/ Indoor Climbing - Steel Krabs

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shkinitrep - on 26 Jun 2012
My local youth organisation has just had a climbing wall and the anchoring system at the top is a chain (secured at 2 points) with an integrated ring on the chain.

I have advised that steel screwgate krabs are used to run the ropes through but my question is does each climb need to have 2 krabs or will 1 be sufficient.

When i run sessions outdoors i use two screwgate krabs back to back just to be extra safe, and since it is group work the weight isn't an issue. I need clarification on whether two krabs are needed on an indoor climbing wall.

Thanks!
Mark Collins - on 26 Jun 2012
In reply to shkinitrep: I would say definitely yes. This is about removing a single point of failure.
highclimber - on 26 Jun 2012
In reply to shkinitrep: two krabs will reduce the radius the ropes run over. I would always use two krabs if available for this reason alone.
Monk - on 26 Jun 2012
In reply to shkinitrep: personally, I don't use 2 crabs when setting up ropes out doors. I know other instructors who think this is over kill too. indoors I think there is a similar lack of consensus. Many walls use 2 crabs and several use one. To be honest still crabs are sip strong I doubt they would ever be the weakest link.
timjones - on 26 Jun 2012
In reply to shkinitrep:
> My local youth organisation has just had a climbing wall and the anchoring system at the top is a chain (secured at 2 points) with an integrated ring on the chain.
>
> I have advised that steel screwgate krabs are used to run the ropes through but my question is does each climb need to have 2 krabs or will 1 be sufficient.

I'm intrigued! How are have you managed to reach an advisory position whilst still needing to ask this sort of question on an online forum?

What risk are you seeking to remove or minimise by using 2 krabs?
teh_mark - on 27 Jun 2012
In reply to shkinitrep:

I used to climb regularly at a wall in Newcastle which used a single screwgate at the top of all routes. Perfectly fine, but with two distinct disadvantages for leaders:

1) Trying to unscrew a really well done-up screwgate at the top of the route while crazy pumped really is no fun.
2) If you'd pulled down a toperope to lead the route, it was always fun trying to get the knot through the krab when pulling the toprope back up (they now insist on people using tape or cord to join the ropes rather than knotting them)

I personally like the system they nave at Westway, where the routes have either double snapgates, or a snapgate and a screwgate, as it means you can clip at the top of a route with less worry of taking a lead fall while trying to undo a stubborn screwgate.

Of course, this is all probably irrelevant if no one is intending to lead at this particular wall.
speekingleesh - on 27 Jun 2012
In reply to Mark Collins:
> I would say definitely yes. This is about removing a single point of failure.

Given they'd both be clipped into the same single middle ring, attached to the same single climbing rope and being belayed by one person I can't see how assuming that a single steel screwgate will not break has any appreciable effect on safety.
hedgehog77 - on 27 Jun 2012
In reply to tec_mark: 2) If you'd pulled down a toperope to lead the route, it was always fun trying to get the knot route, it was always fun trying to get the knot through the krab when pulling the toprope through the krab when pulling the toprope back up (they now insist on people using tape or cord to join the ropes rather than knotting them) or cord to join the ropes rather than knotting them). Take the knot out it wont get stuck!
Neil Williams - on 27 Jun 2012
In reply to teh_mark:

Big Rock also have a snapgate and a screwgate, the former for leading, the latter for any top rope. Seems the best solution for me if leading is a option.

If not, one screwgate would seem fine to me - that's what all their top ropes are through, and this doesn't seem to concern anyone.

Neil
Mark Collins - on 27 Jun 2012
In reply to speekingleesh:
> Given they'd both be clipped into the same single middle ring, attached to the same single climbing rope and being belayed by one person I can't see how assuming that a single steel screwgate will not break has any appreciable effect on safety.

If both krabs were clipped into a single middle ring I would expect a "by" rather than a "with" in the OP. However, let's assume for the moment that they are both secured to a single middle ring. This ring will be closed and tamper proof, which makes it more secure than a single krab (where human involvement is required to secure the rope to it). Granted though, if it failed in your scenario there would be no back up. Now let's take the next link in the chain, the single climbing rope. A single climbing rope is made up of many strands and therefore redundancy is built into this. However, I do consider you have a point with a single person belaying. If they fail, there is no backup. I guess we're now getting into the realms of what is practical versus the amount of redundancy in a system, there is always a balance to be struck.
Fraser on 27 Jun 2012
In reply to Mark Collins:
> (In reply to shkinitrep) I would say definitely yes. This is about removing a single point of failure.

But in the OP he says the chain is secured at 2 points. It's a common enough set-up outdoors, in fact probably the default set-up. In reality, there's not much increased benefit in having a second crab secured to the same single chain. Not sure about the legal requirements indoors however.

Personally, I detest having a screwgate and snap-gate on the same ring at the lower-off, but maybe it's a legal requirement.

AlH - on 27 Jun 2012
In reply to Fraser:
>
> Personally, I detest having a screwgate and snap-gate on the same ring at the lower-off, but maybe it's a legal requirement.

Not a 'legal requirement', the only legal requirements come down to fulfilling a duty of care to users. Interested in why you dislike that set up so much?
jkarran - on 27 Jun 2012
In reply to shkinitrep:

A single locking krab for the top-rope is acceptably safe and the norm at every wall I've ever used. If you think your clients are at risk of tampering with that and perhaps unclipping then take precautions to avoid it happening. I'm presuming this isn't a lead wall?

jk
Monk - on 27 Jun 2012
In reply to Monk:
> (In reply to shkinitrep) personally, I don't use 2 crabs when setting up ropes out doors. I know other instructors who think this is over kill too. indoors I think there is a similar lack of consensus. Many walls use 2 crabs and several use one. To be honest still crabs are sip strong I doubt they would ever be the weakest link.

Sorry for the garbled mess at the end. I was typing on my phone and it seems I wasn't paying sufficient attention!

I was trying to say that steel krabs are so strong (40 kN) that they are very unlikely to be the weakest link in any chain. Regardless, there are several other single points of failure in any system (any of the links in your chain, your belay device/krab, the belayer, the rope, the harness etc).

Basically, I think a single steel krab is perfectly safe (with the added advantage that it is easily replaced in 5 years when a groove has worn in it). However, I am only a lowly SPA - for definitive advice you need to ask an MIA.
Fraser on 27 Jun 2012
In reply to AlH:
> (In reply to Fraser)

> Interested in why you dislike that set up so much?

I find that if you're on a route right at your limit, it can be a real fumble to separate the crabs and clip the snap-gate one before you fail. It might be the way I clip, but I've definitely noticed it on routes that are just at my limit, and particularly on very steeep ones.

AlH - on 27 Jun 2012
In reply to Fraser: Thanks Fraser. I give Technical Advice to various walls and am often interested in climbers opinions vs experience of that works well for walls/wall managers. Its often a compromise but cheers for explaining how you find it to me.
pog100 - on 27 Jun 2012
In reply to Fraser:
I would agree, I also find it a fumble to clip the smaller snapgate with the larger screw gate in the way, and yet I try, because the screw gate is often tough to loosen
climber david - on 27 Jun 2012
In reply to Fraser:

> Personally, I detest having a screwgate and snap-gate on the same ring at the lower-off, but maybe it's a legal requirement.

I don't mind it as it means you can set it up for toprope or clipping it after a lead. It also solves the one or two carbiner debate as well
MJ - on 27 Jun 2012
In reply to Fraser:

I find that if you're on a route right at your limit, it can be a real fumble to separate the crabs and clip the snap-gate one before you fail.

Isn't there a "finishing jug" to enable easy clipping of the lower off. If not, suggest it to the wall management.
timjones - on 27 Jun 2012
In reply to Fraser:
> (In reply to AlH)
> [...]
>
> [...]
>
> I find that if you're on a route right at your limit, it can be a real fumble to separate the crabs and clip the snap-gate one before you fail. It might be the way I clip, but I've definitely noticed it on routes that are just at my limit, and particularly on very steeep ones.

I'll second that. You've done the work, reached the top of the route and just want to clip the lower off without having to resort to grabbing the chain. You then find that you've got 2 krabs with a top rope threaded through both holding them together!

All too often this means that the crux of the route is the fumble to clip the lower-off ;(

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Fraser on 27 Jun 2012
In reply to MJ:

From my experience, there usually there is a decent hold to clip from but not always. I can remember a couple of routes at Ratho where the last hold was exactly the sort you wouldn't want to finish at on an outdoor route!
timjones - on 27 Jun 2012
In reply to pog100:
> (In reply to Fraser)
> I would agree, I also find it a fumble to clip the smaller snapgate with the larger screw gate in the way, and yet I try, because the screw gate is often tough to loosen

I think it's interesting that walls use a system that encourages climbers to undo the screwgate that often carries an in-situ toprope.
Neil Williams - on 27 Jun 2012
In reply to timjones:

I'm not sure why it does. Maybe they need to use larger snapgates, then. I never feel motivated to faff with the screwgate when the snapgate is right next to it and easy to drop the rope into!

Neil
timjones - on 27 Jun 2012
In reply to Neil Williams:
> (In reply to timjones)
>
> I'm not sure why it does. Maybe they need to use larger snapgates, then. I never feel motivated to faff with the screwgate when the snapgate is right next to it and easy to drop the rope into!
>

I can't see why it should happen but people do appear to get into the habit of clipping both before lowering off. Maybe they are just copying what they see others doing or maybe they are members of the school of thought that said topropes should be fed through 2 krabs.
Neil Williams - on 27 Jun 2012
In reply to timjones:

Isn't doing that bad for another reason - if your lead rope rubs on the toprope during lowering, the toprope could be damaged, and as it's right at the top of the wall it might not be noticed?

Neil
teh_mark - on 27 Jun 2012
In reply to hedgehog77:

I think you've misunderstood. By knot I was referring to tying the toprope to your lead rope, and pulling the toprope back through when you pull your lead rope down. Not the knot you've used to tie in, if that's what you thought I meant.
timjones - on 27 Jun 2012
In reply to Neil Williams:
> (In reply to timjones)
>
> Isn't doing that bad for another reason - if your lead rope rubs on the toprope during lowering, the toprope could be damaged, and as it's right at the top of the wall it might not be noticed?
>
> Neil

It's almost certainly best avoided but I suspect that any damage would be pretty insignificant. The lead rope is unlikely to be travelling fast or exert much pressure on the toprope during a lower off. Any damage is likely to be noticed as the part of the rope through the krabs will come down to floor level every time someone completes the route on toprope.
speekingleesh - on 27 Jun 2012
In reply to Mark Collins:
>
> If both krabs were clipped into a single middle ring I would expect a "by" rather than a "with" in the OP. However, let's assume for the moment that they are both secured to a single middle ring.

Well given thats how every single climbing wall I've been to does it I think it's a safe assumption...

> Now let's take the next link in the chain, the single climbing rope. A single climbing rope is made up of many strands and therefore redundancy is built into this.

You have to be kidding. So in your opinion slings are even more safe given they are made up of thousands of strands of dyneema/nylon.

> However, I do consider you have a point with a single person belaying. If they fail, there is no backup. I guess we're now getting into the realms of what is practical versus the amount of redundancy in a system, there is always a balance to be struck.

Yes and this is the point, backing up the 40kN steel krab is well into the realms of the mitigating a very tiny risk. Especially since the other end of the rope is going to be secured by means of a single alloy (24kn) screwgate which is in a much worse position with regards to the gate accidentally becoming undone.

And if you really are worried about the possibility of the climber "tampering" with the gate then the actual solution would be a maillon, not giving them an extra screwgate which they can also undo.
kfv - on 28 Jun 2012
In reply to timjones: The lead rope rubbing on a top rope can and does cause significant damage. I have seen several ropes worn down to the core by doing this. One of these times it wasn't noticed until the climber was at the top of the wall and the ruined part of the rope was right in front of the belayers face.
jkarran - on 29 Jun 2012
In reply to timjones:

> It's almost certainly best avoided but I suspect that any damage would be pretty insignificant. The lead rope is unlikely to be travelling fast or exert much pressure on the toprope during a lower off. Any damage is likely to be noticed as the part of the rope through the krabs will come down to floor level every time someone completes the route on toprope.

Pulling a tensioned rope past another stationary tensioned (by its own weight) rope it a krab can totally destroy the stationary one in just a few meters of lowering, I've seen it happen.

jk
Quay climbing - on 01 Jul 2012
In reply to shkinitrep: If you have had a wall just built, the manufacturer will be the best people to answer your question. At the Quay we have a steel screw gate, and a steel snap link at the top of all climbs. If the climb is a top rope only, the snap link is tie wrapped up and out of the way, if a lead route it is put back in place. We advise our climbers that they can lower off on just the steel snap link, BUT if the route is to be seconded, the steel screw gate must be used as well!
We finish all our routes with a good clipping hold.

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