Mountain Project Logo

Equalizing the Middle Anchor Leg

Original Post
JoeLars41 · · Unknown Hometown · Joined Mar 2015 · Points: 60

(Long-time cruiser of MP, first foray into the den of vipers…)

This question relates to building a three-piece equalized anchor using accessory cord or webbing. I often find that when tying a knot for the master point, a little slack creeps into the lines and skews the equalization. This is why I use clove hitches on the outside pieces – so I can re-adjust the tension. The issue is what to do with the middle leg. How do you adjust the middle leg when it isn’t quite weighted enough?

And to the pedagogues out there ready to spring on me with “learn how to tie a master point properly,” thanks in advance. Of course, if the equalization is way off, I’ll re-tie. But under circumstances in which time is if the essence, etc., what is an acceptable solution? The question is how to adjust the middle leg, not how to tear it down and re-build.

Here are some solutions offered by friends – none of which I find very satisfying:
a) Twist the middle leg once or twice to take up the extra length
b) Use a clove hitch in the middle leg to take up that extra little bit of slack
c) Do nothing and just rock some old-school serial redundancy

Any suggestions?

Bill Lawry · · Albuquerque, NM · Joined Apr 2006 · Points: 1,812

d) Stance with 'c'

:-)

Jon H · · PC, UT · Joined Nov 2009 · Points: 118

Either 'A' or just do nothing at all. Testing has proven over and over and that equalization in the real world is a myth and borderline unachievable, so no point in worrying about it.

Get good gear placements, tie a logical, uncomplicated master point, and move on with your day.

Sam Stephens · · PORTLAND, OR · Joined Jan 2010 · Points: 1,090

Sliding x with limiter knots

wivanoff · · Northeast, USA · Joined Mar 2012 · Points: 674

If you are already tying clove hitches on the outer legs, wouldn't you just adjust them so that the middle leg is loaded properly?

Larry S · · Easton, PA · Joined May 2010 · Points: 872

Just wrap it around the carabiner once if there's extra slack in it.

rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526

Sadly, the best answer is to learn to make that master point knot without messing up the strand tensions.

An extra turn around the middle carabiner only works if the cord used in the turn is exactly right---which means it will usually make the middle strand too short or too long.

Sliding systems with three anchor points really don't work at all.

If, as you say, time is of the essence, quick adjust to get two strands right and run the rope from your power-point tie-in to the piece with the slack strand and get the tension for that piece right in the rope.

Unless you are leading in blocks or the same person is always leading or in some cases if there is a party of three, you will get a better anchor with better tensions if you tie in with the rope and clove hitches and forget about the cordellette.

Or use a cordelette with loops at each end and set it up with clove hitches the way you would with the climbing rope.

Note that once you start using clove hitches, your arm strength goes down to the strength of one strand rather than two.

Greg D · · Here · Joined Apr 2006 · Points: 883
rgold wrote: Sliding systems with three anchor points really don't work at all.
Actually, they work quite well with an equalette and someone competent at this technique. I'm sure a long winded reply will follow.
rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526

No need for wind on this. Every test I've seen suggests that with three anchor points sliding systems can actually be worse than fixed-arm ones.

Then you have things like the three-point equalette in Long and Gaine's anchor book that starts out with 50-25-25 equalization at best. (It is actually worse than this because there is a double strand going to the 50% anchor and single strands going to the 25% anchors, shifting the load even more to the 50% anchor side.) This isn't exactly a sliding system since two of the arms are cloved to the anchor points and don't slide, but genuine three-strand sliding systems may be worse. This type of system is better on four anchor points than three.

I assume when you say "works quite well" you have some links to data that supports that---I'd be interested in seeing it and would be happy to either retract or at least modify my claim.

John Vanek · · Gardnerville, NV · Joined May 2013 · Points: 0

Maybe the issue is how you prep the cord before you tie the master knot. Try hooking a finger over all of the cords and pull them taught, then keep that pressure as you begin making the overhand master knot. This can keep minor slippage from occurring.

johnnyrig · · Unknown Hometown · Joined Dec 2011 · Points: 105

Maybe even worse yet is what happens when you factor in the distance from each piece to the master point, and the fact that even though we attribute a quality of non-stretchiness to things like accessory cord and webbing, it does indeed have some stretch, so that after you make a good show of actually equalizing the legs, they don't remain in equal tension once they are weighted due to the amount of stretch corresponding to those unequal lengths. Maybe strive for keeping the longest leg the one that utilizes the doubled lenght of cord, and the two shorter legs as singles. Or specifically put more tension in that leg, accounting for the stretch that will occur. Best yet, give up climbing and take up rug weaving, so that all that precious cord doesn't simply go to rot.

kenr · · Unknown Hometown · Joined Oct 2010 · Points: 16,608

I forget ... from the last couple of times this sort of question came up on MP ...
Did anyone find a halfway-documented case in the last twenty-five years in North America of a 3-point rock anchor that failed due to lack of Equalization?

M Mobley · · Bar Harbor, ME · Joined Mar 2006 · Points: 911
kenr wrote:I forget ... from the last couple of times this sort of question came up on MP ... Did anyone find a halfway-documented case in the last twenty-five years in North America of a 3-point rock anchor that failed due to lack of Equalization?
it could happen any second now with all these kids who spend too much time at the mall
csproul · · Pittsboro...sort of, NC · Joined Dec 2009 · Points: 330
kenr wrote:I forget ... from the last couple of times this sort of question came up on MP ... Did anyone find a halfway-documented case in the last twenty-five years in North America of a 3-point rock anchor that failed due to lack of Equalization?
If an anchor failed (which is rare enough to begin with), how would you determine that lack of equalization did or did not contribute to the failure? And why just in North America? Do anchors fail differently in the rest of the world?
JoeLars41 · · Unknown Hometown · Joined Mar 2015 · Points: 60

Yeah, so we're talking about a clove hitch worth of slack generally. I just wasn't sure the implications of using a twist or a hitch for anchor strength, etc.

I suppose it's also a matter of personal pride. I don't need to build an uber anchor every time, so I should get over myself and choose a real problem to think about.

Thanks everyone.

rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526

I've heard about the total failure of a belay anchor about once every ten years for the 58 years I've been climbing. Of course no one knows after the fact what contributed to the failure as csproul says. Of the two catastrophic failues I recall at the moment, one was a three-point anchor and one was a four-point anchor. If that four-point anchor had been fully equalized, then each piece would have failed at lees than 2 kN, which seems pretty unlikely for a belay anchor, so there is a reasonable possibility that an unequal load distribution was a contributing factor. It is, however, a very long distance from "reasonable possibility" to any kind of reality, and we'll never know of course.

Although equalization in any strict sense is both unattainable and usually not particularly important, the sliding systems that are supposed to deliver this mythical distribution never seem to go away. (That said, a sliding X is a fast if irredundant way to clip a pair of bombproof bolts. But in this case you could care less about equalization and the sliding X is just a convenience.)

In any case, this is all a tangent to the OP's request for a way to adjust the fixed, not sliding, arms of a cordelette.

Avi Katz · · Seattle, WA · Joined Sep 2010 · Points: 260
csproul wrote: If an anchor failed (which is rare enough to begin with), how would you determine that lack of equalization did or did not contribute to the failure? And why just in North America? Do anchors fail differently in the rest of the world?
because the American Alpine Club is kind enough to publish an annual Accidents in North American Mountaineering book that examines case studies from significant accidents
patto · · Unknown Hometown · Joined Jul 2012 · Points: 25
csproul wrote: If an anchor failed (which is rare enough to begin with), how would you determine that lack of equalization did or did not contribute to the failure? And why just in North America? Do anchors fail differently in the rest of the world?
In other parts of the world they don't equalize. They equalise. ;)
csproul · · Pittsboro...sort of, NC · Joined Dec 2009 · Points: 330
Avi Katz wrote: because the American Alpine Club is kind enough to publish an annual Accidents in North American Mountaineering book that examines case studies from significant accidents
Thanks. I've written a couple of those (and unfortunately been the subject of one). In reality, when an anchor fails, it is nearly impossible to tell if better equalization (equilisation) would have prevented the failure. The ANAM reports do tell when anchors fail, but they rarely discover the root cause of that failure unless it is really obvious...other than to say the anchor was crap.
Greg D · · Here · Joined Apr 2006 · Points: 883
kenr wrote:I forget ... from the last couple of times this sort of question came up on MP ... Did anyone find a halfway-documented case in the last twenty-five years in North America of a 3-point rock anchor that failed due to lack of Equalization?
There was an anchor failure a few years back that led to the death of both climbers. Witnesses reported hearing three distinct pops at the time of the event. Likely each peas got loaded one at a time. But you decide.nobody could say for sure equalization would have prevented this tragedy.but good load distribution is a valuable strategy to employ in my opinion. carry-on
Robert Cort · · Unknown Hometown · Joined Oct 2009 · Points: 800

Why don't you just work some of the slack through the master-point knot before you tighten down on the master-point knot. Yes, then you will have unequal loops in the master-point, but that doesn't matter too much, because the load goes through the master-point to the now (hopefully) equalized anchor points. If I understand your question properly, it would result in one of three loops in the master-point being slightly longer than the other two - I wouldn't sweat that.

Instead of a cordallete, you could just a piece of cord (not tied into a loop) and tie a frost knot for the master point.

Of course, you could build the anchor using the rope, but that is a thread of a different color ;-)

Guideline #1: Don't be a jerk.

General Climbing
Post a Reply to "Equalizing the Middle Anchor Leg"

Log In to Reply

Join the Community

Create your FREE account today!
Already have an account? Login to close this notice.

Get Started.