Soft Halyard or Line Shackle
 

I have come up with what might be a new way to connect a line such as Amsteel to something without having to use a separate soft shackle. It is very fast to use, much faster than a soft shackle and may even be faster that a regular snap shackle. It is based on a soft shackle but with the eye as part of the line and the diamond knot permanently connected to the target, such as the head of a sail. I have used it on my boat in several places and it really works well.



I am not completely sure if it is new and if it is, not sure what to call it. I have been calling it a soft halyard shackle but it has way more uses than just halyards. I would appreciate some feedback.

I completed some strength testing and find it very strong. I pulled it to destruction using a sample made from 1/8 Amsteel. It breaks just like a soft shackle -- at the diamond knot. Tests on a soft shackle show it has about 170% of line strength so I conclude that this shackle is 80-90% of line strength based on the fact that the knot in a soft shackle carries half the load. From previous tests, I felt I was near the line strength when the knot finally let go. It took a lot of force to break it. For example, I observed about 10% stretch on the 7/16 XLS anchor line from from the initial condition of being pulled as tight as a Barient 22 could pull to where the knot broke being pulled by a hydraulic jack.

I have written an article explaining it in detail. http://l-36.com/halyard_shackle.php

Allen

Nice
 

Hi there,
I like this variation on the theme, and would suggest that the way is open, with this and with normal soft shackles, for an even stronger attachment, through the use of four-strand buttons or lanyard knots. That way the shackle would not be the limiting factor, and in your case you'd have deeper redundancy for the permanently-affixed piece.
My favorite sheet configuration remains a 1-piece pair, secured to the clew with a soft shackle, with the whole works coming off for sail or rope maintenance or stowage. With this, one is not limited to HM sheets.
Fair leads,
Brion Toss

You can also make the button loop out of one size larger line and get the strength back and the four-strand button is an interesting idea. I would not use this soft line shackle for sheets as the knot sticks out where it would hang on the rigging. I am using eye splices in XLS and a soft shackle to the clew ring with the knot held in the clew ring as shown below:

I have an extensive writeup on soft shackles here (first of 7 pages)
http://l-36.com/soft_shackle_intro.php

But what do you think about a name? Soft line shackle, or soft halyard shackle, or some combination?

Finally, what is a 1-piece pair?

Allen

Has anyone here done any testing on the luggage tag loop with several diamond knots in a row so as to be able to attach the loop at various points to make it adjustable?

In other wards, if you make the loop with many diamond knots, do all the diamond knots have the same strength?

I suppose I should just do some testing and write it up, but I want to rig my boat and go sailing!

Thanks,

Anton

Shackles
 

Hi,
I haven't done tests with that configuration, nor on Mr. Otto's sling with a series of Brummels, but those both sound like things worth doing. Meanwhile, I finally sent off some more "Improved" shackle samples for destruction-testing, and we might have results as early as today. Stand by.
Fair leads,
Brion Toss

Oh, very cool! I guess I can find the time to do some pull tests, problem is how to rig up a scale.

Maybe a bathroom scale with a lever or something.

I think if I do a loop with multiple knots, and start at the farthest one, it would tell me if the first one is the most likely to break.

If they break sequentially, the only question is at what tension they break.

Hm.

I eagerly await new pull tests!

News
 

Hi All,
Just received a report from New England Ropes, re testing on the improved soft shackle. I will need to go over things in detail, but the design got significantly higher break strengths that the conventional one -- about 200% of rope strength, at least in the smaller sizes, and up to 280% when cycled a few times prior to the break. This compares with around 120% for the conventional design, in previous tests.
When I get things sorted out and averaged I'll be providing more details. Meanwhile I'll mention that these numbers, at least for the non-cycled samples, are lower than the results carried out by the estimable Evans Starzinger on a few preliminary samples. but then he also got higher results for the conventional design. It seems likely that there is a protocol difference that will account for the discrepancy, but in any event both sets of tests show a major increase in strength, and I have a couple of ideas for improving things further.
Many thanks to Stuart MacNeil and all the gang at New England Ropes for breaking these things! Do let them know how wonderful they are: Stuart.MacNeil@teufelberger.com.
Fair leads,
Brion Toss

I just bought a 600Lb hanging scale that I will try to do pull tests with. I got the 600Lb scale because it was $30, I will use a lever to multiply it so I can measure a few thousand pounds. Probably won't be very accurate, but close enough, and might be good enough for comparison. I reckon I can easily do 4K with a come along I already have.

I will post any findings I have.

Anton

Brion,

Please describe the pre-cycling that was done before the test the yielded the higher strength, if you would.

Thanks,

Anton

Test results
 

Hi all,
Here are a few details from the tests.
First, as noted previously, the best numbers came with shackles that had been cycled at 50% of the average tensile result of shackles that had not been cycled. So if we broke 5 shackles, and they had an average break of 10,000lbs., then they cycled a sample up to 5,000lbs, ten times, before taking it up to break. This added about 20% to the shackle strength for most of the samples we broke.
Next, the smaller shackles did the best, with one notable exception. The average of uncycled breaks for 5/32" was 260% of rated strength, which dropped down to 195% for 3/16" and 141% for 1/4". But the 11mm HSR, New England's heat-treated rope, broke at 166% of rated strength (over 52,000lbs.)
Even the lower numbers were well in excess of numbers we have gotten with conventional soft shackles,. Most heartening.
Most of the tests were done with a lanyard through end of the shackle, and a pin at the other, though some were attached to a lanyard at both ends. The HSR started cutting through the lanyards at high loads, so the testers had to insert thimbles for those. With that exception, then, these numbers were for very tight bends, on the order of 1:1. This means, among other things, that we are safe using them to join rope to chain for anchor lines.
Most of the samples broke at the end of the tail bury, so the taper is one of the things I'll be adjusting in the next batch.
I'll be working with the wonderful tech people at New England Ropes to analyze this data further, and to prepare for future destruction.
Fair leads,
Brion