Locking carabiners at the anchor points ???

I have a number of relatively new climbers telling me that the locking carabiners attached to the bolted anchors need to be opposed. I fully understand the need for opposed carabiners at the masterpoint. What I would like is a good resource that explains why it is not necessary at the anchor when these attachments are two separate and independent entities. I understand the argument for being consistent and always opposing because you oppose carabiners in a number of situations. Does anyone have any pointers to some accepted "authoritative" sources on the subject and can anyone give a good argument for and against. Lastly, what is the best method for keeping the locking screw off the rock. When attaching directly to the anchors in a lot of setups here in SoCal, the carabiners are lying flat against the rock which gives the potential for unscrewing. I've seen many pictures of anchor setups where the carabiner attached to the second link of the chain which orientates the screw gate towards the sky thus eliminating the potential for unscrewing. Can an aluminum carabiner cause undue wear and tear on a steel chain link? I believe steel wins everytime. 

Daniel N wrote: I have a number of relatively new climbers telling me that the locking carabiners attached to the bolted anchors need to be opposed. I fully understand the need for opposed carabiners at the masterpoint. What I would like is a good resource that explains why it is not necessary at the anchor when these attachments are two separate and independent entities. I understand the argument for being consistent and always opposing because you oppose carabiners in a number of situations. Does anyone have any pointers to some accepted "authoritative" sources on the subject and can anyone give a good argument for and against. Lastly, what is the best method for keeping the locking screw off the rock. When attaching directly to the anchors in a lot of setups here in SoCal, the carabiners are lying flat against the rock which gives the potential for unscrewing. I've seen many pictures of anchor setups where the carabiner attached to the second link of the chain which orientates the screw gate towards the sky thus eliminating the potential for unscrewing. Can an aluminum carabiner cause undue wear and tear on a steel chain link? I believe steel wins everytime. 

The two locking carabiners on the masterpoint do not need to be opposed. Source: common sense. :}

And, aluminum carabiners will not cause wear on steel chain.

The thought behind using opposite and opposed caribiners on master point is that there is a lot of potential movement due to the rope sliding thru and the climber moving on the route. The thought is that if you have them oriented differently and something wierd happens and unclips one it will not cause both to fail. When using carabiners to attach an anchor setup to fixed hangers there is much less potential for movement which is why it is common practice (not necessarily best practice) to not even use lockers.

Instead of trying to find a resource that proves your point I would challenge your friends to find any resource that supports their point of view, or even mentions the issue.

"Screw down so you don't screw up". It is possible for gravity to speed up the unscrewing process on a screw gate. Orienting it so the collar has to fight gravity to unscrew will mitigate the risk of your screw gate unlocking in most situations.

It's kind of like good, better, best...or; weak, ok, solid.

The only use for lockers on a bolted anchor is in a big wall scenario where additional capacity is ideal.

Learn to clove into regular carabiners and lean back and weight the one you are directly on...it will never come unclipped and a weighted clove has never come unclipped in the history of climbing.

Locking carabiners and webbing master points at bolted anchors is the death of efficiency on a free climb.

We all imagine what can go wrong, some people have more elaborate imaginations than others. You are unlikely to find any authoritative resource that says your friends' imaginary scenarios can never happen.

I can tell you that the majority of experienced (more than 10+ years of regular climbing) climbers don't use lockers on the bolts and generally do oppose the masterpoint biners (probably not because the believe it's strictly necessary but why not? it's just as easy as doing it the other way)

Any material can eventually wear any other material - water formed many of our crags, soft nylon wears our aluminum gear - but aluminum wearing on steel is not something that will happen in our mortal time frame.

Daniel N wrote: I have a number of relatively new climbers telling me that the locking carabiners attached to the bolted anchors need to be opposed...

Assume this statement applies to you as well.  If your locker unscrews, then it becomes a carabiner on one leg of an anchor - an exteremely common and mundane scenario.

It seems like a lot of you mention using two carabineers at the master point. Why are you using two in the first place? Don't you just clove into one at the master point and then belay from another at the shelf?

In the scenario of having a top rope anchor set up, is there any need to have the rope passing through two locking biners?

For multipitch anchors, you often don't need a masterpoint, and can build an anchor with the rope by cloving into the bolts (or pro).  For toprope on a sport climb with a good anchor, I just use 2 quickdraws facing opposite ways.

Edit for aside: it's good to think about safety, but I worry that people focus on the wrong things.  It's highly unlikely that a failed anchor bolt or magically unclipped rope will kill you.  Much more likely to kill you is that you incorrectly thread your rappel device on the way down in the dark after a really long day made longer because you spent 20 minutes perfecting every anchor.

Bobby Hutton wrote: "Screw down so you don't screw up". It is possible for gravity to speed up the unscrewing process on a screw gate. Orienting it so the collar has to fight gravity to unscrew will mitigate the risk of your screw gate unlocking in most situations.

I have never heard this before or even thought about it, but wow that makes so much sense.

I’m taking a guess here- but is the OP in reference to top roping on a sport climb??

Non-lockers on the bolts (or your trad gear if that's how you built the anchor), lockers on the master point. I do this for multi-pitch belays and TR setups. Lockers on the bolts don't always lay nicely because of the bulk in the screw gate part, too.

For an unmanaged anchor, such as a toprope anchor, I'll go two lockers opposite and opposed, and I think that's best practice.  If it's a typical 2 bolt sport anchor, two quick draws opposed is fine, but that type anchor can't usually move around or have biners flip, etc.  For a managed anchor (top belay,  multipitch) a single locker is fine, and I'm usually tied into it with a clove. If I do a redirect, it'll be thru a second single locker.  The risk tolerance on an unmanaged anchor is lower, basically, since you can't detect and correct any issues.

I do it because I like the way it looks. No other reason to do it though. :)

More importantly, focus on orienting your biners attached to bolts in whatever direction doesn’t create sideways loading on the gate.

I appose my NON-locking carabiners for bolted anchors on multi pitch because in my head i'm like well if there was some weird swing and or somthing came in from the side blah blah super unilkely BS but i'm like well there not even lockers, might as well try and be good about it.  But if they are lockers not sure why it would matter.

Lockers didn't used to be the norm and I have felt no need to move to the omg everything must be a locker for max safety train.  2 clips that i can watch aren't gonna magically come undone and hey they are redundant anyway.  I mean most people toprope off 2 draws for sings pitch sport climbs