In recent months the Austrian Alpine Club (ÖAV) decided to change its opinion and recommended the use of semi-automatic belaying devices like GriGri in indoor climbing. This was discussed in detail in the magazine bergundsteigen (issue 2/2014 and issue 3/2014). I was pretty amused since about fifteen years ago, when I purchased my GriGri, those devices were not allowed at all. Now the argumentation was that people in indoor climbing halls could get too distracted to belay with a tuber-like device.
Anyway, the problem with belaying devices remains still the same:
- They should stop a falling climber, even when the belayer is inattentive.
- They should allow dynamic belaying.
- They should not harm the rope.
The first two contradict each other.
Belaying dynamic means that the rope is allowed to slip easily through the device. In case of a falling climber, the belayer is able to let pass the rope through the device in order to lower the impact force.
In contrary, assisting an inattentive belayer requires the device to automatically stop the rope.
The last issue, not to harm the rope, is just a limitation in solution space. We need to keep it in mind when selecting solutions.
The contradiction can be formulated as a physical contradiction:
The rope should be stopped (when falling) and the rope should not be stopped (when belaying dynamically).
The solution of physical contradictions is performed via the principles of separation. A guide of how to deal with separation can be found at Open Source TRIZ. I think that solutions can be found when trying to separate in time or satisfying the contracting demands. Perhaps this is not an easy task …