More things broken

Do you think the lines were breaking at the rigging paws due to the friction and heat generated from the stopper knots rolling and stretching??
 
Scheffa said:
Do you think the lines were breaking at the rigging paws due to the friction and heat generated from the stopper knots rolling and stretching??
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I believe the rigging paw just happens to be where a knotted line would normally break, almost always at the entrance to the knot. It has to do with the stress at the first bend but also, and I hate to say it, but it's like that first wrap is pinching one-off.
 
Watching all of those knots rolling is making me reconsider the length of tail I leave on some of my knots. Thanks for taking the time to do these test.

After all of your test pulls, are you satisfied with a 16 strand rope bridge with a core, or is there another construction of rope that has performed better? I am looking to replace the bridge on my sequioa, but have seen pics of a lot of petzl eyes with loose terminations, so I'd like to use a different bridge.
 
Jehinten said:
Watching all of those knots rolling is making me reconsider the length of tail I leave on some of my knots. Thanks for taking the time to do these test.

After all of your test pulls, are you satisfied with a 16 strand rope bridge with a core, or is there another construction of rope that has performed better? I am looking to replace the bridge on my sequioa, but have seen pics of a lot of petzl eyes with loose terminations, so I'd like to use a different bridge.
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Well I would say four or five times the diameter on a properly set knot is certainly sufficient. I was surprised on the Ashley stopper knot how much it pulled thru but I think it's because it's such a huge knot and is difficult to set well.
I'm running 16 strand on my bridge and after all of this I'm certainly not running anything with an aramid or dyneema fiber or even double braid.
But I still just really do not understand how a bridge can fail when a guy is just riding the crane ball or leaning back on his lanyard. Even those old really overused and abused 16 strand lines I pulled would break a person in half.
 
There is nothing like sitting back with a coffee in the morning and watching Richard Mumford break stuff! The value of this kind of free-ranging independent break testing is impossible to calculate. Manufacturers have to focus their testing on narrowly defined product use, this is the unintended blockade that innovators and any climber that does PPE mods runs into. It's not the product developer's fault, they can't speculate on what is safe or not outside of the specific use-case testing they've done. So thank you Richard, the climber community owes you.
-AJ
 
Some thoughts that came to mind watching Richard break old 16-strand...

The testing illustrates well why we want PPE cordage to have ridiculously strong off-the-shelf performance. It's not how strong it is the first couple weeks climbing a new rope, it's where does the break strength settle in after 6 months of hard use and a few broken strands? Because that's what probably 80% of tree workers are climbing on. This testing fills in that mysterious blank where we simply say "retire a climbing line after one year" etc. Reality is you have to know your rope including its history, inspect regularly etc. There is no mystery, we know what work and UV stiffened rope fibers look and feel like. We know how many broken strands make us uncomfortable. And now we know what kind of strength degradation occurs with these effects of rope use.
-AJ
 
I'm not picking on a particular producer just making a point, seriously a three-year? It truly is about inspection.
And along the lines of what Andrew is talking about, and again I'm not picking on corporations, but I think somewhere in there is an accountant sitting at a desk that says our rope Bridges need to sell for about 20 to $25 or does not worth our effort, make that happen.Screenshot_20180712-092720.webp
 
Bob Bob said:
Very interesting. It looks like Moss's sewn eye survived another pull! I think I'm going to add a few inches to the tail of most of my knots too. Just amazing how much the tails pulled through on those stopper knots. Wish I had something to donate for testing Richard, but all of my ropes are still in usable condition. Would a couple severely worn carabiners be needed? Those I could contribute.
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Ok everyone with me now, “Are you a believer?” Can you hear the Hammond B3 Organ rising in the background? This is the Church of Sewing Faith, get on the train! Here’s some recent music I made, in part to celebrate this journey:
https://soundcloud.com/user-515520383%2Fspeaking-for-the-trees-the-journey
 
yoyoman said:
Well I would say four or five times the diameter on a properly set knot is certainly sufficient. I was surprised on the Ashley stopper knot how much it pulled thru but I think it's because it's such a huge knot and is difficult to set well.
I'm running 16 strand on my bridge and after all of this I'm certainly not running anything with an aramid or dyneema fiber or even double braid.
But I still just really do not understand how a bridge can fail when a guy is just riding the crane ball or leaning back on his lanyard. Even those old really overused and abused 16 strand lines I pulled would break a person in half.
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Yeah, I’ve been taking these tests with a dose of reality. The forces you need to apply to achieve failure are insanely intense! The human torso would be destroyed long before breakage would occur! In other words, this demonstrates to me that the gear does what it’s supposed to... what’s expected of it, and inspection/ replacement is the key factor. Also taking the time to properly set and dress your knots!
 
Stephen Moore said:
Yeah, I’ve been taking these tests with a dose of reality. The forces you need to apply to achieve failure are insanely intense! The human torso would be destroyed long before breakage would occur! In other words, this demonstrates to me that the gear does what it’s supposed to... what’s expected of it, and inspection/ replacement is the key factor. Also taking the time to properly set and dress your knots!
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So why do we continue to have rope bridge failures, that's what has me baffled. People are doubling their bridges and losing trust in a rope bridge, some are afraid to even buy a harness with a rope bridge, that is absolutely nuts to me, it's the best component.
 
moss said:
Some thoughts that came to mind watching Richard break old 16-strand...

The testing illustrates well why we want PPE cordage to have ridiculously strong off-the-shelf performance. It's not how strong it is the first couple weeks climbing a new rope, it's where does the break strength settle in after 6 months of hard use and a few broken strands? Because that's what probably 80% of tree workers are climbing on. This testing fills in that mysterious blank where we simply say "retire a climbing line after one year" etc. Reality is you have to know your rope including its history, inspect regularly etc. There is no mystery, we know what work and UV stiffened rope fibers look and feel like. We know how many broken strands make us uncomfortable. And now we know what kind of strength degradation occurs with these effects of rope use.
-AJ
Click to expand...
That is why I have a DON'T TREAD ON ROPE policy! because of the fiber damage you may not see. Also why I suggest that if a climber works on a large crew, Changes trucks regularly?, that he use his own ropes... he will know the history. Also keep track of the age of a rope, regardless of its use because textiles degrade over time, they become brittle and shitty.
I had an old pair of ski boots that fit me awesome disintegrate on me while skiing back country, I was standing in my boot liners in 4 feet of powder! The plastic just degraded. Rope does the same thing.
 
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