An Introduction to Climbing Anchors: SERENE-SA & Other Important Concepts

Anchor building is an intricate topic, to say the least.

Don’t believe me?

Check out this thread. Or this one. Or any of the other zillions of articles, discussions, and debates that flame on in the corners of the climbing internet.

The reason for all the discussion is a good one: anchor-building is a skill that keeps you alive. It is worth studying, and maybe more importantly, it is worth practicing.

The full scope of anchor-building skills is beyond this article — or any article, for that matter. Instead, I’m going to introduce some of the concepts and factors that you’ll need to weigh when you’re out honing your skills.

If you’re aiming to start your own trad-climbing adventures, this is a good place to start. As always, I encourage you to do your research and read up, but I also encourage you to seek out instruction, advice, and mentorship.

All that out of the way, don’t be too intimidated by the internet quarrels. Anchor-building is built on simple concepts and good sense, and you’ll be building your own in no time.

Elements of an Anchor

Anchors begin at protection. If you’re on a sport route, that’s likely just a couple of bolts. If you’re on a trad route, you’ll often be placing gear of your own.

Although the basic concepts remain the same, choice in anchor-building material varies from climber to climber.

Single- and double-length slings are always handy, and some climbers use them as their primary anchor-building materials. Simple nylon runners will do the trick, although dyneema runners work fine if you prefer it.

Minimalists use only the rope itself to build the anchor — this approach seems a little less fashionable these days, but done well it can be as safe and efficient as any.

One of the most popular approaches is to bring along a cordelette. A cordelette is a length (usually around 20 feet) of thin (usually 6-7 mm) cord, tied into a loop. A cordelette is slightly bulkier than slings or rope, but still easy to pop onto a harness, and it provides versatility and simplicity in various anchor building setups.

Various companies sell pre-cut cordelettes, but often the most reliable option is to head to your local gear store and buy the length you want.

Finally, you’ll need enough locking carabiners to secure yourself, your partner, your belay, and anything else you need to secure to your anchor. The carabiners connecting each piece of gear to your anchor don’t necessarily need to lock, but the ones connecting to you do. Check out our roundup for the ones we like.

SERENE-SA: What Does It Stand for?

Most anchor articles and instructors provide an acronym of some form. The first one I learned was SERENE-SA. Some use SARENE, others EARNEST. Acronyms are useful, especially at first: they provide an easy way to remember what to watch out for.

It’s also worth remembering that no acronym can tell you how to build the proper anchor for every situation. Only good decision-making can do that.

As you’ll discover, anchor-building is a game of compromises — the perfect anchor doesn’t exist, and that’s okay. We just need anchors that effectively manage risk within our practical limitations.

So here’s what all those letters stand for:

  • Solid (or Strong) placements
  • Equalized
  • Redundant
  • Efficient (or Timely, in some versions)
  • NExtension
  • Small Angles

In whatever order you prefer, these are the terms climbers use to talk about many anchor-building concepts. Here’s what they refer to:

Solid Placements

In my opinion, this is the most important of your concerns. Bomber placements with adequate anchors will be much safer than poor placements and an elaborate rigging.

Anchors are only as good as the placements they begin with.

If you start with bad placements, you’ll have to work hard to build a trustworthy anchor. If you have a couple pieces you could hang a horse off of, odds are good that you’ll survive. Two bomber pieces on clove hitches are safer than five sketchy pieces carefully linked.

All the rules for traditional placements still apply, but anchor-building calls for extra awareness.

As usual, suspect rock is a no-go. If possible, avoid anything that moves, jiggles, or looks less than inspiring. When rock does break it tends to be along the lines of features (cracks, seams, etc.).

Loose rock makes for an unsolid placement

Not solid

To prevent a catastrophic failure, place your anchor in multiple features whenever possible.

Whenever possible, use strong natural features like horns, boulders, or trees. Be wary here too: large trees may not be deeply rooted, and large boulders may be precariously balanced. If you sling a feature, make sure that it’s firmly attached to the cliff.

These anchors are valuable; a trustworthy slung boulder or tree can be one of the best anchors you’ll find.

Equalization

Equalization is one of the buzzwords of the anchor debates. It refers to how well an anchor distributes the load between pieces.

If an anchor could theoretically distribute a load completely equally (i.e., 50% each in a two piece anchor or 33% each for three), it would be completely equalized.

Unfortunately, no such anchor exists. Equalization is never perfect.

The equalization can be either static (valid for only one direction of pull) or dynamic (moves with direction of pull), but it will usually come with compromises.

Let’s take the example of the sliding X (or magic X, as some call it).

The sliding X is simple to set up: take a sling, clip it to two pieces, put a twist in one of the strands, and clip a locking carabiner through both the twist and the other strand.

A sliding X is dynamically equalized: if you pull the locking carabiner in different directions, the sling will shift so that both pieces are (close to) equally loaded.

A typical sliding X

Redundant

The definition of redundancy is: if any one element fails, the climber doesn’t die.

This rule of thumb doesn’t apply to gear like our belay device or climbing rope (we need those to hold up), but rather to anchor-building components like protection or slings. If one piece of gear blows, we want backup. If a sling somehow gets cut, the anchor will ideally still hold.

Let’s resume our example of the sliding X.

If the sling gets cut, there’s no backup — the basic sliding X is not redundant. One way of adding redundancy is to form the sliding X out of two slings.

This technique provides redundancy but creates more friction, which means that equalization may not be as effective.

No Extension

Extension refers to the amount of slack that would enter an anchor system if a piece of protection were to fail.

In our sliding X, if one piece fails the system is still connected — but the locking carabiner will slide sharply to the end of the sling. That will create a sudden load on the other piece, which may make it more likely to fail as well.

When possible, we want anchors that don’t extend if a piece fails.

To minimize extension, we could tie limiter knots in our sliding X. A small amount of extension could still happen, but it’s much better than the full extension of the sling.

Limiter knots minimize extension

Limiter knots minimize extension

Small Angles

This one is just basic physics — the greater the angle created by the lines of your anchor, the greater the force on each piece.

On pieces placed far apart, a downward load creates an extra inward force by way of the tension in the anchor. This multiplies the load on each piece.

To avoid any extra load, it’s best to keep the angles in your anchor strands small. That means placing pieces closer together, or using a greater length of anchor material.

This angle is far too big. Around 60 degrees is a good limit.

Efficient (Timely)

I left this one for last because (especially during the learning process) it’s probably the least urgent. That doesn’t mean it’s not important.

In the mountains, speed often means safety, and being efficient can be the difference between an adventure and an epic.

Plus, I can already hear the eager student: if we just tie redundant sliding X’s between each piece and tie limiter knots in each one, we’ll have a great anchor!

This is partially true. The sliding X is a valuable tool, but ideally we have at least three pieces in our anchor — not just two. That means multiple sliding X’s, which means at least four slings, plus limiter knots in each set.

Try setting that up efficiently, let alone taking it down.

This is why anchor-building is a little different from some other climbing skills — it’s less a formula, and more a set of tools you can use to solve problems.

The Cordelette

A three-piece anchor tied with a cordelette

To illustrate these principles once more, let’s take a look at another classic anchor tool: our cordelette. Cordelettes are versatile and can be set up in different configurations, but the most common is a simple overhand.

Again, this is a simple system to create: clip the cordelette to each piece, gather the strands from each piece, pull into one bunch, and tie an overhand knot.

If you gather your strands in the direction of anticipated pull, you have a partially equalized anchor.

Just as before, this solution isn’t perfect. It turns out that equalization is never as good as we would like: different lengths of cord stretch different amounts, so unless each strand of the anchor is the same length, the pieces will never be perfectly equalized.

What’s more, if the direction of pull shifts even a little bit, our equalization is thrown off.

So our equalization isn’t perfect. What about the rest?

This anchor system shows no extension — if any individual piece fails, it won’t cause a shock-load on the other pieces. It’s also redundant, because any piece or strand of cord could fail and the rest would hold. If we set it up properly, the angles can remain small, and because the system is so simple, it’s quick to set up.

So…cordelettes aren’t great at equalizing, but they are good at other things. Which brings us back to:

Compromises

Let’s take a quick run over what we’ve learned.

We want equalization, but pursuing equalization can sacrifice redundancy or extension.

We can create redundant systems, but they may sacrifice equalization or efficiency.

We can create systems with little extension, but they may sacrifice good equalization.

So how on earth do you decide?

As is so often the answer in trad climbing, you assess your situation and manage your risks. If you just finished a pitch that’s straight up (a constant direction of pull), a simple cordelette overhand may be most efficient.

If the line zig-zags, or if the next pitch sets off in a different direction, you might want dynamic equalization.

If you have three pieces you know are bomber, you may not need to worry too much about equalization — but if your only choices are sub-par placements, equalization might be essential.

What’s more, you’ll have to adapt all these concerns to the gear that you have available and the features that you have before you.

One more time, because it bears repeating: an anchor is only as good as the placements it begins with. Place solid gear and make sensible decisions, and you’re well on your way.

A Word on Directionality

While we’re on the subject of pitches, it’s worth mentioning one last concept you’ll need to know: when to build a multidirectional anchor.

Anchors all have to work when the pull comes from below — that’s where our follower is climbing from. In some circumstances, you’ll need an anchor that can also function with a pull from above or the side.

If the next pitch traverses out to one side, for example, your anchor will likely need to function with a pull from that side.

Always be aware of what direction of pull you need to plan for. Cams can be excellent multi-directional pieces, but it’s possible to protect carefully with passive protection as well.

Even when pitches don’t traverse, be aware of what the next pitch will bring.

The greatest possible load an anchor can sustain is if a leader falls from above it without an intermediate piece. Take precautions to avoid this situation as well — make sure that the leader gets a piece in as soon as they can, and make sure your belay is functional in that direction of pull.

Learning More

This is an introduction, but as I mentioned, it’s nowhere near exhaustive. Climbers have spent all sorts of time, money, and brainpower coming up with new ways to construct anchors. Some of these are practically arachnoid.

Elaborate testing has been conducted on equalization, extension, and the various compromises between. The equalette and the quad have both gained followings in various applications.

If you’re interested, I encourage you to dive down the rabbit hole and learn to your heart’s content. It takes some effort to find, but good information abounds in internet forums like these.

On the other hand, don’t get carried away. The upshot of most of the testing is this: in most real-world scenarios, equalization and extension are not the primary concerns. They are important factors, but they tend to come into play when gear failure is a real possibility.

The primary concern is (say it with me now) solid placements.

Anchor failures are extremely uncommon in climbing. For the most part, that’s because trad gear is engineered to hold large loads, and it does its job well.

This is especially true on frequently traveled routes, where the anchor locations will be places where rock is trustworthy and gear placements aren’t too tricky.

The best anchor system is one you understand how to apply well. So keep it simple, get bomber placements, and plan ahead. With practice, it will become like second nature.

In addition to the internet, books are an excellent place to learn more about anchors. Two recommended reads are John Long’s Climbing Anchors and Craig Luebben’s Rock Climbing Anchors: A Comprehensive Guide.

One of the wonderful things about anchors is that you can practice your systems almost anywhere — at the crag, on the ground, or even in your basement if you have a couple hooks to clip to.

The more you know and practice, the more prepared you’ll be when you’re out on the wall.

I wish you bon voyage and safe climbing.