Double-strand rappel

From CanyonWiki

rooloorchior Double-strand rappels are used for three reasons.

1. Ease of pulling rope. If you are in a situation where you will not have a straight pull, and aren't able to set up a more advanced anchor, the last thing you want is for the rope to get stuck, or a 'biner block getting stuck on the way down when you try to pull the rope. Double-strand rappels give you only one thing to worry about getting jammed: the rope.
2. Slow Descent. The friction created by double-strand rappels will slow you down much more than single-strand rappeling will. If you have beginners in your group, they will likely be more comfortable with the slow, steady pace of the double-strand rappel.
3. Avoiding a deadly mistake. You can't pick the wrong side of the rope when you are using both sides. With a double-strand rappel you won't ever rappel off the wrong side of the rope and release the anchor mid-rappel.

Most anchor systems that allow for single-strand rappels will also allow for double-strand rappels. The autoblock will not really do anything if you double-strand it, but it won't mess you up either. (Obvious exception: If you are using a pull-cord to extend your rope to be long enough to reach the bottom of the rappel - don't go double strand on it!)

[edit] Procedure

Set Up:

1. Clip into anchors using a Daisy chain or Canyon Quickdraw
2. Double your rope through a rapide or rap ring fixed to the anchor.
3. Position the approximate middle of the rope at the rapide so that both ends of the rope reach the ground.
4. If there is any doubt that the ends reach the ground, tie an overhand knot in the ends so you can't rappel right off the rope.
5. Double the rope through your rappel device.

Rappel:

1. Test your setup by putting weight on it and making sure it will hold you.
2. Unclip the Daisy chain from the anchor.
3. Anounce to your buddies that you are about to rappel by saying "On Rappel."
4. Rappel down the line.
5. Unclip from the rope when you reach the bottom.

Pull the rope:

1. Before the last one rappels, give a test pull to make sure the rope won't get stuck.
2. Once everyone is down pick a side of the rope and start to pull either side of the rope.
3. Keep pulling.
4. Eventually the end you aren't pulling will pass through the anchor and then back down to you.
5. Yell "ROPE" as the rope is dropping to help everyone around you not get hit unsuspectingly. For added "style points" you can attempt to grab the end of the rope as it falls to the ground. The closer to the end you grab, the more points you get.

[edit] Drawbacks to Double-Strand

There are some notable drawbacks to using double-strand rappels

1. You Need Fixed Anchors: You can't use many of the advanced anchors that allow you to retrieve the sling when you go down double-strand.
2. You can't fix the rope length: If rappelling into water, consider using a 'biner block. This allows the rappeller to set the rope length at the water line and rappel right off the end of the rope. This avoids the problem of the swimming disconnect with its risk of dropping the rappel device.
3. It's extremely slow for long rappels: On a long rappel of several hundred feet or more - it will be extremely slow. Some enjoy this, but many do not. With thick ropes, consider rigging in "Canyon style."
4. Some rappel devices don't like it: The Petzl Pirana doesn't really like double-strand rappels. The Pirana has a horn on one side of it that is a little too short for adequate use with double-strand rappels. (Although some canyoneers choose to disregard the manufacturers documentation and use it the same way they would use a normal Figure-8 for double-strand rappels by taking it off of the biner and running the rope around it.)

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