Double ropes on ice, alternate clipping

[catbirdseat]

If you are using double ropes on ice and assuming the route does not meander from side to side, does it matter whether or not you alternately clip the two ropes?

[Thinker]

Yes. Some of it depends on the situation you're in, like everything else in climbing. My answer is certainly not comprehensive, but it's a start.

 

Clipping both ropes into a single piece of gear increases the maximum force on the piece, but reduces the distance of the fall.

 

So, unless you're risking a groundfall due to rope stretch, I'd only clip one at a time....unless you have a bomber piece to clip.

[catbirdseat]

I wasn't taking about clipping both ropes into a single piece. What I was referring to was alternately clipping the first rope to a piece and then the other rope to the next piece, etc. On rock I can see the importance of alternating, because that way if falling rock cuts one rope you've got the other.

[stinkyclimber]

See this current thread (http://www.live-the-vision.com/wwwboard/messages/3872.html) over on the Live the Vision board that is in the process of beating this subject to death. All the info you want from a bunch of pretty talented (well, some of them, anyway) and nerdy Canadian Rockies ice climbers.

[lummox]

If you are using double ropes on ice and assuming the route does not meander from side to side, does it matter whether or not you alternately clip the two ropes?

you talking 70m ropes?

but in a word: not much. okay. two words.

[catbirdseat]

See this current thread (http://www.live-the-vision.com/wwwboard/messages/3872.html) over on the Live the Vision board that is in the process of beating this subject to death. All the info you want from a bunch of pretty talented (well, some of them, anyway) and nerdy Canadian Rockies ice climbers.

Here is the post that I thought was the best from that thread:

 

quote]"Posted by Rich (161.184.45.72) on January 14, 2004 at 22:37:44:

In Reply to: Double 8.6 vr. Single 8.6 posted by PONY on January 14, 2004 at 22:09:17:

 

Hopefully you've heard this answer to your question before, but if you haven't here's my 2 cents. Double ropes weren't designed to take all the force of a fall on one strand, they were designed for wandering routes where gear is located in various locations, often off to the sides of the climber. Basically the point being that with gear on both sides a climber who falls ultimately would end up below the gear with the ropes each taking some of the load (hard to describe without pictures). Strictly speaking, ice climbers who climb in relatively straight lines and often space out their gear such that a fall would result in one rope taking all the load should not be using double rope technique where each strand is alternately clipped. Having said that I find double ropes very useful when ice climbing, both for the extra safety of two strands and lower impact forces on marginal gear. But I also try to place gear such that I'm not trusting only one rope in the event of a large fall.

I've not found any reason, other than really high impact forces, not to clip both ropes if I'm expecting to run it out a long ways between individual pieces (if the screw is bomber the increased impact force shouldn't be a problem). If the gear isn't bomber then I place two pieces relatively close together, one for each strand. The amount of slack that tends to be in the system means that if I were to fall (and I have) I'll probably end up dangling from both screws (and ropes) as they were meant to work.

 

As a side note, some of the newer 8mm half ropes are thin enough that they blur the line between half and twin ropes and therefore avoid some of the problems I just mentioned around impact force.

 

Ultimately I guess you could do whatever you want, though I'm sure it won't be long before you can go down to the store and pick up an 8.6mm single rope, making any in depth debate somewhat meaningless."

My take then is that it doesn't matter much if you alternate, providing you clip each to a separate piece soon after the belay to avoid a high fall factor load on any one rope.

[Thinker]

I must be a little dense today.

 

So what's the alternative to alternating if you're not considering clipping both pieces into one piece of gear? Would it be cliping the same rope to the pro 2 or 3 (or more) times in a row?

 

That makes it sound like you're just trailing the 2nd rope at that point, given the non-wandering nature of the route you described in your initial post.

[catbirdseat]

I must be a little dense today.

 

So what's the alternative to alternating if you're not considering clipping both pieces into one piece of gear? Would it be cliping the same rope to the pro 2 or 3 (or more) times in a row?

 

That makes it sound like you're just trailing the 2nd rope at that point, given the non-wandering nature of the route you described in your initial post.

Yes, that's exactly what I am talking about. Clipping the same rope twice or more in a row and not the other.

 

Between this post and my last I read some material that made me change my mind. When you fall on one rope, all the stretch goes out of it right? If that same rope is through the next piece below, that piece receives a larger impact because the stretch is gone. If, however, the other rope is through that piece, it can stretch a lot more and absorb more force. Does that make sense?

 

From reading at the Canadian's site about screamers, it seems to me that if you a) fall on a piece and b) the screamer fires and c) the piece fails and d) all the stretch is out of the rope, then you would prefer the other rope be through the next piece because all of its stretch is intact and it can better absorb your impact forces.

Edited January 19, 2004 by catbirdseat

[Janez_Ales]

Clipping alternate strands makes a fall shorter if you blow a clip.

 

My rule is that if I plan to clip two double ropes into single biner anywhere on the pitch I always clip them together.

Otherwise the different lengths can cause one rope to damage the other in the common biner in case of a fall.

 

This does not exclude from cliping them into the same bomber piece after using alternate clips, just use two draws (of different lengths) on that piece...

 

All that said, if you clip them together all the time, why not use twins? True enough, except if there are three of you, then half of a twin is maybe a bit thin for your followers to sling their life on...

[chris]

But you have to watch out. Twin ropes are designed with greater stretch than doubles to lower the impact forces on the gear. If you clip both lines of a double system into an anchor, you are increasing the force on that piece exponentially. I do not recommend following Janez's advice.

My partners and I don't really have a problem using a twin system with three people. The force of a slip on top rope (the followers) is a fraction of a leader fall, and the diameter is only an issue on sharp edges, in which case a double might have been better anyways.

My favorite compromise is the double. It gives you the durability for the edges, and the extra strand for full-length rappels or a third partner.

Mark Twight gives this topic a good discussion in his Alpine book, and I think there's some good information at Petzl and Beal websites.

[lummox]

If you clip both lines of a double system into an anchor, you are increasing the force on that piece exponentially. . .

no. untrue. not an exponential increase. impact force goes up a couple kilonewtons from the data i have seen.

[catbirdseat]

Posters to this thread keep mistaking what the question was. It was NOT whether you should clip both ropes to the same piece of pro. It was whether you should be diligent in ALTERNATELY clipping one rope into one piece, then the other rope into the next piece.

 

Janez_Ales had a good point that by alternate clipping, if you blow a clip you reduce the length fall by the amount of rope you pulled up to make the clip.

[RuMR]

If you are using doubles cause of drag issues, your gear will force the issue...ie if your blue rope is running on the right and you had 3 pieces in a row on the right, then you will clip your blue three times in a row...

 

Probably more of an issue on rock in places like the gunks where doubles are standard issue cuz of wandering routes and availability of gear...

 

Big duh...just reread your original post where you said the route doesn't meander...i'd alternate clipping...

Edited January 29, 2004 by RuMR

[rbw1966]

In addition to mtnfreaks comments re twins I'd add that my twins are rated to hold a fall over an edge. An added bit of insurance in the alpine environment.

[David_Parker]

To be completely clear, we should use "1/2 ropes" or "twin ropes" as "Double ropes" can be confusing to some. I would prefer to alternatively clip 1/2 ropes but in the event I were to clip both into one piece, I'd probably use 2 biners or draws, one for each strand. This would be better in the event previous to that clip, you had alternatively clipped pieces with one strand.

[lummox]

by alternate clipping, if you blow a clip you reduce the length fall by the amount of rope you pulled up to make the clip.

blue. no yellow. AAAHHHHH!

[chris]

The rope manufacturers seem to be using "twin ropes" and "double ropes." A Beal rep I know said the term "1/2 ropes" was getting mistakenly confused the most, so manufacturers decided to sop using it.

 

And CBS, I understand your original queestion. But this thread got a little off the orginal subject, as conversations are sometimes known to do. I'm OK with it - this is a cool subject, and I like hearing ya'lls opinions.

[catbirdseat]

by alternate clipping, if you blow a clip you reduce the length fall by the amount of rope you pulled up to make the clip.

blue. no yellow. AAAHHHHH!

 

Bridgekeeper: STOP! What...is your name?

Galahad: Sir Galahad of Camelot!

Bridgekeeper: What...is your quest?

Galahad: I seek the Grail.

Bridgekeeper: What...is your favorite color?

Galahad: (relieved) Blue! (starts across; oops) No! YELLOOOOOOOOOOOOOOOOWWW!!!!

 

(Arthur steps forward... the Bridgekeeper cackles some more.)

 

Bridgekeeper: STOP!

Bridgekeeper: What...is *your* name?

Arthur: It is Arthur, King of the Britons!

Bridgekeeper: What...is your quest?

Arthur: To seek the Holy Grail!

Bridgekeeper: What...is the airspeed velocity of an unladen swallow?

Arthur: (brief pause) What do you mean, an African or European swallow?

Bridgekeeper: (confused) Huh? What? I...I don't know that... AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAUUUGGHHHHHHH! (he is thrown into the Gorge of Eternal Peril.)

[David_Parker]

The rope manufacturers seem to be using "twin ropes" and "double ropes." A Beal rep I know said the term "1/2 ropes" was getting mistakenly confused the most, so manufacturers decided to sop using it.

 

Aucontrair, the manufacturers still label the ropes on the ends 1/2 or twin. To me, "double" and twin" are synonyms and thereby more confusing, while "1/2" and "twin" are distinctly different and much less confusing. But I was an english major, not a math major in college so what do I know!

Edited January 30, 2004 by David_Parker

[mattp]

Your choice of language here is a matter of what you are used to, I think. Personally, I find it easier to remember the distinction between "double" and "twin" because these are two distinctly different ways in which we use a pair of ropes, though you are correct that in a thesaurus I would find "double" listed as a synonym for "twin." Another way of saying this is that I am simply not used to using the half/twin distinction -- and this is because I only buy "half" ropes anyway.

[lummox]

uh. who cares what you call em. when the ropes look insanely thin you can still clip em one at a time. when the ropes look like accessory cord you have to clip two strands at a time.

[catbirdseat]

[chris]

Well, I'll be damned. I actually called Second Ascent and had a research conversation with Patsy. And discovered that once again I had my head shoved right up my own ass. Here what research revealed:

Single ropes - marked with an "infinity" sign

Half ropes - marked with a "1/2" sign, each piece is intended to be clipped seperately

Twin Ropes - marked with a two interconnected "rings" sign, each piece is intended to be clipped by both strands.

Patsy then gently chided me for getting "double" and "half" confused AGAIN.

I respectfully apologize to everyone who's been having to listen to my pompous preaching on this thread. Thanks for setting me straight, David and Patsy.

[dylan_taylor]

I think most single ropes are marked by a "1" inside a circle, aren't they? the infinity sign sounds like the twin symbol, as does two circles touching - the same thing.

[Skip_M._Kliphiem]

I'm looking at the Mammut booklet (page 13) that came with my 7.5 twin ropes:

 

"WHAT TYPE OF ROPES ARE THERE"

There are basically three different types of rope, each suited for different applications, which are tested...

 

 

a. Single Ropes , symbol: the number 1 within a circle, an illustration with a climber clipping all pieces with the rope.

 

b. Twin Ropes , symbol: 2 linked circles within a larger circle, an illustration of a climber tied in with 2 ropes, clipping all pieces with both ropes.

 

c. Half (double) Ropes , symbol: 1/2 within a circle, an illustration of a climber tied in with 2 ropes, alternatly clipping pieces left and right.

 

In the glossary (page 30) definition of:

 

Double Rope Technique; also known as a Half rope technique

 

There are no definitions for Single or Twin rope tecnique, only a reference to page 13.

 

There is apparently some debate on these terms.