Ultra sling vs deadeye: double the strength?

Muggs

Muggs

Been here much more than a while
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When thinking conceptually about an ultra sling, because it's spliced in the middle of the rope, is that considered basket configuration and therefore double the strength of the sling material, as opposed to a standard straight bury or locking brummel deadeye sling? Obviously the sling is doubled over the entire length of the tail with pockets, but right at the eye it's the same as any other sling. Part of me would like to believe that there's a strength advantage but the other part just can't figure out why that would be so...
 
My understanding of it suggests that it's a basket config, but bending it at a brummel weakens it by almost half, so you derate it back down to full single line strength. I forget where I got that info, but it seems to be the math that the arb suppliers are using. Part of the problem is real world break strength vs testing on a puller. I have had this discussion at some length with the splicers at various shops, and I haven't heard of anyone spending the money to build a good setup to test how they behave around a spar. In a straight pull end to end it will almost certainly be a good bit stronger than when you put the ring through an eye formed only with brummels. If we could fund the testing, we could have hard numbers.
 
Muggs said:
So a regular deadeye with locking brummels and bury is only rated for half the sling strength?
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the brummel is not being spread apart, so it doesn't weaken the rope there in the same way, so you only derate it based on the knot you tie.

I wish there was more money for ANSI or CE to test these things in a more realistic way to give our industry better numbers to work with.
 
Matias said:
We have all seen that one by now I think, but end to end is VERY different than pulling the brummel apart.
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My guess is that the strength of an ultra sling would also depend on how tight you have it cinched around the spar. If it is cinched really tight then the angle of pull against the brummel is really sharp, whereas if you have it cinched very loosely then the pull is more inline and the friction and force exerted on the brummel would be less. That would take a lot of testing to figure out.
 
ARLO said:
My guess is that the strength of an ultra sling would also depend on how tight you have it cinched around the spar. If it is cinched really tight then the angle of pull against the brummel is really sharp, whereas if you have it cinched very loosely then the pull is more inline and the friction and force exerted on the brummel would be less. That would take a lot of testing to figure out.
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bingo
 
Anecdotally, I use 1/2" ultra slings as chokers for our chipper winch lines. They get beat to hell but protect the winch line itself from wear. The hook from the chipper goes to whatever pocket is convenient. We've stalled the chipper winch on pulls that were too heavy to budge or where the material got hung up on a stump, vines etc. The sling doesn't seem phased. Even well worn and abused slings that take the brunt of the drags hold up tremendously well.
 
Phil said:
Anecdotally, I use 1/2" ultra slings as chokers for our chipper winch lines. They get beat to hell but protect the winch line itself from wear. The hook from the chipper goes to whatever pocket is convenient. We've stalled the chipper winch on pulls that were too heavy to budge or where the material got hung up on a stump, vines etc. The sling doesn't seem phased. Even well worn and abused slings that take the brunt of the drags hold up tremendously well.
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sick. I don't think I got quite as much force on my 1/2"er with my cable puller in a 3:1 setup as you got there, but I have seen similar action without strange deformation or fibers welding. The 2 ended hollowbraid is badass stuff.
 
Treetopflyer said:
If there was no spliced slings available…I know that’s sounds far fetched right off the get , but just a bull rope doubled over capturing the porty is very workable and strong
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For real hard pulls we would wrap many and pull few to hang the Garlats for a yarding redirect on a keeper tree. Even favoring long deadeyes joined with a cats paw over thinner diameter stuff. Works so much better for preservation.
 
The way I have committed to memory is that it is still based on the tail bury depth, and the brummel will reach full strength if there is a long enough tail buried. Nobody bothers to do this since the benefit of the brummel is a nice throat that stays in place better, allowing a shorter tail to reliably hold well enough. I don't have a referrence for why I remembwr it that way anymore though.
 
Matias said:
The way I have committed to memory is that it is still based on the tail bury depth, and the brummel will reach full strength if there is a long enough tail buried. Nobody bothers to do this since the benefit of the brummel is a nice throat that stays in place better, allowing a shorter tail to reliably hold well enough. I don't have a referrence for why I remembwr it that way anymore though.
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I don’t think that’s accurate. The locked Brummell is enough, and the bury does two things. It’s somewhere to put the tail and helps from raveling.
The stress from the locking brummel disrupts the lay of the strands which is where the strength reduction comes from.

No splice retains 100% the strongest is sumthin in the realm of 90-95%.

This is all splitting hairs as splices even if fairly shitty are stronger than knots. Unless someone really half asses it
 
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