Clipping To P-Bolts

C.Raven

Member
I have just read the report from the SWCC caver who fell down a 40m pitch in France, it appears he had clipped into the bolt and the crab was positioned on top of the bolt when his weight came on the crab the bottom of the bolt levered the gate open and bingo bottom of the pitch, I have never thought about this happening is this common knowledge I suppose the only way to stop this happening is to use a screw gate grab.
 

Antwan

Member
Have a search for articles on ' back clipping' or 'z clipping' in climbing for a similar phenomenon. Amazingly a colleague at work who had been climbing for many years more than me proceeded to back clip the first indoor route he led with me and was astonished when I showed how easily the rope came out of the crabs.

Back to the original point, you should always have to clip the bolt with the crab orientated in the right direction for the load but as you say a screw gate/quick lock would make any errors safer' though not completely safe as the crab will still be loaded incorrectly
 

ianball11

Active member
There is also the thought that if you clip directly into the bolt, the load in a fall is obviously directly on the bolt, if you clip into the knot, then the tightening of the knot and the small stretch in the rope reduce the force on the bolt.

There has been a warning about using snap gates with p bolts in the CNCC guides for as long as I can remember.

http://www.cncc.org.uk/technical-group/warning.php

 

Mike Hopley

New member
I don't understand why you would clip into P-bolts at all. You have the rope, right? Clip into the knot loop.

Clipping into the rope is much safer because (1) it's far less likely to unclip and (2) you are backed up to all the previous anchors.
 

topcat

Active member
maxf said:
Should have been attached to the rope as well I thought when I read the article....

When you first arrive at a bolt there is no rope.....................
 

cavermark

New member
Bolts are fine if clipped correctly.  It can be hard to unclip krabs out of a loaded knot loop too.

Screwgates could still fail if clipped at the top of a P-bolt - the gates aren't bomb proof, especially to a side load (don't use them in the same way as a maillon rapide).
 

Mike Hopley

New member
topcat said:
When you first arrive at a bolt there is no rope.....................

Yes there is. You have the rope in your tacklesack. So use it.

Rigging should always begin before you are in danger of falling down a pitch. Before approaching the drop, your rope should be attached to a bombproof anchor (typically comprising two good bolts).

If you can reach the bolts to clip in with your cowstail, you can also attach the rope to them. Your arms are the same length in either case. ;)

Now use the rope for safety while you approach the pitch. First clip into the knot you just rigged, using your cowstails. Then progress along the rope using your jammer or your descender.

The jammer is usually more convenient; to progress, carefully disengage it without removing it from the rope. While rigging, keep the jammer under tension as much as possible. Ensure that the jammer's carabiner is also clipped around the rope, so that the jammer will load correctly in a fall. To pass intermediate anchors, first clip your short cowstail into the knot loop at the anchor, before transferring the jammer to the next section.

...but if you can reach the P-bolts to clip, then you don't even need the jammer. Just clip into the knot loops as you go along.
 

Olaf

New member
I assume you are talking about this report, or has any other report been published? http://welshrandomadventures.blogspot.co.uk/2014/09/the-fall.html

The paragraph referred to is probably this one:
It seems as I went to move the short cows-tail I slipped from my stance, bringing me onto the long cows-tail which was still clipped into another of the resin anchors. That should have been it, but to my horror the snap gate carabineer had twisted round with the gate now lying in the danger position across the bolt. As my weight loaded onto the cows-tail the carabineer unclipped itself...
Then it seems to me that maxf is right and he should have rigged and locked his stop onto the rope that he was going to rig further down. I always use that as a second point of attachment while rigging. If no rope or previous bolt is there, as topcat suggests, then stumbling should not lead to a 40m freefall. If it does, then in my opinion the bolts are not in a good place.

Never mind, lesson learned, mind your snapgates! I have to admit that I have so far preferred clipping into the bolts and will reconsider...
 

Burt

New member
Fairly common occurance. A screwgate would lessen the chance of this happening, but I've seen a screwgate's locking collar ripped open by an incorrectly loaded fig 8 just like cavermark said.

Clipping into the rope knot does lessen the chance of shockloading the bolt, but if you've got a dodgy knot or clip into the wrong part of it then that's just as bad.

So on arrival at the pitch head - check the bolts. Clip into them carefully and as soon as possible get a backup clipped in (either on the bolt or your rope.) then check all is well before loading the whole lot.
 

cavermark

New member
Mike Hopley said:
Yes there is. You have the rope in your tacklesack. So use it.

Rigging should always begin before you are in danger of falling down a pitch. Before approaching the drop, your rope should be attached to a bombproof anchor (typically comprising two good bolts).

If you can reach the bolts to clip in with your cowstail, you can also attach the rope to them. Your arms are the same length in either case. ;)

Now use the rope for safety while you approach the pitch. First clip into the knot you just rigged, using your cowstails. Then progress along the rope using your jammer or your descender.

The jammer is usually more convenient; to progress, carefully disengage it without removing it from the rope. While rigging, keep the jammer under tension as much as possible. Ensure that the jammer's carabiner is also clipped around the rope, so that the jammer will load correctly in a fall. To pass intermediate anchors, first clip your short cowstail into the knot loop at the anchor, before transferring the jammer to the next section.

...but if you can reach the P-bolts to clip, then you don't even need the jammer. Just clip into the knot loops as you go along.

I would use a descender in preference to a jammer - won't shred the rope if you do fall onto it, and it's easier to pull slack thru a stop or simple than down-prussik a jammer.

If rigging a hanging traverse, it is likely that you would clip your short cowstail into a bolt to rest on, whilst you rig the rope into the next bolt. The only thing Jules could have done differently is to have a descender on the rope rigged so far.
What Jules did wasn't textbook, but I have done the same myself (without the falling bit).
 
[/quote]

Never mind, lesson learned, mind your snapgates! I have to admit that I have so far preferred clipping into the bolts and will reconsider...
[/quote]

you learned the easy way ;-). Fortunately Jules is recovering / healing well.

As far as  I was aware, stops should not be shock loaded (i.e. don't fall on them when locked off). I always use a stop as a 2nd attachment when rigging, but do this by pulling the required slack through and then tying an overhand some distance below the stop.
 

Mike Hopley

New member
cavermark said:
I would use a descender in preference to a jammer - won't shred the rope if you do fall onto it, and it's easier to pull slack thru a stop or simple than down-prussik a jammer.

A descender is fine, as long as you lock it off before letting go. I would usually prefer a descender when the traverse is on a steep slope.

Neither a jammer nor a locked-off descender should be shock-loaded. You prevent this by not allowing slack to build up.

"Down-prusiking" a jammer is hardly difficult. You just slide it down the rope.

But anyway -- both methods are safe if used correctly.


If rigging a hanging traverse, it is likely that you would clip your short cowstail into a bolt to rest on, whilst you rig the rope into the next bolt.

If you are hanging from a bolt, your cowstail cannot detach. This is not what happened in the accident.
 

Alex

Well-known member
In one occasion while rigging is those ascending traverses, I was guiltily of clipping into the bolts only. I used my stop to absail upwards to the next bolt (which is rather difficult), but I am all the time thinking if I slip here before I get to the next bolt what happens if I swing, that would be a hell of a whack on the wall down below, even if the fall factor would be minimal as the rope is still tensioned. As the rope is tensioned as soon as I can reach the bolts I would clip into the bolts and remove my stop to stop the rope pulling me off balance as its just easier. Clearly in this case I should not have done that, I should have to put up with the pulling until I have attached the rope to the P's, but in doing this I would have needed to adjust the knot once rigged as the rope would not be tensioned enough as its a traverse due to my stop being on it. This is an example of how shortcuts can come in as it is just far easier and quicker to 'cheat'. In my defence I clipped into two separate bolts before removing my stop.
 

Mike Hopley

New member
Alex said:
I would have needed to adjust the knot once rigged as the rope would not be tensioned enough as its a traverse due to my stop being on it.

That is one advantage of using a jammer, rather than a descender.


In my defence I clipped into two separate bolts before removing my stop.

I would consider this safe, especially if you are keeping a close eye on the carabiners.

It's okay to break the "rules", when you understand the hazards involved and can make sensible decisions. I think you were making a sensible decision. :)
 

Pete K

Well-known member
Something to consider when clipping to P bolts

The bolt eye and stem is formed from a single piece of bar bent into a 'p' with a double thick stem. Make one from a paper clip if you can, it helps visualise what I'm about to say. Now, imagine you are clipped into the bolt eye and the bolt is also attached to a rope. If the bolt pulls from the rock the caver would be hanging by their cowstail and the bolt would be ring loaded between that and the krab/knot on the rope.
With enough force the eye of the P bolt would open up and allow the krab/knot/cowstail to slip out from the double stem and the caver to fall.
Try pulling the eye of your paper clip apart and you'll see what I mean.

A few points on this
  • This would probably require more force than the fall would produce.
  • This can be avoided completely by clipping into the loop on the knot that attaches to the P bolt.
  • This is not an issue for solid eye anchors like the SPIT hanger plates and Petzl glue in anchors.
  • This is not an issue with the new BP anchors as they have a twisted stem.

Personally, as a best practice thing, I'd only be clipping to a P bolt if I needed to position myself and ONLY if the other cowstail was in a more dynamic part of the system, i.e. the loop of a knot.
 

Les W

Active member
Pete K said:
With enough force the eye of the P bolt would open up and allow the krab/knot/cowstail to slip out from the double stem and the caver to fall.

Except that the DMM bolts are welded together on the two parallel parts so wouldn't pull apart...
Not sure if the BP anchors are welded or not.

It takes between 4 and 7 tonnes to pull a 'p' bolt from the rock! with forces like that in play I doubt you would be worried about the bolt "opening up"...  :unsure:
 

Pete K

Well-known member
Hence point 1 on the list.
Also, see Derbyshire board. Recent bolt failure in JH and 2 suspect ones in P8 currently. P's are not infallible.

Not seen a DMM P out of the wall for some time and I don't remember a weld. That's the advice I'm going with anyway and what I know is taught professionally.
 

damian

Active member
Pete K said:
Also, see Derbyshire board. Recent bolt failure in JH and 2 suspect ones in P8 currently. P's are not infallible.
Correct me if I'm wrong, but the JH one wasn't a P-bolt. I can't find anything about P8 ... have I missed something?
Not seen a DMM P out of the wall for some time and I don't remember a weld. That's the advice I'm going with anyway and what I know is taught professionally.
They are definitely spot welded. The BP anchor isn't but, as you say, it is twisted so it isn't relevant. All this said I agree completely that it's always better to clip into the rope than the bolt.
 

Pete K

Well-known member
P8 might have come to nothing, it was flagged to DCA recently.
Pretty sure the JH one was a P, it looked that way from the video I saw from the guy who reported it.
Don't mind being corrected when wrong.
 
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