pull-cord set-up: rethinking the dogma

[layton]

i've been taught, and i put it in my book:

 

If you are rappelling on ropes of different diameter, use a rewoven fig-8 (fleischmans) instead of an overhand (EDK).

And if you are using a skinny pull-cord (5mm-8mm) use this set-up: knot on pull cord side, tie knot in lead line on knot side of rap anchor, clip knot to lead line on the non-knot side of anchor - so if the pull cord snaps, you're still on rappel. You have to pull the pull cord first in this set-up, but I've been told to pull it first regardless since the odds of the lead line getting stuck tumbling down are higher than the pull cord getting stuck.

 

Good advice. Don't want that pull cord snapping. Fig-8 won't come undone.

 

BUT!!!!

 

I'd say that the vast majority of rope-pulling, rope stuck issues i have had is because I've used one of both of the above set-ups. And, I HATE getting my rope stuck. Worries about the trip down sometimes ruin the trip up.

 

So what I'm wondering, and would love the input of fellow (ahem) experience climbers is:

How bad of an idea is it to just say fuck it, tie an EDK on a 9.8mm and a 6mm, forgo the back-up knot/biner, and also pull the lead line first.

 

Coming from an odds/risk ratio I'm proposing that the odds of the pull cord cutting on rappel are low enough to mitigate the real risks involved in getting your rope stuck. I'm also suggesting that I would rather have an entire length of free lead line and stuck pull cord than visa-versa.

 

So what do you think? Are most of you thinking, "no shit that's what I normally do" or are you thinking "don't do it, you are being totally unsafe because...."

 

Thanks,

Mike

Edited April 6, 2012 by layton

[Farrgo]

Unless I'm thinking of this wrong rigging the rap to pull the lead line first would mean that you are rapping with both ropes through the device (like a standard double/twin rope descent). I've done that before and it was real crappy and real scary and I wouldn't do it again.

 

I understand the concern of getting a rope stuck and ending up a chunk of cordalette for the rest of the descent. In general for long descents that require more then 10 rappels I figure that it is probably taking a rope system that will expedite the descent (rather than simply a light system that quickens the approach). If you are only going to do a few rappels than it is less committing even if the rope gets chopped.

 

My 2 cents...

[Blake]

Tie EDK

 

1 guy raps on grigri and the (fixed) lead line, undoing tangles on the way, quickly fixing tag line to self or next anchor to prevent knot sliding

 

 

2nd unfixes lead line and raps on both strands and uses an ATC

 

Pull the lead line so you have something stretchy to use when you have to re-lead to free your stuck

Rope.

[JosephH]

I go twin when it gets down to dicking around with cord that can easily become unmanageable in any wind at all - definitely the way to at places like Red Rocks.

 

Mammut Twilight 7.5mm ultra-lightweight Twin rope

 

But if you're going to go that route, I definitely would NOT skip the backup knot and biner in the rope / cord setup.

[layton]

Tie EDK

 

1 guy raps on grigri and the (fixed) lead line, undoing tangles on the way, quickly fixing tag line to self or next anchor to prevent knot sliding

 

 

2nd unfixes lead line and raps on both strands and uses an ATC

 

Pull the lead line so you have something stretchy to use when you have to re-lead to free your stuck

Rope.

 

Exactly, Blake. Except that the first down is not testing the whole system that the 2nd will be doing - like when you back the anchor for the first and pull the back-up piece for the 2nd.

 

Rapping both lines does lessen the load on the pull cord since you are weighting the lead line a bit more.

 

The only way I can see making it safe (assume that this is unsafe) is fixing the lead line to the next rappel and clipping some gear in on the descent so if the tag line does snap (from rubbing over a sharp lip or rockfall) there's at least something to stop you.

[layton]

oh, and yes two twin/double ropes would make this conversation moot. However, twin rope technique is just plain shitty when you have

1. hanging belays and cramped belay stances

2. difficult climbing and belaying is involved

3. rough/abrasive rock

 

[bar-tacked]

I always thought figure 8 is much more likely to flip?

 

Some random webpage I found on the topic:

 

http://user.xmission.com/~tmoyer/testing/EDK.html

 

 

[layton]

i was taking about a re-woven fig-8 not an overhand fig-8.

Anyway, thank for those links. Sounds like an overhand fig-8 is much more likely to come apart. Two EDKs tighened snuggly together may be the ticket.

 

as far as pull cord back-up.....

[dberdinka]

I think you should reconsider which is more likely to get tangled and/or snagged, the pull-cord or the the main line. Because a pull-cord by nature has little mass and tends to be more kink prone I would much rather pull the pull cord and let the rope flop down than vise versa (though the arguement about having something stretchy to lead up on is a worthy one).

 

Tieing the knot and clipping the rope back across itself as a backup does create more hangup potential.

 

I've been content to rap only on the mainline and simply rely on the knot jammed into a small high quality quicklink.

 

Spendy but my life is worth much more.

 

You could always make your pullcord out of 6mm Bluewater Dynamic Prusik cord (60m weight 3.5lbs) if you really wanted something dynamic, though whether it would actually reduce shockloading or just stretch and bottom out is unknown to me.

[akhalteke]

Mike, when we did our SOP's, we found out that the EDK can only flip 2 times under the worst case scenario. We incorporated 18" tails for the EDK and have had a reduction in caught ropes with no failure. Only once (that we know of) did the rope flip at all (in a few thousand rappels we have overseen) and this was done by me on purpose to try and create a failure with a sloppy knot and a factor 1 fall force applied. Despite this testing scenario, the set-up did not fail. Read though, that I only did this once and it wasn't really scientific...

[akhalteke]

also, the chance of the rope being cut (I feel) is less probable than the rope getting stuck and causing a major epic with exposure/injury. I would just make sure I had a sheath that I trusted on the 6mm.

[layton]

darin, i had considered your quicklink idea... if the tag line breaks (you'd have to set it up to pull the tag line) the knot gets jammed.

 

so far, that's the best possible solution. you could use some webbing/cord and tie a smaller bight - but then your making it diffuclt (more friction) to pull the rope. I think I'd rather use some smaller aluminum quicklinks concidering the forces involved aren't going to be huge.

[dberdinka]

The knot already is jammed. With those small high quality quick links I'm rappeling against the knot, no backup (though I do back it up if the pull is straightforward). Why would the tag line break unless you're literally using boot string?

 

I'm using the Imlay 6mm pull cord. It is very durable, strong (2200 lbs they say) and very static which makes it easy to pull. Being poly it won't absorb water like nylon. It's also cheap ($75) compared to a lot of other options. Works great as an occasional haul/tag line too.

 

I guess you could use small aluminum quicklinks but they are going to be quite a bit weaker which means you end up doubling them up which means you're carrying more weight. Ultimately buying a bunch of specific materials that you trust for rapping isn't really realistic for every climb you're going to go do but sometimes it's worth it.

[layton]

darin,

rockfall and sliding over edges with the lines under stress can cut the rope quite easily on small diameter pull cords

[JosephH]

oh, and yes two twin/double ropes would make this conversation moot. However, twin rope technique is just plain shitty when you have

1. hanging belays and cramped belay stances

2. difficult climbing and belaying is involved

3. rough/abrasive rock

I wouldn't in any way confuse twin and double rope technique or comparative hassles. There's no circumstances where I find twins more hassle than a single. Doubles are another matter and can be a desperate hassle if you don't really know what you're doing; more an east coast deal where most experienced folks have belaying with doubles down cold (or used to) and don't think twice about using them.

 

Overall there's not enough combined difference and weight savings between a 9.8/6 pairing and twin 7.5s to make up for the hassle of dealing with the 6. I'd only go there if I was desperate to save every ounce, and even in that case I'd probably just try to lose a pound off myself first.

[Lowell_Skoog]

darin, i had considered your quicklink idea... if the tag line breaks (you'd have to set it up to pull the tag line) the knot gets jammed.

 

so far, that's the best possible solution. you could use some webbing/cord and tie a smaller bight - but then your making it diffuclt (more friction) to pull the rope. I think I'd rather use some smaller aluminum quicklinks concidering the forces involved aren't going to be huge.

 

My preference has been to tie a bulky knot like a rewoven figure-8 then pass the lead rope through a sling or cord with a bight tied in it that is smaller than the knot. Then I pull the lightweight rope. The theory being that the knot will jam in the sling bight if the thin line is cut. As long as the sling bight isn't actually tight around the lead rope, I don't think it adds much friction to the pull.

 

My experience is that smaller ropes have a much higher likelihood of getting jammed because they are so "spaghetti like" so I would rather have the lead rope come down last. I think you're more likely to have an epic due to a snagged tag line than due to a failure of the system I described.

 

A metal quicklink like Darin suggests might be safer, but it's one more thing to carry. I figure that alpine climbing is about managing but not eliminating risk, and I have felt okay using the technique I described. But I could be convinced that it's a bad idea.

 

Edited to add:

 

The other thing I do is to pack the tag line in a lightweight stuff sack. The stuff sack has a loop sewn on it that I can clip to my harness. When pulling down the rappel one guy pulls the tag line and the other guy stuffs the tag line into the stuff sack. When stuffed this way, the tag line always pays out cleanly--no untangling required. When you begin the next rappel you don't throw down the tag line. Instead the lead rappeller keeps it clipped to his harness and the thin rope pays out of the bag into your brake hand. Never a tangle, and no futzing around.

 

[Choada_Boy]

This one always works for me:

 

 

The anchor end is the green sling on the right.

 

[layton]

thanks, that system looks perfect for redrocks

[JosephH]

I'm sure that will work fine, but would note all the locals I know there use twins for anything long.

[layton]

i think that photo was a joke senor Joseph

[G-spotter]

pull cords are the climbing equivalent of rainbow unicorns up your butt. just learn to climb on doubles or twins like the rest of the world.