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Never really understood this, so please enlighten ....
In reply to indigo:
a half rope has less sharp edge protection due to the generally thinner diameter.
Also the UIAA testing is done with less weight and to withstand less falls 65kg instead of 85kg IIRC.
Due to clipping into alternate placements one rope will take the main load in the event of a fall, the second is there for a backup (But often can be useless depending on the position of the last anchor.
For all intensive purposes you could climb on a single half rope if you are happy that there are no sharp edges and the rope would not instantaneously combust like the manufacturers would have you believe.
However i still use two half ropes, never one.
Chris
a half rope has less sharp edge protection due to the generally thinner diameter.
Also the UIAA testing is done with less weight and to withstand less falls 65kg instead of 85kg IIRC.
Due to clipping into alternate placements one rope will take the main load in the event of a fall, the second is there for a backup (But often can be useless depending on the position of the last anchor.
For all intensive purposes you could climb on a single half rope if you are happy that there are no sharp edges and the rope would not instantaneously combust like the manufacturers would have you believe.
However i still use two half ropes, never one.
Chris
In reply to indigo:
Climbing is dangerous in this case the risk is increased yet plenty of people do this to save weight on climbs they find comfortable. The half rope is rated for falls individually so can be used this way. Double ropes in contrast cant.
Climbing is dangerous in this case the risk is increased yet plenty of people do this to save weight on climbs they find comfortable. The half rope is rated for falls individually so can be used this way. Double ropes in contrast cant.
In reply to Offwidth:
Interesting use of the word "Double" in this context. I consider both half ropes and twin ropes as doubles. One uses one double rope technique the other uses a different double rope technique.
Interesting use of the word "Double" in this context. I consider both half ropes and twin ropes as doubles. One uses one double rope technique the other uses a different double rope technique.
In reply to indigo:
Woops I better not mention on here that I have lead the equivelant of scottish V on a single 8.1mm half rope in the alps... lol
Woops I better not mention on here that I have lead the equivelant of scottish V on a single 8.1mm half rope in the alps... lol
In reply to Ciro:
These definitions are a bit confusing at times. What I meant by double is called twin in that link. Single rope and half rope are the most common rope labels and both those types of ropes are rated for falls on a single strand.
The link also says retire a rope after holding a big fall which is plain wrong. Needs an edit.
These definitions are a bit confusing at times. What I meant by double is called twin in that link. Single rope and half rope are the most common rope labels and both those types of ropes are rated for falls on a single strand.
The link also says retire a rope after holding a big fall which is plain wrong. Needs an edit.
Post edited at 13:29
In reply to Ciro:
Seems like an unnecessary confusion to me when halves and twins describe their respective methods of use perfectly adequately. I prefer my way
Seems like an unnecessary confusion to me when halves and twins describe their respective methods of use perfectly adequately. I prefer my way
In reply to chrisbaggy:
For all intensive purposes
Nonsense, it means nothing. Its what people say when they really mean to say "for all intents and purposes".
1. For all intents and purposes = Correct
2. To all intents and purposes = Correct
3. For all intensive purposes = WRONG! You should have paid attention in English class!
by Malicious Matt August 20, 2005
(although I only learnt this recently, wiwwim)
For all intensive purposes
Nonsense, it means nothing. Its what people say when they really mean to say "for all intents and purposes".
1. For all intents and purposes = Correct
2. To all intents and purposes = Correct
3. For all intensive purposes = WRONG! You should have paid attention in English class!
by Malicious Matt August 20, 2005
(although I only learnt this recently, wiwwim)
Post edited at 13:55
In reply to Offwidth:
I agree it's a little confusing - there's one name too many, and "double" would seem a better way to describe the way you use twin ropes than halves, but that's not the definition.
> These definitions are a bit confusing at times. What I meant by double is called twin in that link. Single rope and half rope are the most common rope labels and both those types of ropes are rated for falls on a single strand.
I agree it's a little confusing - there's one name too many, and "double" would seem a better way to describe the way you use twin ropes than halves, but that's not the definition.
In reply to GridNorth:
That's fine, you stick with your way, but I'd suggest the Starting Out forum is not the place to be adding further confusion to the issue.
> Seems like an unnecessary confusion to me when halves and twins describe their respective methods of use perfectly adequately. I prefer my way
That's fine, you stick with your way, but I'd suggest the Starting Out forum is not the place to be adding further confusion to the issue.
In reply to indigo:
It's not.
There are three types of ropes: single, half and twin. That's what's actually written on the ropes when you buy them (OK, I'm ignoring the new 'triple' ropes).
There are two major techniques: single rope technique, which you can do with a single or with a pair of twins, and double rope technique, which you can do with a pair of halves or a pair of singles if you are a masochist.
Single rope technique with both halves at once is dangerous, because you effectively end up with one not-very-stretchy rope and it increases the max forces on your gear.
Single rope technique with one half rope is fine but not recommended if you plan to take lots of falls as it'll wear your expensive thin rope out quickly.
Single rope technique with one twin is dangerous because they are not designed to take a fall alone. They are intended for single rope technique, but only as a pair of ropes.
Have I covered all the possibilities there?
It's not.
There are three types of ropes: single, half and twin. That's what's actually written on the ropes when you buy them (OK, I'm ignoring the new 'triple' ropes).
There are two major techniques: single rope technique, which you can do with a single or with a pair of twins, and double rope technique, which you can do with a pair of halves or a pair of singles if you are a masochist.
Single rope technique with both halves at once is dangerous, because you effectively end up with one not-very-stretchy rope and it increases the max forces on your gear.
Single rope technique with one half rope is fine but not recommended if you plan to take lots of falls as it'll wear your expensive thin rope out quickly.
Single rope technique with one twin is dangerous because they are not designed to take a fall alone. They are intended for single rope technique, but only as a pair of ropes.
Have I covered all the possibilities there?
In reply to Jamie Wakeham:
I'm mildly confused. Why is there a place for half ropes as well as twin ropes? Why not just have halves (and singles)?
I'm mildly confused. Why is there a place for half ropes as well as twin ropes? Why not just have halves (and singles)?
Post edited at 14:19
In reply to Ciro:
Valid point, I didn't really take note of the specific forum we were in. Beginners ignore what I said, I thought this was just a general discussion.
In reply to Tmmd: The ropes are used in different ways. With twins you clip both ropes into the same krab as you progress, with halves you clip separately. The former are usually thinner than halves although that distinction is becoming a little blurred and it can be difficult to judge with furry ropes. My "skinnies" now look and feel the same as my half ropes.
Valid point, I didn't really take note of the specific forum we were in. Beginners ignore what I said, I thought this was just a general discussion.
In reply to Tmmd: The ropes are used in different ways. With twins you clip both ropes into the same krab as you progress, with halves you clip separately. The former are usually thinner than halves although that distinction is becoming a little blurred and it can be difficult to judge with furry ropes. My "skinnies" now look and feel the same as my half ropes.
In reply to Timmd:
As GridNorth says, halves and twins are different (and in fact confusing them is the only actively dangerous mistake that is likely to be made). Twins are typically thinner and stretchier. They are designed only to both take the load simultaneously; they're not rated to take a fall one at a time. They are always both clipped to every piece of gear.
Halves, on the other hand, are designed to take a fall on their own and are only ever clipped one rope to each piece of gear. If you put both ropes into one piece and then fell on it, you have effectively made a very non-stretchy rope. As F = dp/dt, and you've just minimised dt, you greatly increase F.
The only real point of twin ropes is for a situation when you want the simplicity of single rope technique, but also want either a backup if one rope is cut (so they get used in ice climbing) or the ability to abseil twice as far as if you were using a single. I dont' see twins very often - almost all skinny ropes you see on the crag are halves. They don't weigh much more than twins and are rather better for any wandering route. And as a bonus you can use one at a time!
As GridNorth says, halves and twins are different (and in fact confusing them is the only actively dangerous mistake that is likely to be made). Twins are typically thinner and stretchier. They are designed only to both take the load simultaneously; they're not rated to take a fall one at a time. They are always both clipped to every piece of gear.
Halves, on the other hand, are designed to take a fall on their own and are only ever clipped one rope to each piece of gear. If you put both ropes into one piece and then fell on it, you have effectively made a very non-stretchy rope. As F = dp/dt, and you've just minimised dt, you greatly increase F.
The only real point of twin ropes is for a situation when you want the simplicity of single rope technique, but also want either a backup if one rope is cut (so they get used in ice climbing) or the ability to abseil twice as far as if you were using a single. I dont' see twins very often - almost all skinny ropes you see on the crag are halves. They don't weigh much more than twins and are rather better for any wandering route. And as a bonus you can use one at a time!
Post edited at 15:41
In reply to indigo:
"Because ropes which hold 5 falls with 55-kg in practice hold 2 falls with 80-kg, which has been allowed as sufficient security for a half rope which is not used to hold repeated falls on one strand." (Source : bealplanet.com)
"Because ropes which hold 5 falls with 55-kg in practice hold 2 falls with 80-kg, which has been allowed as sufficient security for a half rope which is not used to hold repeated falls on one strand." (Source : bealplanet.com)
In reply to Jamie Wakeham:
In theory this may be true, and in extreme situations it may be relevant, in practice everybody I know uses halves as twins all the time without problems.
> Halves, on the other hand, are designed to take a fall on their own and are only ever clipped one rope to each piece of gear. If you put both ropes into one piece and then fell on it, you have effectively made a very non-stretchy rope. As F = dp/dt, and you've just minimised dt, you greatly increase F.
In theory this may be true, and in extreme situations it may be relevant, in practice everybody I know uses halves as twins all the time without problems.
In reply to markus691:
Any many are rated as such - and I have seen manufacturers even saying it is fine to switch between twin and half technique during climbs (which is usually frowned upon as the ropes move different amounts in the same carabiners).
You increase F but not enormously, and on a bolted route a) it won't matter and b) your ropes will last longer (since each is taking less strain).
Any many are rated as such - and I have seen manufacturers even saying it is fine to switch between twin and half technique during climbs (which is usually frowned upon as the ropes move different amounts in the same carabiners).
You increase F but not enormously, and on a bolted route a) it won't matter and b) your ropes will last longer (since each is taking less strain).
In reply to indigo:
One risk with double ropes is if your technique is poor and they cross over and you fall; they can melt each other or so I've read.
One risk with double ropes is if your technique is poor and they cross over and you fall; they can melt each other or so I've read.
In reply to markus691:
Oh, I'm sure that in 99% of cases, halves used as twins will be just fine, because in 99% of cases falls are onto very strong bolts or well-placed trad gear, with the larger falls more usually in sport where increasing force on the runner doesn't really matter. But why learn bad habits which can lead to problems in the 1%?
Andrew: I don't really buy the extending rope life theory, because most trad falls are actually fairly small (so cause little real wear on the rope) and most people taking repeated big falls on sport will be using a single anyway. I don't think there are that many people taking repeated factor 1 falls onto halves?
Which manufacturer says you can swap between single and double rope technique within a pitch? That, I rather thought, was always a big no-no.
Oh, I'm sure that in 99% of cases, halves used as twins will be just fine, because in 99% of cases falls are onto very strong bolts or well-placed trad gear, with the larger falls more usually in sport where increasing force on the runner doesn't really matter. But why learn bad habits which can lead to problems in the 1%?
Andrew: I don't really buy the extending rope life theory, because most trad falls are actually fairly small (so cause little real wear on the rope) and most people taking repeated big falls on sport will be using a single anyway. I don't think there are that many people taking repeated factor 1 falls onto halves?
Which manufacturer says you can swap between single and double rope technique within a pitch? That, I rather thought, was always a big no-no.
In reply to Timmd:
cos twins can be thinner and lighter than halves. Main advantage over single i think is they give you longer abseil ability
> I'm mildly confused. Why is there a place for half ropes as well as twin ropes? Why not just have halves (and singles)?
cos twins can be thinner and lighter than halves. Main advantage over single i think is they give you longer abseil ability
Post edited at 19:26
In reply to Jamie Wakeham:
There is a long discussion on moutainproject about this (with a quote from a manufacturer), you will probably find the link before I do. However the answer is I think that there is a lack of data of just how bad an idea this this. It seems to be moving from the "never do this" to the "lots of people do this and none have died" category.
> Which manufacturer says you can swap between single and double rope technique within a pitch? That, I rather thought, was always a big no-no.
There is a long discussion on moutainproject about this (with a quote from a manufacturer), you will probably find the link before I do. However the answer is I think that there is a lack of data of just how bad an idea this this. It seems to be moving from the "never do this" to the "lots of people do this and none have died" category.
In reply to Jamie Wakeham:
Baffling! Trad falls all too often whippers, either because the gear is spaced, or the route goes sideways, or because some of it pings out. The trad falls I've taken and that I've held have been quite long.
> with the larger falls more usually in sport
> because most trad falls are actually fairly small
Baffling! Trad falls all too often whippers, either because the gear is spaced, or the route goes sideways, or because some of it pings out. The trad falls I've taken and that I've held have been quite long.
In reply to David Coley:
I stand somewhat corrected - I hadn't realised that there were several ropes now rated as both twin and half. I've not bought a rope for quite a few years! I guess this is due to better rope-making techniques that allow for a rope to simultaneously survive enough big falls to qualify as a half, and have a low enough impact force to qualify as a twin.
Given the forum we're in, it's probably worth making the point that there are still plenty of half ropes out there not qualified as twins. And that in either case, when you use half ropes as twins you certainly increase the force on the top runner (the MountainProject back-of-a-fag-packet physics suggests by about a third). Increasing the impact force is usually OK, probably always OK for small falls, probably always OK for sport or most trad gear, but potentially not OK for big trad falls onto small wires.
And I suspect the overlap of the venn diagrams of 'people taking big falls on small wires' and 'people clipping halves as twins to save wear' is small, if only because people taking big falls onto small trad gear are likely to know about the benefit of minimising impact forces compared to the marginal benefit of not wearing their ropes out - so we don't see any reported failures.
But the quote of mine you used there was about swapping from single to double technique within a single pitch (ie clipping both ropes to some runners, and only one rope to others), and I still don't see anyone suggesting that's safe. That can lead to two tensioned ropes sawing over each other and that's potentially bad.
I stand somewhat corrected - I hadn't realised that there were several ropes now rated as both twin and half. I've not bought a rope for quite a few years! I guess this is due to better rope-making techniques that allow for a rope to simultaneously survive enough big falls to qualify as a half, and have a low enough impact force to qualify as a twin.
Given the forum we're in, it's probably worth making the point that there are still plenty of half ropes out there not qualified as twins. And that in either case, when you use half ropes as twins you certainly increase the force on the top runner (the MountainProject back-of-a-fag-packet physics suggests by about a third). Increasing the impact force is usually OK, probably always OK for small falls, probably always OK for sport or most trad gear, but potentially not OK for big trad falls onto small wires.
And I suspect the overlap of the venn diagrams of 'people taking big falls on small wires' and 'people clipping halves as twins to save wear' is small, if only because people taking big falls onto small trad gear are likely to know about the benefit of minimising impact forces compared to the marginal benefit of not wearing their ropes out - so we don't see any reported failures.
But the quote of mine you used there was about swapping from single to double technique within a single pitch (ie clipping both ropes to some runners, and only one rope to others), and I still don't see anyone suggesting that's safe. That can lead to two tensioned ropes sawing over each other and that's potentially bad.
In reply to Jamie Wakeham:
Hmm, I though climbing instructors were supposed to keep up with developments in climbing equipment, the Beal Joker which is triple rated has been out for years
And fortunately being triple rated we can see directly the difference in impact force when tested as a single strand and with two strands using the same drop test;- single 7.9-8.2kN, twin 9.1-9.3kN so an increase of 14% if you take the middle of the test results.
The required quote is:-
"Hello (deleted),
you had a question on your Mammut rope Phoenix 8mm and whether it can be used in twin and half rope technique in one single pitch. This is the case, you can always clip the two rope strands as twins, then split them as doubles, join again etc. This is exactly the advantage of half ropes compared to twin ropes where you always need to clip both ropes.
Hope this helps you,
best regards from Switzerland,
(deleted)
(deleted) Kind regards
(deleted)
Productmanager Climbing Equipment
Mammut Sports Group AG, Birren 5, CH-5703 Seon
Tel. +41 62 769 81 32, Fax +41 62 769 82 47, www.mammut.ch "
Hmm, I though climbing instructors were supposed to keep up with developments in climbing equipment, the Beal Joker which is triple rated has been out for years
And fortunately being triple rated we can see directly the difference in impact force when tested as a single strand and with two strands using the same drop test;- single 7.9-8.2kN, twin 9.1-9.3kN so an increase of 14% if you take the middle of the test results.
The required quote is:-
"Hello (deleted),
you had a question on your Mammut rope Phoenix 8mm and whether it can be used in twin and half rope technique in one single pitch. This is the case, you can always clip the two rope strands as twins, then split them as doubles, join again etc. This is exactly the advantage of half ropes compared to twin ropes where you always need to clip both ropes.
Hope this helps you,
best regards from Switzerland,
(deleted)
(deleted) Kind regards
(deleted)
Productmanager Climbing Equipment
Mammut Sports Group AG, Birren 5, CH-5703 Seon
Tel. +41 62 769 81 32, Fax +41 62 769 82 47, www.mammut.ch "
In reply to Jamie Wakeham:
I wasn't suggesting that people start leading sport on two ropes to save wear! Just that if you were climbing a sport route on halves it would wear the rope less if you clipped as twins rather than alternately (or just using one half). Perhaps you might do this because you need a pair of ropes for abseiling and would rather take two halves than a single and a twin/half/tag line? (I don't really know what people tend to do on big alpine 10+pitch sport routes though)
> Andrew: I don't really buy the extending rope life theory, because most trad falls are actually fairly small (so cause little real wear on the rope) and most people taking repeated big falls on sport will be using a single anyway. I don't think there are that many people taking repeated factor 1 falls onto halves?
I wasn't suggesting that people start leading sport on two ropes to save wear! Just that if you were climbing a sport route on halves it would wear the rope less if you clipped as twins rather than alternately (or just using one half). Perhaps you might do this because you need a pair of ropes for abseiling and would rather take two halves than a single and a twin/half/tag line? (I don't really know what people tend to do on big alpine 10+pitch sport routes though)
Post edited at 12:12
In reply to jimtitt:
...I mentioned I was ignoring it in my first post
Yes, the Joker has an increase in impact force of ~14% when comparing single and twin use, which is the best comparison for us to make (I just spent a few minutes wondering about the 60% discrepancy between half and twin, but of course they're tested with a different mass).
I'm not sure we can justify extrapolating that 14%, though. That assumes all ropes scale in the same manner, and they clearly don't. Take, as an example, the popular Beal Cobra II - they have an impact force of 5.1kN as halves. That's about 10% lower than the Joker as a half rope (5.7kN).
If all ropes scaled in the same way, we'd expect their impact force as twins to also be about 10% lower than the Joker, which would imply a value of about 8.3kN. But they don't qualify as twins, which presumably means that their impact force as twins is 12kN or greater (that's pretty high given a #1 wire is rated to about 10kN). Unless there is another reason the Cobra is excluded from having a twin rating*, our presumption of scaling is out.
Of course, there's also a non-linear relationship between UIAA impact force and actual forces generated in real-life situations. I suspect that, without access to a drop-test rig, the question is too complicated to figure out on paper.
re that email from Mammut: I'm genuinely surprised by it. Has any other manufacturer claimed this, I wonder? Every thread I look at on the question sooner or later comes back to a reference to that one email from 2011. If it is an urban myth, it's well-established enough that instructors far more qualified than I keep repeating it and writing it in books.
* is there? I don't know.
> Hmm, I though climbing instructors were supposed to keep up with developments in climbing equipment, the Beal Joker which is triple rated has been out for years
...I mentioned I was ignoring it in my first post
Yes, the Joker has an increase in impact force of ~14% when comparing single and twin use, which is the best comparison for us to make (I just spent a few minutes wondering about the 60% discrepancy between half and twin, but of course they're tested with a different mass).
I'm not sure we can justify extrapolating that 14%, though. That assumes all ropes scale in the same manner, and they clearly don't. Take, as an example, the popular Beal Cobra II - they have an impact force of 5.1kN as halves. That's about 10% lower than the Joker as a half rope (5.7kN).
If all ropes scaled in the same way, we'd expect their impact force as twins to also be about 10% lower than the Joker, which would imply a value of about 8.3kN. But they don't qualify as twins, which presumably means that their impact force as twins is 12kN or greater (that's pretty high given a #1 wire is rated to about 10kN). Unless there is another reason the Cobra is excluded from having a twin rating*, our presumption of scaling is out.
Of course, there's also a non-linear relationship between UIAA impact force and actual forces generated in real-life situations. I suspect that, without access to a drop-test rig, the question is too complicated to figure out on paper.
re that email from Mammut: I'm genuinely surprised by it. Has any other manufacturer claimed this, I wonder? Every thread I look at on the question sooner or later comes back to a reference to that one email from 2011. If it is an urban myth, it's well-established enough that instructors far more qualified than I keep repeating it and writing it in books.
* is there? I don't know.
In reply to Jamie Wakeham:
To avoid the stress of worry, could you not clip two QDs to the same gear and clip one strand to each QD?
To avoid the stress of worry, could you not clip two QDs to the same gear and clip one strand to each QD?
Post edited at 13:19
In reply to BnB:
In a situation where you're using double rope technique but you want to secure both ropes to one runner (perhaps because you're bringing up two seconds, both of whom need that runner to protect the start of a traverse) that's exactly what's advised. Other than that I can't see any benefit to switching between single and double techniques mid-pitch, which sort of makes the question moot.
Andrew: agreed.
In a situation where you're using double rope technique but you want to secure both ropes to one runner (perhaps because you're bringing up two seconds, both of whom need that runner to protect the start of a traverse) that's exactly what's advised. Other than that I can't see any benefit to switching between single and double techniques mid-pitch, which sort of makes the question moot.
Andrew: agreed.
In reply to Jamie Wakeham:
Money and Marketing. I remember a quote from one manufacturer (don't remember the source unfortunately) which said that the drop tests required for the rating cost money (presumably they have to pay an independent lab) and are frequently of no use to them, e.g. for a thin single rope marketed to sports climbers it doesn't matter whether you could use two of them as halves or twins.
Here's something similar from Dave Furman at Mammut:
http://www.highinfatuation.com/blog/straight-from-the-mammoths-mouth-half-r...
> Unless there is another reason the Cobra is excluded from having a twin rating*, our presumption of scaling is out.
Money and Marketing. I remember a quote from one manufacturer (don't remember the source unfortunately) which said that the drop tests required for the rating cost money (presumably they have to pay an independent lab) and are frequently of no use to them, e.g. for a thin single rope marketed to sports climbers it doesn't matter whether you could use two of them as halves or twins.
Here's something similar from Dave Furman at Mammut:
http://www.highinfatuation.com/blog/straight-from-the-mammoths-mouth-half-r...
In reply to markus691:
I had read that. The quote in there says you can use [whichever rope they're talking about] either as twin or half; it doesn't specifically say anything about swapping mid pitch. Neither does their rope booklet download, which does issue warnings against friction "if two ropes are both routed through the same anchor point, by mistake".
So far as I can see, every forum post in the last four years which suggests swapping techniques mid pitch is actually OK references just that single email.
Mammut have clearly changed their views on dual (and indeed triple) certification in the last few years as they now have several of each. I suppose this doesn't rule out the possibility that they're not certifying every rope for every class it could actually pass for marketing purposes. I've no idea what an additional UIAA test might cost.
Jim, do you suspect that the Cobra II I used in my example could have passed the UIAA twin tests but they didn't put it in?
> Here's something similar from Dave Furman at Mammut:
I had read that. The quote in there says you can use [whichever rope they're talking about] either as twin or half; it doesn't specifically say anything about swapping mid pitch. Neither does their rope booklet download, which does issue warnings against friction "if two ropes are both routed through the same anchor point, by mistake".
So far as I can see, every forum post in the last four years which suggests swapping techniques mid pitch is actually OK references just that single email.
Mammut have clearly changed their views on dual (and indeed triple) certification in the last few years as they now have several of each. I suppose this doesn't rule out the possibility that they're not certifying every rope for every class it could actually pass for marketing purposes. I've no idea what an additional UIAA test might cost.
Jim, do you suspect that the Cobra II I used in my example could have passed the UIAA twin tests but they didn't put it in?
In reply to Jamie Wakeham:
Well here´s Mammut´s take on the subject of multi rating and whether half-ropes can also be twin ropes but just aren´t certified as such:-
"In continental Europe, outside of a few areas, fewer people use half-rope technique--most people use their half ropes with Twin technique clipping both strands together—consequently most of the half ropes on the market will pass the test for both half and twin ropes, and this is common enough that it is assumed. All of Mammuts half ropes will also pass the twin rope test.....Speaking only for Mammut, we generally don't certify our ropes to more than one standard because there is a very real concern that people make assumptions about a rope based on the fact that it is marketed differently, that often don’t really hold true. As an example, our Serenity 8.9mm single rope was initially introduced with both single and half rope specs and many people assumed that it was “more durable” than a thinner half rope, when the reality is that it was far less durable than our thinner Genesis 8.5mm rope..... In general we would rather steer people into using their ropes in the manner that will result in the greatest degree of utility for most people, which is why we have shied away from dual certifications like this. It isn't right or wrong, but my sincere belief is that more people wind up with a rope that better suits their needs as a result."
The reality is that out there away from the drop tower the actual force you generate with a belay device depends more on the rope configuration than the difference you see given in the rope specs. Used singly you can hold ca 25% more than used as a double and only one strand taking the load, used as a twin with the strands loaded equally you can hold roughly another 25% more so under normal circumstances clipping both strands of a half rope as a twin you really are going to see a major increase in the impact force.
Well here´s Mammut´s take on the subject of multi rating and whether half-ropes can also be twin ropes but just aren´t certified as such:-
"In continental Europe, outside of a few areas, fewer people use half-rope technique--most people use their half ropes with Twin technique clipping both strands together—consequently most of the half ropes on the market will pass the test for both half and twin ropes, and this is common enough that it is assumed. All of Mammuts half ropes will also pass the twin rope test.....Speaking only for Mammut, we generally don't certify our ropes to more than one standard because there is a very real concern that people make assumptions about a rope based on the fact that it is marketed differently, that often don’t really hold true. As an example, our Serenity 8.9mm single rope was initially introduced with both single and half rope specs and many people assumed that it was “more durable” than a thinner half rope, when the reality is that it was far less durable than our thinner Genesis 8.5mm rope..... In general we would rather steer people into using their ropes in the manner that will result in the greatest degree of utility for most people, which is why we have shied away from dual certifications like this. It isn't right or wrong, but my sincere belief is that more people wind up with a rope that better suits their needs as a result."
The reality is that out there away from the drop tower the actual force you generate with a belay device depends more on the rope configuration than the difference you see given in the rope specs. Used singly you can hold ca 25% more than used as a double and only one strand taking the load, used as a twin with the strands loaded equally you can hold roughly another 25% more so under normal circumstances clipping both strands of a half rope as a twin you really are going to see a major increase in the impact force.
In reply to Jamie Wakeham:
The Revelation has been available since at least 2003 - I know because I bought one back then!
> Mammut have clearly changed their views on dual (and indeed triple) certification in the last few years
The Revelation has been available since at least 2003 - I know because I bought one back then!
In reply to chrisbaggy:
My Mammut Serenity single rope has a diameter of 8.7mm. My Beal Cobra half ropes have a diameter of 8.6mm. I don't think 0.1mm is going to make much difference over a sharp edge do you ?
My Mammut Serenity single rope has a diameter of 8.7mm. My Beal Cobra half ropes have a diameter of 8.6mm. I don't think 0.1mm is going to make much difference over a sharp edge do you ?
In reply to jimtitt:
Disappointing UKC. It's a pretty simple question and I deliberately did not mention double ropes.
I guess the answer, most succinctly addressed by Jamie, is 'it's not' is it not?
Disappointing UKC. It's a pretty simple question and I deliberately did not mention double ropes.
I guess the answer, most succinctly addressed by Jamie, is 'it's not' is it not?
In reply to indigo:
I've got a Serenity as well, I think the sheath is thicker than a half rope. It certainly feels a bit 'tougher' to me anyway.
I've got a Serenity as well, I think the sheath is thicker than a half rope. It certainly feels a bit 'tougher' to me anyway.
In reply to jimtitt:
That's the out of date quote I was referring to - it implies they didn't want to dual certify the Serenity, whereas today it's sold as triple rated (along with the Revelation).
Mammut are obviously happy to be a little vague about this; several of their current range are stated in the text to be 'rated for both half and twin', but only show the twin logo on the webpage, and only have the 1/2 logo on the actual rope (whereas the triple rated Serenity and Revelation show all three logos on their web page).
That's the out of date quote I was referring to - it implies they didn't want to dual certify the Serenity, whereas today it's sold as triple rated (along with the Revelation).
Mammut are obviously happy to be a little vague about this; several of their current range are stated in the text to be 'rated for both half and twin', but only show the twin logo on the webpage, and only have the 1/2 logo on the actual rope (whereas the triple rated Serenity and Revelation show all three logos on their web page).
In reply to indigo:
Apologies, Indigo. Tried to keep it as simple as possible but, as you can see, it's not that simple a subject!
For what it's worth, diameter is not the only thing contributing to abrasion resistance. The Serenity is sold as a not-all-that-tough high performance rope (see the quote in Jim's post of 14:48). Your (very slightly thinner) Cobras are probably rather tougher.
Apologies, Indigo. Tried to keep it as simple as possible but, as you can see, it's not that simple a subject!
For what it's worth, diameter is not the only thing contributing to abrasion resistance. The Serenity is sold as a not-all-that-tough high performance rope (see the quote in Jim's post of 14:48). Your (very slightly thinner) Cobras are probably rather tougher.
Post edited at 15:43
In reply to indigo:
We went into classic thread drift since your simple question was answered on the first and second post. Climbing on any or no rope is dangerous, climbing on a single half slightly more dangerous than on a single rated rope unless it´s a dual-rated one.
> Disappointing UKC. It's a pretty simple question and I deliberately did not mention double ropes.
> I guess the answer, most succinctly addressed by Jamie, is 'it's not' is it not?
We went into classic thread drift since your simple question was answered on the first and second post. Climbing on any or no rope is dangerous, climbing on a single half slightly more dangerous than on a single rated rope unless it´s a dual-rated one.
In reply to Offwidth:
When referring to climbing ropes, "double" and "half" are usually synonymous (e.g. as in "double rope technique" or "a pair of half ropes"). "Twin" is reserved for the other sort, that you have to clip together. Those are the definitions which are just about universally used in books, on websites, etc. How about going with the overwhelming majority and sticking to that usage?
> The half rope is rated for falls individually so can be used this way. Double ropes in contrast can't.
When referring to climbing ropes, "double" and "half" are usually synonymous (e.g. as in "double rope technique" or "a pair of half ropes"). "Twin" is reserved for the other sort, that you have to clip together. Those are the definitions which are just about universally used in books, on websites, etc. How about going with the overwhelming majority and sticking to that usage?
In reply to jimtitt:
For clarity's sake, Jim, are you saying here that the advice against using halves which aren't rated as twins (ie Beal Cobra or Ice Line) in this way is indeed well founded?
> Used singly you can hold ca 25% more than used as a double and only one strand taking the load, used as a twin with the strands loaded equally you can hold roughly another 25% more so under normal circumstances clipping both strands of a half rope as a twin you really are going to see a major increase in the impact force.
For clarity's sake, Jim, are you saying here that the advice against using halves which aren't rated as twins (ie Beal Cobra or Ice Line) in this way is indeed well founded?
In reply to Jamie Wakeham:
It doesn´t matter what the ropes are rated for, the impact force on the climber or the gear is governed by what the belay device produces once you get past the loading at which the rope slips. Under that load then who knows as the manufacturers don´t give rope characteristics for low-force falls and we don´t know how linear impact force in a rope is. A rope could well be soft as hell at low forces and hard at high ones.
All we know is that rope used as twins (both strands loaded) a conventional belay device will give higher forces than the same rope used as halves (only one strand of two loaded).
The variation between belay plates is even greater still and for belayers hand strength yet more.
Worrying that a single rope has an impact rating of 9kN is a bit pointless since you´d need a belay device that can produce roughly around 6kN if the rope is through a runner and you also need a belay set-up that can resist that and stop you flying through the air.
It doesn´t matter what the ropes are rated for, the impact force on the climber or the gear is governed by what the belay device produces once you get past the loading at which the rope slips. Under that load then who knows as the manufacturers don´t give rope characteristics for low-force falls and we don´t know how linear impact force in a rope is. A rope could well be soft as hell at low forces and hard at high ones.
All we know is that rope used as twins (both strands loaded) a conventional belay device will give higher forces than the same rope used as halves (only one strand of two loaded).
The variation between belay plates is even greater still and for belayers hand strength yet more.
Worrying that a single rope has an impact rating of 9kN is a bit pointless since you´d need a belay device that can produce roughly around 6kN if the rope is through a runner and you also need a belay set-up that can resist that and stop you flying through the air.
In reply to indigo:
And I believe it is still true that there are no known accidents due to a dynamic rope failing due to simple overloading?
And I believe it is still true that there are no known accidents due to a dynamic rope failing due to simple overloading?
In reply to indigo:
People manage to on the rare occasion have single ropes fail [cut,acid].
I don't think anyone knows of an instance of both halves or twins failing.
But how often does one rope of a pair of halves or twins fail? How common is it?
People manage to on the rare occasion have single ropes fail [cut,acid].
I don't think anyone knows of an instance of both halves or twins failing.
But how often does one rope of a pair of halves or twins fail? How common is it?
In reply to needvert:
Well, undoubtedly this has happened a good number of times if you count rockfall, avalanche etc. Unfortunately when this happens the climber(s) often won't live to tell the tale.
> I don't think anyone knows of an instance of both halves or twins failing.
>
>
Well, undoubtedly this has happened a good number of times if you count rockfall, avalanche etc. Unfortunately when this happens the climber(s) often won't live to tell the tale.
In reply to Michael Gordon:
Although only one country, I think this shows that use of double/twins almost reduces the chances to zero:
http://personal.strath.ac.uk/andrew.mclaren/Turin2002/CD%20congresso/Rope%2...
> Well, undoubtedly this has happened a good number of times if you count rockfall, avalanche etc. Unfortunately when this happens the climber(s) often won't live to tell the tale.
Although only one country, I think this shows that use of double/twins almost reduces the chances to zero:
http://personal.strath.ac.uk/andrew.mclaren/Turin2002/CD%20congresso/Rope%2...
In reply to David Coley:
That mentions 5 instances of misuse and twin and double ropes failing, one instance being a top rope situation. Anyone happen to know any further details about those incidents?
That mentions 5 instances of misuse and twin and double ropes failing, one instance being a top rope situation. Anyone happen to know any further details about those incidents?
In reply to needvert:
They are mostly described in "Sicherheit und Risiko in Fels und Eis: Vol 111" by Pit Schubert.
Activities such as lowering a stretcher and the rescuer on a single half-rope over a sharp metal structure come under "misuse"!
They are mostly described in "Sicherheit und Risiko in Fels und Eis: Vol 111" by Pit Schubert.
Activities such as lowering a stretcher and the rescuer on a single half-rope over a sharp metal structure come under "misuse"!
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