UKC

Ropes don't last forever, and sometimes they get trashed at very inconvenient times. If you find yourself in a situation where you're committed to ascending or abseiling down a gubbed rope, what strategies or techniques can make it safer? The two specific problems with the rope could be core damage or a hole in the sheath. For instance, is abseiling on an italian friction hitch safer than abbing on a belay plate? Is a ropeman 3 with a cam better/worse than a ropeman 2 with teeth? Would backing everything up with a clove hitch do anything to improve safety margin or just slow you down? I am particularly interested in the reasoning and any research that exists on the topic. Cheers!

If you spot the damage before you start up/down the rope, isolate the damage on a bite, and use abseil past a knot technique, or reverse version if going up. If not possible, I'd be more concerned about trying to keep bouncing to a minimum, rather than device selection, but that's based on gut feel rather than any evidence. If it's just the sheath that's damaged... then duct tape as a temporary fix.

Use a blocked abseil to ab on the single good side and use the damaged half as the pull line.

That way your life is never dependant on questionable rope or your ability to pass a knot.

Both solutions posted so far are good answers.

Obviously what you do depends on the exact situation and what you have with you.

So I'll add that if you are in the middle of ascending a rope when you see the damage above you, I would suggest:

1) Try not to bounce around.

2) Place gear if you can and clove-hitch the dead end of the ab rope to it and try to make sure your attachments to the ab rope will work if pulled in either direction (like a prussic) rather than 1 direction only (like a tibloc/shunt/etc.). If you are able to do this several times on the way up, if the rope breaks, you should end up hanging from this gear after a nasty fall. Of course, if the situation is appalling enough, you might want to consider whether a clean death would be preferable to a slow one, bleeding out in agony with a rope fragment and broken bones for company.... 

3) When you get to the damage, if it is short enough to reach past (maybe 50cm or less), try to transfer your gear from below to above the damaged section rather than attaching anything on it.

If mid-abseil and discovering a damaged section, you should be always be able to knot it out as mmmhumous said. If damage is not on the rope you are pulling, go back up and re-rig so it is.

Thanks for your responses everyone, these are indeed good techniques for the situation I described. To further my question a little bit, are there any known prussik/progress capture alternatives that are known to work particularly well when either the sheath or the core is damaged?

I just had a look at the UIAA website where you can find some details of the testing they do to rope clamps, pulleys and braking devices. From what I can see, the testing appears to be very regimented and limited (pass/fail on a specific set of criteria) without much research on the limits or specific merits of equipment. You also can't see the results of tests for individual pieces of equipment. Who else might do experiments on gear? The good people at CE? In house testing by the manufacturer? Seems like the latter would be highly filtered to ensure any information in the public domain would portray the company's products as superior to competitors' products.

The very best scenario is to try not to get into this situation in the first place. Using rope protectors on rub points particularly on sea cliffs not only saves damage when descending, they also protect in the event of having to climb the rope which is probably when most damage will occur. Using static rope helps with this too. 

James

Just about every national organisation in the world such as the bmc have done rope damage tests, plus other independent non rope makers. There must be data going back 20 plus years since ropemen, grigris and other more aggressive devices first entered the market. 

I can recall doing stuff with the bmc technical committee 20 years ago with meters on anchor points measuring forces created with different abseil styles. The results mirrored common sense, descend smoothly and the load is barely any higher than your body weight, pretend you are in Hollywood with lots of leaping & bouncing, stopping and starting etc you can easily treble the load. 

The answer to your question is that unless  you need to abseil to save your life, you simply don't abseil on damaged rope, it's involves a single point of safety and if you can't visibly inspect the ropes interior it's not worth the risk. You just do shorter abseils, or isolate the damage, the data that you seem to be looking for is largely irrelevent, just don't descend on damaged rope.

Just about every national organisation in the world such as the bmc have done rope damage tests, plus other independent non rope makers. There must be data going back 20 plus years since ropemen, grigris and other more aggressive devices first entered the market. 

Is the data from these tests (BMC technical committee etc.) available to the general public? So far the most interesting source I've found is the Black Diamond QC lab https://www.blackdiamondequipment.com/en_US/experience-home?fid=qclab - these are the sorts of tests that I like because they back up a lot of the widely accepted practices with evidence (classic example being double fishermans vs double overhand for tying ropes together when abseiling). Unfortunately they often only measure the test cases once, so there is still significant uncertainty in the results.

Within the context of the original question and the available equipment, I agree with the "just don't do it" approach, making sure to be using an undamaged section of rope instead for any weight bearing. However, if there was a device (or sufficient proof for an existing device) that allowed "safe enough" travel on a compromised rope, it would be interesting to hear about it because it would work in a wider range of situations, eg. ascending a single strand of rope tied off at the top (this happens fairly frequently when climbing on sea cliffs, and it is conceivable that the rope gets damaged due to lack of rope protectors and using a dynamic rope). I think that data on testing of existing equipment beyond their UIAA specified purposes is always relevant, as it allows us to understand the subtleties of different designs and use it to our advantage or avoid gear-specific pitfalls. If there is sufficient evidence that a novel technique involving a particular piece of equipment is faster than an existing technique and safe enough to be acceptable in a pinch, why not adopt it?

Also, if someone were to ask the question "what happens when I try to climb a rope with a damaged sheath using a classic prussik/tibloc/ropeman?" and nobody knows for certain because it hasn't been attempted, wouldn't it be interesting to find out?

You never know, the next time you do a bouncy abseil down a sharp-edged sea cliff, throw your climbing rope and rack in the sea to find yourself stranded with nothing but 30 different rope clamps/ascenders, you might just be grateful of some prior experiments to help you choose your best option!

Why would you test devices and then potentially encourage use on a damaged rope? It would be like a car with faulty brakes or a house with dodgy wiring, only a matter of time before some one dies. 

It's impossible to assess internal damage from the outside. It's better to encourage good practice, edge protection, clean hangs etc etc. 

It won't happen I don't have a death wish. Don't bounce abseil, leave a separate protected static rope in place, learn how to prussik. 

Ps. It would be better a person rang for the rnli that ascend a damaged rope. 

Do you even climb? 

Ah yes, that part was tongue in cheek. Why have a discussion about climbing techniques without an utterly absurd hypothetical situation to make a weak point?

In all seriousness, my hope for this thread was to find links to research into climbing gear and their limitations. I obviously didn't choose a particularly good example case, as you can see from my increasingly pedantic replies to perfectly good responses. Maybe I'll start a new thread.

I do indeed climb, though not as often as I'd like these days.

This held 8kN

https://www.flickr.com/photos/189661952@N05/50217701592/in/dateposted-publi...

Impressive! I assume the failure mode was breaking at the damaged section rather than at the knots? Ever tried this with a rope clamp instead of the figure of eight? I believe that the most common failure mode with prussiks is that the prussik grips the sheath, sheath detaches from the core and slides off the bottom of the core?

Not too surprising, the inner is around 75% of the strength. The outer mainly contains and protects it, makes it easier to handle etc. That doesn't mean folk should ignore outer damage though, as the inner could easily be damaged too.

You can isolate any damage you wouldn't trust your life to with a knot loop which will need passing unless you can rig carefully so it's already passed when you set off. Or cut the damage away and work with a shorter but safe rope.

Anecdotally: ropes are impressively strong, one of mine that had been retired from climbing in a poor way then neglected often wet and outdoors for years. That stopped a BMW 3 series twice from ~20 mph before it snapped, one of those arrests was with the sheath bust completely open.

Still, if I were trusting my life to it I'd isolate any significant damage.

jk

This Beal video shows the sheath slippage failure mode youtube.com/watch?v=jH1fEYsnJLM&

So in certain cases a damaged sheath could fail without the core breaking. Anyone know how this varies with different styles of rope clamp?

After attempting to drag my own thread off topic despite many good answers to the original question, I started a new thread asking for links to research. You can find it here https://www.ukclimbing.com/forums/gear/destructive_testing_of_climbing_equi... Thanks for your responses everyone!

When rapping past the damage torn sheath, pull up the line and put a series or backup knots in place. Release these as you descend

When jugging, use backup knots too

Just the most informative website regarding gear testing I have ever encountered. Thanks for posting. I will now waste a few hours away!