Soft Halyard or Line Shackle

[Essington]

So, I was playing around with the strong soft shackle yesterday and realized that its design lends itself to a "soft halyard" type construction.

The interesting feature of this shackle design is that the tails exit on the same side of the knot as the standing parts. What's to say that we have to bury the tails into the standing parts?
What happens if we make one tail longer? Maybe significantly longer, then bury the other (short) tail into it?
Well, now we have a soft shackle with a spare long tail that we could do something useful with!

I guess you could do this at the end of a halyard, but it would be mildly annoying to build the button knot with such a long tail (the rest of the halyard), and if the shackle eventually failed for some reason, reconstructing it would shorten the halyard by several feet.

One interesting use would be to thread 72 diameters or more of the tail over another line. This would give us a soft shackle that could be slid to any position on the line, but would stay put as soon as a load is placed on it (something like a whoopie sling)!


This type of construction would yield a strength of somewhere short of 100% (of single line strength), but might be useful for something like a backstay pigtail.

[allene]

Originally Posted by Essington

So, I was playing around with the strong soft shackle yesterday and realized that its design lends itself to a "soft halyard" type construction.

The interesting feature of this shackle design is that the tails exit on the same side of the knot as the standing parts. What's to say that we have to bury the tails into the standing parts?
What happens if we make one tail longer? Maybe significantly longer, then bury the other (short) tail into it?
Well, now we have a soft shackle with a spare long tail that we could do something useful with!

I guess you could do this at the end of a halyard, but it would be mildly annoying to build the button knot with such a long tail (the rest of the halyard), and if the shackle eventually failed for some reason, reconstructing it would shorten the halyard by several feet.

One interesting use would be to thread 72 diameters or more of the tail over another line. This would give us a soft shackle that could be slid to any position on the line, but would stay put as soon as a load is placed on it (something like a whoopie sling)!


This type of construction would yield a strength of somewhere short of 100% (of single line strength), but might be useful for something like a backstay pigtail.

I am not following what you have here. It looks like you have one line coming down into a diamond knot but somehow it becomes two strands. I have done a lot with soft halyards but, as I said, not sure what you have here.

This is what I am using now for my halyard. http://L-36.com/HybridHalyard.php

[Essington]

Originally Posted by allene

I am not following what you have here. It looks like you have one line coming down into a diamond knot but somehow it becomes two strands. I have done a lot with soft halyards but, as I said, not sure what you have here.

Actually it is Brion's button knot rather than a diamond knot. When the knot is completed, you have 4 parts exiting the bottom of the knot. 2 legs make the shackle, and 2 legs are "tails". Normally the tails would be buried into the legs that make the shackle, but in this case I left one tail quite long, and buried the other tail into the longer one. That leaves a shackle at the end of a very long tail.

As I said earlier, this construction is probably not ideal for halyards, but might be useful in other applications.

Originally Posted by allene

This is what I am using now for my halyard. http://L-36.com/HybridHalyard.php

Your Hybrid Halyard is what I use for my halyards ... it really is a better solution for halyards. No taper to jam in sheaves, and the shackle at the end can be replaced if needed.

[allene]

^^ I recognized the button knot and misspoke when I said diamond knot. Sorry about that. I guess what you have is a second line inside the cover that comes down into the button knot. It just looked like you had one line coming into the button and one out but there should be four.

Thanks for the kind comment about my halyard shackle.

[Anton B]

I did some destructive testing with my idea of the adjustable diamond knot attachment. Basically what I came up with is that the multiple diamond knots are stronger than the line with spliced loops at the end that I pulled on it with.

I did a very simple eye on both ends, one of them whipped so as to make it an adjustable eye to put over the diamond knot, and a non-secured eye on the other end which I either put over a bolt in my steel table, or luggage tagged to an endless loop that I then attached to the table in some way or another, for adjustability. None of the splices slipped.

I then put the adjustable loop over the outermost of 5 diamond knots at the end of a loop, then luggage tagged the multiple diamond knot loop to a shackle and pulled it with a come-along with a deer scale on it so as to be able to observe the tension at which it broke.

I used 1.75mm dyneema of some sort I had lying around; it is probably be Samson Lash-it, which has a stated breaking strength of 400Lbs.

In 8 tests, in only the first one did a diamond knot fail. It slipped at 350Lbs and failed at 375. It was the first 5 diamond knots I had ever tied in my life. I imagine that the legs were of uneven lengths, as I had trouble making the knots come together evenly.

In all of the other tests, I was not able to break any of the diamond knots on the second set of 5 diamond knots I had ever tied in my life. I am sure were better, more consistent, and tighter than the first 5.

The line mostly broke at the end of the taper in the splice a about 300-400Lbs, even though I tried to make nice long tapers, and I broke one eye at the end where it was hooked onto the diamond knot.

All in all, I am pretty sure that the multiple diamond knots in a row are all at least more than 100% of the strength of the line with loops, which was what I was hoping to prove.

I am assuming that the results would have been the same with the larger line I plan to use, but may do a test later to make sure.

Here is a link to some of pictures of my test rig, and the carnage

https://www.flickr.com/photos/959099...7651093139326/.

[Brion Toss]

Hello,
Great fun. This is similar to the work of rigger Matthew Otto, though he uses a series of locked Brummels. As for relative strengths, first quibble: I believe Lash-It has an average break of 500lbs.
Next, your pictures appear to show the line doubled on the scale, or nearly so (slight angle). If so, the scale will read about twice the load on the rope. Did you take this into account?
Next, there is no question that the Diamond weakens the rope severely. On the other hand the material is doubled in this configuration. Still it is intriguing that the attached eye piece broke. One question: what do you mean by an adjustable eye? I can't picture it, or how a whipping is involved.
With a clearer idea of the configuration we could conduct more formal tests.
Fair leads,
Brion Toss

[Anton B]

First: Yes, Lash-It has a breaking strength of 500 Lbs. I got the 400 number from somewhere on the web which was not the Samson website. Careless Googling...

Basically, this is what allene on L-36 is calling a line shackle or a soft halyard, only with more diamond knots in line so as to be able to attach the eye at various points to make an adjustable assembly. What I am erroneously referring to as the "adjustable end" is the eye that you can enlarge to put over the diamond knot. I am not sure what the name for that part of the assembly is, just "eye"? The soft shackle eye? Retractible eye? Please tell me what I should be calling it so as to make myself better understood. I am going to go with soft halyard for the assembly, even though I plan to use this attachment on a small boat for the shrouds and forestay, hence the need for at least a gross method of adjustment. But what do you call the spliced eye which can be enlarged temporarily to insert the diamond knot? I know I am doing this against the advice and good sense of people smarter than I, but will do it anyway ;-)

In any case, I whipped the soft shackle eye in place, as opposed to sewing it, only out of laziness, as I couldn't find a needle at the time. I figured it didn't matter as long as it held the splice in place so the eye size wouldn't change when opening and closing it to put it on the diamond knot, and since the whipping is not what makes the splice stick, it didn't really matter that I did that instead of sewing. Correct me if I am wrong.

As for the pulling rig, I have the stainless flat bar arranged so the mechanical advantage is 3:1, with the scale reading 1/3 of the load on the line being tested. The scale was reading between 100 and 140 or so, but it is hard to certain since it is bouncing around, and the come-along is a ways away from the scale face. I plan to rearrange it to get an easier read. I also plan to make a holder for my cell phone so I can take video, which will make it very easy to ascertain the maximum reading. The scale goes up to 550Lbs, but I did the lever so I could test higher strength lines. I will probably re-do these tests with the scale pulling directly as I think that will be more accurate.

I too was a bit surprised that the one eye broke, and am not sure why that happened. Could have been bad workmanship; eye too small? At this point, I can do all the splices quickly and easily, so further testing will be easy. Pulling straight with the scale, and getting the break on video will make the test easier to do, more accurate, and I can watch the line break instead of trying to watch the scale while it happens, which is less fun.

I don't have a theory as to why the line is breaking at 400 or so at the end of the taper in the bury, as opposed to the stated breaking strength of Lash-It at 500. I too will try to make better tapers, and also make more accurate sized eyes, etc.

As some point, I will pull the larger lines and see if the testing with the big line is proportional to the little ones.

But again, the main thing I was interested was whether the multiple diamond knots would break before the rest of the assembly. The soft halyard with luggage tag loop with a single diamond knot is well tested, but I could not find anything written up about using multiple diamond knots, nor could I get anyone to venture an opinion on it.

I will always do the right thing, but only after trying everything else ;-)

Anton

PS: many thanks to allene for putting all that great info up on the L-36 site, it has been very interesting and useful to me.