Types of Climbing Rope

Single rope
This rope is used as a single strand.
It is best adapted to difficult routes which are fairly straight-line, to easy routes without change-over belays, and where descent is not by abseil. It is in particular the rope for sport climbing.

Half rope
A ‘rope’ formed of 2 strands which the leader is tied into but, unlike twin ropes, two seconds may each be tied into just one of the strands. The leader clips only one strand into each runner so as to reduce drag. Half rope is recommended for mountaineering and long ascents where abseil descent is necessary. It is equally preferable whenever belays are less than perfect, notably when ice climbing, because with just one strand clipped, you reduce the shock load in case of a fall. In addition they offer better protection against stonefall or falling on an arete; to limit the drag, and thus the fall factor, you can clip the the strands separately.

Twin rope
This rope is always used with the two strands together, remaining parallel: each climber ties into both strands, and these are always clipped together. Its advantage over single rope is that it allows for abseils as long as the rope. It is lighter than half rope but does not allow for separate strand clipping.