Christian_Chourot
New member
Cave_Troll said:
I know the rest of these but can somebody enlighten me on this one?
Breaking krabs (not braking krabs!)
- Thread starter Christian_Chourot
- Start date
I know the rest of these but can somebody enlighten me on this one?
cap n chris
Well-known member
I think he is referring to cross-loading the karabiner gate by inadvertantly loading your weight onto your descender without ensuring the metalwork is nicely aligned. The significant leverages caused by fig 8s and racks can instantly break open your karabiner.
I've been searching for images to illustrate this but to no avail and can no longer be arsed with it.
I've been searching for images to illustrate this but to no avail and can no longer be arsed with it.
Christian_Chourot
New member
Ta.
Ian Adams
Well-known member
cap 'n chris said:
This is excellently put.
In this world, here, today and right now... we are all too frightened of doing and saying the wrong thing in case someone is offended, we cause upset, someone complains, we break a HSE rule etc. etc.
It is extremely refreshing that Cap 'n chris felt he was able to say exactly what he meant.
Even better ... we all know exactly what he means and exactly how he feels about it.
Long live free speech :halo:
Ian
ps. sorry you didn't find a pic though
Stu
Active member
One of the investigating team is a friend of my family. He demonstrated how easy it is for this to happen - we set it up in our garage and managed to bust one with nothing more than a hefty sag into the set up.
It's possible for the descender to nip the top portion of the sleeve and break it off (the barrel isn't that substantial in that area, they're quite easy to damage in day to day operation) thus allowing it to open.
Won't happen if you set everything up before setting off.
It's possible for the descender to nip the top portion of the sleeve and break it off (the barrel isn't that substantial in that area, they're quite easy to damage in day to day operation) thus allowing it to open.
Won't happen if you set everything up before setting off.
Perhaps I can help. I was on the BMC technical failures committee at the time this was investigated.
Basically the eyed device - be it fig 8, rack, whatever can act as a lever when the eye gets across the gate. What happened in the incident was that the magnified force ( lever and fulcrum) actually notched the gate sleeve which was fully tightened and still was when recovered. On this particular alloy krab the locking overlap was very small - if I recall about 2mm - when fully screwed up.
The very small notch allowed the gate to open and the fig 8 and krab to part company. This in fact took a bit of finding by Neil, the notch was really quite small and could have been seen as normal wear and tear, and explained how the fig 8 was on the rope and the closed krab still attached to the abseilers harness.
The instructor who had rigged the abseiler, (a novice on a sponsored abseil from a bridge with no safety rope), and guided him over the edge, reported that he had heard a clunking noise as the weight was taken. It is ASSUMED that this was the karabiner and fig 8 eye realigning - during which the damage occurred. The abseiler fell, to his death, almost immediately.
There had been a similar type of fatal earlier but the equipment had not been kept so it is conjecture that the incident investigated by the BMC was not the first.
I did a bit of playing and found that any eyed attachment COULD cause this leverage to occur. The moral is to check that your gear is 'in-line' before loading.
I circulated a short article at the time but these things do get forgotten, missed and of course newcomers never saw it.
As with most accidents of this type there was no direct evidence so the conclusion of the report is that the explanation given was the most likely cause and subsequent tests proved that the event was repeatable.
Jopo
Basically the eyed device - be it fig 8, rack, whatever can act as a lever when the eye gets across the gate. What happened in the incident was that the magnified force ( lever and fulcrum) actually notched the gate sleeve which was fully tightened and still was when recovered. On this particular alloy krab the locking overlap was very small - if I recall about 2mm - when fully screwed up.
The very small notch allowed the gate to open and the fig 8 and krab to part company. This in fact took a bit of finding by Neil, the notch was really quite small and could have been seen as normal wear and tear, and explained how the fig 8 was on the rope and the closed krab still attached to the abseilers harness.
The instructor who had rigged the abseiler, (a novice on a sponsored abseil from a bridge with no safety rope), and guided him over the edge, reported that he had heard a clunking noise as the weight was taken. It is ASSUMED that this was the karabiner and fig 8 eye realigning - during which the damage occurred. The abseiler fell, to his death, almost immediately.
There had been a similar type of fatal earlier but the equipment had not been kept so it is conjecture that the incident investigated by the BMC was not the first.
I did a bit of playing and found that any eyed attachment COULD cause this leverage to occur. The moral is to check that your gear is 'in-line' before loading.
I circulated a short article at the time but these things do get forgotten, missed and of course newcomers never saw it.
As with most accidents of this type there was no direct evidence so the conclusion of the report is that the explanation given was the most likely cause and subsequent tests proved that the event was repeatable.
Jopo
Ian Adams
Well-known member
Jopo,
Excellent and thorough reply to the original question and I am sure many of us will be very grateful to you for your explanation. I, for one, did not know this was a possibilty.
..... all I was getting at was that Cap' n Chris was not afraid to say exactly what he meant
Ian
Excellent and thorough reply to the original question and I am sure many of us will be very grateful to you for your explanation. I, for one, did not know this was a possibilty.
..... all I was getting at was that Cap' n Chris was not afraid to say exactly what he meant
Ian
cap n chris
Well-known member
Jackalpup said:..... all I was getting at was that Cap' n Chris was not afraid to say exactly what he meant
I'm not afraid to say it, however, I mostly think better and put something diplomatic instead. Anyway, it's the voices........
