Single rope technique (training)

FS120421

(Published January 2022, replacing June 2001)

Prior to using any SRT equipment underground, the caver must have practised on a rope above ground. The rope should be hung from a suitable tree, climbing wall or beam and the use of all equipment thoroughly mastered a metre or two above ground level. You must be able to cope with a weighted rope, to lock off the descender at any time, and be perfectly happy with all the techniques. Novices should first learn to use a self-locking descender such as Petzl stop.

Self-locking descenders work on the principal that they grip the rope when the user lets go of the device. To descend, the lever should be squeezed with the left hand, allowing normal descent control with the right. Panic can lead to the clutching of the lever with the possibility of instant and uncontrolled descent. Initial practice is therefore vital.

Once the response let-go-to-stop has been mastered, self-lock descenders such as the Petzl stop are both easier and safe to use.

In a cave an experienced caver should descend first. When at the bottom of the pitch it is possible to safeguard the one on the rope by pulling the rope-end, the friction on the rope running through the descender is increased, and so the sliding caving can be slowed down.

Bottom Lining

A safeguard against loss of control by the abseiler. The caver at the bottom should not be directly underneath, and should hold the rope in both hands ready to pull if necessary.

The practice of Bottom Roping should be carried out both above and below ground and must be implemented on all SRT activities.

Additional Technical Note

There has been a growing number of accidents involving the use of the “Petzl Stop”. These have resulted in an uncontrolled descent and subsequent injury when hitting the ground at the bottom of the pitch. The loss of control may well have been due to the incorrect operation of the Petzl Stop.

Petzl Data Sheet No D09:

“The red lever is for on/off safety control. When abseiling the speed of descent must be controlled by holding the free end of the rope below the
descender.

It is often a tempting practice to control the speed of descent using a combination of a partially depressed red lever and hand breaking, especially when not using a gloved hand. However a small movement of the lever will cause a large change in the stop’s breaking force and will result in either a jerky descent, sudden increase in speed or free fall."

The “ stop “ unlike the “ rack “ is not a variable friction device and speed regulation should be by the control of the rope. Additional breaking force using a karabiner is desirable especially when using muddy or smaller diameter ropes.

Those of you who introduce people to SRT or cave with novices must ensure that adequate above ground training take place, as direct supervision of these people underground is rarely possible.