“Twisted” & “Reinforced Super Strength” Soft Shackles

[Seaworthy Lass]

Soft shackles that do not need to take a heavy load are extremely useful on board, particularly for hanging lines and a host of other items, both inside and out. When super strength is not required they can be made from single braid polyester, but this is often difficult to source.

I have occasionally thought it would be nice to have a technique for making these when you have no single braid on hand. The problem with using any material that is not woven as a single braid is that an eye of adjustable size cannot be formed conventionally.

Well, I have come up with a quick, simple solution . Time spend playing with rope during lockdown has not gone to waste .

Any softish rope or twine can be used for the method I describe below. Short lengths of any leftover rope or finer cord or leather can be utilised as long as it is not too stiff. I have tried 8mm double braid polyester, paracord, leather and 3 mm polyester with braided cover & core. UHMWPE (eg Dyneema) can also be used, but an eye can be created so easily in single braid that I would just use a conventional technique for this.

The length of rope required depends on length of soft shackle needed and the diameter of the line. I needed approximately 70 cm (28”) for the paracord (around 3-4 mm diam) & leather as shown in the photos below and about 1.8 m (70”) for the 8 mm double braid polyester.

This is the appearance in 8mm double braid polyester (ends not trimmed yet) and paracord:

[Seaworthy Lass]

You may think that when the soft shackle is undone or when the stopper rotates then the legs will untwist, but this is not the case.

Once tied as I describe below it will stay permanently in its twisted postion.
The legs do not unravel:

[Seaworthy Lass]

METHOD:

Secure one end of the rope and twist the other end until it starts to hockle numerous times. You need far more twists than expected.

- Bring the two ends together and hold firmly while smoothing the twists until they are evenly spaced. An eye will automatically be created at the apex. The size of the eye is determined by the number of twists.

- Tape the twists together tightly at the working end leaving enough length to tie a diamond knot. I needed 12 cm for the 3-4 mm line I was using. Leave more if you are not adept at tying this knot.

- Tie the diamond knot. Instructions can be found here:
https://www.cruisersforum.com/forums...ot-187913.html

- Dress the knot evenly so it sits close to the tape, starting at one standing end near the tape and tightening all the way around to the working end. Repeat for the other end. The amount of tightening required will depend on the expected load. If only light, then the knot need not be super firm.

- Remove the tape and pretension the shackle on a winch if higher loads are expected. Snip the working ends, leaving short tails.

- Depending on the material you are using, the ends may be melted onto the top of the stopper knot if the stopper has been well pretensioned and it will only be used for light loads. If you press down on a flat surface while still warm it will create a neat, smooth top to the stopper.

None of these have been load tested, but I suspect that if the Diamond stopper is well pretensioned and the ends are not cut short, the strength of this soft shackle will at a minimum be greater than line strength. The line itself does not end up twisted, only curved in the formation (follow the line if that does not makes sense), so I do not expect this will be the factor limiting strength.

The ones below have been made from paracord and leather:

[dougweibel]

Wait - I can see how once this soft shackle is attached and put under load the twists are going to stay in place but if I tie one and toss it into a drawer for a week where it gets jostled around a bunch aren't the twists just going to come out? Does this work because twist is introduced into the individual legs when the shackle is tied and that makes the legs want to stay twisted together?

I can see I'll have to make one of these tomorrow to satisfy my curiosity.

[Breaking Waves]

The normal soft shackle noose is self-tightening, and it gets higher and more secure the higher the load.

How secure is this loop? It looks like it is not 'self-tightening?

I have never tried, but with these sorts of lines can't you still have a noose in the normal way - poke a hole thru with a fid/needle and put an end thru the hole?

just as another idea - what about tieing a one-strand stopper on one end of the cord and a slip knot on the other end. Might be more secure but harder to get open, might want to add a pull tab to the slip knot to help open it.

[s/v Jedi]

About 40 years ago it was fashionable to have a new kind of soft shackle to attach sheets with eye splices to the genoa. This soft shackle was made out of 3-strand rope. One end had a ball & crown tied using the individual strands and the other end just an eye splice that could just pass the ball. Fixed eye.

We used it forever and no matter how wildly flapping around, it never came off by itself.

[Breaking Waves]

Originally Posted by s/v Jedi

One end had a ball & crown tied using the individual strands and the other end just an eye splice that could just pass the ball. Fixed eye.

yea, that is like the toggle designs - fixed eye that just passes the toggle.

[StuM]

A long time before 40 years ago. Ashley's description of a "Strap and Button":

679. Beckets are employed here and there about ships for suspending and securing objects. A common becket has either a stopper or a button at one end, and an eye at the other. It is sometimes called a “Strap and Button.” Falconer describes this becket in 1769.

Or for a variation - his "messegner strap" using a Spritsail Sheet Knot ABOK#889 / 1520.

[Seaworthy Lass]

Originally Posted by dougweibel

Wait - I can see how once this soft shackle is attached and put under load the twists are going to stay in place but if I tie one and toss it into a drawer for a week where it gets jostled around a bunch aren't the twists just going to come out? Does this work because twist is introduced into the individual legs when the shackle is tied and that makes the legs want to stay twisted together?

I can see I'll have to make one of these tomorrow to satisfy my curiosity.

I knew there would be disbelievers .

Have a go making it following the above instructions. The initial twisting before doubling the line over induces the final fixed twists.

The two legs end up twisted around each other. Each individual leg is not actually twisted so it cannot unravel.

I have been playing around with the method and have found the twists can also be induced by doubling the line over first, holding onto the line just below the apex between two fingers, then with your other hand twirling the apex around. The lines between your fingers (and the working ends) then spin around. It may be a better method, as the number of twists can be better controlled. As the number of twists determine the final eye size, this is helpful.

[Seaworthy Lass]

Originally Posted by s/v Jedi

About 40 years ago it was fashionable to have a new kind of soft shackle to attach sheets with eye splices to the genoa. This soft shackle was made out of 3-strand rope. One end had a ball & crown tied using the individual strands and the other end just an eye splice that could just pass the ball. Fixed eye.

We used it forever and no matter how wildly flapping around, it never came off by itself.

Originally Posted by StuM

A long time before 40 years ago. Ashley's description of a "Strap and Button":

679. Beckets are employed here and there about ships for suspending and securing objects. A common becket has either a stopper or a button at one end, and an eye at the other. It is sometimes called a “Strap and Button.” Falconer describes this becket in 1769.

Or for a variation - his "messegner strap" using a Spritsail Sheet Knot ABOK#889 / 1520.

The difference with the above design is that the eye size is variable ie it can be pulled larger to fit the stopper through, then it will reduce naturally back to the original size. The eye size depends on the number of twists induced.

The other advantage is that if an eye is actually going to be created, no stitching is needed. In fact, no tools at all are needed (other than some way of cutting the rope) unless the shackle is going to be subject to higher loads and needs to be pretensioned.

[Seaworthy Lass]

Originally Posted by Breaking Waves

The normal soft shackle noose is self-tightening, and it gets higher and more secure the higher the load.

How secure is this loop? It looks like it is not 'self-tightening?

I think a lot of misconceptions (and as a result badly made soft shackles) have arisen because the eye has been erroneously called a noose. It is only a noose if the soft shackle has been made poorly with the eye too small. The load is then not evenly distributed between the two legs and the strength of the soft shackle will plummet.

If well made, the eye is an eye with a throat, not a noose that firmly grips the object it encircles.

In the past I have been guilty of referring to the eye as a noose, perpetuating this misconception, but lately I have been making a real effort to stop doing this.

Originally Posted by Breaking Waves

I have never tried, but with these sorts of lines can't you still have a noose in the normal way - poke a hole thru with a fid/needle and put an end thru the hole?

I can’t see anyway of poking a hole in double braid polyester large enough to pass the whole line through. I struggle enough just creating one big enough to take out the core if I am making a conventional eye splice .

Originally Posted by Breaking Waves

just as another idea - what about tieing a one-strand stopper on one end of the cord and a slip knot on the other end. Might be more secure but harder to get open, might want to add a pull tab to the slip knot to help open it.

This would in fact create a noose and as you point out, opening the soft shackle would be difficult. Adding tabs would make it easier, but still slows the opening and just complicates construction.

If only light duty such as hanging objects was applied, then I think a fixed loop (eg a figure of eight loop) would be simpler.

[Breaking Waves]

Originally Posted by Seaworthy Lass

misconceptions.... noose

well . . . ok . . . but does not really answer my question - which was whether your eyes could open larger under load? They look like they could/would. Perhaps you are saying it does not matter because this design is only for casual use?

Originally Posted by Seaworthy Lass

None of these have been load tested, but I suspect that if the Diamond stopper is well pretensioned and the ends are not cut short, the strength of this soft shackle will at a minimum be greater than line strength.

I would be careful making such an assumption. All that twisting will not be good for the line strength.

[Breaking Waves]

effect of twist on strength:




https://samsonrope.com/docs/default-...rsn=10649876_2

[Seaworthy Lass]

Originally Posted by Breaking Waves

well . . . ok . . . but does not really answer my question - which was whether your eyes could open larger under load? They look like they could/would. Perhaps you are saying it does not matter because this design is only for casual use?

The eye size is determined by the number of twists, not the load, so no, I think there would be no tendency to open under load. There will be no tendency to untwist under load, as the line itself is not actually twisted.

Originally Posted by Breaking Waves

I would be careful making such an assumption. All that twisting will not be good for the line strength.

Originally Posted by Breaking Waves

effect of twist on strength:.......

I know that twisting reduces strength .
I take a great deal of care when working with Dyneema (both for the legs and even the knot itself in soft shackles) that no twist is induced.

If you look closely at the image of the 8mm blue double braid polyester, you can see that the line itself does not end up twisted on itself, one leg just curves around the other. The curves are gentle. I may be wrong, but I do not think this will be the limiting factor in this design.

I will enlarge the image and draw along the markings to try and illustrate this.

[Seaworthy Lass]

Originally Posted by Breaking Waves

I would be careful making such an assumption. All that twisting will not be good for the line strength.

I think the image below illustrates the situation better. I have followed the weave in one entire leg and marked it in white. There is ZERO twisting of the line. One leg simply curves around the other leg. The effect is a twist, but the line itself is not actually twisted, only curved.

For this reason there is no tendency to “untwist” and also (I think) no loss of design strength. I think something else will fail first eg the base of the diamond knot if double braid polyester behaves the same way as Dyneema in this regard. If not, I think the eye will break first. That is my best guess regarding failure point.