# Thread: Samson Ropes Provides Whoopie Sling Info

1. Yeah, me too! I know I don't weigh anywhere near the breaking point, even when I'm moving about in the hammock,

2. Originally Posted by Knotty
Bottom line is that a whoopie will break where the adjustable tail exits the bury.

I guess we don't need the question mark anymore.
And Im taking a stab here, But I believe because thats the only place in the sling where there is a single stretch of line.

The section between the end of the dead eye bury and the beginning of the adjustable bury is the weak link in the sling.

3. The point where the non-tapered bury comes out of the core is weak because the continuous braid is interrupted, there is an inflection and a pinch, and the strands do not work together as well as they do in the normal braided standing part.

IOW, the transition from buried splice to normal braid concentrates stresses. At other places, stresses are distributed more evenly along the line.

- MacEntyre

4. Yes, thats what I meant to say.

5. Originally Posted by MacEntyre
The point where the non-tapered bury comes out of the core is weak because the continuous braid is interrupted, there is an inflection and a pinch, and the strands do not work together as well as they do in the normal braided standing part.

IOW, the transition from buried splice to normal braid concentrates stresses. At other places, stresses are distributed more evenly along the line.

- MacEntyre
Yes, but...can you express that mathematically?
*That's not a challenge Grizz, just a joke!*

6. When the load on rope AD is greater than the capacity of deformed rope segment BC, the rope breaks.

7. Originally Posted by Albert Skye
Good work, thanks!

Please convince them to do some D:d testing (because that data is fundamentally useful); ideally, a plot like this. When I requested that data they said they didn't have it, but perhaps you can talk them into doing it.

Usefull for a sheave, but doesn't each side of an eye or loop only have to support half the load? If the bend only reduces the strength to 50% or more than i dont see how it has effected the breaking strength of the rope. It should still be 100%. A sharp bend creates a fatigue point so it might matter in use over time and be important as the rope weakens there, but thats a more complicated test.

You do have to make the eye at least 3 prefably 5 times longer than the diamter so that the two legs dont connect to the splice at a wide angle.

8. Originally Posted by Knotty

Recently the reduction to 60% of average break strength for Amsteel Blue whoopie slings was suspected to be a low value. Testing showed that it is actually around 80% depending on the size of the rope. On every test done the break location was at the point of the adjustable whoopie tail exit.

Depending on the size? What sizes is 80%? The 7/64 is small and it has a smaller number of strands(8) than the other sizes. I wonder what the break strength reduction is for that and also how many fid lengths of bury are needed for the adjustable and locked brummel ends of the whoopie sling in 7/64.

9. Originally Posted by mike99
[...] i dont see how [...]
Testing D:d would be useful in understanding the behaviour of HMPE (the plot in the link is for wire rope, and I'm told the performance of HMPE is likely to worse).

Of course, a spliced eye (close to twice the strength of a single line) can tolerate significant loss of strength efficiency before falling below the strength of the single line, but a line passed round a sheave/pin/toggle and loaded on both legs cannot.

In short, it depends how one uses the cord.

10. I use dynaglide slings , been ok so far.

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