loopie slings

I did one fid length, and compared it to one I had purchased, and the bury was shorter than the one I bought.

Done some testing and it has held fine. Just wanted to make sure that its good before I put it to full use.
 
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I use a '2 fid length' bury on loopies. I've had the running end slip while loaded on a 1 1/2 fid bury on Tenex tec. With 2 fids bury, it hasn't slipped.

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Was it choked in the bury section? What was the radius?

People mostly don't know this, but the choke is much more effective when it is close to the little dead stub of the cover. When it is near the other end, where the long adjusting tail exits the cover, the choke has much less effect. The reason for this is there is no tension in the cover between the choke and the little dead stub. The finger-trap effect is missing over that section along with all the holding strength it could provide.
 
It slipped during testing. I wanted to see how it would perform with the bury in the 'pull', not choked.
3/8's" tenex tec started slipping between 6 & 7 hundred pounds pull with a 1 and a half fid bury. Two fid bury got to 2,000 lbs. before slipping.
I do put the bury in a 'bight' when I use a loopie, and recommend that all user's do that.
 
Norm, have you done any tests of the loopie pulled in a choked configuration? If so did you measure any slipage on the bury? Also, what strength loss/increase can be measured between that of a loopie, a spliced loop, whoopie sling, and the breaking strength of the rope in a straight pull?
 
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It slipped during testing. I wanted to see how it would perform with the bury in the 'pull', not choked.

[/ QUOTE ] Aha, you have not turned my world upside down after all. Yes, they definitely slip if not choked. Didn't Yale stop making loopies for sale because they realized they are dangerous if used the way you tested yours?

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If so did you measure any slipage on the bury? Also, what strength loss/increase can be measured between that of a loopie, a spliced loop, whoopie sling, and the breaking strength of the rope in a straight pull?

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I have done a lot of testing on these very questions. The last 3 questions have easy answers. A spliced loop is as strong as the rope. The loopie and whoopie lose about 10% of their strength at the spot where the adjuster tail emerges from the cover. At that point the cover is under full tension, but it also has a big hole in it where the tail comes out. Obviously that has to weaken the rope, and I have measured it a couple of times at very close to 10%.

The question about the choked bury on the loopie is much trickier. All my tests were done over a 3/4-inch steel pin, perhaps a bit smaller than the radius in a normal arborist application. On the other hand, the sling itself was set up for a straight pull, not wrapped around a stem as it normally would be. All things considered, I think my experimental setups were much more challenging for the sling slippage wise than an arborist setup. [Edit and correction: the question of slippage in a straight pull is complicated. Even when properly choked they can sometimes be made to slip completely apart. See Loopie Thread for a long discussion of this very issue.]

So I don't have a definitive answer as to what it takes to get a choked loopie to slip. But if the question is can a loopie with a 1-fid length bury wrapped around a stem and properly choked slip, then I am quite sure the answer is no.
 
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Norm, (1) have you done any tests of the loopie pulled in a choked configuration? (2) If so did you measure any slipage on the bury? Also, (3) what strength loss/increase can be measured between that of a loopie, a spliced loop, whoopie sling, and the breaking strength of the rope in a straight pull?

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(1) Yes, around 2" pins. It broke at 12,000 lbs. (3/8" diameter Tenex tec)
(2) Absolutely no slippage.
(3) A loopie will have approx. twice the strength of a single strand rope of the same fiber and diameter. The bend radius will add into the equation.
 
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People mostly don't know this, but the choke is much more effective when it is close to the little dead stub of the cover. When it is near the other end, where the long adjusting tail exits the cover, the choke has much less effect. The reason for this is there is no tension in the cover between the choke and the little dead stub. The finger-trap effect is missing over that section along with all the holding strength it could provide.

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Could you show a pic, please?
 
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Could you show a pic, please?

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Here is a link to a long thread a couple of years ago concerning loopies, with plenty of pictures.

Loopie Thread

I also have to correct what I said earlier about loopies not slipping in a straight pull when the choke is in the spliced part. What a crappy memory I have! They do slip. Sometimes they slip a limited amount and then lock up, other times (in Tenex Tec, 5/16 inch) they can slip and completely come apart. It is surprising that Amsteel Blue seemed to do better than Tenex in this regard.

The choke helps tremendously, and putting the choke in the right place helps even more, but they can still come apart. The type of rope seems to be quite important as can be seen in the above link.

The evidence shows that a loopie in a straight pull, even choked correctly, can be pulled apart by a sufficient load. The safe advice would be to never use a loopie that way.
 
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