UKC

Hi all,

Quick question for more knowledgeable folk - what's the quickest/safest way to (temporarily!!) shorten a cordelette by say a foot (without re-tying the double-fishermans)? 

In this situation I was using a couple of in-situ bolts on the top of the crag (over the top, on the horizontal surface) and wanted to extend an anchor to a mini-line a few metres away for my 5 year-old to climb. I used two long cordelettes on lockers (one to each bolt) with a simple overhand strong point and opposing lockers for the toprope.

To equalise I needed to take a short length out of one of the cordelettes. In the event I just put in a fig 8 on a bight in one strand of one of the loops to shorten it slightly (due to the distances involved a failure of that shortening knot would have only led to a short jolt), but using this method the load spreads the tails in opposite directions and I'm not convinced it's the most appropriate knot)?

In hindsight I could have attached the cordelette on the shorter run with two clove hitches on the karabiner at the bolt end (one on each strand of the cord loop) to take a little of the length out, which may be a more appropriate solution? Or put a couple of random overhands/fig 8s in both strands of the loop somewhere in the length before the strong point? Or simply extended both bolts with slings and then use a normal equalette off the slings?

Secondary question - is it okay to larks foot cordelette / slings to fixed bolts or should you always use a locker (have always done the latter)?

Note - clearly not a trad climber! I can (slowly) build an anchor using the rope but prefer faster solutions (where appropriate) with the child to keep her engaged!

I'd just tie an overhand to isolate the unwanted bight. An alpine butterfly would be easier to untie but it's overkill really.

On a forged or wire 'bolt', one with nice radiused edges it's fine but wouldn't usually be first choice*. In extremis I would thread a stamped & bent hanger with thin dyneema tape as part of a belay or to lower off but I'd be pretty reluctant to do it with cord and not on lead unless I were out of better options. With edges involved it's generally a bad idea.

*I have actually threaded a slingdraw through a staple half way up a route in order to use both krabs on the rope, I was totally paranoid about it unclipping itself as it was the only thing between me and a big groundfall.

Efficient and safe is good, enjoy.

jk

Why is it worse with cord than dyneema tape?

I was also wondering this. At least with cord the core it protected by the sheath, with a dyneema sling its the load bearing fibres that are stretched over the sharp edge.

Would this do the trick? I've been using this recently to equalise distant(ish) anchor pieces with slings:

https://www.mountainproject.com/forum/topic/112428831/shortening-slings-ano...

Really fast and effective once you get the hang of it. 

Clip one bolt normally with the cordelette. Pass a loop of cordelette through the other. Tie master point. If that isn't clear, pop over to multipitchclimbing.com for photo instructions 

Would taking a bight with an alpine butterfly do the job?

Good question. It might not be but I don't like it. It's to do with the thickness, when you make a very accute bend over an edge the material at the outer part of the bend is severely strained, the thicker the material (cord) the greater the strain. Tape is thin and dyneema is tough. In reality it's not that simple but I still don't like it. I've done it and I'm still here but if i'm making suggestions i'd say avoid cord over hard edges.

Jk

Never seen that before, very clever.

Jk

Thanks all.

jk - good to know an overhand on a bight is good enough, my fig 8 was safe enough! And thanks for the info on hangers/slings, common sense really I guess, it's so rare I see anything that's not a wire / U-bolt (Dorset boy) I forget other types exist

Geogert - I like that, will experiment.

David - can't see exactly what you're referring to but plenty on there, thanks.

Pbob - now I've googled how to tie an alpine butterfly (don't flame me, no need on single-pitch sport!) that looks just the ticket for a knot solution, tails exiting in opposite directions, ideal.

Best climbing tech site on the web!

go to: https://people.bath.ac.uk/dac33/high/6TheBelay.htm#belaysthatlargelydontuse...

scroll down a bit. The standard way is that shown with the lime green cordelette. Clip one bolt, bight through the other, master point.

Got it, thanks. Taking the bight back to the master point wouldn't have worked here as not enough length and I was using two cordelettes (one to each bolt), but another useful trick in the bank. Again they show shortening a run with just an overhand on a bight (which would have been sufficient to know in this situation). Will have to take a look around that site, trying to convince the wife to try some easy multipitch sport if we can get abroad later in the year.

This isn't necessarily true. When two ropes are tied together to make an abseil they are loaded in much the same way as your knot-on-a-bight. An overhand knot is preferred for this as a figure of eight can roll. Whether that is true for cord I don't know, and of course if it does roll your main loop should be conserved.

Thanks - noted!

Sheepshank
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Joke - DO NOT USE!