1/2in Stable Braid vs True Blue

Brocky said:
If you dropped a load of say 20,000 # on both ropes separately which one will break first?
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They'll both break.

But the point is exactly that.. the original question was about dropping loads onto the rope, not about tensile strength, which doesn't measure energy absorption. The cycles of failure of a rope trying to pick up a load that weighs 20% of its tensile strength is a big number, regardless of the material used in its construction. Drop that same load onto the rope from a few feet up, and the ropes with the highest tensile strength aren't the ones with high cycles to failure ratings. In fact, for some of them the number will be quite low... as in, zero. Broke on first drop.

The question was about whether higher elongation ropes were actually stronger when dropping loads onto them like that. If we're talking about modern rigging ropes of high quality, the answer is yes, they are. If we want to talk about which materials have the best UV resistance, abrasion resistance, or the prettiest colors... well, I'm sure a thread for that will generate a lot of responses. I was only trying to answer the OP's original question, and point him to the research every rope company and a lot of other gear companies have already done.
 
I would like to point out that concentrating on elongation for an all purpose rigging line is just as bad as concentrating on the tensile strength figures alone. Take a 100% nylon, 3-strand, 5/8" rope, for example (I actually have one). Very high elongation due to both materials and rope construction. Absolutely worthless rope for pulling a tree down. So much elongation it's like trying to walk a dog on a rubberband string. If you hook it to a vehicle and take most of the stretch out by pretensioning the rope, then you just took away it's real strength. Now, it will break quite easily. A polyester rope works so much better for that. Or try keeping a load from bouncing around, and that rope will frustrate the hell out of you. Again, the polyester rope is the superior product for that job.

In a perfect world, your stingy customers would all give you a $500 bonus at the end of every job so you could have a special, enclosed trailer full of nothing but ropes.
 
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Let's get really really like really real! these are the best pencils for everything ever!

Reed Wortley
CTSP #01739
ISA CA #SO-6953A
 
I prefer arbormaster (with it's tighter cover braid that resists picking better) for a 1/2" rigging line. Esp. if any natural crotch lowering or rope against bark rubbing is going to occur, which is more often than not. Like on a conifer dismantle, it is a lot faster (when removing limbs in sequence as you ascend to them) to use a higher limb/trunk junction (crotch) as a temporary lowering point instead of having to repeatedly install/remove/ a block. Yeah, Arbormaster has a lower WLL / MBS than Stablebraid, but rope economics and durability factor significantly into my working practices, and I don't think using 1/2" Stablebraid would make my time spent aloft any more efficient.
 
Worthaug said:
In pull tests true blue may elongate more before breaking at 7300 pounds but stable braid breaks at 10,400 lbs. There's no doubt that stable braid is stronger. Now, in real life rigging scenarios, true blues stretch or elongation may be a more appropriate choice when blocking down to reduce forces on the standing stem as long as the pieces are not heavier than the rope can stand...
I'll take a good rope man and stable braid over true blue any day.

Reed Wortley
CTSP #01739
ISA CA #SO-6953A
Click to expand...

Nail on the head.....Bam
 
Worthaug said:
In pull tests true blue may elongate more before breaking at 7300 pounds but stable braid breaks at 10,400 lbs. There's no doubt that stable braid is stronger. Now, in real life rigging scenarios, true blues stretch or elongation may be a more appropriate choice when blocking down to reduce forces on the standing stem as long as the pieces are not heavier than the rope can stand...
I'll take a good rope man and stable braid over true blue any day.

Reed Wortley
CTSP #01739
ISA CA #SO-6953A
Click to expand...


Here's REAL WORLD for you

 
Worthaug said:
True blue does you no good when lifting a storm damaged limb off a house or positive rigging... it's not the single do all rigging rope...
The initial conversation is not about strength (tensile) it's about appropriate rigging system choice. Know your limits and don't approach them. The rope should be the weakest point in the system...
Semantics are huge, being detailed is important.

Reed Wortley
CTSP #01739
ISA CA #SO-6953A
Click to expand...


Even if the rope should be the weakest point, it is often the tree.
That will bring everything back to the basic "It doesn't matter, use the right system for your situation" argument every time, and that can be quite an involved conversation.
Wait, what were we arguing?

Brocky said:
Both true blue and stable braid are both made of polyester so I don't see the relevance of bringing up nylon and dyneema.
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I believe it was just illustrating extremes that have been tested of stretch vs strength originating from material instead of rope construction. The material creates a huge difference, but rope construction can create a huge performance difference as well, and it is one that parallels nicely. It is pretty universal that less stretch means worse performance in shock loading scenarios.
 
JeffGu said:
I would like to point out that concentrating on elongation for an all purpose rigging line is just as bad as concentrating on the tensile strength figures alone. Take a 100% nylon, 3-strand, 5/8" rope, for example (I actually have one). Very high elongation due to both materials and rope construction. Absolutely worthless rope for pulling a tree down. So much elongation it's like trying to walk a dog on a rubberband string. If you hook it to a vehicle and take most of the stretch out by pretensioning the rope, then you just took away it's real strength. Now, it will break quite easily. A polyester rope works so much better for that. Or try keeping a load from bouncing around, and that rope will frustrate the hell out of you. Again, the polyester rope is the superior product for that job.

In a perfect world, your stingy customers would all give you a $500 bonus at the end of every job so you could have a special, enclosed trailer full of nothing but ropes.
Click to expand...


Good Post there. Hit the nail on the head.

The best rigging lines begin elongation at higher loads. Hence, when low loads are experienced the rope remains relatively "low elongation." When loaded heavy the begin to elongate and absorb energy.

Another way to absorb force is to add rope. You can add it in terms of length, diameter, or number of ropes.

Tony
 
The one major thing I miss about true blue is that if you pre tension the stretch outta the rope, you can trip tip ties to snap after the climber gets to move just dump the stretch outta the line.
 
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