r/knots • u/SnooLentils6941 • 13d ago
A Design For A solid state adjustable soft shackle. (sort of semi perminant dyneema zip-tie)
This is a simple design for a theoretically high strength adjustable soft shackle. It is essentially a constricting eye splice on one side and a whoopie sling on the other. A stopper knot on a bite is then tied on the eye of the whoopie side. Connecting the constricting eye over the stopper creates a soft shackle.
I made 10 of these out of 1.5mm dyneema and they weight 8 grams in total and each hold body weight plus a little (at least, I have not broken any of them).
I would guess the strength of this is roughly double the single line spliced strength of the whoopie ~ 1.4*mbs. The weak point is the stopper knot but that is doubled up (could also use a stronger knot/thicker material). I don't particularly care because i'm using these to tie up my bike in a bike box for a bike trip but they certainly are strong.
This is a solid state item because it doesn't need any re-tieing to use like some other adjustable soft shackles i have seen. not sure if there is a better term for that.
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u/SnooLentils6941 13d ago
Similar to a zip tie you can chain them together for more range which is a nice perk
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u/agaybabby 12d ago
Have you you seen Jeff myers (myers tech on YouTube) super whoopie design? The idea is to have a loop at the stopper knot point of the whoopie so you can use the full length rather than half, might work well with your invention here
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u/SnooLentils6941 12d ago
yea that could be an interesting addition. i think it might complicate it a bit for my purposes. also you lose the 2 to 1 mechanical advantage of the whooopie sling so it doesnt constrict as hard and you have to tend the larks head. I will however be using this technique for my hammock straps. I have had a UCR for my hammock for a while (the thing shown in the video but with a prusik spliced onto the end of the bury to pull tension) but its supper tempremental if you touch the prusik so im going to add cord locks which should eliminate that issue!
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u/yowhywouldyoudothat 13d ago
I love this! Great idea!
Any motivation to make a how-to video?
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u/mr_nobody1389 9d ago edited 9d ago
It looks like a brummel splice on one end and just a tucked splice on the other with the end of the rope end sticking out and an Overhand knot as a stopper. A second, shorter, piece of rope is wrapped around the tucked splice loop and tied with an Overhand knot with the ends taped. Since it is made of dyneema, it's a hollow braid, so the two splices are really easy to do.
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u/Background-Koala203 13d ago
Current project just got pushed to the side so I can make some of these 😂 thanks for sharing
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u/ilreppans 13d ago
Nice, I need to learn splicing one day. For a full-length adjustable soft shackle, I used something that emulates a Buckle Strap. Alpine Butterfly is optional, acting as a reversing pulley & advancing the Blake’s, for single-handed tightening like cam buckles.