Worth mentioning having less rope in the system as you move down the tree as well. The rope absorbs energy, so the less you have, the less it absorbs. It's pretty crazy looking at peak force calculators (like Samson's), keeping all things equal except amount of rope in the system and how much that can raise peak force to the system.
Thanks for your comment 🙏 Great point, definitely worth a mention. So the ways in which this could have been prevented include; Cutting the piece smaller, using a higher capacity rope (or one with more stretch), adding more rope in the system (impact block installed on the rigged piece), reducing the distance to fall (between pulley and half hitch), and by letting it run (but move the truck first)
Glad you mentioned rushing and competitiveness as root causes, I've seen really senior pros make basic mistakes and break stuff/endanger ground crew because they were rushing. I always overquote on time and take it easy - if all goes well and you get done sooner, shave a bit off the invoice, happy customer. I've had scary near misses because I was rushing - have to consciously stop myself. Thank you for the video
They’re both contributing factors for sure! A lot of the time it does come down to the money/time on the job. If you’re under pressure to get done for whatever reason, that’s asking for trouble. Like you rightly said, keep the prices high and even the crap jobs aren’t that bad.
The distance between the half hitch and the block absolutely have in impact on the forces loaded on the system. If there were two identical scenarios, same sized piece with the same sized face cut in, but one half hitch was 1m away from the block and the other was 0.5m from the block. One would free fall for 2m until the block catches it the other would free fall for 1m. The one falling for 2m will have more kinetic energy and exert more forces on the rigging system. What you’re saying isn’t necessarily wrong about the cut because the size and position of the cut will determine the distance between the half hitch and the block.
@LukeDJohnson Look it it this way. The distance the piece falls is determined by where it falls from and where the fall stops. The end of the fall depends on where the block is placed and how far the rope man let's it run. Obviously, we want to block to be as high as possible to aid the stopping position. Where the piece falls from is determined by the cut. Where the knot is is located on the piece has no bearing on where the piece is falling from.
@@zaccheusI agree that the distance of the fall remains the same as long as half hitch is below the centre of gravity. My view is that by configuring the half hitch closer to the block will reduce possibility of slack getting into the system from the piece free falling resulting in shock loading.
@LukeDJohnson The amount of slack that enters the systems is also dependant on the distance of free fall and not the position of the knot. The entire rope is slack during free fall. The only way to reduce slack during free fall is to shorten the rope during free fall by having the groundy pull more rope through the friction device at the bottom of the tree.
@@zaccheus In the Arb Association Technical Guide for Rigging (UK Guidlines) it says: “14.3 How to Reduce the Potential for Shock Loading and High Peak Loads 14.3.1 Several factors affect shock loading and peak loads, most of which can be controlled or directly influenced by the operators involved in the operation: * Rigging technique selected: For example, when the pulley is below the load, snatching causes the greatest peak loads because the section of wood will momentarily free-fall before being caught by the system, which means there will be an inevitable 'impact' on the system. * Distance of fall: The further the section is allowed to fall, the greater the speed it will gain. If the falling section is then stopped suddenly by the system (snubbed off) the resulting shock load will result in a high peak load. * System configuration: A poorly configured system where the cut sections are allowed to fall further than is necessary before being 'caught' by the rope, or which prevents the free running and gradual slowing of the piece, or which has little or no flexibility/elasticity built in will result in potentially high peak loads.” My personal interpretation of this is by moving the half hitch closer to the block. You reduce the distance of free fall before it catches. It’s not that you reduce the distance of fall, that’s exactly the same, it’s the difference of free fall that may increase shock on the system. I could be wrong, I had to draw a sketch out to double check my logic, and I still believe it adds up to what I’m saying. Appreciate the debate though 🙏🤣 I will send you a copy of my sketch to your Instagram. Cheers
Great video brother, fellow climber here. It takes a lot to show mistakes, and that sets you in front of all the other keyboard warriors. In this case, having no chipper but a grapple loader/ tipper trailer available, I'd go with no rigging. Just make a cushion of branches, drop down a million fireplace fit logs, and bob's yer uncle. anyway, great lessons showed, cheers mate, keep on the good work! Thanks for the effort of editing and uploading, I know what it's like :)
Thanks for your comment, I appreciate the kind words 👍 We had a Bandit on site you can just about see it at the start. It was a long time ago now but yeah you're right. Cut it up into rings and drop it down. Plenty of drop zone available. It may have stretched the job out a bit longer and been more time on the saw but would have been the better option right here. Sometimes it takes mistakes to get better and that definitely happened after this job. I figured if I can learn from it so can other people. I've just given you a follow 🫡
@@LukeDJohnson that means a lot man, again, it takes a lot to share mishaps, but it's the best for the upcoming arborist to learn. That is why it's so valuable. Thanks again, mate!
@@andrehak Definitely. I find it interesting that the Aviation Industry literally have to report mistakes and near misses. If they fail to report it they will be penalised more heavily. All reports are published for all other Pilots to see and learn from. All about desensitising failure and I thought our industry would benefit massively from a system like this.
A half hitch would decrease the load on that carabiner by at least 50%. If not more, depending on Clutch (of the rope) You also want rope in the system to absorb shock that way it’s not all on the rope being cut by the apex bend in the biner. Because there wasn’t a half hitch all the shock goes to it. Add a half hitch, or 2, …or pull the rope go around twice then up under the overstrand to make a half hitch, the rope would be closer to the rigging point and then the clutching forces of the rope cushioning the forces and means what % wasn’t clutched (grabbed) then that goes to the carabiner. Clutching is what the rope will grab - species of tree obviously there are no clutching forces on a Sycamore vs a Scaly bark ass pine tree.
There was a half hitch used on all the cuts including the one that snapped. I agree with that you’re saying the half hitch definitely helps. In this case that wasn’t the issue 👍
Yep this video shows you what not to do. I’ve seen guys get crushed,lit up like a Christmas tree cut themselves out of trees when you are a climber and running a crew you are responsible for everything on the job you gotta watch out for obstacles and you guys won the ground before you start cutting
Yep there is a lot to learn from within the video. I prefer the crew leader to be on the ground as the climber needs to fully focus on the job in hand and not what’s going on around the chipper. But you’re absolutely right the climber is responsible for how the tree comes down.
Pretty sketchy having the grapple operator directly under the rigging as well. With a good rope man, you can get away with going big on 1/2" rope. He can run it smooth enough there's very little forces put on the whole system. Thanks for posting and breaking down learning experiences for the rest of us to learn from.
I'm no arborist, and it's been years since I've worked with ropes, but I do know that there's a difference between mountain climber's ropes and caver's ropes (regarding their elasticity). Do you guys even take those types of considerations in?
Thanks for your comment👍 Yes in Arb there is a huge range in ropes ranging in capacity and elasticity. Climbing Ropes differ from Rigging Ropes in their construction. In this case we were using a rigging rope but well beyond its capacity.
That is such a long fall - weight of piece × every foot it falls + it's own weight at the end of the fall. Get that block and half hitch closer together to minimize the weight put into the system.
I made this point in the video and also had a discussion with @zaccheus in the comments about this. We were having opposing views on whether or not this makes a difference. In my view it most certainly does. Thanks for the comments 🙌
@@LukeDJohnson sorry I made that comment a bit premature, later in the video I noticed you talked about it and were keeping the distance smaller. Though I definitely would keep it smaller up high also just in case for some reason it doesn't run. Anyway God bless and thanks for the video and response.
Cycles to fail on a rope are going to be a lot fewer when you’re maxing out the capacity of the rope over and over again. A 300lb piece drops far enough it can have a 3000lb shock load. Therefore a 3/4” rope was in order. I know that’s a 5/8” rope and block and I’d say it’s been used a lot looking at the condition of the rope. New rope yearly. Inspect your gear. Don’t work your gear to its max potential and a grcs would’ve absolutely been the answer for this bigger wood. Stop using port a wraps on big wood. The bend is to hard on the rope making rope management harder and it’s definitely harder on the rope. A $3500 grcs is key.
100% agree with everything you said. This was filmed 5-6 year ago while I was employed at a company. They did have GRCS and Hobbs but we didn’t use it on this job. Nowadays, I’ve got my own company, GRCS, full range of rigging ropes and I’m qualified to inspect arb equipment here in the UK (LOLER inspector) This mistake in the video was a key learning opportunity for myself 👍
Cutting the piece smaller, using a higher capacity rope (or one with more stretch), adding more rope in the system (impact block installed on the rigged piece), reducing the distance to fall (between pulley and half hitch), and by letting it run (but move the truck first) Hindsight is a wonderful thing 🙌
Not really used the Ultra slings much. My only issue buying expensive textiles is they expire within 5 years of use and after that they won’t pass a LOLER inspection. You can end up spending an arm and a leg on rigging gear. I can definitely see the advantages of them though.
@@LukeDJohnson yeah looked like 1/2” I’ve had the jacket on 5/8 tear and the log went running down! It was early in the job I was telling the guy to stand back and why.
Yer for me if on the rope. Doin top or negative. Make the pulley or ring close as can to cut no slack to build speed n load. Cheers good vid all can be better. Sure i can. Thanks
