6mm cord for rappelling

Does anyone uses an accessory cord for rappelling instead of taking a second rope when rap stations are more then 140ft apart? If so, is 6mm acceptable? 

People do use 6mm as a pull cord/tagline for increasing rappel length.

It has pros and cons compared to climbing with twins.

I just did it yesterday with a 12m section of 8mm, though I used it to turn a 70m rope into an 80m with a carabiner block. 6mm would work, but smaller diameter cords can get unwieldy and tangled easily.

I’ve used this Imlay Pull Cord 6.0 for a couple desert towers and routes in Cochise. It was $84 + tax from Neptune. I would suggest gloves and/or a rope grab. I used a microtrax. I don’t believe 6 mil falls within the device's specs, but it works for pulling a lead line through an anchor. We also used the microtrax + 6mm pull cord to haul a 30L pack on one of the towers. The biggest downside I can remember off the top of my head is that it easily turns into a knotty mess if it’s not minded meticulously.

i've done it a bunch, joined to a 9.0-9.4 rope (i wouldn't go much thicker than this) with an EDK. Just make sure the thinner cord is under the rope when tying the EDK otherwise the rope could roll over the 6mm cord. The ropes can definitely feed through device at different rates causing the knot to move and the ends to become uneven. In order to avoid this I have my partner pre-rig their rap device then the first person down stays on rappel so the rope doesn't slip for the second. Lots of benefits to this over the biner/knot block and pull cord method, just make sure the 6mm cord is in good shape.

I used a 6mm x 65 m BD static cord canyoneering last month, and again on a few rappels in Red Rock, with a BD Alpine Guide ATC, which is designed for thin ropes. When I was rapping in the canyon the wet rope had plenty of friction: when I was doing free raps with a dry rope it took a fair bit of effort to keep my descent rate to a reasonable level. Years ago I would rap with an 11mm lead rope and a 7 mm static tag line. Both the 6mm and the 7mm are very easy to get snagged, and tangle very easy, so careful rope management is a must.

I just started a similar post in the gear forum.

I used 6mm pull cord for the first time in a multi-pitch scenario yesterday on Royal Arches. It knotted up and snarled a lot so I asked on here for some tips on managing it. The key seems to be not throwing the tagline down but rather keeping it with you, feeding it out as you descend.

Here's the link to that discussion: https://www.mountainproject.com/forum/topic/120611185/taglinerope-management

I use a 65m BD 6mm static (10kN MBS) as a second rope for full length rappels. I stack it into a hyperlight stuff sack and throw it in the follower pack; then I clip that stuff sack to a gear loop for the down.

I join ropes with a flat overhand bend with the 6mm on the bottom like mentioned above, then toss down my 9.2mm lead rope and let the static feed out of the stuff sack as I’m headed down.

I always extend the rappel with a reverso and a hollowblock wrapped as an autoblock for the third hand.

If the 6mm cord ends up being through the rings instead of the rope, I add an extra rope bearing biner to just the 6mm cord at the rappel device. This makes it so there is the same amount of friction on both sides of the device, and the knot doesn’t creep.

Really helpful posts above, dealing with the various issues surrounding skinny tag lines for pulling the rope after rap.  

I’ve done pretty much all of them, though these days I prefer to take twin/half rope now.

Tangles: In addition to bagging the tag line on rap, I’ve also just had the tag line’s tail attached to me. While I rap, my partner at the anchor feeds out the tag line. This avoids tossing the tag line but can introduce the need for coordination across an ever increasing distances if there is a snarl.

I think there are a couple cautionary points above what one does for a raps with just ropes.

Best is if both partners know of the issues that are relatively unique to tag lines.  The more knowing eyes, the less chance of an error with these things that need special consideration. Or, if with someone new to the system, maybe rehearse on the ground and discuss a lot before each rap?

The technique that Demetri mentions of loading the tag line to avoid knot creep works.  It also puts more weight on the skinny 6mm.  Maybe treat the skinny tag line with extreme care in general since it is not usually of a strength we trust our lives to.

And an alternative to loading the tag line for avoiding knot creep is the reepschnur rappel. Of course, it also introduces a couple issues with which to deal.

We utilized a 6mm cord and 9.8 mm rope for escaping McGregor slab in RMNP this weekend and it worked like a charm. Edk with a double fisherman's back up. Knot didn't budge at all although that skinny line is unerving.

I don’t see a good reason to actually rappel the 6mil line. A couple times, I had the pull cord in my pack and let it feed itself out as I’m rapping. I think just rapping the lead line and using the pull cord as a pull cord is the way to go. YMMV.

Marc H wrote:

I don’t see a good reason to actually rappel the 6mil line. A couple times, I had the pull cord in my pack and let it feed itself out as I’m rapping. I think just rapping the lead line and using the pull cord as a pull cord is the way to go. YMMV.

There's two reasons you might want to rappel the 6mm line.  For one, if something gets snagged, you'll have your lead line in your hands.  Second, there's less friction at the anchor and it's easier to hold onto a thicker rope while pulling.  The issue is the ropes feed at different rates and the joining knot can move down, shortening the 6mm rope.  This can be mitigated by placing some sort of block on the 6mm rope for the first person down, fixing the 6mm to the lower anchor, then having the final person rappel without the block.  

Adam Fleming wrote:

The issue is the ropes feed at different rates and the joining knot can move down, shortening the 6mm rope.

If you pass the lead line through anchor, your knot will stay at the anchor. I’ll give you that it’s easier to pull the lead line vs 6mil line.

Marc H wrote:

If you pass the lead line through anchor, your knot will stay at the anchor. I’ll give you that it’s easier to pull the lead line vs 6mil line.

I understand and agree.  But I was talking specifically about when the 6mil line is through the anchor.  I think the larger advantage of threading the 6mil is being able to lead back up on a fully-rated rope if any snags happen.

I suggest an 8mm or the strongest 7mm cord you can get your hands on. The reason for this is there is a slight chance if your rope gets stuck you could be ascending or lead climbing off the little cord that was only intended to be a pull cord. Scary stuff. I still use one though, love it. Something to consider though.

Jake G wrote:

I suggest an 8mm or the strongest 7mm cord you can get your hands on. The reason for this is there is a slight chance if your rope gets stuck you could be ascending or lead climbing off the little cord that was only intended to be a pull cord. Scary stuff. I still use one though, love it. Something to consider though.

Wrong thread, Jake. This thread is about using 6mil pull cords, not 7/8mil lead lines.

Marc H wrote:

Wrong thread, Jake. This thread is about using 6mil pull cords, not 7/8mil lead lines.

I know. Think about it though, if you are using a pull cord to rap and as you pull the rope you get a the point where you can no longer reach the lead line, then if the rope gets hopelessly stuck how do you get up to the lead line when all you are stuck with is a pull cord attached to a stuck lead line? You have no choice but to sit and wait for help or ascend the pull cord up the the lead line while someone belays you with the left over tail. 

Thanks for the insight all. I’ll definitely try the sac next time out when longer rappels are involved. The terrain where I had to use it was a low angle slab without many terrain features to snag the rope or tagline. One of the issues I was thinking about was line/rope getting snagged on something and then having to ascend a 6mm cord if rope was stuck. 

I have both the 7.1 edelrid skimmer and 7.3 beal gully, wouldn't hesitate to lead on either cord, albeit more cautiously. I can't see the miniscule weight/space savings being worth it, over a 6mm cord of similar length. 

Perhaps as important (maybe total noob observation), w/ most 6mm cord, you're solely using this as a pull cord for a biner block, no?...unless you're spending the wad of cash for an edelrid rap line or petzl rap line, which I think are well north of $200. I'd much rather spend $150 on a 1/2 rope that can be multi use... with the skimmer or gully, at least I'm actually rapping on double strand, vs rapping single strand and pulling a tiny 6mm cord (7mm is hard enough to pull!)...unless you're taking the (inordinate amount of) time to rethread the lead line, ever time.

Christian Hesch wrote:

I have both the 7.1 edelrid skimmer and 7.3 beal gully, wouldn't hesitate to lead on either cord, albeit more cautiously. I can't see the miniscule weight/space savings being worth it, over a 6mm cord of similar length. 

Perhaps as important (maybe total noob observation), w/ most 6mm cord, you're solely using this as a pull cord for a biner block, no?...unless you're spending the wad of cash for an edelrid rap line or petzl rap line, which I think are well north of $200. I'd much rather spend $150 on a 1/2 rope that can be multi use... with the skimmer or gully, at least I'm actually rapping on double strand, vs rapping single strand and pulling a tiny 6mm cord (7mm is hard enough to pull!)...unless you're taking the (inordinate amount of) time to rethread the lead line, ever time.

You may find reading the other thread replies useful as a few other people have made similar points. 65m x 6mm cords can be easily found for under 75$ and for people trying hard routes, or/with long  approaches the weight savings are noticeable and highly appreciated. You also do not need to set up a biner block or rethread it as mentioned earlier in the thread. 

Bug Boy wrote:

You may find reading the other thread replies useful as a few other people have made similar points. 65m x 6mm cords can be easily found for under 75$ and for people trying hard routes, or/with long  approaches the weight savings are noticeable and highly appreciated. You also do not need to set up a biner block or rethread it as mentioned earlier in the thread. 

though it may be surprising, I actually did learn to read by time I quit school in 7th grade, thus I did indeed read the other responses. I appreciate weight savings but not sure I can confidently place my trust in a cord that weighs 9g/m compared to something weighing 32g/m. YMMV...