6mm static as secondary rap line

[specialed]

Does anyone have any experience using a 6mm static line in conjunction with a larger diameter rope, like a 9.6, to rappell with? I can't think af any reason why it wouldn't work, but I've never tried it myself.

 

[jtulinsk]

The problem with this system is that different diameter ropes (and a static combined with dynamic rope would make this even worse) move through an ATC at different rates which leads to a non-symmetrical load on the anchor. As a result the ropes can move through the anchor. This is probably not a problem if you're rapping off of rings but if you rap off of a runner it can cut through it. Everyone knows you never run nylon over nylon but everyone also raps off of runners all the time. Take an old scrap of rope sometime and saw it back and forth through a runner--you'll be amazed at how quickly the runner fails.

[willstrickland]

quote:

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Originally posted by jtulinsk:

Everyone knows you never run nylon over nylon but everyone also raps off of runners all the time.

---

Well, not everyone...I certainly don't. I call it my 'biner retirement system, and it works pretty well. If I need to bail, there are no rings, and I don't have a couple on me I just take my shittiest racking 'biner and leave it. It keeps me from retaining antiquated gear and it'll be there for the next party. If they decide to filch it and rap the slings I don't care because it's their ass on those slings, not mine. A $3 biner...c'mon it's cheaper than a good pint.

 

Good info on the details of the system though. While you should always knot the ends of your rap ropes, it's super critical in this case. If you forget to put the knot on the right side of the rings, or it's a small knot and could pass through a biner, etc, you could easily rap off the end of the skinny line since it'll be feeding faster. The feeding discrepancy is easy to remedy, just pay attention and brake a little harder on the skinny line to even out the feed rates.

[Rodchester]

mmmm...good pint.

[specialed]

It seems to me that always having to put a rap biner on slings is just one negative of this system. I am trying to decide between a twin rope system (two 8mm's) or a 9.4 single rope and a 6mm trail line for alpine rock routes. They're both about equivalent weights. But the single rope system will allow you more versatility if the route has some aid pitches on it, and would be simpler to use. On the other hand twin ropes can take more falls and rapping with them would probably be easier. I was trying to determine whether rapping with a 6mm and a 9.4mm would be such a pain in the ass that it would make it preferable to get twin roupes instead. Any input?

[Alex]

I use a 6mm rap line combined with a 70m 9.4 single PMI lead line for ultra-light trips where long rap retreats are a real possibility. Only actually rapped on it once..you dont notice the differential feed rates through the ATC until a ways down the rap, and (as you mention) if you have a biner on the rap sling there is no issue. Strength isnt really an issue, but I wouldnt rap on the 6mm for years and years like I do my thicker ropes, either..

Alex

[Matt_Anderson]

Ive rapped multipitch retreats on a ten mil and a seven mil. Not to much of a pain. I just made sure that the knot butted up against the rings/biner/whatever in a way that counteracted the differential speed thing. The non-rapping partner kept an eye on the knot (if he's the second one down) or held onto the seven mil (if he's the first one down.) I always thought that there was a small risk that the knot could jam into the rings b/c of the differential speed, but that cluster never occurred.

If you prefer climbing on a fat rope, go for it. The system also allows the second to free a pitch at his limit w/o the extra weight of a pack b/c the leader can haul a light pack on the hard pitches if you choose (That, and the weight savings are the only reason I choose this system over doubles).

matt

[DPS]

I too use a 9.4 lead line coupled with a 6 mm rap line. If you have to haul or aid/jug pitches, it is more workable than half or twin ropes. I have made many rappels with this sytem and have never had any retrieval problems.

The problem mentioned of rope movement sawing through slings is perhaps the biggest downside to this system. I don't know if there is any real advantage to this, but I use 6 mm cord rather than tubular webbing for the rap sling. Seems like it is more 'saw' resistant.

[fishstick]

Using conventional rap methods, I'd be very concerned about cutting a 6 on rock edges or with rock fall. Having sliced both strands of a pair of 8.5s in the former manner, I think a 6 would have proved fatal in my case. If you're rapping purely on ice, it might work.

I do use a 5/8.5mm rap combo for soloing waterfalls. Tie a clove hitch about a meter from the end of the 8.5 and put a small locking biner through it. The idea is to feed the opposite end through the anchor until the clovehitch/biner jams against it, then clip that strand with the biner (and lock it). Tie the 5mm cord to the short end of the 8.5, but toss it via a throw bag or carry it in a fanny pack, feeding as you rap, otherwise the 5mm will tangle instantly. Rap strictly on the 8.5 single, but pull it down using the 5mm. Do not weight the 5 except for pulling the single.

Note that the system is prone to snagging in trees and blocks. It works OK on pure ice raps or as a very light weight and inexpensive (737 grams for 50 meters)"just in case system" when climbing on a single rope. It can be time consuming re-loading the throw bag on long routes. Be very careful to test it before weighting it in the real world.

Caveat emptor!

[erik]

will, if you are taking orders!

and here is some relevant stuff from awhile ago. before all the legends left

http://www.cascadeclimbers.com/ubb/Forum9/HTML/000013.html

[This message has been edited by erik (edited 06-21-2001).]

[Cpt.Caveman]

Specialed,

I personally would frown upon using anything but a conventional rope. But if you had to do it I bet you could work through the difficulties of the rope gunslingin through the rap device if you had gloves. But maybe not too. So in general I don't think it would be accepted practice. However who knows I could be full of shit and maybe in the Beckey days when they tied the ropes to thier dongs and lead 5.8 cracks in all star converse they did it once or 20 times....

-Cpt

[This message has been edited by Cpt.Caveman (edited 06-22-2001).]

[specialed]

What are you talking about? you're making this way more complicated that it is. This whole post has been discussing the pros/cons of different rope systems. One of the sytems discussed is a single rope system (9 - 10 mm) with seperate 6mm rope for rappeling in case of retreat or if the descent required rappelling. I was simply asking people who have used this system what type of 6mm rope they have used and where they got it.

[This message has been edited by specialed (edited 06-22-2001).]

[mikeadam]

Good topic Specialed!

[This message has been edited by mikeadam (edited 06-22-2001).]

[specialed]

Can anyone answer my question? Fishsick? Alex? Anyone... Anyone... Buhler... Anyone...

[Cpt.Caveman]

http://www.cascadeclimbers.com/ubb/Forum23/HTML/000053.html

Wee saw your comments before they were erased.

[DPS]

specialed,

Mtn Gear in Spokane sells a Black Diamond, 6mm, 60 meter line that works perfectly when paired with a 9.4 mm or similar lead line. (I think they advertise it as 7 mm, but is actually thinner than most 6 mm that I have used.) The cost is about $100.00.

Dan

[specialed]

danpatsmith: thanks for the beta. I've talked to someone at mtn gear and asked if they carry this item or a similiar one and he says they don't. Maybe I'll ask about a 7mm though. Thanks.

[erik]

hg

[This message has been edited by erik (edited 06-22-2001).]

[fishstick]

Having thought about it some more, I would not use 6mm to rap except with the system I described in an earlier posting (using the clove hitch/biner). I'd be too scared of cutting it with rock or destroying it with high impact dinner plates. If you chose to go with 6mm, just buy it off the spool at your local shop. Mammut should be fine.

Another system I've used a bit is a small single/small ½ rope combo. It weighs more than two 1/2 ropes or your small single/ 6mm combo, but it has some practical benefits. First and foremost I'm on somewhat of a budget. I can go out and buy a pair 60 or 70 meter ½ ropes, but I still want to own a 60 or 70 meter single. Buying only one ½ rope and the single saves perhaps 140.00 CDN (guess). Tie into both strands when climbing, but clip primarily the single (clipping both strands gives a high impact force in this case unless using beal ropes)(they also have very different stretch characteristics) as long as rope drag isn't a huge issue. Clip the half rope strand (only) on bad pieces to lower impact force, or cut rope drag, or protect your second on traverses. In a sense this blend of ropes offers the benefits of both double and single rope systems.

Remember that when using uneven sized ropes, the second individual to rappel should always check that the ropes haven't "migrated" to uneven lengths due to uneven friction on the initial climber's rappel device. The total amount of rope movement may not prove troublesome for the first climber, but the cumulative effects after two or three climbers rap from a station could prove fatal.

I hope this helps!

 

[Cpt.Caveman]

Specialed,

I know you are in one of these pics

[specialed]

Dude where did you find those pics of me? Those are from my former glory days in the Special Olympics. I competed in all those events in the pics, but the sport climbing comps for "special" people was what I was mostly interested in. Unfortunately, I could never decide what type of rope system would be best to use so I kept getting disqualified before I even tied in. Darn.

[Cpt.Caveman]

I always thought around the neck mit hemp rope was the standard.

[haireball]

question was raised, is there a difference between 6mm accessory cord and 6mm "static" cord. answer: no. rope manufacturers make "high-stretch" or "dynamic" ropes specifically for belaying a lead climber, where fall-factors greater than 1.0 are possible. all "accessory" cord, as far as I've been able to determine, is low-stretch or "static". interestingly enough, in the test data that I've seen, the stretch differential between low-stretch or "static" line, and high-stretch ("dynamic") rope, is very small at low loads and really only becomes "funtional" as you approach the "impact force" of the high-stretch rope.

for the record, I'm a fan of double-rope technique, and have found it to have advantages even on wall routes - three <9mm ropes means if you damage one of the belay lines, you can switch the damaged rope to the haul-bag, and when you''re jugging a line that's running over an edge or two, you can be on belay with the other belay rope.

I use half-ropes, and I usually twin them, even though I am aware of the difference between "twin" and "half". I don't worry about the impact force because most modern belay devices allow the belay rope to slip atloads well below the impact force of any "dynamic" rope. To generate the impact force of almost any "dynamic" rope, you pretty much have to take a high-factor fall on a belay that is tied off, or clamped with a mechanical ascender. One question you might ask yourself is how you'd feel about twinning the 6mm low-stretch rope with your lead-rope in the event that the lead-rope were to be damaged and your best escape is continuing upward...

[specialed]

Will accesory cord suffice for a 6mm rap line?

[Cpt.Caveman]

How about gear loops can I tie into those?