Multi-pitch rap sequence with single rope + tag line

Hi folks.  I've been experimenting with a single rope + tag line combination.  

To explain my question, I'll review my usual rap sequence for a multi-pitch raps using two ropes of equal diameter, for example, ice climbing. 

Two ropes equal diameter: I rap down, get to an intermediate anchor, clip in, get off rap, then thread the rope I will pull through the anchor to speed things up, my partner raps down, they pull the rope while I keep feeding the pre-threaded end through the anchor, when the knots come up against the anchor we clean and toss the ropes, and away we go for the next rap.  Using this system, we pull first one and then the other rope on alternating raps.

With a single rope and a tag line the sequence above doesn't work.  If you pre-thread the tag line, then you end up with the tag line as the main line through the anchor weighted during the rap.  To avoid that, what I've started doing is either 1) pre-threading the tag line through the anchor as above, and then re-tying the knots so that the single rope is weighted through the anchor, or 2) not pre-threading anything, and just waiting for all the ropes to come down before setting up the next rappel.  The first option is perhaps faster but involves tying and untying knots, while the second option is perhaps slower but the knots stay tied.  

Ideas?  I'm curious to learn about how others are doing this.

Thanks, Bruno

What are the diameters of the two lines? If they’re not too different then just double rope rap on them the same way you’ve been doing.

You’re not doing something foolish like using a 6mm tag line, are you?

Marc801 C wrote:

What are the diameters of the two lines? If they’re not too different then just double rope rap on them the same way you’ve been doing.

You’re not doing something foolish like using a 6mm tag line, are you?

Why is that foolish?

@Marc--I am using a 6mm tag line.  Whether or not that is foolish or not is an open question :)

I'm curious about using thin tag lines, so I'm experimenting.  Not set on anything yet, but it seems like an interesting system.

Specifically, I'm using an Edelrid single rope about 9.6 mm, and an Edelrid tag line, 6mm, with a some dynamic properties, a soft, flexible hand feel, and a little extra weight (31 grams/meter) compared to some of the thinner, lighter, static, stiffer tag lines that are available. 

What is it that you don't like about using tag lines?  

Happy to hear thoughts on this, but I'd also like ideas about my original question and rap sequence. 

Thanks, 

Bruno

Demetri V wrote:

Why is that foolish?

Tangles.
Can be incredibly difficult to pull on a high friction anchor, esp without gloves. 
Can’t be used as a lead line if things get hung up or stuck. 

Bruno Schull wrote: What is it that you don't like about using tag lines?  

I use one when necessary. Mine is 8mm and can be used as a lead line if needed. 

Marc801 C wrote:

Tangles.
Can be incredibly difficult to pull on a high friction anchor, esp without gloves.
Can’t be used as a lead line if things get hung up or stuck. 

To this re: skinny tag lines I would add ...

Both partners in a rope team should be familiar with all pitfalls of a skinny tag line - not just those listed - including ways to mitigate. In other words, I feel it is not really a system for anyone very unfamiliar.

It is slower a la the issue the OP brings up.

And I am someone who has used a skinny tag line a lot, and still would under some circumstances. :)

Edit: For skinny tag lines. I would go with static cord.  Otherwise, high friction anchors can be a pain in the arse with just managing the stretch needed to make progress on the pull. 

Bruno Schull wrote:

With a single rope and a tag line ....  If you pre-thread the tag line, then you end up with the tag line as the main line through the anchor weighted during the rap.  To avoid that, what I've started doing is either 1) pre-threading the tag line through the anchor as above, and then re-tying the knots so that the single rope is weighted through the anchor, or 2) not pre-threading anything, and just waiting for all the ropes to come down before setting up the next rappel.  The first option is perhaps faster but involves tying and untying knots, while the second option is perhaps slower but the knots stay tied.  

In the past, I largely went to untying and retying.

But there are such a large number of variations on the overall process and on anchor types that choosing just one process would sometimes be suboptimal.

I made 3 raps yesterday with a 6mil tag and a “9.4” BD rope, no problems. Just have to be  careful the tagline doesn’t slip if the knot is on the skinny side of the chains. Partner can put both ends through rappel device before first person raps and then the first person down can hold both rope ends (tie them to an anchor on bites or something) so the line doesn’t slip.

I have used the Edelrid 6mm line the OP is using. Note: It is designed to be used as a twin rope in case you need to lead back up in an emergency. 

I usually pull both ropes down, then re-thread. YMMV.

Bruno I often use the same setup as you and Gregger do. Depending on the ring situation, either retie or just thread the skinny line and pop the knot through the ring. This is often possible with a rap ring vs chain link. Also flat overhand tails give you something to yank on. If I need to retie, I'll still thread skinny to get going, but clip a BHK with both strands to the anchor (just below the knot) so I can untie/retie as my partner gets the ropes down. 

I'll throw in the beal escaper as an option, but not as a full endorsement.  It also might have it's drawbacks but I've been happy with it the few times I've used it. I bailed on a slab route because I realized that endless friction slab gets boring, and was happy I brought it...

Third option if you are using an “alpine grigri” setup (1 grigri and one atc). I use this setup with a 7mm tag line and  9.2-9.8mm single.

Fix the rap with a “stone knot” so the first can rap with a grigri. The 2nd removes the stone knot and unfixes the ropes and raps with an atc as normal. If the ropes are fixed with a stone knot then you can pull either end depending which side you need to pull and thread as you would with two ropes. Note: This is with a 7mm and a BD ATC. I would test that you have plenty of friction when using a 6mm and definitely use a 3rd hand and high friction mode on your ATC/Reverso/etc. 

I f I know all the pitches and raps are 99' or less, I have a 10 mil gym length lead rope 120' and an 8 mil static tag 120' for hauling and then tie the two together for raps. This allows a lighter overall rope weight for a long hike approach. There are limitations and I don't always run this system but when I have it has worked fine. Leader is unencumbered and then able to haul a light pack with the water. Follower is also climbing free of extra weight. Follower wears a helmet as hauling can knock off loose rocks and follower has to stay below the bag to clear hangups.

So I’ve been pre threading a 9.0 lead line and a 6.0 tag line swapping back and forth pulling opposite lines at each station.

whats wrong with this?

edit: this post makes it seem like I have more experience with this than I actually do. It should read something to the effect of, “I have rappelled on a 9.0 lead line and a 6.0 tag line swapping back and forth pulling opposite sides at each station.” Just for a couple of pitches. I specifically remember that we pulled thin then we pulled thick at the next station.

Demetri V wrote:

So I’ve been pre threading a 9.0 lead line and a 6.0 tag line swapping back and forth pulling opposite lines at each station.

whats wrong with this?

Are you rapping on a single strand? You can't pre-thread the lead line if you have to pull the tag line. A reepschnur rappel is what I've always used when using a tag line. The stone knot (actually a hitch) is really useful as well. 

http://www.traditionalmountaineering.org/FAQ_ReepschnurRappels.htm

http://ropewiki.com/Stone_knot

Cam Brown wrote:

Are you rapping on a single strand?

No. Why wouldn’t you put both strands through your belay/rappel device every time?

Bruno Schull wrote:

@Marc--I am using a 6mm tag line.  Whether or not that is foolish or not is an open question... What is it that you don't like about using tag lines?  

Rita?

Demetri V wrote:

No. Why wouldn’t you put both strands through your belay/rappel device every time?

Alpine grigri

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. 

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. 

This didn't happen to us when rapping with a 9.0/6.0 combo. Maybe it's because we always pre-rig our rappels extended with autoblocks?