i'd agree, the line is super slick and a reason it's efficient. but at that accute angle you don't think it might/could be a participant?
Not a synthetic snatch block
- Thread starter LONGJP2
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i'd agree, the line is super slick and a reason it's efficient. but at that accute angle you don't think it might/could be a participant?
Except that the phenomena exists, as Blaine has observed on the Warn hawse. There must be a balancing of multiple factors at play.
i got this fancy new 1 now ..............came all the way from southern Cali. i don't think i'll have any issues, but i do have a new Warn roller lead and a cheap hawse in the spare parts box now.
It bothers me enough that I've got to find an easy way to test a few samples I have with the much larger radii to see if they melt the line.
I'm gonna say no, at least for normal winching speeds. Larger is better, with diminishing returns.
And with a small bend radius most of the heat generated is internal to the rope as it deforms. When this type of rope fails it often shows signs of melting from the heat generated as it fails.
Lots of fun reading here:
https://nwlinejatc.com/wp-content/uploads/Rope_Users_Manual_WEB.pdf
Every user should read the section on "inspection and retirement," too.
page 38:
"Where a rope is deflected more than 10 degrees around a surface (i.e., bitts or chocks), the
effective diameter of that surface should not be less than three times the diameter of the
rope. Stated another way, the diameter of the surface should be at least three times the rope
diameter. Even larger diameters would be better yet because the durability of the rope increases
substantially as the diameter of the surface over which it is worked increases."
p39:
What do you mean?
For the question, "can the bend radius be too large," my answer is "generally, no."
We are dealing with a bend radius in two different applications. A sheave scenario is entirely different that a rounded edge we are dragging a rope over. The sheave creates very little to zero friction and therefore we are not dealing with the rope melting.
What I see and have witnessed first hand is a too small radius damages the line, and a too large radius like the Warn fairlead has burns the fibers off of the rope and starts a build up in the corners that only gets worse as the winch is used more under load.
We don't see the same on radii between the too small and the larger Warn. Why?
The 3x minimum rule for bitts and chocks includes fairleads.
Just to get an idea of scale, what dimeter or radius would you estimate is too small and what is too large? For 3/8 line, 3x is 1-1/8D or 5/8r.
There is WAY more study on marine applications than 4x4 recovery, so that's where the bulk of the data is. And the focus in marine use is on longevity. Even applications that may appear static, like mooring lines, have frequent load cycles and are dragging rope over a rounded edge even when tied off.
The winch line on the most active jeeper sees less load cycling in a year than a boat does in one day during heavy weather. So our winch lines are worked much closer to peak tension capability, poorly handled, and are relatively single-use disposable items.
So you may be right, and the relevant data just doesn't exist.
For testing I'd want to measure temperature of the line as it comes off the bend. If an IR thermometer could be set up to work that could be ideal.
Different sized shackles would make for easily-changed dimeters.
If we were closer I'd love to help. This sounds like a neat experiment.
I'm aware.
No, our lines are not even worked close to max capacity. If they were, Warn would have never shipped 9800 lb breaking strength lines on 9500 lb rated winches.
I'm pretty sure we don't have a heat issue that will be able to warm up the line. Someone will have to prove that to me.
Ls swapt 99 Tj
Member
A proper snatch block wont hurt the line as it rotates in the soft shackle.
I run my rope over a 1.5" tube on my chassis to double my winch power, for my front suck down winch and it does in fact damage my rope on a regular basis and it only has the front spring pressure against it. 3500 lb winch 7/16 line.
https://www.amazon.com/dp/B096GC17X6/?tag=wranglerorg-20
I run my rope over a 1.5" tube on my chassis to double my winch power, for my front suck down winch and it does in fact damage my rope on a regular basis and it only has the front spring pressure against it. 3500 lb winch 7/16 line.
https://www.amazon.com/dp/B096GC17X6/?tag=wranglerorg-20
Here is what the stupid specification collectors have done to the recovery industry. This is the most retarded crap ever for a manufacturer to put on that product.
Not one iota of that makes any sense whatsoever except the first line and then only partially since the temper always follows the alloy designation. The crush load to collapse that ring is far higher than 10,000 lbs, so that is a bogus number. It can't be 50% stronger than a traditional snatch block if you can't break it. No one I know besides me has ever designed a sub 2 lb conventional snatch block so that is another bogus number. What limits the lifetime warranty?
It makes some sense if you look about where that copy originated. Hint: think about forty unscrupulous people that take other people's possessions without permission. I know because I've seen that exact verbiage recently and in more than one place, and you know exactly how that happens.
I agree that it's entirely retarded.
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