Close Call: Rigging Point Failure

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TreeMuggs

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A couple weeks ago I had a very close call rigging out the last top on an ugly Silver Maple at the cemetery. My rigging point failed and a 25 ft chunk of log went freefalling towards the earth. Nobody was hurt – thank God. One stone got hit but it didn’t do any damage. As fate would have it, my apprentice wasn’t there that day to see and learn from what happened. After much thought and analysis, I believe it ultimately comes down to complacency and normalcy bias: the top was just too big, and I knew it.



“Normalcy bias causes people to underestimate both the possibility of a disaster and its possible effects, because it causes people to have a bias to believe that things will always function the way things normally function. This may result in situations where people fail to adequately prepare.” That pretty much sums it up. I knew the top was bigger than what I would normally take, but that’s all I could reach with the lift.

Do you know how many times I have done something similar when I'm in a lift? I end up cutting something bigger than what I am totally comfortable with, and, at least up until this incident, it has always worked out fine. It makes me question my own judgement in a way, like, if I was uncomfortable with it but it turned out fine, is it just that I have drawn the line in my head between what's safe and unsafe, in the wrong spot? You know, like can I actually take stuff far larger than what I first thought? I mean, you start thinking about tensile strength with the gear we use. When I was in school, we always talked about designing rigging systems with the rope as the weakest link. But I think, in reality, we have designed our gear to make the tree as the weakest link, in the majority of cases.

For anyone wanting more detail, I have a more in-depth article about this incident, available here:

https://www.educatedclimber.com/clos...point-failure/

I am embarrassed to admit that, right when this happened, I was thinking, ****, I don't want to share this with anyone. This makes me look like an idiot. But later that night, I had made a 180, and I thought, first, much of the time, I am an idiot, and second, this is exactly what I need to share with the world. This is the kind of stuff that can help someone. So, like I said in the video, I'm actually glad that it happened. It was a real eye-opener. If this helps someone, sometime, to second guess a decision, or think critically about a setup, then I am so glad that this happened. Go small AND Go home.

So, I wanted to hear from other professionals. What would you have done differently, or is it simply a case of "right to refuse"? Bottom line, I shouldn't have taken that top where I did. I knew it was too big right from the get-go, when I went up initially to set my blocks. I ignored my gut and made a huge mistake. But thankfully, nobody got hurt and I came away with a greater awareness of my own complacency as well as an excellent teaching video. So, any thoughts?
 
To be honest I'm not sure if I would have done much differently other than put the first block way lower for some better angles. If you had enough line you could have double blocked it with a rigging ring or something.
Thank goodness you weren't climbing this but it still must have been scary with you lift right underneath.
 
I watched a guy do the exact same thing but, dropped a branch onto power lines. He took out power to a neighborhood for about 3 days. Same guy did similar the week before, took a chunk out of his thumb with a saw but did not take out power to a neighborhood. For obvious reasons the power company no longer hires him.
 
Nice share, close calls are important to share so we can all learn! I also work in the avalanche world, and this is a big push the last few years. Nice debrief. This is a HEAVY paper but I have a feeling you might be into it and this is directly from the source. Even though it says recreational users at the top, we are finding that this also affects pros a great deal.

Human factors
 
Before watching the video I would have probably taken the top with it rigged off the stem you were cutting which would have been fine. I might have considered rigging a much larger piece off the secondary tip to avoid as much shock load which would have been catastrophic.

After watching the video I think I see something you didn't consider. In a normal loading situation if the branch exerts a ton of downward force the load will be doubled by the tail of the rigging line. In the video the force in the downward direction was just a ton on each stem but there was an extra ton of lateral force on both stems pulling them together by the rope connecting them. That force is in a direction that the trees aren't built for. To minimize the lateral force in the future you can use two separate rigging lines so when the load is caught it will be roughly vertical compression force.

Or you could cut a branch and wedge it between your anchor points to absorb the compression force. I have never tried it but it seems like it could work.
 
I agree that the lateral pull is an unnatural force on the tree. It seems to me that a tree could take a greater force pulling nearly straight down as opposed to a sideways pull. I didn't catch exactly what you were using for a block. Was it an actual pulley block or rings? I have been using aerial friction for the last year and it's amazing how much less the rigging point flexes and moves using aerial friction . I don't hear a lot about using a pole saw in the tree but I do it more often than I'd like. I'm talking about a Stihl telescoping, heavy, long, gas powered, shoulder tearing pole saw. I'll go as high as the bucket will go, and use a throw weight to set the line and have my entire rigging set sometimes 12 ft higher than I could go otherwise. Sometimes it's hard to find the right spot to hang the rope in. You have to make the notch first. It will take a few minutes to set up but has saved me from catching something bigger than I feel comfortable with or having to climb something sketchy multiple times. The fishing pole method might have changed things. And it might not have. I have had to catch pieces before that I was pretty sure couldn't have been totally stopped before hitting the ground without something breaking. So I would have the ground man get less wraps on the brake. Deliberately not enough wraps so it wouldn't be possible to stop the load, but just enough to slow it down. There's a fine and dangerous line there. First of all you would have to be able to allow the piece to hit the ground with some force. Everyone has to be aware of what is going on and the ground man has to make certain there is no kinks, loops or knots in the rope or any chance that anything could snag or get caught around anything such as an arm or leg on the way down. It's dangerous but sometimes the only choice.

You got the tree down with no damage and no one was hurt. So it could be considered a success. A learning experience. There have been a lot worse things happen. Thank you for sharing these vids. Be safe.
 
We have access to a 60ft spiderlift through a friend, so that's the size of lift that we were using. No, it was not ideal for this particular tree by any means, but it was still safer than climbing. This tree was sketchbag. This is one of the biggest cemeteries in the city, and they let stuff go way, way too long. But at the same time, they are our biggest client, so I couldn't just pass on the work. Yes, at the point that I had to make that final cut, I was way too invested to just pack it in and tell the guys that we would have to figure something else out.

As far as the rigging is concerned, as a concept, I have always split the load between at least two spars. This concept however makes far more sense when the spars in question are at roughly 45 degree angles, so that they load in compression. The leader that broke in this case was basically vertical, which meant that it was being side-loaded. It snapped at a big squirrel's nest 25 feet below where I was cutting. There were 3 little gaffers all curled up inside. I should have been much more critical of that spar and done a much more thorough inspection before rigging off of it, but it had been supporting a live crown, so I figured it would be ok.

For my first 3 years, I used natural crotch rigging almost exclusively, and I agree, it makes more sense in a ton of situations. In this case where I was using pulleys, NOT splitting the load would actually have been much safer.

Like most accidents, it was not just down to one single error, there were a whole bunch of things that I did wrong that compounded to produce that result. What I didn't explain very well at all in the video is that, in the moment, the thing that I was actually the most concerned about was that big hanger, which completely blinded me to the actual danger staring me in the face...
 
Glad your safe I cut stuff smaller than most. I have had experiences like yours which caused me to go small. There was a time I hung half trees static and rigged whole tops but I'm older and those days taught me kissing a spar at 40 is nothing like it would be now. I have bid a few jobs lately including the cost of 90 foot snorkel because A. I have nothing to prove to anyone and doing the impossible is not as cool to me as it was in my 30s n 40s B.If they cannot afford my safety then they cannot afford me C. I'm not quite ready to leave this world and would prefer natural causes to be my end.
 
I used that rigging technic for years mistakenly beleaving i was shareing the weight between both points. But the reality was i was creating forces many times the weight on my rigging points compounded by side loading.
Physics can be hard to comperhend sometimes( at lest for me.) Glad no one or anything was hurt. Thanks cor sharing.
 
I used that rigging technic for years mistakenly beleaving i was shareing the weight between both points. But the reality was i was creating forces many times the weight on my rigging points compounded by side loading.
Physics can be hard to comperhend sometimes( at lest for me.) Glad no one or anything was hurt. Thanks cor sharing.
I still use it at times but not where failure is eminent and I use it for a different reason. I use that set up as a built in shock absorber if a suitable neighboring tree is present!
 
Glad you are all safe.

Looks like the single rigging point below your cut would have been fine since it held both branches without failing.
 
Portawrap? How many wraps?


Great question and also at 4:46, what he said about the lift affecting the outcome.

Of course, just climb out rig a small section from higher up , send it and let it run.

Maybe not though being deemed unsafe to climb. Those chewed up maples get scary when you look at them.

And really, good margins of personal and crew safety and not such a bad margin of property saftety were evident. What? A crusty old pecker pole of a maple really going hurt a rock that's stickin half out the ground? And anyone who is going stand below that like it has no chance of breaking is probably better off dead anyway... well not for him but good for me and you.
 
Muggs I hope your ok you just sorta quit posting, most here know stuff occurs don't let it beat you up, all in all you still effectively had the job planned fairly well. You did several things well; especially placement of yourself the lift and the men! Sometimes we do it on auto piolet, other times we knowingly plan for the what if. If I had a grand for every time I screwed up I could retire and probably sail the seven seas! I fortunately like yourself set up my site for the what if's and have never endured a serious injury as a result!
 
Hey TreeMuggs massive thanks for sharing your close call, we've all made mistakes and it's important we can all be open about them and learn as a community. Obviously with hindsight the top was too large but in your situation I probably would have gone for it too, but I like to think I would have placed the first block alot lower (easily overlooked though) so the force compressed down through the stems instead of pulling them together as your setup rang alarm bells with me, I think that would have just been ok. Now having seen the video and knowing how even that slightly modified setup would be pushing the rigging points so close to failure I will think twice in future when a situation like this arises on one of my jobs. Really appreciate the share it's not the sort of thing you usually get to see and definitely helps to take the guesswork out of rigging big lumps
 
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