Double rope use

Got in a discussion with a partner the other day about double rope use. He was under the impression that you alternate clipping every piece. I was under the impression that you alternate, but that you could also clip both ropes through the same piece, just like twins, if you wanted to for some reason (say, taking repeated whippers at the same spot to spread it over 2 ropes versus just one). I thought I remember seeing something about this in FotH, but I can't find it, and it does appear to show what my friend was describing.

Anyone have any info on this, one way or the other? And if you should clip JUST alternating pieces, should I be worried about twin ropes being clipped through the same piece?

Thanks

There is no need to alternate, clip whatever rope makes sense i.e. if there are several placements out to your left, continue to clip your left rope, then clip your right rope as the route moves back right.

It's very important however to use only twin technique (clipping both ropes to the same piece) or only use half rope technique (clipping only one rope into each piece) on a particular climb. Not doing so can cause one rope to rub against the other potentially cutting one or both of your strands. This is not an issue in twin technique because an equal amount of rope is out on each strand so the ropes will move together. If not all pieces have both strands clipped there are different amounts of line out on each rope. Rope stretch caused by a fall or a pulled piece will cause one rope to run over the other one. If you're worried about whipping in a certain spot with double ropes put in a separate piece of gear for each rope and clip them apart.

Also, be sure you know how your rope is rated. Only use twins for twin technique (twin clipping two half ropes may result in significantly higher than normal force on your gear in the event of a fall due to less rope elasticity) only use halves for half rope technique and even if your ropes are rated for both do not clip together and apart on the same route.

Anthony Baraff wrote:There is no need to alternate, clip whatever rope makes sense i.e. if there are several placements out to your left, continue to clip your left rope, then clip your right rope as the route moves back right. It's very important however to use only twin technique (clipping both ropes to the same piece) or only use half rope technique (clipping only one rope into each piece) on a particular climb. Not doing so can cause one rope to rub against the other potentially cutting one or both of your strands. This is not an issue in twin technique because an equal amount of rope is out on each strand so the ropes will move together. If not all pieces have both strands clipped there are different amounts of line out on each rope. Rope stretch caused by a fall or a pulled piece will cause one rope to run over the other one. If you're worried about whipping in a certain spot with double ropes put in a separate piece of gear for each rope and clip them apart. Also, be sure you know how your rope is rated. Only use twins for twin technique (twin clipping two half ropes may result in significantly higher than normal force on your gear in the event of a fall due to less rope elasticity) only use halves for half rope technique and even if your ropes are rated for both do not clip together and apart on the same route.

+1
Also for more reading....
mountainproject.com/v/climb…

And just a note...twins are meant to clip through the same piece. They HAVE to. They aren't meant to take a fall alone.

EDIT: I stand corrected on the double rope 55kg thing. Interesting read:
supertopo.com/climbing/thre…

based on the language you used in your post, i thought it would be worth pointing out that there is a difference between double ropes and twin ropes.

double ropes are rated to catch a fall individually and should be clipped indiviually. there's been an open debate about clipping both double ropes through one piece, but it's generally not advised. either way it shouldn't be done through one 'biner. the suggestion to use two individual 'biners on slings of differing length is a good one to follow if you're going to do it.

while it may be ideal to alternate clipping right and left, you will find that it's not always possible. and, if you're on ice 30 feet above your last screw and looking at a potential ground fall, just getting in another screw is way more important than finding a placement that allows you to alternate.

i don't agree with the statement that alternate clipping is intended so that both ropes play a part in the catch. for one, double ropes are perfectly well suited to catch a fall individually. plus, if you're using double ropes, you're likely climbing in a situation with runout protection. and, you're gonna have to fall a loooong way before that second placement comes into play. unless you're really high up on a vertical wall, the ground is going to come into play before that second placement does.

twin ropes are intended to be clipped together. a single twin rope is not rated to catch a fall by itself.

I am aware of the difference between double (half) ropes and twin ropes.

So far though, the claim that clipping doubles through the same biner will/could cause melting is unsubstantiated. I'd like some reference other than just assertion, because frankly, I can't find anything one way or the other in print.

Any help would be appreciated.

Here are some other threads about double rope use:

mountainproject.com/v/climb…

supertopo.com/climbers-foru…

The main issue with clipping both double ropes to a single piece is that you will increase the impact force in the case of a fall. My understanding goes something like this:

Think of a rope like a spring and picture the following.

You have a spring on the piece and you fall. Spring expands a long way (elongation %) and the force is distributed over that distance.

Now you have two springs on the piece (clipped with both ropes) and repeat the scenario. Now the springs, since you have twice as much resistance, do not extend as far and the fall is caught over a smaller distance. In this scenario the force on the piece is higher.

I avoid clipping both double ropes to a piece due to this. If you must use the suggestion above(different biners, extension, etc) to make sure the ropes don't rub together!

- Luke

i think the "dont alternate single and double clipping" argument is based on some theoretical scenario of massively different pay out speeds on the two ropes. I've never seen a accident report where it was a factor, but I havent looked for one either. I'm sure the "by the book" manufacturer suggested practice is to never alternate twin/half technique on the same pitch. In practice, it is probably more of a do what you want thing, but accept that you are introducing a new failure mechanism into the system.

Peter Springs wrote:... unsubstantiated. ...

Well, do what you want, but just because you can't find literature on it does not mean that it is not an important idea to consider. When you are climbing with doubles, I don't really see a great reason to clip both ropes into a piece of pro anyway, so why not just error on the side of caution?

IMO, there's more potential for double clipping to jeopardize the system than there is reason for double clipping. if you feel it's absolutely necessary, clip two biners to the piece of gear and clip each rope individually.

sure, there's room for debate. but, i know i don't want my name in the accident report that ends the debate.

Mammut claims half ropes can be used as twins. However, I personally don't use them this way nor am I saying others should. What follows is an excerpt from their info book on ropes:
"Half ropes, with regard to strength and
weight, lie between single and twin ropes.
They only offer standard safety when they are
used as a pair. But here you have the choice
between twin rope technique, where both
ropes run parallel through the protection and
half rope technique, where the «left» and
«right» ropes run separately through different
protection points. This technique allows friction
to be reduced in the case where protection
points are widely spread and reduces
impact force. This is of benefit when climbing
traditionally protected routes. A belay method
which enables the independent control of
each rope must be used. Half ropes are tested
singly with a 55 kg mass and must withstand
five standard falls. They come in diameters
from 8-9 mm and weigh 42-55 grams per
meter. In single strand form they are suitable
to belay two seconds."

I just mean... a lot of ideas here are just that... ideas.

For example, rope running on rope and melting is a logical idea, as several of you have suggested. But people catch lead falls on Munter hitches which is also a fully rope on rope friction scenario which is an accepted practice. So I want more of a written guide on use, appropriate and inappropriate. My fall-back of Sterling Ropes doesn't actually have a "how to use half ropes".

I'm not trying to debate anything, I'm trying to get a printed source from some sort of authority that actually describes uses and abuses, not just logic from climbers that may or may not be right.

I appreciate all of your guys input, and I think it's good to think about things and discuss them, but I'm looking for something a little more solid than just climber logic and thoughts on things. I want hard and fast recommendations and descriptions of use.

edit: Thanks Jay, I'll look into the Mammut info!

Peter Springs wrote:I just mean... a lot of ideas here are just that... ideas. For example, rope running on rope and melting is a logical idea, as several of you have suggested. But people catch lead falls on Munter hitches which is also a fully rope on rope friction scenario which is an accepted practice.

I hear what you are saying, but your example above is not a good analogy because while the munter hitch is indeed using friction between two ropes to arrest a fall, there is a huge difference between the heat generated between two pieces of rope that are more or less statically generating friction (munter) versus two ropes moving past one another at high velocity (double rope in the same biner example). The heat generated is actually the killer, i.e. when ropes fail the sharp edge test it isn't actually from the rope being 'cut', but rather from the sharp edge generating a high amount of heat in a very localized area; the heat is then transferred strand by strand by conduction. This principle is how they design ropes that withstand the edge fall test; each strand of the core is individually coated with an insulating material that attempts to stop the transfer of heat which 'cuts' the rope.

I stand corrected on the double rope 55kg thing. Interesting read:
supertopo.com/climbing/thre…

J. Albers wrote: I hear what you are saying, but your example above is not a good analogy because while the munter hitch is indeed using friction between two ropes to arrest a fall, there is a huge difference between the heat generated between two pieces of rope that are more or less statically generating friction (munter) versus two ropes moving past one another at high velocity (double rope in the same biner example). The heat generated is actually the killer, i.e. when ropes fail the sharp edge test it isn't actually from the rope being 'cut', but rather from the sharp edge generating a high amount of heat in a very localized area; the heat is then transferred strand by strand by conduction. This principle is how they design ropes that withstand the edge fall test; each strand of the core is individually coated with an insulating material that attempts to stop the transfer of heat which 'cuts' the rope.

Again, I'm asking for evidence. Personally I think that saying that any belay system is "almost static" is borderline ignorant, especially the Munter hitch. But we could argue for hours about that as well.

Concerning your rope-cutting test, you should know that the UIAA has rescinded that test, because the test is inconsistent among other things and actually means nothing in the climbing world. There was a thread on that here not to long ago. Plus, I think you are getting your arguments mixed. Ropes that have been "chopped" on flakes and whatnot are not "melted", they are sheared through. I think the accident from last year? in Seneca? had some great pics of CUT ropes.

Again, looking for sources of "how to" as opposed to arguments from physics. It's nice to talk things up, but usually "thought up arguments from physics" are missing one piece of the equation, which can lead to catastrophic accident, hence I'd like some real hard evidence from a rope company or equal that has tested and been able to recommend or not recommend certain uses.

shit in one hand, wish in the other

Since this thread started....

Double Rope Question.

First draw when leading with double ropes. Do you clip one or both ropes????

one

Seems like you're so focused on scientific data that you're not happy with the common sense that has been offered up by many. Common sense is much more valuable.

Edit to add: You can find a study that may address the questions by searching for "Determination of the redistribution shock load in climbing double rope systems". The report costs $42.

sunder wrote:Since this thread started.... Double Rope Question. First draw when leading with double ropes. Do you clip one or both ropes????

With the double (half) ropes you are leading with 2 seperate independent lines, each tied in with their own figure 8 to your harness. As they previous guys have said, each line is designed to take a fall, and thusly can be clipped by itself.

Peter Springs wrote: Again, I'm asking for evidence. Personally I think that saying that any belay system is "almost static" is borderline ignorant, especially the Munter hitch. But we could argue for hours about that as well. Concerning your rope-cutting test, you should know that the UIAA has rescinded that test, because the test is inconsistent among other things and actually means nothing in the climbing world. There was a thread on that here not to long ago. Plus, I think you are getting your arguments mixed. Ropes that have been "chopped" on flakes and whatnot are not "melted", they are sheared through. I think the accident from last year? in Seneca? had some great pics of CUT ropes. Again, looking for sources of "how to" as opposed to arguments from physics. It's nice to talk things up, but usually "thought up arguments from physics" are missing one piece of the equation, which can lead to catastrophic accident, hence I'd like some real hard evidence from a rope company or equal that has tested and been able to recommend or not recommend certain uses.

Wow. I'm borderline ignorant and on top of that, I'm mixing up my arguments that in the end mean nothing anyway. Thanks for the tips chief, your arrogance is heartwarming. Here's a tip for you since you want a "How-to" manual: Go buy 'Freedom of the Hills'.