broke my first rope

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The friction at the shackle as well as the fulcrum point and tension... Agreed, Trev. I think Daniel gets it, too. I'm glad for this thread, though, it gets all of us thinking.

-Tom
 
I wouldn;t disagree with that... NO science to back that up... just gut instinct... Still I now have to re-think the balance point rigging and must agree (though somewhat reluctantly) that Jomocco had a point in his words of caution about near balance point rigging, as the hinge becomes the fulcrum as long as it is in tact.. so as the limb is moving down and away from the overhead anchor point, the limb acts like a giant lever putting a lot of added force on the line...

I thin the near balance point rigging threads were in the video and rigging forums.
 
have you thought about the shackle if it was a crosby there is imprinted load ratings your rope probably cut on one of those as they would be highly abrasive to a fiber line
 
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Thanx Blinky, I'mallways tryinto broaden my horizions when it comes to rigging ropes and blocks. I've seen heat transfer to figure 8, but to the rope ? I thought the rope kept a movin, the idea of lettin it run was to not shock it and feather it to a stop. Maybe Norm can chime in on this, Thanx Allen

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Even if a polyester rope is on a rope friction device, porty, figure 8 descender, and the lowering person is letting it run fast, enough heat can build up to melt the rope to the device. I've seen 2 steel large porty's with melted polyester rope on them. On one, an eye witness told me the rope had to be pulled off with vise-grips. It was actually melted to the porty, "They were one." I'll see if I can find the digital image I took of it.

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Could this be like post avalanche freeze-up? This is where the snow particles are in motion and grinding against one another creating heat and slight melting. Upon stopping the snow/ice refreezes like concrete.

In this case, is it a matter of the porty getting so hot from friction that it transfers the heat to the rope, when the rope stops and is stationary, it melts, then re-solidifies (freezes), whereas the rope which passed through became glazed?
 
I can't speak to the thermodynamic principles in play but I've seen 9/16" stable rope ruined twice by friction. Once over a biner (described above) and again when lowering a hangup on a porty that got away from the roper. Both were severely damaged for long continuous lengths so it couldn't have been heat transfer from the device after the rope stopped.
 
Another thing when thinking about melted rope and portys is that the steel will hold heat for a while. so if your lowering piece after piece the porty is just going to get hotter and hotter. Groundies may not feel the heat due to gloves.
 
I quickly ran through some numbers and here is what I get

True blue 7300 lbs tensile new
-general use I will use 30% loss, the rope is now at 5110 lbs
-use of a knot 40% loss, now at 3066 lbs
-sheave diameter loss, 2146 lbs

and if the weight of the limb created enough friction to get up to 350 F you would be losing 50% which puts you very close to the weight of the limb. Hopefully my numbers aren't too far off:)

Unfortunately we learn more from mistakes than the 1000's of times we do it right. Good on you for talking about your mistakes, we all make them, we don't all like to talk about them though.

Brent
 
Hi,
On even a semi-balanced setup, the angle that the rope forms ABOVE the limb can magnify the load right out of sight, in much the same way that steep sling anles do. This is why cranes have different pick capacities at different boom angles.
As for other deductions, I believe it is a mistake to deduct cumulatively, so for instance one wouldn't deduct for strength lost to sheave radius plus strength lost to a knot, but rather to whichever one was greater.
Fair leads,
Brion Toss
 
In retrospect there is no question in my mind that the movement of the piece relative to the overhead rigging point, makes a huge difference in the force.. If the piece hinges/swings sideways there is going to be a lot less force than if it falls straight down and away from the block..

Combine that with a piece that should have been taken in two cuts, and a shackle instead of a block and there are multiple causes for this accident.. Take away any one of the factors and all would have went well.. another lesson reminder...
 
You show up on a 4' plus dia. TD with no block,and a highly degraded 1/2" climbing line for lowering. You consider the tensile strength of the line and not the WLL which you should consider as this is a dynamic not a static situation.

Then you decide to bend this over an immobile 1" wide clevis crotch.

Then you decide to go big despite gm's warning even
though you have a significant target under it.

Breaks at the shackle.

Now 2 years later you are giving lessons to a forum of experienced riggers. Go figger.
 
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In retrospect there is no question in my mind that the movement of the piece relative to the overhead rigging point, makes a huge difference in the force.. If the piece hinges/swings sideways there is going to be a lot less force than if it falls straight down and away from the block..

Combine that with a piece that should have been taken in two cuts, and a shackle instead of a block and there are multiple causes for this accident.. Take away any one of the factors and all would have went well.. another lesson reminder...

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In other words - You didn't do anything wrong really. If only one variable changed slightly, everything would have went well.


"Take away any one of those factors, and all would have went well..." I think that quote would look good on your gravestone.


Keep going big, Daddio.


SZ
 
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You show up on a 4' plus dia. TD with no block,and a highly degraded 1/2" climbing line for lowering. You consider the tensile strength of the line and not the WLL which you should consider as this is a dynamic not a static situation.

Then you decide to bend this over an immobile 1" wide clevis crotch.

Then you decide to go big despite gm's warning even
though you have a significant target under it.

Breaks at the shackle.

Now 2 years later you are giving lessons to a forum of experienced riggers. Go figger.

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Really does make you go hmmmmm. I shudder to think about any wannabe tree guy watching his latest video and actually considering it to be "training".

SZ
 
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You show up on a 4' plus dia. TD with no block,and a highly degraded 1/2" climbing line for lowering. You consider the tensile strength of the line and not the WLL which you should consider as this is a dynamic not a static situation.

Then you decide to bend this over an immobile 1" wide clevis crotch.

Then you decide to go big despite gm's warning even
though you have a significant target under it.

Breaks at the shackle.

Now 2 years later you are giving lessons to a forum of experienced riggers. Go figger.

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Really does make you go hmmmmm. I shudder to think about any wannabe tree guy watching his latest video and actually considering it to be "training".
EZ and Treevet you guys are right to rag out this dude, what is so funny is that any sensible tree worker with enough experience can see staight away that these techniques are peculiar to say the least and I personally stick to proven rigging methods, no way in Rome am I taking instruction from a youtube video especially with so much egos out there( there are a few exceptions ). If I care for some instruction I jolly well know where to find it. Someone is going to get hurt someday from some of these " learning " videos which in my opinion is being very irresponsible on the poster's part. JMHO.
frown.gif
 
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You show up on a 4' plus dia. TD with no block,and a highly degraded 1/2" climbing line for lowering. You consider the tensile strength of the line and not the WLL which you should consider as this is a dynamic not a static situation.

Then you decide to bend this over an immobile 1" wide clevis crotch.

Then you decide to go big despite gm's warning even
though you have a significant target under it.

Breaks at the shackle.

Now 2 years later you are giving lessons to a forum of experienced riggers. Go figger.

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Really does make you go hmmmmm. I shudder to think about any wannabe tree guy watching his latest video and actually considering it to be "training".

SZ

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Especially when he literally states that it is training. Been watching his zany vids for years but many involve dangerous technique bypassing the earliest lessons learned....

if you get hurt...you are doing something wrong.

Maybe if there has to be some censorship on these forums, then it should be in the direction of safety to the novice.

His vid on the other thread with all the forces strung like a bow and arrow with the business end of the arrow pointed right at the climber is a first year lesson a rigger learns, hopefully with minimal pain. If detachment happens during the cut or hinging 1. you can get speared, or 2. the long section above the tied point can come in and ram you.

Murphy's law comes into effect if your senses are not operating like they should (or you are Murphy himself I suppose) "anything that can go wrong, will go wrong (esp. if you set it up to go wrong)".
 

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Not to derail this learning thread BUT did anyone else notice some 18 positive posts and just 4 negitive,could it be that two people are close minded about learning? Enough said we now return you to the thread.
 
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Not to derail this learning thread BUT did anyone else notice some 18 positive posts and just 4 negitive,could it be that two people are close minded about learning? Enough said we now return you to the thread.

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And just what did you learn from this thread Jersey? To bring the right equipment to the job and if you forget it, not to use under rated equipment? If you do wrongly choose to go ahead and use it, to use it in a way that puts the least stress on it and/or doesn't damage it any further?

Thought so.

I suppose a "non close minded" learner like yourself must have many credentials and an extensive library. Please post credentials, certifications, licenses and amount and type of continuing education units you have attained and books in your library so we "2" can learn and emulate you.

Thanks, humbled by your presence,
Treevet.
 
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I suppose a "non close minded" learner like yourself must have many credentials and an extensive library. Please post credentials, certifications, licenses and amount and type of continuing education units you have attained and books in your library so we "2" can learn and emulate you.

Thanks, humbled by your presence,
Treevet.

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You list all kinds of credentials on your website, then post videos of an old guy (think its you) falling trees with nothing more than a baseball hat on, once while wearing short pants.. and then there is your stump grinder operator grinding with the same baseball hat and a pair of sunglasses. What good are credentials if you don't have the common sense to wear a hard hat... And if you are willing to post videos showing no hard hat when grinding stumps and falling trees, what other kinds of stupid are you doing?
 
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