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toaster_rancher


Dec 8, 2004, 9:54 AM
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Twin Rope System
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I'm thinking about getting into Ice Climbing this winter, and I was just curious as to why ice climbers prefer a twin rope system (I know they're two different things), to one rope. Thanks!


rongoodman


Dec 8, 2004, 10:06 AM
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There are lots of sharp edges around the ropes when ice climbing. Using either half or twin ropes minimizes the danger of chopping one. Being able to do full-length rappels is a nice side benefit.


bandycoot


Dec 8, 2004, 10:10 AM
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I think that having two ropes present would logically INCREASE the chance of chopping one. The reason (speaking from a complete lack of experience) that twin or half ropes are used is that IF you chop one, there is still another to protect you. It's all about front pointing through a $150 rope. DOH!


davidji


Dec 8, 2004, 10:16 AM
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In reply to:
Using either half or twin ropes minimizes the danger of chopping one.

In reply to:
I think that having two ropes present would logically INCREASE the chance of chopping one.

As Ron indicated, it's much more dangerous to chop one if it's your only rope. With two skinny ropes, you may be more likely to get one severed, but it's less dangerous than if it's your only rope.


bandycoot


Dec 8, 2004, 10:46 AM
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For some reason I read Ron's "danger" as "chance." :roll: My bad.


jackscoldsweat


Dec 8, 2004, 11:00 AM
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Come on people...

The REAL reason are the forces generated on twins vs. half vs. single.


Look it up....

Although all the above are a bonus :)

JCS


cfnubbler


Dec 8, 2004, 11:16 AM
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In reply to:
I was just curious as to why ice climbers prefer a twin rope system (I know they're two different things), to one rope.

In my experience, they don't. I don't know anyone climbing ice on twins these days, though back in the day we often did so. All of my partners and I, and everyone I meet at the crags climb on doubles if using a 2 rope system, Double offer all the advantages of twins, and have lower impact forces (generally speaking) to boot. I use twins for some applications in the summer, but in the winter either a skinny single or doubles for longer routes.

-Nubbler


cgailey


Dec 8, 2004, 11:27 AM
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In reply to:
In reply to:
I was just curious as to why ice climbers prefer a twin rope system (I know they're two different things), to one rope.

In my experience, they don't. I don't know anyone climbing ice on twins these days, though back in the day we often did so. All of my partners and I, and everyone I meet at the crags climb on doubles if using a 2 rope system, Double offer all the advantages of twins, and have lower impact forces (generally speaking) to boot. I use twins for some applications in the summer, but in the winter either a skinny single or doubles for longer routes.

-Nubbler

Lots of people climb on twins...for the above mentioned reasons. :wink:


tradklime


Dec 8, 2004, 11:35 AM
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A search will yield you some extensive discussions.

Full length rappels, weight savings, perhaps some redundancy, easier rope management than doubles...

Impact forces should be managed through screamers.


cfnubbler


Dec 8, 2004, 12:07 PM
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In reply to:
Lots of people climb on twins...for the above mentioned reasons.

Yes, I know lots of people climb on twins...I'm one of them on ocassion. Long routes with predominantly solid rock pro and rap descents are the ideal application. But I don't personally know of anyone climbing waterfall ice on twins these days...and I know quite a few ice climbers. I know some folks do, but not many as far as I can tell.

With lightweight doubles readily available, I cannot see a single advantage to using twins for waterfall ice.

Doubles offer all of the advantages of twins, combine with lower impact forces for hard to assess ice pro.

As for the comment about managing impact forces with screamers, I do. But I also tend to opt for cords with the lowest impact forces available for ice. I'm willing to make an informed choice to trade increased elongation for lower impact forces.

The OP inquired about twins. That's my 2 cents on the question. Not worth it for waterfall ice. YMMV.

-Nubbler


crotch


Dec 8, 2004, 12:14 PM
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Hmm. Rope management on doubles can be a pain. If I was buying a set now, I'd opt for something rated both as twin and double. If the line wanders, climb as with doubles, and if it's a pretty straight shot, use em as twins.

Or at least that's the plan after I retire my doubles.


jackscoldsweat


Dec 8, 2004, 12:32 PM
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Why is it so hard to manage doubles/halfs? I don't see the problem? Hanging belay or not.

Crotch, you 'know' Guillaume from wreck. I adopted his double rope methods. One method he called, 'flipping the stack'.

Whats wrong with putting both ropes into a small pile and then 'flip the stack'? Or better yet...when swapping leads...don't do anything.

I think the myth behind rope management and double ropes is just that....a myth.

Of course it's going to be a big deal for someone using them the 1st few times but once you've got your method down...it's cake.

I took me more than a few belays to figure out the best system when trying to build a trad anchor with doubles. But bolted anchors are as cool as ice and smooth as butter when using doubles. And God bless the clove hitch. If there was any one knot that I absolutly love, it's the clove. Strong yet easily adjustable.


JCS


tradklime


Dec 9, 2004, 10:24 AM
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In reply to:
I think the myth behind rope management and double ropes is just that....a myth.

Not a myth, there is more to rope management than just belays. The fact is that they are more complicated, now whether they are significantly more complicated will vary from person to person.

Other considerations: remembering which rope to clip, ropes getting twisting when only one is pulled, two ropes travelling two paths- avoid kicking one, etc. On the surface simple stuff, but sometimes in practice...

I have found, especially on ice, rope drag issues can easily be mitigated via other means than alternate clipping.

Now that said, the beal ice twins are 7.7 mm, and the ice line (?) which is rated for both twin and double use is 8.1 mm. Probably a good compromise. However, if I have enough rope out, a certification won't stop me from alternate clipping my twins if I feel there is a need (very rare).

My opinion, pure ice climbing is the best application for twins. Also my opinion, twins are the best compromise for trad and alpine routes. Other's will have different opinions and folks reading/ trying to learn something will ultimately end up with their own opinion that could disagree with everyone who has posted.

The only indisputable advice when leading ice with single/ double/ twin ropes- USE SCREAMERS. Oh and have fun.


crotch


Dec 9, 2004, 10:52 AM
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In reply to:
Why is it so hard to manage doubles/halfs? I don't see the problem? Hanging belay or not.

I don't have a problem managing the stack (and twins wouldn't help if that was my issue), rather giving the best belay I can. Yarding in one strand while paying out the other can IME compromise the belay in terms of the amount of slack my partner gets and the distance she would fall. And when I'm climbing, I know I'd fall quite a bit further on doubles, which makes me more conservative than I already am.

Would you agree that a leader clipping only one strand above her head to protect a crux makes for more complicated belaying than if both strands were clipped overhead and behaved as one?

Doubles aren't unmanageable. In fact, they worked fine for us last weekend. I'm just saying that if the option of getting a system certified for both double and twin use was available when I purchased my ropes, I would have opted for that. It just seems like the best of both worlds to me.

I read somewhere that a new rope has come out that's certified as single, double, and twin. That might be interesting as a bicolor in a 100m length.


jackscoldsweat


Dec 9, 2004, 11:37 AM
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In reply to:
I think the myth behind rope management and double ropes is just that....a myth.

In reply to:
Not a myth, there is more to rope management than just belays. The fact is that they are more complicated, now whether they are significantly more complicated will vary from person to person.
True.

In reply to:
Other considerations: remembering which rope to clip, ropes getting twisting when only one is pulled, two ropes travelling two paths- avoid kicking one, etc. On the surface simple stuff, but sometimes in practice...
I could nit-pick this one to death...but to make it simple for us all, please refer to the true statement above in bold.

In reply to:
The only indisputable advice when leading ice with single/ double/ twin ropes- USE SCREAMERS. Oh and have fun.
True.

NEXT

In reply to:
...And when I'm climbing, I know I'd fall quite a bit further on doubles, which makes me more conservative than I already am.
Now wait a min...leading on doubles means a shorter fall....given the belayer is doing their job properly. Am I missing something?

In reply to:
Would you agree that a leader clipping only one strand above her head to protect a crux makes for more complicated belaying than if both strands were clipped overhead and behaved as one?
I do. Also longer fall potential. lets clip one at a time folks...one at a time please.

In reply to:
I'm just saying that if the option of getting a system certified for both double and twin use was available when I purchased my ropes, I would have opted for that.
I got lucky in this aspect. I was shopping for doubles in mind and purchased the dynamics 8.3 by edelweiss. I can use them as both...I hope...because I have.

getting fatter by the min. sitting here reading/mulling over the details...


JCS


tradklime


Dec 9, 2004, 12:38 PM
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In reply to:
Other considerations: remembering which rope to clip, ropes getting twisting when only one is pulled, two ropes travelling two paths- avoid kicking one, etc. On the surface simple stuff, but sometimes in practice...

I would add to my own statement that this becomes more of a factor when you are pushing your limits.

When cruising up WI3 ramps, the differences matter little, but then I'd also say either does having a rope at all.

Longer falls occur with falling on one double rope due to the increased rope elongation. Oh and more rope slipping through the belay device


jackscoldsweat


Dec 9, 2004, 1:18 PM
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In reply to:

Longer falls occur with falling on one double rope due to the increased rope elongation. Oh and more rope slipping through the belay device

hence a 'softer' catch than a single or twins.

slipping...hmmm...

"The slack required to clip the next piece will not increase the length of the fall as with a single rope."

JCS


tradklime


Dec 9, 2004, 3:04 PM
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Yes, more rope elongation is directly related to lower impact force, but a lot of rope elongation may or may not be a good thing.

You can clip twin ropes seperately into the same biner and mitigate falling with a bunch of slack, similar effect to that of doubles.

The one real benefit of double ropes that I haven't seen discussed is equalization of marginal pro. Often, when I place a sketchy piece, I like to back it up with at least one more piece. Often these pieces are not right next to each other. You can clip each one with a different rope. If you fall, the force will be distibuted between the two pieces, the % of distribution will depend on how close the pieces are, direction of fall, and if they are the same level which each other, etc. Now you may not get true equalization, but anything that helps in that situation is good. It can even be effective if one piece is several feet higher than the other, depending of course on the fall and the amount of rope involved. This tactic can be used with twins, in certain circumstances, but you are more limited than you are with doubles.


cfnubbler


Dec 10, 2004, 4:59 AM
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In reply to:
The one real benefit of double ropes that I haven't seen discussed is equalization of marginal pro.

Yes, and this is a huge benefit on ice and traditionally protected mixed pitches. Made extensive use of this yesterday, in fact, and do so very often. This is also a huge reason not to use twins. Despite what's been mentioned by others in this thread, I do not feel comfortable clipping my 7.5 twins individually as doubles, no matter how much rope is out. It may in fact be a reasonable practice in some circumstances, but until I see some firm test-data, I won't be doing it. I see no reason to do so.

What I am willing to do is clip my doubles like twins in certain circumstances, when I find solid rock pro, and if it makes sense in terms of rope-drag. Did this yesterday as well.

-Nubbler


adnix


Dec 10, 2004, 6:31 AM
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I think you folks should read this one:

In reply to:
First of all let me mention that the provider of the UIAA web site went bankrupt recently and it will be a while before a new one is operational. However, you would not have found the information you are looking for at this site.

The UIAA standard deals with three different rope types: single, half and twin. In the UIAA drop test the single rope is tested with an 80 kg mass, a single strand of half rope with a 55 kg mass and both strands of a twin rope with 80 kg. The single and half ropes must sustain at least five falls and twin ropes at least twelve to pass the standard. There are also differences among these ropes for elongation and impact force (single and twin < 12 kN; half ropes < 8 kN).

Single ropes are obviously designed to be used in a single strand.

Half ropes, or double ropes, are designed for (aid) routes with many runners at close spacing and are then clipped in alternately. The idea was to reduce friction, particularly in the days, when climbers used only carabiners and no sling extensions (the rope went zig-zag). These ropes should not be used in this way (i.e. clip in alternately), as often happens these days, for regular routes with runners further apart. Keep in mind that the rope is not tested with an 80 kg mass. A single strand of half rope, when new, may just hold one fall with such a mass.

The twin rope was designed to be used in the double strand and both strands must be clipped in every runner. Generally these ropes have a diameter of only 8 mm. The benefit of a twin rope is its essential safety and the advantage in the mountains for a full length rappel.

Present day ropes will not break at a runner or at the tie-in knot of the leader in a fall. This does not even happen with very old ropes. A rope fails when a sharp edge cuts it. As a rope is used, the capacity to hold a fall over a sharp edge decreases. Generally speaking, a rope which holds many falls in the UIAA drop test will resist cutting better than a rope which hold fewer falls.

A half rope used singly is, therefore, much more likely to be cut than a single rope. It could potentially be used for all climbing, but you better not plan on falling off. A twin rope is much safer, because of the higher capacity and the redundancy (only one strand may be cut). Using half ropes like a twin, clipping both strands in every carabiner is, of course, the safest solution (a pair of decent half ropes, tested like a twin rope will most likely hold over 30 falls).

The maximum allowable elongation for half ropes (10 %) is indeed larger than for single or twin ropes (8 %), but this would hardly be noticeable in most fall situations. Elongation is more often than not only a problem for a second with the rope out 100 feet. An 80 kg climber could drop eight feet under body weight even though the rope contains no slack.

Final advice: do not use your half rope as a single strand and when the runners are further apart, clip both strands. You only live once.

Ice climbers in USA routinely use the double rope technique placing gear (ice screws) very sparsely using half ropes.
So:

1. In this situation is the second half rope for backup purposes?

On pure ice faces and water falls, there are generally no sharp edges and the danger of cutting a rope are greatly reduced. A new half rope may be reasonably safe, although I would advice against it when there is a lot of dry tooling and runners are still far apart (I personally would not climb on it regardless of the situation). In the latter case it may be called a back up rope, because of cutting on an edge.

When the climber is on a water fall or smooth ice face, where there is no friction to speak of, the question can be asked, why not climb with a single half rope and clip all the protection. The result would be pretty well the same in a fall situation as having two ropes. If the rope breaks, it is because the fall energy was beyond the capacity of the rope. With two ropes clippped alternately and the runners the same distance apart, if the first rope breaks at the first runner and the second will fail on the one below.

One of the reason for two ropes on waterfall ice is that one must generally rappel and two ropes get you down faster and cheaper.

2. If I were to clip both half ropes together into one carabiner, wouldn't that increase the load on the protection beyond safety levels for the carabiners and protection as opposed to a single or twin setup?

Using two half ropes clipped in together will produce forces on the protection higher than when using a single rope. Twin ropes act like a single rope.

The forces in the system are, however, determined by the belay method. Any modern dynamic belay method will limit the forces inherent in the device. The impact force (the maximum obtained during the UIAA drop test) and provided on the rope tag, is of no consequence. Thus the forces generated, particularly in a near frictionless system, which may occur on a waterfall, are not very high.

These forces are, as a rule, vastly below the capacity of any equipment (carabiners, ice screws, pitons, slings, etc.). The problem lies in the holding capacity of the ice screw, piton, nut, etc. If the ice is of poor quality, a screw capable of holding 20 kN in good ice is no more helpful than a coat hanger, if that is the holding power of the ice.

So in a scary, poor ice, situation the only thing, which may be of value, is to put protection at very close spacing. That unfortunately is often not possible. But it would help to clip both ropes in the last bomber protection.

3. How soon/often do I have to retire the half ropes provided I take falls on them (very few climbers are 55kg and under, I am 90kg)?

If there are no sharp edges, a rope could most likely be used until the mantle starts shredding and can no longer be used in a belay device. This applies mainly to a single rope. The half rope is simply not designed to take major leader falls. But as mentioned before, the forces in the system are determined by the belay device. With a properly working dynamic belay, not much will happen to the rope. Do not belay with a static belay device such as a Grigri, which should be used for top roping only.

4. Is the conclusion that one just should not buy or use half ropes? Or they are still manufactured for cases where falls are not dead vertical, in alpine terrain wit lots of rope drag? Or perhaps they are manufactured out of inertia and for marketing purposes?

They are most useful in alpine terrain where lots of friction may result, if the ropes are clipped in all the runners. An additional advantage is that there is a backup rope of sufficient capacity, should a rope be cut by rock fall. Finally the rope offers redundancy in the case of sharp edges. Double ropes have more holding capacity over an edge to start with. Even if both ropes run over the same sharp edge, it is less likely both get cut because one will get loaded more than the other. In a retreat, being able to rappel the full length of the rope is invaluable.

The other option is to climb with twin ropes. Extra edge strength (remember twelve UIAA falls minimum), redundancy, lighter ropes, in a severe case the option of clipping in alternately, rappel convenience.

I personally have not owned a single rope for at least 25 years. I used to climb with two half ropes and clipped them together when it was suitable. Now I climb with twin ropes. I use these ropes in any terrain.

And:

http://www.needlesports.com/...e/artscrews/fig2.JPG

Lowest rating out of 262 samples was 8.8kN, which is less than ropes will produce in any real fall. Tested on solid ice. The whole story can be found at:
http://www.needlesports.com/...ce/placingscrews.htm


zoob


Dec 11, 2004, 6:37 PM
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My 2 cents, you are provided witha back up rope, lower impact forces, smaller diameter offers more suppleness and in my opinion easier knot tying. The biggest thing I like about half ropes is the ability to make a full 60M rap....
My partner and I liked the 2 rope system so much we started using it in our trad climbs. I guess it is all personal preference.
Cheers


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