question about shock loading a rope and blocking

zbanghead.gif
here it is since you couldent find it!

i find it funny how a buncha old grown men have arguments over these subjects and argue with such passion and emotion. im going to just sit back and drink my beer.
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Yes I AM OK with working within a 15-20% ABS load limit, providing shock loads are controlled and vector forces are directed to ensure the tree will not fail... I do it all the time. 10% is an arbitrary figure. When a person does not understand how to control shock and manage vectors, then he better stick to 10%. I AM quite comfortable exceeding 10% in low risk situations..



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How do you know the weights that you are putting on your ropes? Do you own a dynamometer or do you have some sort of upgraded GRCS fitted with a weigh scale that nobody else has?

You said 40' red oak leads, now maybe you don't have the same red oak down there (common names could be different), but here during a wet spring in an open area where the tree could grow alot of leaves a 40' lead could weigh well over 3500 or 4000 lbs

Heres on that oldirty posted, a 6500lb pick of oak, no leaves and most of the water from the sapwood would be down in the roots and scaling it to the climber I'd say its 40' or less

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Are you sure your only loading the rope to 15-20% of the ABS?
 
If you can't seem to teach the idiots on here anything then why do you keep trying? "Insanity is doing the same thing over and over again and expecting different results" Albert Einstein.
 
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Once again I have to explain it to you Chip... How thick are you that you can't understand the concept?

Yes I AM OK with working within a 15-20% ABS load limit, providing shock loads are controlled and vector forces are directed to ensure the tree will not fail...

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Suit yourself, your rope doesn't keep the same ABS the way you use it. You destroy most of the ropes best properties when you yank it with a skid steer.



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do it all the time. 10% is an arbitrary figure. When a person does not understand how to control shock and manage vectors...

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I love when you talk like this as though you understand what you're saying. this is what I mean by parrot-phrasing.



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THIS IS THE POINT:

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No it's not the point. It's your attempt at redirection because you know you are wrong and unable to admit it. We're discussing rope and shockloading, primarily in blocking situations. The tree is usually not an issue when your blocking unless it's very dead or butt rotted. This is Daniel folks, back him into a corner (which is easy by the way) and he wiggles around and evades.


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Watch the video.

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This is too easy. I'll put my 16 year old son... no, my 13 year daughter on the load line of that test bed and we'll land that weight over and over, all day long on a piece 1.75 Zing-it... which doesn't stretch much. It's not the rope, it's the roper.


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Stretch in the line will greatly reduce the load put on the tree.

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This is what I'm talking about when I say Daniel only understands examples, not principles. The difference between 2% stretch and 4% stretch is not great, significant yes, great, no. Further, shock absorption due to elasticity is affected dramatically by HOW MUCH rope is in the system. You would think Daniel would be all over this since he knows so much about dynamic rope and all.

Tell us about fall factor Daniel... and we'll know if you looked it up.


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If a rope breaks I AM going home for dinner and maybe the only damage done is to the lawn,

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If you broke a rope you failed utterly, you SHOULD go home and not come back.

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Chisholm's abscence around here is HUGE! For some reason you all can't hear it from me, no matter how I try to explain it. Two sentences from him and you all would shut right up..

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Why is that 'HUGE'? Mark has never embroiled himself in this petty crap before, why would he start now? I do this for fun.

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Big Jon sent me an email after the white oak riggin video, congratulating me for the rigging and telling me to stop trying to teach this stuff.

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He gave you great advice, take it.
 
Josh,

lets look over the original question.
when dropping wood down the factors that need to be considered vary largely due to the object that is being dropped...WOOD...through out the year wood weights vary due to water transport...we have a green log chart availible for reference..although experience with its use is helpful..
next we have the rigging point which can be any thing from the tree being removed to a crane over head to an adjacent tree.structural integrity of the tree being used as a rigging point is a question that needs to be examined..as is the angle of the cranes boom or the distance that the adjacent tree is fron the wood to be removed...next is the number of points (places where the rope will bend or redirect its angle)in which the rope will travel from the piece being dropped to the ground worker running the lines... then the type of rope being used, meaning the ropes construction and materials used in that construction and because of this the rope will have various things to be looked at when rigging, such as the ropes tensile strength,working load limit,and days of service and the history of its working use. then the techniques used will have a big impact on all of the above factors..such as the experience of the ground workers using the ropes as well as the angle of the notch used...if the piece will run or if it will stop before lowering (the shock load factor). Once you understand these factors and the various applications you will be ready to apply them in the field.. Hope this settles the confusion..
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SteveP.... southcountytreeservice.com

"love trees"
 
Steve outlines the factors well. So how do you take that and make it useful when you're on a spar? It's hard because calculating stuff on a spar isn't practical, you need a plan and I think that's what you were asking for in your OP.

How big of a piece can you take with a given rope? If you intend to hold it fast without letting the rope run (snubbing), you can calculate piece size on the ground using a 10:1 safety factor and be safe every time, if you use a block. I think you'll find that 700# wood is plenty big if you're kinda new to blocking. Blocking big chunks is nerve wracking at first, ease into it. Besides, when you do small pieces you'll develop a faster 'tie-cut-lower' cycle and give your ground person more experience figuring how much friction to use.


If your groundie can run rope, you can take MUCH bigger pieces once you have the hang of it but bigger pieces aren't necessarily faster. The groundie has to untie and clear the LZ between cuts, big pieces have to be cut, take longer to move and keeps your help under you for longer. Big pieces are fun but they aren't necessarily good tree work.
 
If your groundie can run rope, you can take MUCH bigger pieces once you have the hang of it but bigger pieces aren't necessarily faster. The groundie has to untie and clear the LZ between cuts, big pieces have to be cut, take longer to move and keeps your help under you for longer. Big pieces are fun but they aren't necessarily good tree work.

-I like this thought. I had a guy on our crew that wanted everything BIG. I tried to explain that the LZ needs to get cleared, and other factors involved with the whole job. He doesn't work with us anymore.
-I often say 'We don't cut trees down, we put em thru that yellow hole over there (chipper).' That seems to make sense to the customer who is trying to understand what the hell we are doing with all those ropes and pulleys.
 
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Reg & crew, super smooth!


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This morning Mom and I went out for breakfast. I showed her the video. Here are her comments:

WOW!!! That's a long way up!
Those are big pieces.
What did that land on? [To the pic of one of the lower pieces that dumped onto the log pile at the base and didn't tip over.]
 
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Yes I AM OK with working within a 15-20% ABS load limit, providing shock loads are controlled and vector forces are directed to ensure the tree will not fail... I do it all the time. 10% is an arbitrary figure. When a person does not understand how to control shock and manage vectors, then he better stick to 10%. I AM quite comfortable exceeding 10% in low risk situations..

Its going to put a lot less stress on the tree to use a line with a lower ABS and more stretch.. That was the point of the Yale video.. How F'in stupid are you people that you can't get that concept.. Its frustrating that I doesn't do any good! Where is the beating your head against the wall icon anyway?


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Check out this vid at 1:55.
http://www.youtube.com/watch?v=0xEbjtEO2yU
He's not exceeding 15-20% at all.
zbanghead.gif
 
Pardon me, by no means a derail. I just merged a couple of blocking videos together after reading through the thread, for anyone not familiar with the subject....originally promotional stuff so ignore the text that flashes up from time to time. Shock loading talk, too heavy for me tonight. Have a great Christmas guys: http://www.youtube.com/watch?v=BjqJs7YYnMo
 
Daniel, I will say, there is probably a good place for Polydyne in our work and i would like to try it.

I will have to be cautious as I might not be use to the stetch and don't want to make a mistake like Tom did.

There has been about 5 or 7 times a groundman messed up and bounced me around more than I ever wanted. In those cases, I bet I would rather have been using Poydyne to lessen the wiggle.

that being said, you still suck.

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