just dont clip 'em to the same piece...i think thats about all that would be worrisome.

oh, and until you clip your first bomber piece on a pitch, make sure your belayer only has his hand on one of the lines, this will prevent you from being caught by two single lines in the event of a factor 2 fall...

just dont clip 'em to the same piece...i think thats about all that would be worrisome.

oh, and until you clip your first bomber piece on a pitch, make sure your belayer only has his hand on one of the lines, this will prevent you from being caught by two single lines in the event of a factor 2 fall...

okay so when belaying a double line you are only belaying one line at a time??????

just dont clip 'em to the same piece...i think thats about all that would be worrisome.

To clarify VTG's point, you must avoid falling onto two singles clipped into the same piece, as the impact force will be dangerously high.

-Jay

The impact force will be higher on the piece, the climber, or both?

It'll be higher on the piece (which may be the belay anchor!), the climber, and the belayer.

-Jay

Gotcha! Would it make sense to only belay on one rope for a couple pieces, including the anchor?

Josh

Frankly, I think the best solution is to go ahead and buy your doubles and practice with them on a couple of easy routes.

By the way - you should avoid this with doubles too. Only twins are designed for it.

Can you document that? It is a common practice to clip both double ropes into the same piece at the start of a pitch.

-Jay

I might be wrong on this, but I thought that there were only 2 classes for ropes from the UIAA, Single and double/twin and that using them as double or twin was personal preference.

SINGLE ROPE - for use in a single strand as a link in the safety chain.
HALF ROPE - for use together with another rope of the same type in a half rope system.
TWIN ROPE - use in pairs and parallel within a twin rope system.

You are mistaken. Okay, here's just one source:

From https://commerce5.the-information-age.com/Bluewater/Uploaded/Downloads/727200514235.pdf


Note - there are some ropes that are certified as both Half and Twin. (E.g. page 15 of http://www.singingrock.cz/Data/files/SINGING_katalog_EN_5.pdf )

And some that are certified as both Single and Half (e.g. http://www.bluewaterropes.com/home/usechart.asp )

But most are certified as only Twin or Half (e.g. http://www.bluewaterropes.com/home/usechart.asp
http://www.mammut.ch/mammut/images/ropes/overview_e.jpg (all of mammut's twins and halfs)
http://www.bdel.com/gear/detail/ice_twin_detail.php#compare (all of Beal's twins and halfs)

JT512 - all certification tests for EN 892 (upon which the UIAA requirements are set) are done with a single strand of SINGLE, a single strand of HALF, and two strands of TWIN. There are lots of references to this online, but to get the actual EN 892 text costs around $150. I'm sorry, I don't have that kind of chump change lying around. If you can find a pirate copy on the web - more power to you - I've got to get back to work!

GO

none of this really implies that doubles (halves) can't be clipped together. Clearly, twins aren't intended to be strong enough to be clipped separately.

-Jay

And, generally, when those half ropes which are not certified as twins are clipped together, they exceed the maximum impact force of the UIAA test, and thus fail the test for certification as twin ropes (peak force less than or equal to 12 Kn.)

The "hard catch" resulting from clipping both strands can be quantified; the sum of the tensions in both ropes will be the square root of 2 times the tension that would have resulted had only a single strand caught the fall. Since the square root of 2 is approximately 1.4, clipping both strands will result in loads to the system that are 40% higher than the loads imposed by a single strand.

Clearly, there are advantages and disadvantages to clipping half ropes to the same piece. Folks who do not know what those tradeoffs are, should not be climbing on half ropes.

To say you must clip them separately because the UIAA only tested them in a single strand, is like saying that we all must go on a diet, because UIAA only tested doubles with 55kg of weight (121 lbs).

make sure you're never looking at a fall where both {single} ropes will catch you using the same upper piece. This is a very easy problem to avoid. By the way - you should avoid this with doubles too. Only twins are designed for it.

I didn't say you *must* do this or *mustn't* do that. I said they weren't designed to do so.

My point is that when you put two ropes on the same piece, you're effectively doubling the diameter of the rope catching you

You agree that for non "joker" half ropes, a 40 percent increase of force is likely on that crux piece? f--- that! Look, do what you want, but when I get to a crux and I think I might fall, the *last* thing *I* want to do is to increase the impact force on my last piece by 40%!

If anything, we are cautioned against taking a high FF fall on a single strand of doubles. I'll have to go back and dig it up, but I do believe people have posted recorded incident in which a climber took a high FF fall on a set of doubles, but only one strand caught the fall, and that strand broke.

When I clip my doubles to a single piece there is always a reason...

Is the reason fear of one rope breaking under the force of a severe fall? Are there other reasons to clip both ropes together? If so, under what circumstances?

I would argue that a smart belayer would have you on belay on both ropes, but with more slack in one than in the other.

To divert the path of the ropes from areas of loose rock.

I found myself doing this recently, not with twins or doubles, but a single lead plus static trail line (belayed by only the single, of course). Same principle would apply to twins/doubles, I imagine. I didn't read much of the thread, exuse me if this is out of context.

With both ropes running through the same piece? ... Maybe if the ropes were clipped into separate biners, it might make sense to keep more slack in one rope than the other.

-Jay

A single thin line is more likely to be cut if sharp rock is present.

The only argument I've ever heard for consistently clipping both strands of a double rope system together early in a pitch was to avoid taking a high factor fall on to a single strand of rope that isn't designed to withstand it. In a perfect world, one strand of a double rope system would never catch the full force of a fall because the next lower piece (that would be close enough for you to fall past) would be involved in catching the fall (to some degree) and therefor the other rope would share the force of the fall (to some degree). I think that's the rational behind using 55 kg in the test instead of 80 kg.

Of course, that's a perfect world and doesn't account for run out climbing.

I often heard people state that they don't understand the use of twins. Personally, having used both twin and double systems extensively, I don't understand the use of double ropes. Dual purpose, twin/double systems probably make the most sense.

The attached link offers a good discussion on the subject http://groups.google.com/...8?hl=en&lr=&ie=UTF-8

If you could dig up any cautionary tales about the risks of taking hard falls on one double rope, or any advice from a respected source to clip both doubles together, I would appreciate it. The rationale for clipping both ropes into a single piece is not at all clear to me.

Is the reason fear of one rope breaking under the force of a severe fall? Are there other reasons to clip both ropes together? If so, under what circumstances?

Note that manufacturers do not recommend using a single half rope. The reason is that, tested singly with 80 kg, half ropes do not (as yet) pass the UIAA drop test. They do not, as far as I know, ever break on the first drop, but they cannot reliably sustain five fall factor 1.78 falls.

Fantastic series of posts, by the way.

This is interesting. How did you arrive at this conclusion?

Take a chill pill and relax a bit, don't get so worked up about this. I do not advice clipping both doubles to a single piece protecting a crux, that would be unwise.

You may have gotten this impression when I posted earlier that I like to place two pieces evenly with each other before a crux, and clip each of my doubles to each piece separately. This let the two pieces share the load if I fall, so the impact force on each piece is in fact lowered.

My earlier concern was not the impact force on the gear. My concerned was that in this practice, the climber experiences roughly the same impact force as if the doubles are clipped to the same piece. And if brutusofwyde is right when he said the impact force is greater than 12kN in this case, I may very well be doing damage to my own body in a big fall.

I'll have to go back and dig it up, but I do believe people have posted recorded incident in which a climber took a high FF fall on a set of doubles, but only one strand caught the fall, and that strand broke. [edited because I could not found this accident report, it might be a figment of my imagination] That's why I do not like the UIAA's test with doubles. Testing them with a 55kg weight is unrealistic at best, misleading at worst.

But, it is necessary to add eight(!) rope failures more in the time since 1983 amongst German and Austrian mountaineers and climbers. The causes were either a misuse of the rope or the rope was already damaged by some kind of polyamide contaminant, such as acid. The details are as follows.

The misuse was using a half rope or a twin rope in a single strand. This happened five times out of nine times altogether. The reason why they are not recorded in the table is because it is a misuse. Such misuse happened in 1973 on the "Schreckhorn" in Switzerland, in 1981 on the "Olperer" in Austria, and in 1990 on the "Grossglockner", also in Austria (all three climbers were killed), and two rope failures in the last year (2001), one when toprope climbing (bottom lowering), the other during abseiling by a mountain rescue team of two persons and a stretcher a few meters above bottom level (all three survived).

The only argument I've ever heard for consistently clipping both strands of a double rope system together early in a pitch was to avoid taking a high factor fall on to a single strand of rope that isn't designed to withstand it. In a perfect world, one strand of a double rope system would never catch the full force of a fall because the next lower piece (that would be close enough for you to fall past) would be involved in catching the fall (to some degree) and therefor the other rope would share the force of the fall (to some degree).

I'm not worked up at all. I do think it's an interesting discussion, though! On the above point, we agree completely.
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Absolutely. I do the same thing.

Perhaps this article by Pit Schubert is what you were thinking of? From http://www.uiaa.ch/article.aspx?c=231&a=147

If I recall your post correctly, you said exactly that, and then in the next paragraph you said you sometimes clip both pieces together, but didn't explain under what circumstances. This left me scratching my head, thinking "hmm, that could be bad..."
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In a later post, you give your reasons for putting both ropes on a single piece. This was helpful to seeing your perspective.

I just wanted to point out the fact that just because a climber falls past both pieces, does not mean that both ropes will share the fall.