UKC

Forgive any impending ignorance, but after a good few years of trad I've got around to buying some half ropes. As I understand it, it's common knowledge that half ropes are fallen on together and some manufacturers and gear websites suggest retiring the rope entirely if just one has taken a big fall. 

The issue is, as one pushes upwards into the E's, is it not far more likely to be taking unexpected falls where one rope takes 90-100% of the impact force? Followed by the "better safe than sorry" approach of buying a whole new rope for £70-100... 

Is there any reason not to just use triple rated from the outset? I can imagine there's better peace of mind when facing a long fall, or bringing up a second on a traverse, where they will predominantly fall on the higher rope? For another £50 or so per rope and avoiding premature retirement, it seems worth it to me? Ta in advance 

In reply to Rowan Morgan:

Half ropes are perfectly safe when fallen on individually — that's the expected sort of fall, really. I have a triple-rated rope, but it's for flexibility reasons rather than safety reasons. There's also a counter argument in that (I am hypothesising, I haven't looked at any rope specs) a triple-rated rope will probably impart a higher impact force on the top runner, which might be suboptimal in cases of crap gear.

99% of the time, I doubt it'll make any difference either way.

Edit: are you confusing half ropes with twin ropes, which are meant to be used identically as a pair, both clipped to every piece of gear?

In reply to Rowan Morgan:

I have to admit that I'm slightly mystified as to why anyone would use half or twin ropes these days. Full strength singles can be so light and thin that I've never considered buying anything else in the last decade.

Have I missed something really obvious?

In reply to chris_r:

Weight?

In reply to chris_r:

Rope drag on wandering pitches? More options for protecting the second on traverses? Short routes like on grit protected by a spaced pair of cracks, or with crucial gear in a horizontal break pre-crux and the ground 'just there'? Climbing as a three? Ab descents? Ab approaches?

I agree with the sentiment — I climb on a single wherever I possibly can — but there are still many compelling reasons for wanting to climb on halfs.

In reply to tehmarks:

I think he means he uses lightweight singles as half ropes

In reply to tehmarks:

No confusion re. twins vs halves, although I don't blame you for assuming as such haha! One of the sources of the top of my head is this site, which I usually find quite trustworthy for rope and mountain skills: https://www.vdiffclimbing.com/half-ropes/

"For a single rope to pass UIAA testing, it must hold five falls of 80kg at a fall factor of 1.77. A half rope must hold the same five falls at the same fall factor, but only with a mass of 55kg.
If half ropes are tested as single ropes (with the full 80kg), most hold between one and three falls before failing.
This means that half ropes are safe to fall on individually. However, they shouldn't be relied upon to hold massive whippers. If you were to take a large fall on one half rope, you should retire that rope afterwards."

In reply to Jon Read:

He specifically says the weight is fine.

In reply to tehmarks:

So yeah I'm happy that just one half will take a fall, but in the event of gear popping or as I said, when on a route with minimal gear, a triple-rated might set the mind at ease better! Good points though thank you  

In reply to DubyaJamesDubya:

Cost then  

In reply to Rowan Morgan:

In my experience (full disclosure' I'm a wuss and fall on trad 2-3 times a year at most) more often that not a fall on half ropes results in only one rope being loaded.

The testing for half vs single really covers impact forces and strength. Any half rope is more than strong enough on its own to catch a big fall, it isn't gonna snap but it will wear out at a faster rate compared to a fat single rope.

so if you plan to fall off a ton then maybe it makes sense to get triples or even thin singles. but if its just catching the odd fall every now and again (most low e grade climbers?) then half ropes are fine. 

I have a tendon triple rope and its awkward when paired with a proper half rope and much heavier/bulky. It feels more cut resistant and that's nice to have on some routes but its definitely not a "one rope to rule them all" as I had hoped. 

In reply to Rowan Morgan:

Just checking

A 'pure' half rope of equivalent spec may also be more durable, because it probably has relatively more sheath than core compared to the rope that also has to pretend to be a single. Compare the Mammut Serenity with the Genesis, for example: 36% sheath for the Serenity versus 49% for the Genesis. Interestingly the impact force in 'half rope mode' is similar — 6.3kN versus 6kN.

I have a Serenity, previously an Edelweiss Performance, and I love being able to chuck one rope in the car and not think about it any further. But I also have a chunky short single for grit and similar, so it doesn't get abused too badly. I wouldn't fancy using one as my primary rope in the Peak or on Dartmoor because I reckon it'd get trashed in short order.

In reply to Rowan Morgan:

The first thing to realise is undamaged* ropes don't snap. If you take a whipper, and an 1.77 FF fall is definitely a whipper, your half rope won't snap, you'll be fine. This is a whipper we are talking about, not an everyday fall, and after such a massive whipper, I would be inspecting my rope and considering retiring it. Day to day falls, I just inspect for abrasion and carry on.

What does cause ropes to fail is that they get cut. Take a swinging fall across an edge, it doesn't have to be that sharp, and have a look at your rope**. You can protect against this by getting a rope with a thicker sheath (rope diameter does not tell the whole story) or one of the newish Edelrid ropes with an Aramid weave.

My climbing partner and I currently both have skinny (8.9) triples that we use a singles or as doubles. This seems to give us the maximum flexibility. When mine dies, I will replace it with a skinny triple with Aramid and might pair it with a skinny double with Aramid should I need/want a pair myself.

*exposure to chemicals, excessive abrasion, cuts and nicks etc

** youtube.com/watch?v=K9Wzx-9JzsI&

In reply to DubyaJamesDubya:

That would make more sense...sorry Chris!

In reply to Rowan Morgan:

If a rope has taken a really big fall, the manufacturer's advice would probably be to retire it regardless of whether it was a half rope, single, or triple-rated.  The number of falls shown on the packaging isn't guaranteed. It's possible you might have to retire a rope after the first time it was used, if it were to take a really huge whipper, or of course if it were to show physical damage.

In reply to Rowan Morgan:

By a big fall on a single half rope they are talking about something exceeding factor 1 (i.e. Past the belay) where only one rope is loaded (lots of slack on the other strand, cut in the other rope, that kind of thing).

The UIAA test fall is pretty serious if you think about what fall factor 1.77 means, it's also difficult to get such a high fall factor on one strand if your belayer doesn't belay properly. 

In reply to chris_r:

As someone who climbs predominantly on grit, the thought of one rope catching me on extended gear (as is often required) leads me to only worry for my ankles. My single rope has been reduced to making dog toys, despite being more or less brand new.

In reply to Jon Read:

The difference between a Beal twin (47g/m) and a Beal single (52g/m) is half a kilo presuming you're carrying two 50m ropes of each. I guess that would matter for alpine climbing, but maybe not for single pitching?

In reply to mrphilipoldham:

Absolutely.  Sorry, I made my point very poorly. I meant that I use 2 single-rated ropes, rather than 2 twins or half ropes.

In reply to chris_r:

At the scale of the UK hills, I can't help but feel that any bonus phys can't really be a bad thing - it's all good training at the end of the day, isn't it? How do you get fitter for carrying loads up a hill? Carry loads up a hill...

In reply to tehmarks:

I was told years ago, that half ropes give a lower impact fall on the gear.  Is this definitely true?

I have always believed so, but never actually seen proof.

In reply to Rowan Morgan:

Awesome advice thanks folks, much appreciated!  

In reply to Steve Claw:

Mammut's data for the Serenity and the Genesis suggests that there is very little difference between the pure half and triple-rated rope in 'half mode', against my original point and speculation.

I suppose it's hard to draw comparisons between a single and a half rope given the difference in testing methodology. Impact force must be fairly directly correlated to dynamic elongation though, and it seems intuitive that a stretchy half will impart less peak force on the runner than a fat and relatively less stretchy single. The stretch is essentially dissipating the energy of the fall over a longer time period, and so the peak force at the runner will be lower. How much difference does it make in the real world though? I imagine it's probably quickly dwarfed by real-world practicalities like the effect of rope drag.

I'm neither a physicist nor Jim Titt though, so please take my reasoning with a healthy pinch of salt!

In reply to Steve Claw:

Yes, in general, though not as much as many people think. Some ropes are stretchier/softer than others so will impart a lower peak force but this is a small difference. The major factor, oft forgotten, is drag. The more drag on the rope, the higher the impact force on the gear (and consequently the lower force on the belayer) so having a clean running rope with little/no drag ( a lot easier with doubles than a single) will haver the biggest impact on minimising the peak force on your RP1 as you peel off and whip. 

The "peak force" during the first drop of the EN892/UIAA 101 test is normally published on manufacturer's websites, though you need to pro-rata the values in line with the different masses used. Its also interesting to look at the numbers for double/twin dual certified ropes.

To see the effect of rope drag, Petzl have done some research and this is shown on P.9 of the this link:

http://theundercling.com/wp-content/uploads/2014/03/PetzlDynamicRopeExperie...

It's clear from this than minimum drag (i.e. doubles) with a Pivot/ATC Guide/Reverso is your best bet to minimise that peak impact force on your runner.

In reply to galpinos:

I disagree. The less drag, the higher the peak impact force. Essentially, the more efficiently the load is 'transferred' to the runner, the higher the impact force. All the little bits of friction — running over a krab here, around an arete there — reduce the efficiency by which that happens. They all need work to be done to overcome their effects. Anything which reduces the force felt by the belayer will reduce the force felt by the runner (gross simplification), because the system is essentially a pully with a fallen climber on one side, and a belayer on the other. The more efficient that pully (less rope drag), the greater the effect that will be felt on the belayer.

Yes, rope drag has a massive effect — but in entirely the opposite way to which you're thinking. The less rope drag, the higher the peak load on the runner. There aren't all the little inefficiencies helping to spread out the force across the system. Direct belaying around a spike is a great example — there's a massive amount of friction, and so the force felt by you holding the other end is massively reduced. Thankfully, you think, as your pie-munching mate slips on the grassy top-out

In reply to tehmarks:

It's worth remembering that the EN892/UIAA 101 test is done on 2.8m of rope. That's not a lot of rope to absorb the fall through stretch. The more rope out, the larger the difference in those numbers.

Rope diameter does not determine "stretchiness" alone, you need to consider sheath %, weave pattern etc. Beal aren't renowned for having the softest catch just because their ropes are thin.

You are right, rope drag increases the peak force at the runner (see my reply to Steve Claw).

I am also neither of the above......

In reply to tehmarks:

You may disagree, but you are wrong! As drag increases, the peak force on the gear increases the most, the force on the climber increases a little and force on the belayer decreases. The drag effectively stops the force being as equally spread across the system.

This proves my point, not yours I'm afraid. The belayer sees less force due to the friction. The anchor is "the other side of the spike" in your scenario and unaffected by the spikes friction, but there is now less rope to dissipate the force.

If I sound terse I'm not being dismissive, just actually have to finish some work before taking the kids to their swimming lesson!

In reply to chris_r:

An Iceline is 39g/m which equates to 780g per rope in a 60. Like you say not really an issue for cragging but I'm definitely going to take that kind of reduction for a winter or even multi-pitch day.

In reply to tehmarks:

I'm plenty fit so I'll go for the lighter bag every time! 

In reply to chris_r: I don’t know where you got your weights from but they don’t sound right. Lets just ignore twin ropes, they are a rarity and most twin ropes nowadays are rated as half ropes as well. A typical half rope will weigh around 40g/m whereas a light weight single that is also rated as a half will probably weigh 50g/m. A standard 9.5/10mm single for sport climbing will be 60g/m or more, so some significant differences.

If you’re into climbing trad in a number of different locations you’re going to be better off with half ropes. They make it easier to protect a route, give more escape options.

Ropes don’t snap during falls unless they run over a sharp edge(generalisation). The runner or the rock will break before the rope does. 9 times out of 10 ropes get retired because of wear due to abrasion, or they become old, stiff, twisted etc.

In reply to galpinos:

I'm not at all convinced that I'm right, on reflection, and I'm always happy to be educated (and told when I'm spouting dangerous reasoning). Intuitively, to me it seems that increasing friction is essentially going to increase the time over which the force is applied to the runner, which would decrease the peak impact force on the runner — same energy, more time.

But...

That's obviously a gross simplification of what is actually happening, and there are considerations in a real dynamic system that are somewhat beyond a rudimentary understanding of physics. Clearly how complicated dynamic systems act is often entirely outwith how the simplified or static system will act. And I think that probably it ultimately goes to prove that the real-world practicalities make far more difference than rope spec ever will.

The direct belay was a rubbish analogy.

In reply to galpinos:

The more drag on the system, ie. the more runners, then the less force on the top runner and on the belay. So a 12 metre climb with 10 runners in, with the last runner at 10 metres will have less force on the top runner in a fall than the same route if the climber only places one runner at 10 metres. At least that is my understanding, but I am happy to be corrected as I am no expert.

In reply to tehmarks:

The friction is between the anchor/gear and the belayer, not the climber and the anchor/gear

Agreed, though Petzl have tested it, as per p.9 of this link:

http://theundercling.com/wp-content/uploads/2014/03/PetzlDynamicRopeExperie...

TL : DR, they agree with me......

In reply to galpinos:

Really, I should have read the research before feeling compelled to argue...

• Significant drag prevents the full length of the rope from absorbing the energy of the fall. Only the last section of rope stretches, the actual fall factor increases

Is the key point, really, that's easy to miss in a schoolperson appraisal of the physics at play. Alas, I'm not allowed to give my own post a dislike/downvote...

In reply to tehmarks:

That's what I was attempting to explain. Who'd have thought Petzl would explain it better!

In reply to Martin Haworth:

The more drag in the system, the more force on the top runner, the more force on the climber and less force on the belayer. See the discussion with tehmarks.

Key point is:

• Significant drag prevents the full length of the rope from absorbing the energy of the fall. Only the last section of rope stretches, the actual fall factor increases

In reply to galpinos: I can understand that logic.

So i need to start placing less runners if my top runner is going to be in a poor placement!

In reply to Rowan Morgan:

The issue of weight is not so much carrying it on the walk-in, when presumably your partner will be carrying one, but at the end of a long run-out when you're dragging both behind you.

Most people are content with half ropes and you don't often hear of them having any problems.  Having two skinny singles allows you the option as using them either as singles or as a pair of half ropes, but other than that I can't see any reason to carry the extra weight. On the other hand, modern single ropes are about the same diameter as half ropes were back in the day (but probably stronger), so it wouldn't be much different from how we climbed then.

Unless you are attracted to routes with the prospect of mega falls I suspect the chances of trashing a rope with a single fall (ignoring the possibility of physical damage) are fairly small, and in such a situation I doubt whether it would make much difference which rope you used. 

In reply to Howard J:

I have the triple rated Beal Jokers and tbh i find them too stretchy to be ideal as a single, and too heavy to be ideal as a half…

In reply to galpinos:

This discussion has been fascinating, with intuitively odd forces at play.  Amazing that the loads of runners principle might actually make the loads at your hypothetical RP1 higher.  I can't see this changing my approach (and nor can Martin it seems), but it is really interesting and the discussion has been in good spirit.  Mind you, having done a route today, with half ropes and a critical RP, I might have considered loading the other rope with all / most of the lower, back up gear, to reduce the load on the RP

In reply to Derek Furze:

It is a wonderfully counterintuitive result, isn't it?

OP: the real world evidence is that ropes, even half ropes, do not fail unless there are significant extenuating circumstances such as prior damage or sawing over a sharp edge.  There's almost a kilogram difference between a 50m pair of my favourite doubles (Apus 7.9) and a pair of Beal Jokers, so if I were you I'd stick with the doubles.

The UIAA test is not terribly realistic - it involves an utterly brutal fall, repeated with little relaxation time, until failure.  Bear in mind that even something like the famous fall from Gaia ( https://www.rockandice.com/videos/weekend-whippers/weekend-whipper-hard-gri... ) is something like FF0.8.  If you are subjecting your ropes to anything even remotely like the UIAA FF1.77 test on a regular basis then you should consider taking up tiddly winks instead

In reply to Derek Furze:

Glad it has been informative! Double ropes and long extenders are the key!

Your other option is to get your belayer to stand well back from the crag so all your runners unzip in the fall, leaving you drag free with just the top runner in place…..

In reply to Jamie Wakeham:

Well this all has given me plenty of good bedtime reading that's for sure :') funnily enough Gaia isn't on my ticklist, and my initial question was more posed along the lines of just increasing the safety margin where possible etc. Thanks for the summary though!

I'm already the town champ at tiddly winks, you've got the wrong guy  

In reply to Jamie Wakeham:

oh and just wondering, how have you found sub-8mm doubles? Have my eye on the tendon master 7.8 but am concerned about the difficulty of handling - not too thin and slippery? 

In reply to Rowan Morgan: I use Edelrid Apus 7.9mm ropes, really like them, no handling issues.

I do worry a bit about whether they might snap when I am climbing with Andy, he’s carrying a lot of timber nowadays and is prone to falling off.

In reply to Rowan Morgan:

The Apus are great, but they are a fairly specific tool.  I have a dodgy back so I'm always looking to minimise weight, and they are astonishingly light.  For such slim ropes they handle well - they're much less prone to tangling than my old Icelines, for example.  And as long as you have a good grabby belay plate then they handle just fine - they work very well in a DMM Pivot.  Longevity looks good - I've had mine a while now and they are holding up very well.

They are veeery stretchy under load.  I had a second fall off about 20m below me, and despite me having locked them off even as they fell, they must have gone down three metres or so just on rope stretch.  

In reply to Jamie Wakeham:

Ah ok, thanks for getting back to me that's really helpful! That stretch could earn me some harsh words from my climbing partners haha, might opt for the Petzl rumba 8.0 as a compromise.

In reply to Rowan Morgan:

No problem!  I think of the Apus as my ropes for when I don't think falling off is going to be part of the day's plan; if I anticipate catching lots of falls then I'll take something else. 

The Rumba was high on my shortlist when I got the Apus, though I wonder if they might also be quite stretchy - the two models look pretty similar.  Edelrid Starling is probably worth a look?  

In reply to Rowan Morgan:

I've climbed with a pair of Cobra 8.6mm half-ropes for...6 years? They've taken a reasonable number of falls in that time. In all of the falls, one rope took the brunt of the force. They've held up marvellously.

Although it is against official advice, on a couple of occasions on low-grade climbing where weight was crucial, I've felt fine to lead on one rope used as a single. I've also had two seconds, one on each rope and never had any particular concerns.

I've just bought a pair of Mammut Phoenix ropes (8mm). They're great, but... I no longer feel they're adequate for bringing up two seconds on separate ropes and wouldn't lead on one used as a single. I just feel they've crossed the line where that seems reasonable. The idea would give me visions of ropes being sawn across sharp edges... and of my second tumbling into the void!

I'm not a rope tester and don't have technical knowledge of rope construction; these are just the "feelings" of a punter on bending/breaking the manufacturer's instructions. But, if you do get half ropes, it might be worth getting something more robust (i.e. thicker - 8.6mm or so). 3-rated ropes would be ideal, but are usually significantly more expensive than cheaper half ropes.

In reply to C Witter:

I agree.

I use 8.5mm Mammut Genesis, and chose them over something smaller as I value robustness over weight with ropes.

I think unless your climbing in the high E's (E6+) then the very small weight saving isn't worth it (except Alpine stuff)

In reply to Rowan Morgan:

When looking at skinny singles, be aware of the sheath thickness/percentage. The Apus, for example, only has a 33% (I think) stealth so for me, an 85kg chap plus rack, a swinging fall and the rope is toast. No idea about the Tendon you mentioned.

I’d be looking at the Starling Protect at 8.2mm* if you are keen for skinny(-ish) half rope.

*if you are thinking about weight, don’t go by diameter but by the actual weight per metre and ignore diameter. There is an effective approx +/-0.2 tolerance in the measurement of rope diameters so your 7.9mm rope could be thicker than your 8.2mm rope…….

In reply to Martin Haworth:

Not if there is any chance that the lower runners would either protect lower moves or stop you hitting something if the top one failed. Just try to have the ropes running as freely as possible so the whole rope has a good chance to stretch. The big impact forces come when only the small bit at the leaders end stretches much. As an unrealistic extreme that still illustrates the principle, if there was so much friction at the top runner (e.g. if the rope ran at a sharp angle through the karabiner and was also trapped between karabiner and rock) that the rope was effectively fixed at the top runner, a fall would be factor 2 on the short length between the leader and the top runner with a slack rope lower down and no force transmitted to the belayer.