Why The Overkill?

Whoopie slings are spliced adjustable slings but Samson's instructions say that the bury has to be so long for the adjustable eye that it's almost unusable. For our 1/4" or 6mm Amsteel Blue sk75 Dyneema, that is a minimum of 3 feet long. Of course, it can be as big as you are willing to make the tail.

We wanted to test if you can get away with smaller bury lengths and also the strength a whoopie loses because it doesn't have a gentle taper, but abruptly comes out of the side. Samson says you can expect 70% of the average breaking strength which is believable but it is sure fun to test it anyways.

Why should the bury be so long?
01:08 What we are testing
02:59 Whoopies Tested
05:42 Eye to eye control tests
07:35 Soft shackle whoopies
09:12 Conclusions
11:47 Metric Police

[jarodlojeck]

Thank you for testing the soft shackle whoopies. I hope my samples bring about an informative conversation.

[bbudziszek]

Hi HowNOT2, I’ve recently took a job with Teufelberger Rope in Lifesafety Rope applications. I am new to the Rope industry and your videos have been my sort of educational crash course. I’m a mechanical engineer so I geek out as often as I can. But in terms of this video I can provide some insight on how those numbers are achieve. I can send you my information privately so we can share notes.

[mully]

In engineering they have "stress concentration factors" for things like a hole in a bar or a rounded corner. These then come with tables for a reduction in total strength based on the hole size or the corner radius. I think that it would be really valuable to have a similar result for ropes and other climbing gear. For instances a test against carabiner diameter could be done. Or with knots or splices.

[ArahoMan]

Really liked how this video was organized / framed, with the great intro to the units under test, the results on the table and everything! Was very easy to follow along.

[CW-govv]

Thank you for these videos! Ryan, you dont realize how many lives your saving with this kind of testing and information. This type of testing platform makes me think of safety issues I had not previously thought possible. It is really great to see you guys taking off! Keep up the great work man!

[davemason]

Happy YouTube recommended this video to me. I've been using whoopie slings as an option for hanging hammocks. Early on, when I first got into Dyneema rope I purchased some from SK-Amazon. I ended up using it to create a whoopie sling, as a way around needing a variable lenght of rope. It was 8-9mm and I used 6ft as the length of the bury. Used it the other day to pull a several 1000 lb vehicle up a ramp onto a trailer. It did not obviously slip, and after the pull I inspected the bury, and it had pulled tighter than what it was when I started.

Two observations: When using a whoopie sling always milk the bury before using it. The other is the lenght of the bury shortens up when there is rope inside. For me, the bury length shorted by 1/2 a foot. I really enjoy the videos on rope specific topics, as the climbing and rescue gear tests are interesting but it's something I'm not into.

[OurDee]

I'm a hammock dyneema user. I may risk an 18 inch fall. So, I get away with hanging on 1/8" Amsteel and 7/64" Samson loops. I do hang without trees on Tensa Solo poles at times with two whoopy slings running to a couple of home-made boom stakes at each end. I use 14" x 5/16" titanium stakes in 12" long 1" OD 1/8" wall booms with the stakes at 72 degrees. I can use 10" of boom length but stick to 8". Learning the failure points from your channel has been enlightening. Thank you very much! It would be fascinating to watch boom stakes pulled to failure.

[paulnormandy]

Well done dude, don’t sweat the comments. You’re doing the hard work and we appreciate it.

[mattdryden]

Apologies if you have already covered this in another video, but I'd love to see how wet dyneema impacts these results. I use dyneema a lot in the snow where it often gets wet and am curious if these splices slip more easily. Maybe that's why they recommend longer splices.

[thomasdalziel]

Long time a subscriber and a designer here. I have actually done some of these tests before, from my limited testing and experience the type of eye splice makes a huge difference. From what I’ve found a locking Brummell is much weaker than a full burry (2.5 fid lengths) straight eye splice with a lock stitch. My understanding is that somehow a locking Brummell doesn’t distribute the force across the 12 stands evenly and often ended up breaking 6 stands at the splice. I believe this straight eye splice with a locking stitch is actually how many of the manufacturers test their 12 braid products… (not totally sure though). If you’re interested I can see if I can dig up the charts from the tests I did and maybe even the videos/ samples from the tests.

[lebulba]

Great video! i dont know that ill ever use a whoopie but love seeing the equipment other people are using. Good work!

[trcrissinger]

ryan, just important, terrific work! Thank you!
I've not had a failure in a single item I have made, primarily for the sailing community but have noticed on several occasions that uneven tapering seems to add roughish points (slight bulges) noticeable after numerous cycles that might...could...possibly lead to a weakness or failure? Hasn't happened...yet...as the generally well oversized and highly inspected nature of synthetic rigging used shows. In practice we find "creep" the far more problematic nature of UHMWPE.
One thought I did have but have not been able to test is temperature buildup during cycling. Would be interesting to see if you could setup a non contact infrared thermometer and see if the friction increase inside a taper is possibly a culprit. Especially in the manufacturers recommended bury and taper lengths.
Once again, thanks.

[halisidrysdale]

Fantastic to see "closer to real world" test setup - the larger radius has its place for absolute measurement, but much more useful to daily use (or failure awareness) is the shackle radius directly on the eye.

Thanks for this information; you are doing fantastic work.

[hanelyp]

I noticed perfect consistency in where the rope broke, the transition from the splice to a single rope. Tells us clearly where the weak link is, and it's not the length of the bury splice.

[NativePrideNinja]

In the tree industry we use the whoopie as an anchor point by wrapping it around a tree and putting the fixed eye through the adjustable whoopie eye. Kind of like how an ultra sling works.

[williamcole]

Good seeing you yesterday at the rope shop in arlington, learned lots from you.

[coffeegonewrong]

First, thanks for explaining why you didn’t include metric in the video. I agree that trying to have both tables would make it harder to make actual comparisons.

As for my thought on breaking better, since the strands aren’t all perfectly parallel I assume this means some strands take the load faster than others and have to give more.
From your other videos, I think I understand that the stretching of the ropes generates heat and that contributes to the failure.

Is the reason pulsing works because it gives those strands a chance to shift?
Or could be those strands heat, then fail and cause the remaining strands to pick up the load and quickly fail. The pulsing would give the strands a chance to dissipate some small amount of heat before being loaded again
The explanation about manufacturers loading the item up to a point, letting it “rest”, then loading it to the breaking point would seem to support that since it would let the built up heat dissipate before loading it fully.

To support why this makes sense, if you look at industrial use like slings for a crane those loads aren’t “jerked” up, they should be getting gently lifted so the load doesn’t shift. Then if it isn’t lifted gently, it’s operator error and not the slings fault.

Please let me know if I’m wrong or completely out to lunch.

(Yes, I mostly watched this because I want whoopie slings for my hammock)

[ing.pagano]

I think the standard whoopie sling is very inefficient: 90% of the thing has 2 parallel stands, but you only get 70% of the single stand MBS because of a short piece that is single stand.

I did mine a bit different: i buried the moving tail INSIDE the bury of the fixed eye. Probably the loss of strength is higher because of a wider separation of the fibres, but you get the load split over two strands all the way. Even 50% of 2 stands would be better than 70% of 1 stand.

It would be interesting to pull my version and see the results

[nicholasdark]

Hey Ryan, great video. I would have loved to see a test with the whoopie fully extended. In other words, would the stopper be pulled through, create a weak point etc??

[anotherriddle]

To be honest, I don't really care about the units, even though I use metric. I can do a rough translation between units on the fly. On the other hand, when both units are shown, I usually automatically jump to the one I am more familiar with without even recognizing that there is another number there. Maybe including both units is more difficult for you and people that are very familiar with both metric and imperial. ... not quite sure, the human mind is strange :P
great video by the way! very informative