Courage cannot be approached with caution

Thursday, July 26, 2012

Tag Lines

I find that there are numerous discussions on internet forums and at the crags regarding techniques or recommendations for retrieval ropes in a rappelling application.  The following are some tips and guidelines I use for selecting the appropriate system. 

Typically a “tag line” or “pull cord” is an auxiliary rope intended as a retrieval rope for double rope rappels.  When deciding what type of tag line to use, I will ask myself two questions.  First, do I intend to rappel the route?  And second, am I using this rope as an emergency retrieval cord because I need to descend due to extenuating circumstances?

If my intent is to rappel, I will bring a tag line that I would still be able to lead on if my ropes became stuck.  A simple solution is to bring an 8mm-ish half rope.  If you are concerned with weight savings there are a few ropes rated as half and twin ropes that are smaller diameter.  Sterling Ropes makes the “Fusion Photon” at 7.8mm.  This now allows you to thread either your initial lead line or your retrieval rope in the rappel anchor.  In addition, if your lead line is damaged, you have the ability to still lead on your tag line.

If I am climbing a route where my intent is not to rappel, but I still want the added security of a secondary rappel rope, I will use 6-7mm on nylon accessory cord. This allows you to have a small, compact, and lightweight emergency rappel rope.  I will also use this system if I am climbing something difficult where it is necessary to haul a small bag on the crux pitches.  There are a few limitations to this system.  First, if your lead rope becomes damaged or stuck, leading on the 7mm cord is not advisable.  Also, the smaller diameter cord can become extremely difficult to pull on long rappels.  In addition, the small knot where the ropes are tied together can become stuck in the rappel anchor, or worse, pull through the rappel anchor.  Furthermore, you must always thread your lead line through the rappel anchor, not the 7mm cord. 

Flat Overhand/Patagonia Knot
Whichever system I use, I tie my rappel ropes together with a flat overhand or Patagonia Knot, not to be confused with the European Death Knot.  Make sure your knot is adequately dressed, tightened by pulling all strands, and has at least 15 inches of tail.  I choose this method because the knot will roll over edges decreasing the likelihood of stuck rappel lines as opposed to using a double fishermans or Flemish Bend that will get caught on edges.
European Death Knot: Improperly tied Flat Overhand- loose, not tightened, and without adequate tail.

A Flat Overhand/Patagonia Knot is still used when tying ropes of various diameter together.  I will add a small overhand knot in the smaller diameter cord on the tail side of the Flat Overhand.  This keeps the knot from “slipping” at all. 
Flat Overhand with 7mm Cord.  Notice the additional overhand backup on the tail side of the knot.

When rappelling on large rings or carabiners as in an emergency rappelling scenario;  add a “backup” in the tag line so the Flat Overhand will not get pulled through the rings.  Keep in mind this will add friction in the system and make pulling your ropes more difficult.     
Tag line with backup on the rappel rope.


  1. Hello,

    Thank you for the post. In the final picture, might you consider tying the backup in the larger rope? As shown, if the flat overhand knot joining the ropes fails, the backup will be ineffective. I do see that if the smaller rope were cut over an edge during rappel, the backup as shown would be effective. Take care, Jim

  2. Hey Jim, great comment. Its effective to tie the backup in either the tag line or the climbing rope, just depends on the situation/terrain. The knot in the climbing rope tends to add bulk but is potentially a stronger configuration. Hopefully, you have tied the flat overhand well so it does not fail. The backup is used so that the knot cannot pull through (the wrong direction) of the rings you are rappelling off of.

  3. Hi Eric, thanks for the write up. I have come across plenty of misinformation about this subject, often coming from experienced climbers. When using the set up described here, are you typically rappelling on both strands, or making a single strand rap on the larger rope?

    1. Generally rappelling on both strands. This allows for two things. First it keeps the knot from jamming up against the rappel anchor, facilitating an easier pull and second, it prevents the knot from slipping through the rappel anchor if the rings are large enough for the knot to slide through. If rappelling on only one strand and the knot did somehow slip through the rappel anchor, the consequences would be dire.