Rigging point failure

[thood]

I have been wanting to post about this for a while now. On a large property line job at work about a week ago. We were removing trees overhanging a new steakhouse up on a top a steep drop off. Needless to say there was the need to rig about everything back to the property (wooded section) to leave to decay. There was a sourwood which had a hollow in most of the tree about 30 foot of a stub. We devised a plan to intall a remote block in a nearby white oak, beast of a tree. The block was hung on the limb, about 15 feet from the trunk. BIG, HUGE, mistake..once the tree was severed it rest on the ground, we had no knowledge of the decay inside the 14" limb (estimate). Once a couple of chunks were cut the limb broke falling rapidly to the ground. The one cutting was hit and hard hat was knocked off and he fell back. The one on the Hobbs was luckily on the right side of another nearby tree to provide a block. I was still bagging a throwline uphill, it was a HUGE eye opener.

One, our work IS and always will be full of variables to always stay alert and take home message ONE CAN'T DO ENOUGH TO PLAN..PLAN AND PLAN AGAIN. As I look back a lot of things could have prevented this accident. One, climbing to inspect the oak limbs before rigging, two always keeping the rigging at the branch/ stem union. Another idea is two blocks which would distribute the load more evenly. If we take the bit of extra time to rework a plan or in a way which may require more set up time..it can make all the difference in a potentially catastrophic event.

 

[Jamin_Mayer]

Good observations as to how to prevent this from happening again. Thanks for posting this.

 

[Treezybreez]

I hope the guy who was hit wasn't hurt to bad. It has been at the front of my mind to evaluate my rigging more carefully ever since it happened to me. Thanks for sharing.

 

[thood]

Treezybreez, none was hurt..it could have been a lot worse. The absolute need for PPE.

 

[chris_girard]

Glad you guys are all right and thanks for sharing your story.

I hate remote (sole) blocks as rigging points, especially if you're away from the union. Like you said, much better to spend the extra time climbing and inspecting your rigging/anchor points and using multiple blocks to distribute the loads.

 

[Raven]

Thank you for posting this, give us all something to think about, Always Be Careful, ABC,,,

 

[whiz]

Thanks for the share. Story share...food share...music share...gear share...education share...don't forget LOAD share! Glad you guys are ok

 

[Daniel]

You can't always trust your eyes..

Any questions at all, and its best to climb and set the lowering line by hand...

 

[whiz]

That's great advice Daniel. I know you can set a block remotely from the ground and even load share with some good manipulation of a throwline but I never do it. I always set my rig by hand no matter how long it takes. With pre-planning and decent set up skills it doesn't take that long to set up and tear down a 2 or 3 block rig. I know the old guard believes you should never climb a tree, or any part of a tree more than once and that to do so is just a huge waste of time but I don't know if I can agree with this and still support what I've learned about load sharing with relatively frictionless pivot points.

 

[Rickytree]

Also I think the weight would be times 2 because of the suspended rigging point.

 

[Treeminer]

Yeah its so easy to forget that your rigging point sees twice the load, and if you rig from a different tree and take that rope strait down the tree to its base then your force is directed back toward whatever you are rigging at about half the angle of the rope which puts a lot of sideways pull on your rigging tree. If I use a different tree I like setting a pulley from the ground but I make sure if the rigging point fails there is a decent limb under it to take over and if possible I secure the end of the rope to whatever friction device at the base of yet another tree creating sort of an equilateral triangle. This directs the force more into a strait downward direction on the rigging point and the rigging tree. Maybe this seems like a lot but multiple backs up are always incorporated into my plans so it requires no more time than other rigging methods. This way too if i don't have built in backups, then the "danger areas" are that much more obvious to myself and my crews as to where to avoid during loading.

 

[treehumper]

If you have a block set from the ground and the line tied to the base of the tree the force is up to 4 times the load at the TIP. Always worth having multiple blocks and load points to distribute the force.

 

[Blinky]

I've broken a rigging anchor in live white oak. It was all my fault, poorly selected and set from the ground, but still, I was pretty shocked by how easily that crotch failed given the size and species.