My First Soft Shackle

[Dockhead]

OK, so I finally got around to making one of these, which are needed to attach my new racing dyneema sheets to my jib.

I spent some time in Copenhagen a few weeks ago trying to make a button knot, and gave up.

So I decided to use the "Starzinger Improved Shackle", using long bury spliced eyes on either end of the length of rope used to make the shackle, and looping the middle part through it to make the stopper knot. Much better suited to my low level of skill, which is adequate for a long bury splice but not for the horrendously complicated button knot.

I'm not completely sure I did it right. It looks like this:



Things I'm not sure about:

1. The instructions talk about tightening up the stopper knot using a winch. How? I put the entire shackle under load (a huge load actually -- about the limit of what my big sheet winches can do), but I don't believe that this is tightening up the stopper knot.

2. The whole construction seems to be very sensitive to exact centering of the "noose" in the middle. If it's not precisely centered, then the noose doesn't tighten up. Yet you can't precisely center it just by measuring. How to do this? This is different from the beautiful soft shackles a friend on here made for me, which have only one leg.

3. To keep the "noose" coming undone when the sheet is not under tension, wouldn't it be useful to put some velcro or something on this? Or maybe it would be better to attach both sheets with a single shackle, so that it's always under tension?


All comments and criticisms welcome!

[Dockhead]

A related question: I need to make up a number of dyneema strops with low friction eyes.

I have been through two generations of these already and I'm still not satisfied.

My second generation has a brummel eye on both ends, both of which are put round the low friction ring, making a loop which can be cow-hitched onto a pad-eye.

The only problem is that the brummel eyes are never quite tight enough to stay on, and so I have to whip them.

I was recently on board a Swan 60 racer, and this boat's strops were simple spliced loops, with a bit of velcro to hold them together enough to stay on the ring. Much less trouble than making my type.

What are people doing about this?

[Stumble]

Originally Posted by Dockhead

OK, so I finally got around to making one of these, which are needed to attach my new racing dyneema sheets to my jib.

I spent some time in Copenhagen a few weeks ago trying to make a button knot, and gave up.

So I decided to use the "Starzinger Improved Shackle", using long bury spliced eyes on either end of the length of rope used to make the shackle, and looping the middle part through it to make the stopper knot. Much better suited to my low level of skill, which is adequate for a long bury splice but not for the horrendously complicated button knot.

I'm not completely sure I did it right. It looks like this:

Attachment 125939

Things I'm not sure about:

1. The instructions talk about tightening up the stopper knot using a winch. How? I put the entire shackle under load (a huge load actually -- about the limit of what my big sheet winches can do), but I don't believe that this is tightening up the stopper knot. you probably are, but think about the design strength of this shackle, your winch likely isn't strong enough to actually load the soft shackle up high enough to fully tighten it down. You just have to do the best you can.

2. The whole construction seems to be very sensitive to exact centering of the "noose" in the middle. If it's not precisely centered, then the noose doesn't tighten up. Yet you can't precisely center it just by measuring. How to do this? This is different from the beautiful soft shackles a friend on here made for me, which have only one leg. the single legged ones just bury the imbalance inside the leg, again, exact is good, but there is a little wiggle in the design. It will self balance under load to some degree. The difference is how open the throat remains under high load. So long as it is close enough to not slip over the knot it's fine.

3. To keep the "noose" coming undone when the sheet is not under tension, wouldn't it be useful to put some velcro or something on this? Or maybe it would be better to attach both sheets with a single shackle, so that it's always under tension?early soft shackles of all designs did this. In practice it use really hasn't been an issue. In my experience they just don't open, even when flogged badly.


All comments and criticisms welcome!

I still prefer the older design, because I like the single leg. But I recognize its a little weaker than the improved. To me the sleekness of it is appealing though.

[Stumble]

Originally Posted by Dockhead

A related question: I need to make up a number of dyneema strops with low friction eyes.

I have been through two generations of these already and I'm still not satisfied.

My second generation has a brummel eye on both ends, both of which are put round the low friction ring, making a loop which can be cow-hitched onto a pad-eye.

The only problem is that the brummel eyes are never quite tight enough to stay on, and so I have to whip them.

I was recently on board a Swan 60 racer, and this boat's strops were simple spliced loops, with a bit of velcro to hold them together enough to stay on the ring. Much less trouble than making my type.

What are people doing about this?

I prefer lock stitching to brummels. It makes it far easier to tighten the eye to the exact size you want. Just keep pulling the tail thru until the eye is closed, then stitch it before it slips.

[Dockhead]

Originally Posted by Stumble

I prefer lock stitching to brummels. It makes it far easier to tighten the eye to the exact size you want. Just keep pulling the tail thru until the eye is closed, then stitch it before it slips.

That sounds like a good tip -- thanks!

[estarzinger]

Originally Posted by Dockhead

I spent some time in Copenhagen a few weeks ago trying to make a button knot, and gave up.

The button is one of those things that after you have figured it out once it is then relatively easy. I think the SL sequence of photos are the best available to learning it solo. I think my photos may have an error in them (have never gone back to double check) - but it is much easier if someone actually shows you - get SL live on video skype and have her walk you thru it, or go down to KMI and see their boat and get personal instructions . Don't give up on this - it is a puzzle and you will have a sense of achievement when you figure it out

1. The instructions talk about tightening up the stopper knot using a winch. How? I put the entire shackle under load (a huge load actually -- about the limit of what my big sheet winches can do), but I don't believe that this is tightening up the stopper knot.

all you need to do is tighten up to your working load, which is unlikely to be all that much above what your strongest winch can pull. So you are probably just fine . . . . . but I think you have a hydraulic ram vang - right? That is probably rather stronger than your winch and I suspect you could find an easy way to use it to load up a shackle.

2. The whole construction seems to be very sensitive to exact centering of the "noose" in the middle. If it's not precisely centered, then the noose doesn't tighten up. Yet you can't precisely center it just by measuring. How to do this? This is different from the beautiful soft shackles a friend on here made for me, which have only one leg.

The 'one leg' soft shackles actually also have two legs, just one inside the other. They also need to have the legs roughly even length to be full strength.

With the noose design there is a very easy trick to making sure the legs are exactly the same length. Make the center noose and then make the two end loops but do not cut off and bury the tails, leave the tails sticking out of the braid, then take two rods (fid, pencil or such) about the diameter of the line, put one thru the noose and the other thru the two end loops . . . . then pull the rods apart until the tail ends suck back into the braid just a bit - this will automatically make the two legs exactly equal length. Sew the loops just a bit to hold their size, then clip the tails off and taper and smooth back into the braid in the normal fashion.

The above will get it exact, but it does not really need to be exact. Just close enough and the noose (how much it actually closes) will adjust for small imperfections.

3. To keep the "noose" coming undone when the sheet is not under tension, wouldn't it be useful to put some velcro or something on this? Or maybe it would be better to attach both sheets with a single shackle, so that it's always under tension?

They honestly dont seem to come undone even when flogging. You can put a velcro loop on them or a rubber o ring, but it really does not seem necessary.


All comments and criticisms welcome!

.....

[Seaworthy Lass]

Originally Posted by estarzinger

The button is one of those things that after you have figured it out once it is then relatively easy. I think the SL sequence of photos are the best available to learning it solo. I think my photos may have an error in them (have never gone back to double check) - but it is much easier if someone actually shows you - get SL live on video skype and have her walk you thru it, or go down to KMI and see their boat and get personal instructions . Don't give up on this - it is a puzzle and you will have a sense of achievement when you figure it out

These instructions with photos can be found here:

http://www.cruisersforum.com/forums/...ot-155591.html

Dockhead, I am happy to give you a hand online.

By the way, the above instructions for the button stopper are followed by instructions for the high strength soft shackle. This particular soft shackle (I have only ever made the one) has just been used to connect our chain to our boat. A leap of faith :

Originally Posted by Dockhead

The instructions talk about tightening up the stopper knot using a winch. How? I put the entire shackle under load (a huge load actually -- about the limit of what my big sheet winches can do), but I don't believe that this is tightening up the stopper knot.

I have been recently tightening the stopper by using Estarzinger's recommended method of closing the soft shackle and pulling it between two winches. I will find a photo in a second. This does not tighten it symetrically which bothers me a bit, so now that I have more dyneema on board I plan to make a length of dyneema with spliced loops on each end, hook the stopper into them and pull the soft shackle while it is open to tighten the stopper symmetrically. It probably won't make difference practically, but will keep me happy .

SWL

[Seaworthy Lass]

Photos of tightening up the stopper using a winch.

This is the shackle lightly secured:




And here it has load applied and is 'sitting' for the recommended 20 min:

[Dockhead]

Originally Posted by Seaworthy Lass

Photos of tightening up the stopper using a winch.

This is the shackle lightly secured:




And here it has load applied and is 'sitting' for the recommended 20 min:

OK, I guess I did do it right after all.


Some day I will find more time to have another go at the button knot. But meanwhile, is there anything wrong with Evans' "Improved Soft Shackle"? I've used the reduced knot version, and it looks ok to me, even if it's not as pretty as yours. Apparently the strength is similar, no?


After putting under tension, my shackle seems to be ok. The "noose" is not too big as I can now see, considering the bulk of the knot.

[Dockhead]

Originally Posted by estarzinger

.....

Thanks!!

[Seaworthy Lass]

Originally Posted by Dockhead

Some day I will find more time to have another go at the button knot. But meanwhile, is there anything wrong with Evans' "Improved Soft Shackle"? I've used the reduced knot version, and it looks ok to me, even if it's not as pretty as yours. Apparently the strength is similar, no?

Evans will be able to answer this better, but I think great care needs to be taken not to make the loops in the tail too large or the overhand knot can pull through under load. This is the only drawback as far as I can see.

The strength is apparently similar to the high strength shackle.

[estarzinger]

** if you pulled it with your winches and it held - then you almost certainly made it correctly and yes, it is 'full strength'. They fail pretty much immediately on significant loading if done incorrectly. "People" generally don't like it for aesthetic reasons - the knot is not symmetrical and not as pretty as the diamond or button. But it is easy to make and perfectly functional, equal in strength to the best alternate designs. I personally make the 'stronger button' now just because after tying it for a while I can do it easily and it is more attractive.

SL - you going to have a hydraulic vang on your new boat. I was giving shackle lessons on a 50' Little Harbour and found their vang to be perfect for very controlled and powerful knot setting - I even did it the way you wanted (straight line rather than as loop). It almost exactly matched what I was doing on my test bench - I also able to put my load cell in-line (duct taped to the vang tube) to get precise calibration.

[Seaworthy Lass]

Originally Posted by estarzinger

SL - you going to have a hydraulic vang on your new boat. I was giving shackle lessons on a 50' Little Harbour and found their vang to be perfect for very controlled and powerful knot setting - I even did it the way you wanted (straight line rather than as loop). It almost exactly matched what I was doing on my test bench - I also able to put my load cell in-line (duct taped to the vang tube) to get precise calibration.

A load cell is one item on my wish list . Testing apparatus as you set up at home is another item. We may need a bigger boat .

[steamgoat]

I got creative,passed the loop through a couple of stout washers then through a link of chain,the chain went around a tree and the loop to the tow hitch on my truck. Got the knot nice and tight [dug some holes with wheelspin !]

[Dockhead]

Originally Posted by estarzinger

** if you pulled it with your winches and it held - then you almost certainly made it correctly and yes, it is 'full strength'. They fail pretty much immediately on significant loading if done incorrectly. "People" generally don't like it for aesthetic reasons - the knot is not symmetrical and not as pretty as the diamond or button. But it is easy to make and perfectly functional, equal in strength to the best alternate designs. I personally make the 'stronger button' now just because after tying it for a while I can do it easily and it is more attractive.

SL - you going to have a hydraulic vang on your new boat. I was giving shackle lessons on a 50' Little Harbour and found their vang to be perfect for very controlled and powerful knot setting - I even did it the way you wanted (straight line rather than as loop). It almost exactly matched what I was doing on my test bench - I also able to put my load cell in-line (duct taped to the vang tube) to get precise calibration.

OK, thanks a lot!

I don't think this shackle is actually ugly, and I can now see that the geometry of the noose and knot are fine. I only need two at the moment so I'm going to make one more of the same and call it a day. When I have more time, maybe next winter, I will try again to learn the prettier button knot. I have to ration my time a bit as I still have a lot of things to do to the boat.


Now to the strops with low friction rings --

Any advice on this (or from you SWL? BTW, are you using these wonderful devices?).

The racing boat I was on used pair of the rings joined by doubled spliced loops, with velcro to hold it together. Very neat and very simple. I don't use pairs of them because you can easily have two different lines running through the same eye of sufficient diameter. I guess they're doing that to eliminate chances of chafe?

So how should I make my next generation? My last one I made with a brummel eye in both ends, then put both eyes around the low friction ring. I then seized the two legs together to hold the ring in the eyes (which can never be made tight enough). I made a mistake with the last one by just threading one leg through the padeye, so that there is only a single strand of Dyneema going through the padeye bail, which now looks to me less strong than just looping it through and cow hitching, which would give more material to bear on the padeye bail. Thoughts?

Now I think to skip the brummel eyes altogether and just do spliced loops. I could make a "noose" in them (like the shackle "noose") to catch the rings, or I could just seize the legs together or lock stitch them together. Thoughts? I am thinking that the brummel eyes are unnecessary and might even reduce strength of the strop -- retaining the low friction rings does not require any strength at all.