Multi-pitch rap sequence with single rope + tag line

Andy Wiesner wrote:

Has anyone ever had the thinner rope in a double-rope (ATC) rappel slip through the device in an uncontrolled way? Seems at least possible. I've never thought about that before, because I use the reepschnur in this scenario. 

I've had this issue with a 9.8 and 8.2 - the thinner side fed through faster, even with a prussik, and led to some unsavory shenanigans trying to equalize them while hanging above the next station, with the end of the 8.2 approaching every time I would rap a little lower.

I’ve rapped a whole lot of pitches with a 9ish and 6mm setup and more or less always treat it as I would two ropes of equal diameter. Sequence: prerig 2nd rappeller’s camp ovo and tie a blocking knot on the skinny brake-side strand in case the ropes creep in the scenario everyone is concerned about. (When this happens it’s usually very slow and can be mitigated by just grabbing the brake strand of the device) Rig the 1st rappeller's grigri on the lead line and they zip down. Once they’re at the next anchor, the 2nd person unties the blocking knot in the skinny rope and raps. You have to be careful to keep the rope from creeping if the knot is on the tag side, but it’s not hard to do and usually stops being an issue after the first 10-20'.  Your partner can also help accomplish that with a firefighters belay.  

Max Tepfer wrote:

I’ve rapped a whole lot of pitches with a 9ish and 6mm setup and more or less always treat it as I would two ropes of equal diameter. Sequence: prerig 2nd rappeller’s camp ovo and tie a blocking knot on the skinny brake-side strand in case the ropes creep in the scenario everyone is concerned about. (When this happens it’s always very slow and can be mitigated by just grabbing the brake strand of the device) Rig the 1st rappeller's grigri on the lead line and they zip down. Once they’re at the next anchor, the 2nd person unites the blocking knot in the skinny rope and raps. You have to be careful to keep the rope from creeping if the knot is on the tag side, but it’s not hard to do.  You’re partner can also help accomplish that with a firefighters belay.  

Two questions: 

1. Which 6 mm line do you use for this purpose (i.e the Edelrid Rap Line ii, the Imlay line, random 6 mm accessory cord, etc...). How is it?

2. What knot do you prefer to join two ropes of notably differing diameters. EDK or something different?

Hey.  I thought I'd jump back in as the OP.  Thanks for all the replies.  There's some great information.  

Personally, I'm using a 9.5 rope, and a 6 mm Edelrid rap line, generation one I think, 31 grams/meter, with some dynamic properties. I'm joining these ropes with a flat overhand with adequate tail, backed up by a second flat overhand, as I do with most rappels with ropes of equal diameter.  

I think that pre-rigging the second is a good idea and generally good practice, but I have not incorporated it into my climbing on a regular basis yet, unless I am climbing with beginners.  

My partner and I observed no thin rope slippage on the four rappels we did so far, but I'd say it's definitely a possibility, and something to think about and mitigate.  

I am placing both strands into my belay device (Reverso) and treating it as a rap with two ropes of equal diameter--there is no blocker knot as you might use with a GriGri rappel. 

So that's my system so far.  I'll probably use this on routes where I want to climb with a single rope, yet know that there will be 50 or 60 meter raps.

Once again, thanks for the replies.  

B

Bruno Schull wrote:

Hey.  I thought I'd jump back in as the OP.  Thanks for all the replies.  There's some great information.  

Personally, I'm using a 9.5 rope, and a 6 mm Edelrid rap line, generation one I think, 31 grams/meter, with some dynamic properties. I'm joining these ropes with a flat overhand with adequate tail, backed up by a second flat overhand, as I do with most rappels with ropes of equal diameter.  

I think that pre-rigging the second is a good idea and generally good practice, but I have not incorporated it into my climbing on a regular basis yet, unless I am climbing with beginners.  

My partner and I observed no thin rope slippage on the four rappels we did so far, but I'd say it's definitely a possibility, and something to think about and mitigate.  

I am placing both strands into my belay device (Reverso) and treating it as a rap with two ropes of equal diameter--there is no blocker knot as you might use with a GriGri rappel. 

Do you ensure that the thicker rope is always through the rap ring, like others have mentioned here? Or do you just rap two strand like normal, no matter which side the joining knot is on?

Artem Vasilyev wrote:

You can use the new edelrid dynamic rap tagline to lead on in emergency situations as explained by an Edelrid rep. Also used by Tommy and Alex to simul climb on. 

I didn't know that existed. Thanks. I'd be super freaked leading on it though. Hell, I'd be freaked following on it!

Super thin line. Won't tangle all that much if you only have 35-40M of it. Thin taglines are nice because they weigh nothing

Totally.

I have to say, I wouldn't be comfortable rapping with two lines of such different thickness threaded through an ATC. Adds to the number of things that can go wrong. Good simple discussion here. 

@ Demetri--So far I always make sure to have the thicker rope threaded through the anchor.  That's really why I was asking the original question, to know how people deal with pulling, threading, and so on.  I saw an video from ENSA (French guide organization) that showed how the knot can follow the rappel device down if rigged the opposite way.  Don't know if that's realistic, but I like having the thicker rope through the anchor. 

@ Andy--I understand your concern.  I can say that it all behaved well so far, and that many people do use it that way.  As you said, it adds some more things to think about, but, at the same time, you can save weight, and the hassle of climbing with two ropes.  

Like so much in climbing, there's no perfect answers...just a lot of different variables. 

B

Bruno Schull wrote:

you can save weight, 

How?

Edelrid Eagle Light 9.5mm @ 62g/m + Edelrid 6mm cord @ 25g/m = 87g/m x 60 = 5.22kg

Beal Gully half-twin @ 72g/m per pair x 60 = 4.32kg

Mammut Phoenix half-twin @ 84g/m per pair x 60 = 5.04kg

JCM wrote:

Two questions: 

1. Which 6 mm line do you use for this purpose (i.e the Edelrid Rap Line ii, the Imlay line, random 6 mm accessory cord, etc...). How is it?

2. What knot do you prefer to join two ropes of notably differing diameters. EDK or something different?

I've done it with a bunch of different tag lines at this point.  The first one I used was the semi-static one sterling made like 6 or 7 years ago.  When that one gave up the ghost I got an Edelrid and have also used partners' esprit alpine escape rope a bunch. (the one that Maxim started making a knockoff of recently)  I always use an EDK and sometimes tie a backup.  It's more important to pretension, dress it, and have adequate tail than it is to back it up.

Demetri V wrote:

Do you ensure that the thicker rope is always through the rap ring, like others have mentioned here? Or do you just rap two strand like normal, no matter which side the joining knot is on?

You don't really need to do this as it's easy to manage it while you're rappeling in the less-optimal scenario.  It for sure can slip and cause the knot to travel away from the anchor, (which can be a useful trick if you want to move your junction knot away from a feature it could hang up on before rapping further and abandoning it) but it's easily mitigated by holding the skinnier strand more tightly as you rappel. (usually you can stop doing this after it runs over an edge or two and the added friction helps solve the problem) If you're really gripped about it slipping, your partner can fix it at the anchor (either above or below you depending on the scenario) which is faster and less prone to user error than retying your junction knot over and over again and less bulky and prone to hanging up than a reepschnur. (the other option)

@Paul, the primary benefit of a semi static tag over a traditional half-twin is that it's way nicer when pulling the rope because you don't have to pull the stretch out of it.  They also haul better for the same reason and, depending on which one you get, hang up less because they're stiffer than a twin.

Max Tepfer wrote:

You don't really need to do this as it's easy to manage it while you're rappeling in the less-optimal scenario.  It for sure can slip and cause the knot to travel away from the anchor, (which can be a useful trick if you want to move your junction knot away from a feature it could hang up on before rapping further and abandoning it) but it's easily mitigated by holding the skinnier strand more tightly as you rappel. (usually you can stop doing this after it runs over an edge or two and the added friction helps solve the problem) If you're really gripped about it slipping, your partner can fix it at the anchor (either above or below you depending on the scenario) which is faster and less prone to user error than retying your junction knot over and over again and less bulky and prone to hanging up than a reepschnur. (the other option)

@Paul, the primary benefit of a semi static tag over a traditional half-twin is that it's way nicer when pulling the rope because you don't have to pull the stretch out of it.  They also haul better for the same reason and, depending on which one you get, hang up less because they're stiffer than a twin.

Max, that was one hell of an answer. You're the man. Thank you.

Max Tepfer wrote:

If you're really gripped about it slipping, your partner can fix it at the anchor (either above or below you depending on the scenario) which is faster and less prone to user error than retying your junction knot over and over again and less bulky and prone to hanging up than a reepschnur. (the other option)

Thanks Max. I’m curious. Has anyone had a reepschnur hang up at the knot / carabiner? I’ve not, but I’m always a little anxious about it.

And if you secure the thin line to the lower anchor, doesn’t it go taut and impede the rappel?

Andy Wiesner wrote:

Thanks Max. I’m curious. Has anyone had a reepschnur hang up at the knot / carabiner? I’ve not, but I’m always a little anxious about it.

Not up at the anchor.  But I would not be surprise to hear of it. 

I have had the knot / locker hang up on an otherwise minor looking shrub.  That was a case when I had rapped and left the tag (being pulled) going down one side of the shrub and the fat line going down the other side. Doh.

And on a pull (I think that's when it happened), I've had the rope somehow flip around and unclip from a non-locker biner at the anchor.  Non-lockers should probably be avoided - but that's not often the case anyway.

And I've had a locker with an I-beam cross section catch in a very shallow crack at the lip of the rap ledge during the pull.  It then wouldn't move in either direction under harder pulls from below.

All that said, I'm a pretty big proponent of using a reepshnur when appropriate and with care.  Imagine having just a single rope with a core shot knotted off somewhere on one half of the rope.  A reepschnur can allow everyone to rap the strand that doesn't have the knotted off damage and still retrieve the rope.  ... but now I'm off topic.

Andy Wiesner wrote:

Thanks Max. I’m curious. Has anyone had a reepschnur hang up at the knot / carabiner? I’ve not, but I’m always a little anxious about it.

And if you secure the thin line to the lower anchor, doesn’t it go taut and impede the rappel?

I don't remember a specific time when the reepschnur hung up for me, but I don't use it very often.  I've for sure had plenty of ropes hang up in the past and having that much extra bulk and loops isn't stacking the odds in your favor.  I see it as a specific tool that I use in fairly limited applications.

It doesn't really come tight because it only takes a small amount of added tension (or friction) to keep it from travelling.  It's also easy to experiment with this stuff on a tree or beam.  (keep in mind that that's the absolute worst case/lowest friction scenario)

Andy Wiesner wrote:

Thanks Max. I’m curious. Has anyone had a reepschnur hang up at the knot / carabiner? I’ve not, but I’m always a little anxious about it.

Yes, and it sucked major balls. Was abseiling down No Glow in the Gunks with two students and when we went to pull the rope, it wouldn’t budge. In this specific case, it’s because of the absolutely idiotic rap anchor on top, not sure why this route was chosen as a rap route, because it sucks.

Basically, the anchor is a tree a ways back from the cliff with a cable tied around it and extended out to 2’ before the cliff edge where there’s a big ass quicklink to rap off. The weight of the ropes hanging caused enough friction that the knot refused to move, obviously exacerbated by the rope taking a ninety degree bend, then a 180 degree bend, and and then another ninety degree bend...eventually the rope miraculously started moving and I didn’t have to ascend 200’ of rope.

If you’re asking about the knot itself becoming lodged in anchor, that happened to me once coming down off the Predator ledge in Rumney. Just needed a few sharp jerks and I can’t imagine it being any worse without becoming completely stuck and then doing what Artem said. 

Andy Wiesner wrote:

Has anyone ever had the thinner rope in a double-rope (ATC) rappel slip through the device in an uncontrolled way? Seems at least possible. I've never thought about that before, because I use the reepschnur in this scenario. 

I actually had an article on this topic published years ago.   I've never used a designed "rap" line, as others mention.  Do they change the mantel or materials to give it friction to match the lead line?

As you say, the tag line will often feed faster, especially if the lead line has some wear (fuzzed) and the tag line is smooth and slick, and it varies between devices, too.

Buy your tag line 4-5m longer than your lead line.  It's worth the few extra grams and gives you some margin when it slips.   It's often handy when hauling, and when you need to move the knot below a lip or other potential snag.  You do know how to move the knot while on rappel, right?    

Depending on your device, you can add a biner to add friction to the tag line.

You can squeeze the two ropes together with your hand and feed them, instead of letting them just slide through your hand.   Gets tedious though. 

BTW, I always alternated ropes on the rappels.  

John Byrnes wrote:

BTW, I always alternated ropes on the rappels.  

Thanks John. By "alternated ropes" do you mean you threaded the line you intended to pull through the lower anchor regardless of whether it was the fat or skinny line, and regardless of which side of the lower anchor rings the knot ended up on?

Andy Wiesner wrote:

Thanks John. By "alternated ropes" do you mean you threaded the line you intended to pull through the lower anchor regardless of whether it was the fat or skinny line, and regardless of which side of the lower anchor rings the knot ended up on?

Yup.  Way faster, less things to go wrong, especially when you're tired and the T-storm is pounding you.

EDIT: You guys will laugh, but for multi-pitch rappels I always used a biner rig.   Having more metal and surface area, it wouldn't get nearly as hot as a belay device.  You can adjust the friction by adding or removing cross-biners.  You can't drop it (Yours is HOT!) getting on/off rappel.   It feeds very smoothly and, added bonus, it squeezes the two ropes together naturally so the tag line doesn't slip very much. But I doubt any of you modern climbers will try it   

John Byrnes wrote:

You guys will laugh, but for multi-pitch rappels I always used a biner rig.

Ha! What kind of biner? I just carry the little ones anymore.