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Soft shackles

frans

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This is got to be one of the weirdest knots I’ve ever tied. It’s an unholy mix of two different knots, a crown knot and a wall knot.
The knot was developed by Brian Toss. Soft shackles have been used a long time in boating but not with this exact same knot.
You can also tie them with much thinner amsteel or dyneema to make shackles similar to the same size as a carabiner
The shackles are stronger than the steel ones of the same size this one’s rated at 25 tons!
I always liked them because it’s less weight and if they fly around they don’t knock you out.
The drawback is is that they’re not as durable as steel you have to really protect the fibers from ‘picking’.
I will coat it with some sort of a coating, or a chaff guard for hydraulic lines.
 

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frans

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I've always done them internally. Still struggle to remember the knot unless I'm looking at a picture of it
What is the name of the knot you are referring to?
 

frans

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Uhh okay. How do you tie a knot ‘internally’ ? just curious.
The ‘knots by grog’ web grab you referred to is not the knot I used btw.
knotsbygrog is a great web resource!
Look up: soft shackle, stronger.
 

Tree09

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They aren't rated higher than steel shackles, steel shackles have a 5 times higher breaking point than the value they say on them. From what I've read about them they have a rating the same as the size they are made from, so if you have a half inch amsteel one it would have the same breaking strength as the half inch line itself.
 

Tommy_B

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Uhh okay. How do you tie a knot ‘internally’ ? just curious.
The ‘knots by grog’ web grab you referred to is not the knot I used btw.
knotsbygrog is a great web resource!
Look up: soft shackle, stronger.
Sorry, I meant that I always feed them internally. The ones I've made had a single leg as opposed to the two on yours.
 

frans

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They aren't rated higher than steel shackles, steel shackles have a 5 times higher breaking point than the value they say on them. From what I've read about them they have a rating the same as the size they are made from, so if you have a half inch amsteel one it would have the same breaking strength as the half inch line itself.

Could it be that the strengths are comparable?
are we talking Working load limit? Or breaking point?
the 12mm diameter dyneema shackle I made broke at 25tons or 50,000 lbs.

What is the working load limit, and how does that compare to a half inch steel bow shackle working load limit? Also what is the breaking point of a half inch bow steel bow shackle?

truly just wanting to learn about this
Thx
 

cory

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According to this info, breaking load is 3x working load


 

Tree09

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Us cargo control is for tying down stuff, aka 3 to 1 load limit for trucking tie down. Overhead rigging is 5 to 1 for static applications. Here's the crosby screw pin, pretty standard rigging shackle. Notice they are very conservatively rated. This is from the convention of having a set strength for each size, so there was no question of what stuff was rated for. Same with wire rope, everything is rated using their nominal strength, ignoring advancements in wire. Makes rigging choices easy on the fly, especially back in the day with hand spliced gear. If you spliced one of those up and it broke at 50k pounds that's amazing! With it being rope tho i would be more timid and use a 10 to 1 wll with that, which would be comparable to a steel shackle in size.

Screenshot_20210221-205024_Drive.jpg
 

cory

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Thank you for elucidating that, I was sure it was 5-1 but now I see why the chart I posted was for 3-1
 

Tree09

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Rigging is one of those things that is complicated enough, but it's often made more complex by all the different little rules and historical stuff like nominal size strengths. One of the many reasons why we don't need the metric system :lol:
 

frans

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My primary purpose in making these is to use it in conjunction with a dynamic rope for vehicle recovery.
my first experience was having a Ford ranger yank out my 1 ton chip truck fully loaded with chips from being slightly buried in mud.
5/8” 30’ dynamic rope. Freaking amazing. Just popped out my chip truck smooth and easy. No jerking.

another trick is to use an old tire hooked between two static straps.
 

Tree09

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They definitely are handy for all sorts of stuff, I'm glad you have a use for them. If you can, please post how you are making those because they're different from the "normal" ones
 

frans

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They definitely are handy for all sorts of stuff, I'm glad you have a use for them. If you can, please post how you are making those because they're different from the "normal" ones
The ones I made are different because they are a mix of a crown knot and a wall knot. So no tail sticking out.
look up bubba rope soft shackles or yankum ropes and see what soft shackles they sell.
 

Marc-Antoine

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According to this info, breaking load is 3x working load
In the chinese shackle's chart from your link, they say " safety factor : 6/1", and in their pdf for the detailed data, the wll and the mbs are consistent with the claimed safety factor. As respectively 2 and 12 tons for the 1/2" clevis, or 8.5 and 51 tons for the 1" for example.

Here, the safety factor for metal gear in lifting is 5/1 too, but for synthetic fiber gear, it's 7/1.
 

Brocky

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The Diamond knot soft shackles, tails coming out of the top, can get up to one and a half times the break strength of the cord, the Toss Chinese Buttonhole can reach slightly over 2x. Both types need to be loaded enough to set the stopper until it is rock hard. The buried tails of the Buttonhole gives a bigger bend radius for the eye, which is the “weak link”.
I recently came across the superflyinc.com website for paragliding gear and they offer a shackle that uses a girth hitch instead of the expandable eye. This type is easier to make, just a loop and stopper knot, which doesn’t need to be so large because the girth hitch is clamping down rather than bearing against the stopper only. Two inches overall seems to be close to the how short is possible, This method can also be used with a sewn sling.
547A13CF-DFAB-4401-B753-B6DFC75A4B73.jpeg
 
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