Dyneema Soft Shackles

[cartercd]

I stumbled across these "soft shackles" and thought they would have interesting applications for recovery. They are made of Dyneema fiber (same stuff as Amsteel Blue) and originated in the marine industry. I found some that had a breaking strength of 16K pounds and working load limit of 8K pounds. The way the Dyneema rope is fed back into itself, when it is placed under load it it self-tightens. When not under load it can easily be undone by hand. They would be easy to make yourself, but the trick is the stopper knot at the end. I haven't found what type of knot this is, and I think the knot may need to be placed under a heavy load in order to set it. As Dyneema fiber has very little friction, knots do not tend to hold well.

Advantages I could see:
- light and compact
- minimize the risk of a flying metal object in the event of component failure

Disadvantages:
- High cost. $30 for one with 2K pound working load limit
- Less chaffing resistance. Probably not good to use on some recovery points with sharp edges

I could see these being used to attach lines/straps together. I bet these will eventually be commonplace in off-road recovery, much the way synthetic rope became so popular. Here are some links if you want to do a little more research:

Liros rope catalog. See page 16. http://www.lirosropes.se/pdf/XTREME Catalogue.pdf

How's your French? Here are instructions on how to make yourself, although the stopper knot is not detailed. Brancaleone, dalla Bretagna verso...: Un grillo in tessile

Anyone want to give this a try and do some load testing?

 

[e9999]

I stumbled across these "soft shackles" and thought they would have interesting applications for recovery. They are made of Dyneema fiber (same stuff as Amsteel Blue) and originated in the marine industry. I found some that had a breaking strength of 16K pounds and working load limit of 8K pounds. The way the Dyneema rope is fed back into itself, when it is placed under load it it self-tightens. When not under load it can easily be undone by hand. They would be easy to make yourself, but the trick is the stopper knot at the end. I haven't found what type of knot this is, and I think the knot may need to be placed under a heavy load in order to set it. As Dyneema fiber has very little friction, knots do not tend to hold well.

Advantages I could see:
- light and compact
- minimize the risk of a flying metal object in the event of component failure

Disadvantages:
- High cost. $30 for one with 2K pound working load limit
- Less chaffing resistance. Probably not good to use on some recovery points with sharp edges

I could see these being used to attach lines/straps together. I bet these will eventually be commonplace in off-road recovery, much the way synthetic rope became so popular. Here are some links if you want to do a little more research:

Liros rope catalog. See page 16. http://www.lirosropes.se/pdf/XTREME Catalogue.pdf

How's your French? Here are instructions on how to make yourself, although the stopper knot is not detailed. Brancaleone, dalla Bretagna verso...: Un grillo in tessile

Anyone want to give this a try and do some load testing?

my french is OK, thanks. How is your Italian?


These are cute. Not quite sure what I would use them for, though.

 

[roalco]

Looks like a celtic button or a turkshead knot to me.
I've heard of yachties (never heard of them actually being used in the commercial marine world) using these so they don't lose a shackle when they drop it over the side (they float).
Honestly, I don't think I'd use those in recovery to replace a shackle on a stressed line.... only a 2:1 safety factor and for attaching to a hard point? You use a shackle to remove the line from hard edges and even then you should use a thimble in an eye to keep from damaging the line (extremely tight bends are not good for the strength of a line, which is why a knot seriously reduces a lines ultimate strength).
Be very careful.....

 

[cruiser7773]

Looks like a "monkey fist" or heaving knot. Simple enough to tie with a little practice. You can tie it around a small steel shot (bearing) to keep it round and hard. The trick is to make your loop the right size for the knot, before you tie the knot.

 

[Cherry Zhou]

Very cute dyneema sling knot. I am studying in those related products made from the dyneema fiber
Our company is specialized in manufacturing SK75 Dyneema Lines and Rope.

 

[Cherry Zhou]

Very cute sling knot. I am studying in those related products made from the dyneema fiber.
our company is specialized in SK75 Dyneema lines and rope.

 

[Southeast Overland]

Holy thread resurrection Batman!

We make and sell these on our website HERE. They definitely don't replace a hard shackle, but are better in some situations such as attaching to a tube on a slider, bumper, etc. I used one a few weekends ago to very quickly attach a winch line extension to a tube on a bumper to keep a truck from rolling. I tell people that it is good to have one in your recovery kit, you don't need half a dozen. I only carry one, sometimes one of each size for demo purposes.

Re ratings - ours have been load tested, both 3/8" and 1/2". I have the broken shackles here. No knots pulled out. I even marked the tails coming out of the knots and saw no significant slippage. When loaded the knots get very tight and hard.

The knot is the most intensive part. There are other pieces that have to be done correctly, but the knot takes the most time and needs the most attention. We went through several knot revisions to find the one that works the best. We have also gone through numerous design revisions to find out what works best in regards to the knot, but also the length of bury, abrasion guard length and tightness, size of loop to go around the knot, length of tail coming out of the bury, now to secure the bury, and length of tail out of the knot. Oh, we also tested a 7/16" diameter but settled on 3/8" and 1/2" for options.

These did originate from the sailing world from what I can tell. I'm not a sailor but I can see how it would be much preferred to have one of these smack you rather than a hard shackle. And they float too.

3/8" = 29,000 ABS and a WLL of 7,250 lbs at a 4:1 safety factor.
1/2" = 42,000 ABS and a WLL of 10,500 lbs at a 4:1 safety factor.