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How to rappel on a loaded rope?

PostPosted: Tue Sep 08, 2009 11:45 am
by neghafi
Hello guys
I wana know of any secure solution for climbers/cavers to rappel on a loaded rope? I've seen some techniques using carabiners but I'm not sure they are secure

PostPosted: Tue Sep 08, 2009 4:14 pm
by sixfingers
Please explain further what you mean by loaded? Fully tensioned such that no slack can be pulled to thread a descender?

PostPosted: Wed Sep 09, 2009 10:15 am
by Day Hiker
sixfingers wrote:Please explain further what you mean by loaded? Fully tensioned such that no slack can be pulled to thread a descender?


I think this is the only definition it could be . . . unless he means "drunk."

PostPosted: Wed Sep 09, 2009 11:27 am
by nattfodd
Unless you have a dead bear on the other side of the line, I think you could rig a small pulley system (like the one to use when you have stuck hair in your belay device) to create enough slack to thread your belay device in. With two prusiks, a carabiner and a sling, you get 2:1 in no time.

PostPosted: Wed Sep 09, 2009 12:55 pm
by neghafi
Yes I mean fully tensioned. It's not a case of a dead body. I'm thinking about rappeling 2 or 3 guys in a same time because of the lack of time for example.
I've seen some use of carabiners but they don't look safe.

PostPosted: Wed Sep 09, 2009 2:33 pm
by The Chief
neghafi wrote:Yes I mean fully tensioned. It's not a case of a dead body. I'm thinking about rappeling 2 or 3 guys in a same time because of the lack of time for example.
I've seen some use of carabiners but they don't look safe.


Why don't you just "Simul Rap"? It's safe and reduces time considerably...

PostPosted: Wed Sep 09, 2009 2:44 pm
by Rob
Cavers use a brake bar for that purpose...

Image

AKA Rappel Rack.

PostPosted: Wed Sep 09, 2009 2:46 pm
by rickford
I don't know about descending a fixed line.

But, if your goal was to save time on your rappells and you have two people- then you could do a tandem rappell. There are many ways to do this. I have never heard of three people rappeling together, but I suppose its possible using the same techniques used in tadem rappels.

PostPosted: Wed Sep 09, 2009 3:22 pm
by The Chief
Another option to Rob's post is this device which I use regularly when soloing and have to rap on my tensioned fixed haul line.....

Petzl STOP
Image

PostPosted: Wed Sep 09, 2009 7:23 pm
by fatdad
Wouldn't the weight of three guys on a rope effectively act as a fireman's belay and prevent all but the bottom person from moving?

Also, I don't really buy into the wisdom of you're purpose. What's the urgency that would warrant three people rapping on the same line at the same time?

PostPosted: Wed Sep 09, 2009 8:01 pm
by Day Hiker
fatdad wrote:Also, I don't really buy into the wisdom of you're purpose. What's the urgency that would warrant three people rapping on the same line at the same time?

Yeah, a 600-pound rappel. I hope you are using a bomber anchor and thick rope. I'm not saying it would break an undamaged rope, but of course the forces involved are more than the 600-pound static weight, and that much mass on a rope is narrowing the safety margin a lot, just for the sake of saving a minute.

I've done a lot of single-strand solo rappels and also a few tandem rappels (one person on each strand), and I personally feel comfortable drawing the line there. Barring extreme circumstances, I wouldn't want three simultaneously on a rope or anchor, just for the sake of saving time.


Being unfamiliar with those, I need to ask: What is one's descent speed on one of those, in comparison to using a conventional rappel device? In other words, considering the original poster's inquiry for the purpose of speed, would the descent speed of two people on a strand using a descender be enough more than half the speed of one person using a standard device to justify doing the multiple rap?

PostPosted: Wed Sep 09, 2009 9:40 pm
by Nikolas_A
nattfodd wrote:Unless you have a dead bear on the other side of the line, I think you could rig a small pulley system (like the one to use when you have stuck hair in your belay device) to create enough slack to thread your belay device in. With two prusiks, a carabiner and a sling, you get 2:1 in no time.


But then you still can't rap...


Although I agree that there are better ways to save time in rappels, there’s another situation where rapping a weighted line is necessary. Say your second is hit by rockfall and knocked unconscious. You can't haul him up because there's gear between the two of you. I wouldn't carry a Petzl Stop just in case. So any ideas of what would work using more generic gear?

PostPosted: Wed Sep 09, 2009 9:51 pm
by Rick Kent
Speed is often an important element of canyoneering. Simul/tandem rappelling can be quite useful if the terrain allows for it. As previously noted however the process of setting up anchors (unless they're already set up) can consume more time. If there are multiple raps involved then speed comes down to how efficiently the entire process is handled. The place where the most time is lost is at bottlenecks that form at a rappel. The more people you have the bigger the bottleneck. Let's say you have a group of 8 and 3 raps to do and no anchors have been established. It will take time to set up the first anchor so while some of your buddies work on it you can do a "meat" anchor where one or two guys act as a temporary rappel anchor. In this way you can get people down before the first anchor is even established. Those guys can then begin work on the next anchor. The goal is to keep people moving and reduce the bottleneck. Another thing you can do is to set up a "Stone" knot. You can do a google on this to see how it works. It allows one person to get set up for rappel on one side of the rope while someone is rappelling the opposite end. You can also simul rap on it safely. Yet another thing you can do to speed things up (assuming you have a 2nd rope) is to set up more than one anchor at a rap station.

Every rap is different so what you do will depend upon the terrain, group size, etc. I don't see trying to get more than 2 people on a rope being a very effective option without specialized gear. If everyone is experienced with rappelling and you use some of the tricks above things should go smoothly. Also, pay attention to where you set up your rappel. The last thing you want to do when in a hurry is to get a rope stuck. This always seems to be when it happens.

PostPosted: Wed Sep 09, 2009 9:58 pm
by nartreb
any ideas of what would work using more generic gear?


The old chain-of-'biners trick (see bottom photo here: http://climbinglife.com/tech-tips/tech- ... -know.html ) requires smaller bends of the rope than a device like an ATC, so should work better with tension on the rope, especially if you rig it for mimimal friction. (It works just like the brake bar shown in an earlier post.) Back it up with a prussik in case the rope gets unweighted for any reason and you lose that fireman's belay...

Very slow option: two prussiks (or bachmans, or ascenders), just like jugging but in reverse direction.