Abseiling with a single rope plus tag line

Sometimes you want to climb on a single rope, (for example, shortfixing and second is jugging) but still want to do full length abseils. Rather than bring a 2nd full rope to abseil off, you can bring a lightweight tag line (6mm). This is too thin and weak to abseil directly on, but can be used to pull your main rope down.

To rig this system, thread the climbing rope through the anchor, tie a figure 8 on a bight and clip back into main strand. Clip one end of tag line into same biner. Abseil off single strand of climbing rope.

The tag line is easily tangled, so I prefer to clip the other end of tag line to descending climber and have 2nd climber at top feed out tag line as they descend to prevent tangles.

The down side of this method is that the rope is harder to pull down (more friction) and more likely to get stuck. I would generally prefer to climb and abseil on 2 half ropes if this is an option.