Bumps on rope?

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 JonLongshanks 22 Feb 2021

I've got an 8.5mm rope that I was using in the icy conditions a couple weeks ago.

One particularly wet and freezing climb it got properly coated in ice (becoming stiff as a wire). Towards the end of the routes the ice had formed sort of 'collars' every inch or so. 

Once home and dried out all these little bumps became apparent, you can feel them distinctly. They're along nearly the whole length of the rope:

https://photos.app.goo.gl/HTLgKeNRA4W3e8a39

https://photos.app.goo.gl/1uvjL1ZY2zkezkAN6

I've flaked it back and forth, wiggled it, stretched it, but they don't seem to go. 

Had a few icy ropes but never seen this before. Any ideas on why and how to fix it?

 greg_may_ 22 Feb 2021
In reply to JonLongshanks:

Any falls taken on the rope?

 muppetfilter 22 Feb 2021
In reply to JonLongshanks:

If you dont get an answer on UKC try Rope Test lab on Facebook.

In reply to JonLongshanks:

That doesn't look good. Looks like the sheath has shunk unevenly.

If the ice formed these collars you mention, the rope may have 'rucked' up

In reply to JonLongshanks:

I'm thinking about the effect if the core got frozen, and then you tried to bend it. If the core is locked in ice, it would not be able to stretch using the entire length of the core when flexed; this would make the effective elongation of the flexing section a very high %age of the effective length. This high effective elongation may have damaged the sections where they were flexed, if only to have caused disturbance to the lay of the core. At worst, the high effective elongation at local flex points could have significantly weakened the rope.

That's only my theory; I'd seek advice from a rope test specialist.

 JonLongshanks 22 Feb 2021
In reply to greg_may_:

Yes, but not on the day.

 JonLongshanks 22 Feb 2021
In reply to captain paranoia:

Interesting thought. There shouldn't have been much stretch, no falls taken and wasn't kept particularly tight. Shouldn't be that many 'local flex points' - when I started noticing it on the final pitch I was body belaying, no tight turns around a krab, and we only used maybe 40m out of 60m but it's along the nearly whole length! 

I've seen 'rucking' on a rope sheath and it doesn't look like that either, it does feel like it's inside...

It's unicore or whatever Beal call it where the core and sheath are bonded.

 henwardian 22 Feb 2021
In reply to captain paranoia:

It looks certain that it was the ice as it is not localised to a specific bit, so another cause seems unlikely. I'd be more general than captain paranoia and just say that "something that happened on that day with the ice that has altered the structure of the rope". When you look at it that way, I'd also say "time to retire it" because you just don't know how strong the new structure is. Might be fascinating to open it up and try and see what the cause of the bumps is though (manufacturer might be quite interested to see it too, this is the sort of thing that leads to product recalls if it turns out there is a design weakness).

 C Witter 22 Feb 2021
In reply to JonLongshanks:

Not sure why it happened, but it looks like it's set for the bin, sorry But, maybe Henwardian is right and it's worth contacting the manufacturer to see what they say re: whether there's a design fault and/or whether you can get a discount a new rope.

Post edited at 14:59
 Cobra_Head 22 Feb 2021
In reply to DubyaJamesDubya:

> ..., the rope may have 'rucked' up

It looks well rucked up to me.

I'm normally one for suggesting things would be ok, if I would probably continue using something. I don't think I'd use this though.

Do you think the bumps are the sheath, or internal under the sheath?

I think I'd be tempted to cut a bit out and see what's underneath, hopefully near an end.

Post edited at 15:01
 99ster 22 Feb 2021
In reply to JonLongshanks:

Personally, I wouldn't feel at all happy using that.  Unfortunately, I'd bin it.

But that's a good suggestion about contacting the manufacturer - I'm sure they'd be keen to inspect it.

In reply to JonLongshanks:

> There shouldn't have been much stretch, no

But if the core is frozen solid, any flexing will cause stretch of the fibres at that point, because the fibres either side of the bend are locked in place. Think of a stick of liquorice; bendy when warm, because the whole thing can deform and stretch through the body of the stick, and thin across the bend. Freeze it hard, and it will snap, because it cannot deform or stretch through the entire body. You exceed the elastic limit of the material in that very small, local section.

 Gavin 22 Feb 2021
In reply to captain paranoia:

I once saw something like this on a brand new, still coiled rope.

Taking a hot knife to the bumps revealled that the core had bunched, but there was no visual damage.  I ended up using it as a demo for the sort of things to check when inspecting equipment and the power of being able to feel a 'difference' in a rope when flaking it out.

 johnt 22 Feb 2021
In reply to JonLongshanks:

It could be the glue on the core of the Unicore rope 'clumping' - i've seen it on Unicore climbing ropes before albeit only at the rope ends and nowhere near as bad as that.

 JonLongshanks 22 Feb 2021
In reply to captain paranoia:

right! I get what you mean now. Think I'm going to have to put it under and have a look inside...

 Mr Lopez 22 Feb 2021
In reply to JonLongshanks:

> It's unicore or whatever Beal call it where the core and sheath are bonded.

Have you ever got the rope wet before this climb? My (wild) guess is the sheath shrunk when getting wet as they do, but did so unevenly because of the ice, and the unicore thingy made it set like that.

Best thinkg to do is to contact Beal and send them those photos. They'll give you a definitive answer to what's going on and how to go from there

Post edited at 17:41
 jayjackson 22 Feb 2021
In reply to JonLongshanks:

Drop Dan Middleton (BMC Technical Committee) a line as I expect they’d be interested to investigate this...

May be slower than usual depending on who’s furloughed, and they may want you to send them some of your rope, but it looks like it’s write-off anyway  

dan@thebmc.co.uk


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