Double ropes … why the twist (rgold)?

Using double ropes (Mammut Genesis) for multi-pitch rock (target use is alpine >10pitch). Standard mode is to swap leads, using guide mode w/ plaquette style device. Getting twists in the system as we get further into routes. What are the causes of this (e.g. creating a twist when setting guide mode belay, where/how second comes up to belay, then shoves off to lead next pitch)? Seems like this would be straight forward but continue to create the twist, clearly missing something simple here. Rgold or someone that uses doubles would appreciate insight into the secret here (!).

Thinking about it I always assumed it was turning around at the belays or the second turning around while putting on shoes on the ground etc. But it actually will also happen even if you both keep facing the rock the entire time depending on which side of the leader you swap leads. i.e. if your second comes up to your belay on your right hand side and continues, you've got a twist. If you pass them on the left on the next pitch it will un-do it but if you pass on the right again now you've got two.

How you put your ropes into the belay device won't cause problems, if you make a twist that way it will just undo itself when you remove them, you haven't actually passed the ropes around each other.

Easy enough to un-do if it gets clustered, just go into the anchor, untie one of the ropes and pass it around to undo the twists, re-tie.

Edit: I'm talking here about doubles twisting around each other, not twists in the individual ropes. I assumed that's what you meant

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I think your rope is always twisted to some extent. And when you tie in to both sides you lock it off. Then as your belaying each other your just ironing the twists to one end and it becomes more pronounced.

But if you're talking about the ropes twisting around each other. There's some voodoo magic I've never quite figured out 100%. Like even climbing on singles, what is the mantra stack the rope in long loops -> shorter loops for swapping leaders, and short loops increasing size for same leader?? idk magic?

I think the easiest way to understand what's going on is to simulate the the system in action:

Take two pieces of string or cord (different colors would help, or mark one of them). Take two pens or pencils and put them on the floor or a table (to simulate the rock face they will be climbing). Place the perpendicular to the direction of travel and tie one string to the left side of each and the other string to the right side of each.

Don't rotate or turn the pens as you do this next bit. Now mimic the action of the lower pen joining the right pen at the belay on the right side and then passing to the next belay. Now have the following pen join the leading pen at the belay on the right side, and passing. Repeat this a few times and you'll see twists develop.

Now untangle your mess and repeat the process but have one pen always pass on the right and the other always pass on the left. I don't think you have any twist this way.

Essentially, if you both pass on the same side, one of the ropes crosses the other one each and every time you pass.

Edited: I'm pretty sure (providing the belay allows it) that if you do a 360 degree turn towards the direction your partner passed on, you undo the twist. They pass on the right, turn clockwise. They pass on the left, turn counter-clockwise.

Are you speaking about individual strands becoming progressively more kinked or about the two strands wrapping around each other?

... the later, the 'two strands progressively wrapping around one another'. Is most notable as the number of belays accumulate.

It's well-known that if you don't keep an eye on them at all times then double ropes inevitably sneak off into the fourth dimension and twist around themselves.

More seriously, on multi-pitch climbs you often alternate between facing in (when climbing or belaying the leader) and facing out (when belaying the second). Depending on your turn directions your net rotation could be 0 degrees, 360 degrees, or some multiple of 360 after multiple belays. If two climbers don't mimic each other's turns exactly then the result will be twisted ropes.

And then there are weird chimney pitches like the crux on Syke's Sickle where you could rotate through 360 just by climbing the pitch.

Yup, I'd go with Martin's answer. Eliminating the results of 4-dimensional motions, either the leader or second or both have to induce rotations in complementary ways in order to put twists in. It turns out this is easy to do, and the rotations may not be obvious. Wide cracks that the climbers turn around in can create twists, but I'd say the vast majority happen at belay changeovers. It is also possible, when changing from belaying the second to belaying the leader, to turn the plaquette over in a way that creates a twist, and the belayer can initiate a twist by threading the ropes for the leader's belay in the wrong order.

Almost all of the time, when the ropes are taken up, the second will see they are twisted and can undo the twists by an appropriate rotation. Taking one strand and dropping it over the head (perhaps repeatedly) is a worse approach, because this will put kinks the the strand that is being moved and these might eventually get bad enough to cause their own problems.

As for kinks, as a way to keep ropes as kink-free as possible, we don't have the second tie in on the first pitch if is is feasible to be unanchored. The leader takes up the ropes without them being anchored at their ends and so at least some of the kinking can dissipate. It makes good sense to knot the rope ends to prevent them running through the belay plate on long pitches, and once the second is off belay, they can clip each strand through a carabiner on their harness. This allows the ropes to de-kink as they are taken up but still keeps the second in control of the ends, which will lodge in the carabiners.

The main downside of this approach is the second doesn't get a partner check when tying in. I don't care about this at all, but many people might and so would not use this method. Perhaps I should add that I would never leave a novice at the base to tie in by themselves; this is a technique for practiced climbers only.

Thank you for all the feedback - will test it out this weekend.

Mathiaswrote: I think the easiest way to understand what's going on is to simulate the the system in action: Take two pieces of string or cord (different colors would help, or mark one of them). Take two pens or pencils and put them on the floor or a table (to simulate the rock face they will be climbing). Place the perpendicular to the direction of travel and tie one string to the left side of each and the other string to the right side of each. Don't rotate or turn the pens as you do this next bit. Now mimic the action of the lower pen joining the right pen at the belay on the right side and then passing to the next belay. Now have the following pen join the leading pen at the belay on the right side, and passing. Repeat this a few times and you'll see twists develop. Now untangle your mess and repeat the process but have one pen always pass on the right and the other always pass on the left. I don't think you have any twist this way. Essentially, if you both pass on the same side, one of the ropes crosses the other one each and every time you pass. Edited: I'm pretty sure (providing the belay allows it) that if you do a 360 degree turn towards the direction your partner passed on, you undo the twist. They pass on the right, turn clockwise. They pass on the left, turn counter-clockwise.

I am finding this 10 years later and wondering why this nugget of information isn't more widely known. I guess because most climbers don't do routes long enough to encounter multiple twists and either the route ends or they naturally pass on opposite sides due to the nature of the route. Thanks for this information!

I don't think keeping track of what side to pass on is practical in the real world,  But all twists can be undone by the second at the stance with a simple step or two; just don't let them build up pitch after pitch.  (Is this too much information?  The second can pull down a few feet of slack, clip the strands to the anchor to isolate the twists between the anchor and the second, and then undo the twists by turning in place, stepping over the ropes at each turn.)

It is possible to think of the twists as a feature rather than a bug, because the twists also detect that you've put a twist into each single strand.  With a single rope, such twists are undetectable until they begin to cause kinks, but with half ropes, you know right away and can undo the problem.  But don't de-twist by untying one rope and unwrapping it, because that defeats the "feature," as you are leaving all the installed twists in the strand you didn't untiebv.

rgoldwrote:

I don't think keeping track of what side to pass on is practical in the real world,  But all twists can be undone by the second at the stance with a simple step or two; just don't let them build up pitch after pitch.  (Is this too much information?  The second can pull down a few feet of slack, clip the strands to the anchor to isolate the twists between the anchor and the second, and then undo the twists by turning in place, stepping over the ropes at each turn.)

It is possible to think of the twists as a feature rather than a bug, because the twists also detect that you've put a twist into each single strand.  With a single rope, such twists are undetectable until they begin to cause kinks, but with half ropes, you know right away and can undo the problem.  But don't de-twist by untying one rope and unwrapping it, because that defeats the "feature," as you are leaving all the installed twists in the strand you didn't untiebv.

For some reason I nearly always manage to make things worse when I try to remove the twisting like in your first paragraph, but thats due to my own thickness as I invariably start turning the wrong way. I tend to just do the untie ons strand in twist build up, I hadn't thought about your point about twists in the other rope.

Oh and I'm pretty sure others are right above and it is more belay stance shananagins than whilst climbing that the twists sneak in.

Neil Bwrote:

For some reason I nearly always manage to make things worse when I try to remove the twisting like in your first paragraph, but thats due to my own thickness as I invariably start turning the wrong way. I tend to just do the untie ons strand in twist build up, 

If you drag the twists right up to your tie-in point, the strand closest to you that is above the twist gives the direction you want to turn---this is for stepping over the rope. When I say "gives the direction," I mean that the top strand will angle either left or right, and whichever it is, that is the turning direction.

Always shake out 20 ft of rope to feed through the belay device rather than feeding directly from the coils draped over your tie in points. Stay 20 ft ahead of it at all times. Otherwise you might get the dreaded twisted mess that won't fit through the belay device. 

rgoldwrote:

If you drag the twists right up to your tie-in point, the strand closest to you that is above the twist gives the direction you want to turn---this is for stepping over the rope. When I say "gives the direction," I mean that the top strand will angle either left or right, and whichever it is, that is the turning direction.

I mean you'd think that but trust me I can still feck it up   .

Kermantle ropes have a core (kern) inside the sheath (mantle).  The components typically are not attached to each other except at the ends where a hot knife fuses core to sheath (not with Kevlar and similar).

 there seems to be some innate quality that twists ropes.  When I sailed, and coiled rope rather that flaked it, I saw that the twists all went in one direction.  When I DIY this phenomenon doesn’t occur with power cords which lack yarn and can twist is different directions.  For this reason I suspect that the yarn in the core is all twisted uniformly.  (Curious if folks here know.)  running the rope through a belay plate or gri gri moves the rope over a sharp angle where the inside of the bite is moving at a different rate from the outside which provokes the yarn in the core to twist uniformly differently from the sheath.  Because the sheath is fused to the core at the ends, the twist travels to the ends and the twists in the rope become easier to generate with greater intensity over time.  

Sailors coil with a half twist to counter the twist build up.  Climbers also need to actively balance out the twists in the rope

Flaking the rope can cause twists.  Some use both hands to flake and others the same hand.  Using the same hand, e.g right hand to flake to the right and left around one’s neck creates an asymmetry which reduces rope twist.  

Pulling a rope through an anchor after each pitch removes twist.  Great for cragging but not multi pitch.

With two ropes one can safely untie and retie each strand separately (and carefully) to relieve twisting at belays.  

Perhaps 360 moves are the cause, but imagining a person always twisting clockwise is difficult.

I believe that pulling a rope through a carabiner does not impart any twist only if the rope crosses the carabiner at a right angle. Otherwise it does impart a twist to the rope. The further off 90 degrees, the more twist. 

I have climbed a fair bit with double (half) ropes. I don't recall ever having a significant issue with the ropes twisting around each other. I am wondering, if I now know this is a problem,  am I now going to have said problem?

I am guessing that the little twirl thing by the second (or maybe even untying one rope then retying after untwisting) has happened. But never had sufficient issue to make me rethink the wisdom of using 2 ropes. 

I have absolutely untied and retied on big climbs but the biggest issue has been a twist happening below the belay device. the worst was on the promenade in single digit temps and no communication due to wind. shortest day of the year, running out of daylight and trying to keep the ropes running fast enough for the out of sight leader with fingers that were frozen  numb. we managed. 

If you really want to  get kinks  in your rope try belaying with munter hitches. To eliminate this problem, one person should be dyslexic and tie their hitches backwards.