I have a near miss to report:
Last year in the Cornish coast I was doing some socially distanced self lining.
My favourite spot was a rock fin, only about 12m high but with some good hard (for me) routes on it and walking distance from home.
I had been many times before and had a routine. I could scramble up the seaward arrêt of the fin and set up a belay on an existing stake backed up with a cam in a slot. The stake was ancient and rusty but was thick and solid pin designed for holding railway sleepers in place. I trusted it.
I would tie an alpine butterfly at the half mark of the rope, and then back the belay up with the rope tied round a Boulder on the opposite side of the fin I was climbing.
Bearing in mind I should never take falls while self lining I assessed this as a solid, safe set up.
When I’d had enough I could dismantle the belay and abseil off the fin with the rope still tied to the Boulder on the beach on the opposite side.
All went fine many many times. Then one day I came down, walked around the fin and saw this :
The rope I had just abseiled on had slipped round the boulder and was being held in place by the smallest of forces. The constraining rock roiled away with a slight shove of the foot.
Only this and the friction of the rope running over the top of the fine stopped me from plummeting to the rocky beach when I leant back on the ab rope.
I had got lazy and complacent about choosing suitable anchor boulders (the beach changed twice daily and even the biggest stones were never the same twice).
After this, I backed up the belay to a second, upward pulling belay, built at beach level on the fin itself. And always checked it before my final ascent of the day.Thanks for all the “content!” I for one am benefiting from it greatly.
All the best
Ted (St Helena)