X-Rigging Slings

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No problem Rumination, now on saying that I dont rig everyone like that, mainly anything over 50' I will. I do find that it does reduce the ride but its doesnt mean your groundy can't let it run. I know that a fishing pole isnt the best example but the easiest way I could explain it.

Ben
Bushwacker Tree
 
I don't generally get into really tall, really skinny trees (thank goodness!). Once in a while I might have to do an Auracaria, though, and taking the top off on those can send you for a serious ride. If I have access to enough slings and rings/shackles the next time I'm in that situation I'll give this a try.

It would be cool if someone could make a slow motion video showing this bending effect in action, with and without the fishing pole rigging.
 
<iframe width="560" height="315" src="http://www.youtube.com/embed/ofGCgVc4M7k" frameborder="0" allowfullscreen></iframe>If you go onto the Xman's youtube channel (search ArborX) he has a video there I think that shows them testing the slings and using spar pole rigging. Good video shows how much a spar will take rigged this way, not to sure about the slow-mo nver mind here it is youll have to fwd its near the end of the video. It starts about 8:26.

Ben
Bushwacker Tree
 
I watched the video (well only part of it, actually), but it still didn't really show what I'd like to see. Which is a full clear slow motion side view of a bare stem with some kind of reference marks that can indicate the amount of bending, with and without the fishing pole rigging. At the very least, he should have showed the difference on that 500 pound log between with and without rigging. I know, I'm a demanding guy...

After your explanation, the concept makes sense. But I still would like to see the difference in action.
 
When the piece tips over it has lateral force, thus pulling the stem somewhat at an angle when it's caught by the rope. That's what makes you go for a ride. If the force was only straight down you'd never go for a ride.

It does make sense. On the other hand, I can't remember the last time that I felt this would have been useful. May just be the trees I work on.
 
As stated by bushwacker this technique is viable/useful with very skinny trees. With trees that flex when loaded the load is not straight down the stem but is between the block and the porty. When the stem starts to bow side load is introduced, remember ropes can only apply force in the line that they run. By adding a few rings along the spar the rope is then forced to follow the run of the spar hence the rope will more follow the wood thus the force will keep the wood under compression where it is strongest. This technique is helpful if you are loading the spar to close to its failure point which I never really do anyway.....
 
I like to set up multiple blocks on a lot of the removals, but it is usually to set the highest block on a small diameter stem. It is nice on wide spreading canopy's. Having, let's say three blocks or x-rings, on a straight 30' stem seems a little silly.

On the point of how they were brought to market, I don't like it. It just kind of feels greedy. I think if he were to develop that ring, it would be a different story. It is not like the GRCS. If the common man were to build a GRCS, they would find with the cost and time involved, they might as well of just purchased the real thing. Most people wouldn't be able to build it as well as Greg. I think the x-ring is much easier to "do it yourself" for the common man. With that said, I don't want to knock the overall idea. I think the idea to use these in this field is good. It may not be something that we use everyday, but maybe like a speed line kit, it is good to have when you need it.
 
If I was ever worried about bending the tree that much, I'd put a redirect 90 degrees behind the pulley, at the top.

But, IRL I'd just cut a smaller piece.
 
A block does side load a tree.

Those slings/fish polling a spar makes next to no real world difference in reinforcing the trunk.

Let's say they managed to deflect the line 10 degrees by using a block and bowing the trunk. With a 500lb load, it would give the trunk 85lbs of support while lowering the weight on the block by 10lbs. On a 50' spar, 10 degrees of deflection would move the top 8.8 feet. But factor in the angle lost by the head height of the block (distance from the centerline of the tree to the inside of the rope bend). So lets say it would take 15* of deflection on the stem to yield a 10* deflection from the block. That equates to moving the top 13.4'.


Who here rigs like that? Point made?
 
Now if you could have said that with the voice of the Simpsons science geek that would have been awesome.:)
Besides don't the ,rings/bieners/shackles/xrings/antal rings/or what ever metal do hicky, need to be up tight against the trunk? I mean if they are "loose" does that not negate some of the benefit?
Besides there is no way I am going to catch a 500lb chunk on a bean pole, bombs away and the lawn be damned.
 
I can see the possibility of needing to disperse the load at times, but I still prefer to cut the force more dramatically by using the brake up top in those situations. Better to have 500# of force and the stem "reinforced" or to just have 250# of force exerted on the top?
 
flushcut said:
Now if you could have said that with the voice of the Simpsons science geek that would have been awesome.:)
Besides don't the ,rings/bieners/shackles/xrings/antal rings/or what ever metal do hicky, need to be up tight against the trunk? I mean if they are "loose" does that not negate some of the benefit?
Besides there is no way I am going to catch a 500lb chunk on a bean pole, bombs away and the lawn be damned.
Click to expand...

lumberjack said:
...But factor in the angle lost by the head height of the block (distance from the tree to the inside of the rope bend). So lets say it would take 15* of deflection on the stem to yield a 10* deflection from the block. That equates to moving the top 13.4'...
Click to expand...

Yep, exactly! Especially trying to rig down 500lb pieces on a tree so small your heels touch when standing on spikes!

And I agree Scott, regarding the friction up top.

I also agree with a need to disperse the load from time to time. My point is these slings do very little actual dispersement.

To go one step further, let's say you only get 5* of deflection at the block/sling. With that 500lb load, you're giving the tree 45lbs of support! That would be a good bra, but it does nothing for supporting a tree.
 
Yep, I think that is always the safest option. But when it comes to production and doing multiple jobs a day, the fewer cuts the better. I want to maximize the machines potential and try to be as efficient as possible, so the bigger I can rig the better, and multiple blocks helps me achieve that.
 
FJR said:
On the point of how they were brought to market, I don't like it. It just kind of feels greedy. I think if he were to develop that ring, it would be a different story. It is not like the GRCS.
Click to expand...

The part that pissed me off, was the " you can only buy these already spliced" deal.
Get real.
A product that is already on the market, and all of a sudden you can't splice the rope on it yourself.

Complete bullshit, and I'm glad Nick exposed him on treebuzz!
 
Im standing my ground on this one. The rocking you get from blocking down wood is usually the wood banging into the bole. ORRRR, the push factor against the bole as the cut piece hinges over. With a good ropesman, there is no taking a ride on the bole other then the what is caused by the wood on wood bang initially. If your groundman hits the brakes fast or just doesn't let it run at all then yes, I agree that the dog comes to the end of the leash while the log is travelling outward away from the tree. In that case, and in the case that the wood cant run at all, I see a side loading factor. Letting that piece run a bit and make its way back towards the bole with light friction resistance from the groundman creates the slightest bit on side loading and when he slows that wood down, its downward pressure. I will agree that there is a side loading factor, but its minimal, unless its a leaning tree of course.
As far as the idea of rigging a 500 pound piece off a a tiny bole, yes, you would have a problem with the tree bowing out. The comparison is unrealistic though. That's like suggesting rigging a 20,000# piece off of a 24" bole. Shits gonna break. Why, because the unrealistic ratio of downward force against the strength of the wood, the brutallity going to manifest itself in the first spot of imperfection on the tree. I do agree with your analogy Carl, but its only fair if you keep the ratio realistic I think.
To sum my thoughts up, your groundman has all the responsibility on his sshoulders of determining how the tree takes the weight. If he is shocking the load to a halt the instant it comes off the hinge, then yes, there is some side loading. My groundmen catch spankings for that.
 
Tucker943 said:
... The rocking you get from blocking down wood is usually the wood banging into the bole....
Click to expand...

Tucker, this is not right. This excerpt is from a Rigging Forces article in HSE Research Report 668 by Detter, Brudi, et al (Read: Big ass, complex, lot-of-math report.)
Bold-emphasis within this excerpt is mine.

David



However, rigging operations
will always generate considerable bending moments on stems, due to the angle of 32 to 42° at
which the peak force occurs in the lead of the rigging line.Secondly, the log still has considerable
speed when the peak load occurs and will gain even
more as it accelerates during the pendulum swing towards the stem.
 
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