking you have to untie the stop knot in the end of the rope you are on in order to add the new rope? In which case what stops you abseiling off the end if you do something wrong?

The capucin method leaves the end knot tied at all times - you just thread the new rope through the centre of the knot and tie half a double-fishermans. No potential to ab off the end.

 

[damian]

No hidden agenda, just trying to visualise how cave trolls method would work. Am I right in thinking you have to untie the stop knot in the end of the rope you are on in order to add the new rope? In which case what stops you abseiling off the end if you do something wrong?

The capucin method leaves the end knot tied at all times - you just thread the new rope through the centre of the knot and tie half a double-fishermans. No potential to ab off the end.

I'd agree with that, MartinR. I do always feel a little concerned if I've had to untie the knot a few metres beneath my descender. I feel much happier if I've also put my Upper jammer on the rope too.

 

[ianball11]

I've only had to join rope on the biggest of pitches like say Eldon Hole where I would prefer the chunkiest eco hanger will break first knot. 

So I go for a fig 8 knot which both ropes form with two double fishermans wrapping up the slack and forming the protection loop.  I see that as having two knots joining the rope not just one.

I once joined it with two fig 8 loops joining each other at a krab and a short double fishermans loop to make sure, but although I went past it without any trouble on the way up, all the 5 foot girls claimed to have no chance. 

Ian B.   

 

[MSD]

ACT recommends tying a "normal" fig-8 in the top rope and then threading the lower rope into the knot where the loop come out and following your nose around the knot and out the top (if you see what I mean). I've used this method quite a lot and it seems excellent. Easy to add rope in mid air, uses relatively little rope, compact knot, loop conveniently placed, easy to undo and (according to ACT) is OK even for ropes of different diameter. I was worried a bit about this last point, so I tested it at the top of a 54 metre pitch on expedition this summer 8)

Actually I did stop the bottom rope off just to be sure, but there was absolutely no sign of any creep despite all the traffic it was exposed to. I think the reason it's secure (as opposed to threading back through a single fig-8 which is NOT secure for ropes of different diameter) is that three ropes "bunch" together much better than two, giving higher internal friction in the knot.

Mark

 

[Downer]

No hidden agenda, just trying to visualise how cave trolls method would work. Am I right in thinking you have to untie the stop knot in the end of the rope you are on in order to add the new rope? In which case what stops you abseiling off the end if you do something wrong?

The capucin method leaves the end knot tied at all times - you just thread the new rope through the centre of the knot and tie half a double-fishermans. No potential to ab off the end.

I'd agree with that, MartinR. I do always feel a little concerned if I've had to untie the knot a few metres beneath my descender. I feel much happier if I've also put my Upper jammer on the rope too.

Thanks, you two. I was just wondering as I haven't done very much SRT and what I did was a while back. So I'm intrigued by seeing old hands debating rather basic things like knots!

 

[wormster]

If I'm dangling down a shaft and someone else is shouting down at me that the manual purists recommend an XYZ knot...

Oh dear...... Dep I hope I didn't upset you by posting that link.

I was only passing on what I've read.

Having read the rest of this thread and looking at some very interesting pictures, I'm willing to accept that there are as many ways of joining a rope as there are ways to set up a pub.

 

[Downer]

Been playing with an AB. If you repeatedly unload it and then load it again, albeit only with hand forces, it seems to work loose very easily. With a bit of twist in the rope a hitch (?) can come off the knot and flip over the loop, effectively undoing the whole thing. Or, with a bit of wiggling, the whole loop looks like it wants to pull through the knot leaving nothing but the DF. Is this anything to worry about?