Ultra slings - spliced loops strength

samsquatch

Active Member
Hey guys, looking at buying a redirect pulley and sling. I'd like to go the ultra sling route, just because it seems fast and easy to use. My worry is: when running the block thru a spliced section of the sling, and when the block is loaded and massive stress is put in the crotch of that splice working to rip the splice apart. Will the splices hold with the same strength as a dead-eye (where stress is put not on the splice but on a normal section of the loop)?

Do we have access to any testing done pulling on the inside of a spliced loop like the ultra sling?

Cheers
 

RBJtree

Well-Known Member
I would think the tensile strengths and working loads published by the company's who sell them are probable fairly reliable. If they were way off to the side of being weaker it would be a hell of a liability.
 

RBJtree

Well-Known Member
Usable length 6' ?! So you can wrap it around a 1.9 ' diameter tree, max? Seems a little short for a 3/4 inch tenex "block" version. Screenshot_20190319-225622.png
 

RBJtree

Well-Known Member
It is a little short at times, but quite convenient. For larger diameter trees, if using a pocket sling, I use the one treestuff sells for the portawrap. Same size tenex, and much longer.
I'm just giving tree stuff a hard time. Plenty of times that's all you need.
 

samsquatch

Active Member
I would think the tensile strengths and working loads published by the company's who sell them are probable fairly reliable. If they were way off to the side of being weaker it would be a hell of a liability.
True. But in what other situations do we have a rigging load splitting the crotch of a splice? It's not that common. Most splices (think eye splice for instance) are loaded in the "pull" direction. I would think the rope dynamics are different when the load is working to split the crotch in the splice.

Maybe this type of roping hasn't been done in the past; should we test the strength of the crotch of the splice in an ultra sling?
 

RBJtree

Well-Known Member
True. But in what other situations do we have a rigging load splitting the crotch of a splice? It's not that common. Most splices (think eye splice for instance) are loaded in the "pull" direction. I would think the rope dynamics are different when the load is working to split the crotch in the splice.

Maybe this type of roping hasn't been done in the past; should we test the strength of the crotch of the splice in an ultra sling?
I would love to see some break testing videos!
 

New2trees

Well-Known Member
I would also wonder how it would wear over time as the rope would always be riding on the Brummel.
 

JeffGu

Well-Known Member
I rarely use anything but ultraslings and have yet to see one fail or show any more wear than any other 12-strand hollowbraid sling. They have so much friction around the limb that the brummels probably aren't taking nearly as much of the shock load as you imagine.

TreeStiffy broke plenty of them before they started selling them, to get a good break strength formula. Nick even told me how much to derate the sling for self-abrasive fibers.

The sling is constructed so that it is essentially in basket mode (the rope is doubled) then used in a choked configuration.. so whatever the listed break strengths for the Tenex-TEC are, that is pretty much the break strengths for the ultrasling.

They take a lot of rope to make, but they're quick and easy to use. Very easy to splice them up, but a bit time consuming.
 

samsquatch

Active Member
It is a little short at times, but quite convenient. For larger diameter trees, if using a pocket sling, I use the one treestuff sells for the portawrap. Same size tenex, and much longer.
Not gonna lie, had to Google "pocket sling rope". But be warned for if you do, the first result (I mean before any Arb related results AT ALL) will be this.
Dear God. And then there's the laugh at time 4:03. WTF who are these people! And then "but wait, not just for catchers" :oops: I just about crushed the dog rolling on the floor laughing so friggen hard.
 

Mitch Hoy

Active Member
My favorite negative rigging setup is an ISC mini on a 7’ 5/8” Tenex ultra sling with pockets sized for the block for a tight choke. I use a spliced line and connector, and it makes work on the spar really fast and light. The ultra sling does great with the impact loads.
 

JeffGu

Well-Known Member
Now, there's a conversation for the books... we're worried about the strength of a spliced product, and we suggest a knot as a solution?
 

treebilly

Well-Known Member
I think it’s technically a hitch @JeffGu

I trust ultra slings for anything I throw into them. Just inspect them like any other rope product. I’ve managed to break two whoopie slings over the years. Both were well past their prime and in a very low risk set up. I’ve retired prolly close to 50 tenex products though. Of that group is a dozen ultra slings.
 

samsquatch

Active Member
Actual time saved, maybe an jour a year?...
I’m sure some feel that way, just like I’m sure others feel that they save a lot of time with an ultrasling.
I am not worried about it Jeff. the guy who started this thread is...
I don’t think anybody is complaining about an ultrasling being too weak, including myself. I’m just starting a discussion about the topic.
You know, the type of discussion that maybe eventually lead to someone making a test and maybe discovering a flaw and maybe ultimately avoiding a serious product failure at height. Manufacturers should be responsible for their due diligence, and I assume when they list a MBS that is in the choked configuration pulling into the crotch of one of the splices, as intended use, not just pulling the sling laterally until it snaps.
 
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Mitch Hoy

Active Member
Ultra slings are the ultimate KISS principle answer to rigging. Anything that I can do to reduce time or stress makes me really happy in the tree. I can tie a cow hitch, fast, with my eyes closed, but if you can skip it, you’re ahead of the game in my book.
 
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