Anchor angles

[Murph]

When building anchors, a "threshold angle" before forces start to multiply on individual anchor points is 60 degrees. The problem is I have no idea what 60° looks like and I’m not about to bring a protractor when I go climbing.
Ok, so try to imagine an anchor on 2 bolts (reasonably level to each other, route doesn’t trend left or right) with an equalized sling tied in a figure 8 and the angle is exactly 60°. Visualize a triangle from the bolt, knot to bolt (not an ADT, just an imaginary triangle). At each point, the angle would be 60°, forming an equilateral triangle. Then you could assume that the strands of the anchor would be equal distance as the bolt spacing.
So back to my problem of having no idea what 60 degrees looks like. A quick and dirty method to check for a proper angel is to grab a strand and see if it extends past the other bolt. If the knot can’t touch the opposite bolt, you know for sure that the angle is greater than 60 degrees.


I hope I didn’t confuse anyone, I can post pictures if this is not clear.

[*Chris*]

Ryan,
I think I understand the equilateral triangle analogy, and as such, your check sounds good to me. Honestly though, if your ever in question... just ask somebody nearby to inspect your anchor setup. I wouldn't mind and I'm sure nobody else would either. That said... I remember seeing a few of your anchors in the past and they were all bomber. That said... if you want to carry around a rack of protractors, I'd consider that totally good form!

[Burley]

Less than 90 degrees for sure.

To minimize force, minimize angles. When equalizing two points of protection use angles below 60 degrees.

Below we see the weight distribution for varying angles. Assume 100 pounds of force at the bottom of the “V” (focal point) attached by two opposed locking carabineers and each piece of protection is labeled “X”.
•20 degrees or less at the “V” distributes 50% of the force to each piece of protection.
•60 degrees distributes 60% of the force to each piece of protection.
•90 degrees distributes 70% of the force to each piece of protection.
•120 degrees distributes 100% of the force to each piece of protection.
•150 degrees distributes 200% of the force to each piece of protection.
•Angles greater than 90 degrees create dangerously high forces.

Remember... always avoid the American Death Triangle, sliding 'X', and girth hitches... no need for any of these in a top rope situation.

[Murph]

I’ll just post pictures to clarify

[Shawn B]

Your second picture down looks fine to me. The bottom is obviously the best. And the top one is definitely bad. My only criticism is that this system lacks total redundancy. You would have to add a second sling and knot it all together to achieve redundancy.

Eric, I somewhat disagree with your suggestion of not using a "sliding x". In a toprope situation the rope will often vary the direction in which it pulls on the anchor. With a sliding x the anchor can adjust its angle to keep the forces equalized. With a knotted sling or cordellette it cannot adjust and equalize. So you are applying more forces to one of the bolts. Yes there is potential for extension if one anchor point were to fail, but there is less chance for one point to fail with forces being equally distributed. There is no perfect anchor that does everything. The closest would be a sliding x with limiting knots tied to limit extension. Then again, the knot will reduce the strength of the runner. With two solid bolts imo a sliding x is perfectly bomber and in some cases better than a knotted sling. In other cases where a route is plumb below an anchor, a knotted sling may be better. With a trad anchor, the extension may be a bit more of an issue if one piece of gear is questionnable. But with two bomber bolts the chances of one of the equalized bolts blowing is pretty low. One thing I see alot is people using only one sling or cordelette on an anchor which as I mentioned above it lacks redundancy in the sling arm from each bolt. So bottom line is to have many tools in your anchor repitoire and apply whatever best suits the situation while best trying to be redundant and equalized.

[chossmonkey]

Your second picture down looks fine to me. The bottom is obviously the best. And the top one is definitely bad. My only criticism is that this system lacks total redundancy. You would have to add a second sling and knot it all together to achieve redundancy.

How is a knotted sling not redundant?

If it was a sliding X you would need two slings to make it redundant since if one leg gets cut the other leg would pull through. With a sling knotted you can cut one side and the other side will still have all its strength.

[The Mitt]

There is a huge debate on the sliding x and many mods on RC.com. John long has rewritten and revised his views on anchors. I think the bottom line is that if you are using bomber gear on bomber anchors both are acceptable. And both anchors are situationally dependent.

S

[Burley]

Shawn,

I'm really not a fan of the sliding X. That is just my opinion. It might have its place, but not in my bag of tricks unless it is backed up... this is easy to do. I haven't read many articles that this it is the way go when building an anchor. On a wandering route you can use a directional (when possible).

One issue is that it is extendable. I can see too many cons. I had this low opinion of the sliding X before this past weekend and after I watched a hanger wiggle totally off a bolt (directional while toproping) I'm even more sure that it is not the best option in most cases. One assumes bolt anchors are safe if the the hangers don't move when you set the anchor. The same incident could have occurred at the anchor... if it did and a sliding X was in use it could have been bad... even more so if only one sling was in play. The extention can be limited with a backup sling(s), but this can reduce the movement of the X...

Another time to not use it in a TR situation (in my opinion) is if the anchor is extended over an edge... the X will rub over that edge.

I feel the best option is the use of directionals for wandering routes when TRing... rather than the sliding X.

I'm not going to say it doesn't have its place, but I will say that I think there are better options and those new to the sport should try to following the SARENE rule... the more Sarene the better. If you're new to this, don't limit yourself to only a bolt anchor if you can also back it up with a tree.

[STeveA]

My vote is for the sliding X. I saw the introduction of the knotted cord in the early 90s and I did not like it then and I don't like it now. I like to equalize my anchors and this is done by the sliding X. I don't use 2 slings unless there is some rubbing action taking place. I like the KISS principle and believe that this is just as important as redundancy.

Bolts should be placed one above the other if you can. The forces are then split equally between them. Anything other than this is a compromise. However, if you are setting up rap anchors then they need to be side by each.

[Adam]

try to following the SARENE rule...

wanna give an explanation for people?

[Murph]

Thanks for the input but the main point I was trying to get across is when you are uncertain if angles are too large (greater than 60 degrees). If all things are done correctly, and the knot can extend past the opposite bolt (Figure 3) you are good to go. If the knot can not extend past the opposite bolt (Figure 1), a longer sling should be used to lower the angle above the knot.

Or you can carry a full rack of protractors like Chris suggested.

Of course, anytime you are in doubt of an anchor, use an alternative method and/or have an experienced person check it over.

[Burley]

Keeping it simple is important in a lot of cases, but if you are just getting into toproping or building anchors you should keep it safe... super safe.

Everyone will have their own rules that they like to follow. The sliding X has its place and can be used in a way that minimizes extention.

SARENE... I got this from a John Long book and a few other sources that probably stole it from him.

SA=Secure Anchor Points
R=Redundant
E=Equalized
NE=Not Extendable

One sling to build the sliding X doesn't meet two of the criteria... it is not R or NE. Two slings would allow the sliding X to meet three of the four... but it still is Extendable.

One sling with a knot is considered safe, but use two slings and a knot if you like. If you combine this with the directional when needed and you meet all four criteria without question.

This is just my very limited opinion.

[granite_grrl]

Keeping it simple is important in a lot of cases, but if you are just getting into toproping or building anchors you should keep it safe... super safe.

Everyone will have their own rules that they like to follow. The sliding X has its place and can be used in a way that minimizes extention.

SARENE... I got this from a John Long book and a few other sources that probably stole it from him.

SA=Secure Anchor Points
R=Redundant
E=Equalized
NE=Not Extendable

One sling to build the sliding X doesn't meet two of the criteria... it is not R or NE. Two slings would allow the sliding X to meet three of the four... but it still is Extendable.

One sling with a knot is considered safe, but use two slings and a knot if you like. If you combine this with the directional when needed and you meet all four criteria without question.

This is just my very limited opinion.

I would agree. I only use the sliding when I question the quality of my anchor points and really feel they need to be equalized. In the simplist form I will normally view two good trees or two bolts as two bomber anchor points. I feel a single one of these anchor points could take the full load, therefore perfect equalization isn't critical. I just have two for redundency.

[STeveA]

I have some John Long videos where he recommends using a Swammi Belt for a harness. He does mention you can add leg loops but they are not required. I have a how to book that shows how to use a Gri Gri, only the picture shows it set up backwards. I have a huge training manual from ORCA that gives numerous knots and other advice for climbing, none of which I would ever use. The how to books by Royal robbins would have killed a couple of people in Bar harbor if I had not stepped in to explain things differently.

Books and videos are fun things and have a valid place in climbing, however I would not use them to make absolute decisions about right and wrong.

This is a general comment for people who are just getting into the sport or starting to set up there own anchors, and does not reflect on any of the comments or people posting to the thread.

[Shawn B]

How is a knotted sling not redundant?

It lacks redundancy within the arms themselves. You have 2 bolts, 2 biners (o&o) and only one piece of webbing forming each arm between the bolt and the biners. Adding a second sling and knotting it all together provides redundancy for all aspects of the anchor. Plus it makes it easier to untie as there is more material within the knot and it doesn't cinch as tight. One of the new super long sewn runners doubled up and tied in a knot works very well. I just got one and like it as it is light, bundles up small and is long enough to equalize 3 pieces in a natural anchor or two bolts doubled up.

Eric, it is virtually impossible to have all characteristics of SARENE in a real climbing world anchor. The closest thing would be a knotted sling from two bolts and the route is a plumb line that does not wander. An anchor cannot have full equalization and no extension. So it is 6's. You have to choose which is more important for any particular application. If you equalize with a sliding x the forces are shared and there is less likelyhood that one point will fail, yet if it does the other point gets shock loaded. With a knotted sling there is more likelyhood that one point will fail as the load is not shared but there will be less shock loading (there will still be some but it will be minimal). With a directional there is probably more chance for the load on the main anchor to not be equalized unless you can somehow estimate the angle that the directional will place on the main anchor when the rope is weighted. If the directional is off to the right, chances are the left bolt of the anchor will take most of the weight. And not surprisingly, I have the opposite view of ggrrl in that I would likely use a knotted sling moreso if one piece of an anchor was questionnable because there is more chance that it will blow thus shock loading the other(s). I don't think either done correctly is wrong. Know how to use both. Know the strengths and weakness of each and apply accordingly dependant on the situation.

ps i always use 2 separate pieces of webbing for a sliding x (and a knotted sling for that matter) so the debate comes down to which is more important...equalization or no extension.

pps to further throw into the equation, a sliding x does not place a knot in the sling. knots lower the strength of the sling. a further reason for using two pieces of webbing when using a knot in my mind. plus as i mentioned before with two webbing the knot has more surface area within itself thus not cinching tighter...extra important with a skinnier sling.

All good points by everyone i think and if it makes someone think about their anchors this post is actually useful. I don't think you can make an anchor too safe. Well maybe Eric can.

[Burley]

Shawn and Steve,

I agree... it is great to have discussion on this topic and that is my intention when I post... discussion.

I don't care to debate about FA's, ethics of here vs there, or whatever... I suck way too bad for all that. What I think is important is climbing sweet routes, having safe anchors (gear, bolted or tree), trying to wear my helmet, and helping new climbers... just like many on here helped me (and continue to help) when I started.

These are just my opinions so please do criticize. SARENE is a good thing to keep in mind when you're staring out.

Shawn hit is bang on: "Know how to use both. Know the strengths and weakness of each and apply accordingly dependant on the situation."

[*Chris*]

Exactly... anchors are situational and both setups have advantages and weaknesses. Use whichever is more appropriate for the case in point. I will add however, that shock loading due to extension doesn’t concern me in a top-roping situation like it would in a multi-pitch leading scenario. Typically, you’re going to be talking about very small fall distances with a whole lot of dynamic rope at play. Good discussion.

[Fred]

one sling with an overhand knot is redundant same a cordelette with a figure eight

[Shawn B]

Slightly ot but did anyone see the new cordelette by blue water that is dynamic? I wonder how much dynamic properties it has and whether it would make much of a difference due to it's short length. Could just be marketing bs to sell more...dunno. it's on the mountain gear website. i just wish cordelettes weren't so heavy and bulky. it could make up for some short comings of a knotted anchor with respect to equalization.

[granite_grrl]

And not surprisingly, I have the opposite view of ggrrl in that I would likely use a knotted sling moreso if one piece of an anchor was questionnable because there is more chance that it will blow thus shock loading the other(s).

Er, not really what I was saying, but I catch you drift on what you're trying to say.

I'm honestly not sure if I've ever bothered with a slidding x in an anchor, though I have used it on route, and its certainly a good thing to keep in your bag of tricks.