Illustrations by Margaret Wilson-Briggs
Start with a six-foot long piece of 
-inch Spectra/Dyneema single-braid rope, like New England’s Endura 12. Middle the rope, and pass one end through the rope, to form an eye that fits loosely around two diameters of the rope. Seize the ends together with a Double Constrictor, about 18-inches from their ends.
Form a Wall Knot with the strand ends. The diagonal line at the center is the seizing. This and the rest of the instructions for this button are for a two-strand version of Ashley’s 880 (see page 90).
The finished Wall Knot
Form a Crown Knot on top of the Wall Knot. In 2 strands, this forms an Overhand Knot.
The finished Crown Knot
Pass each end up through the opposite Wall chamber, ahead of the other end
Pass each end down through the center of the knot, into the further of the two openings. Draw up firmly.
Finished shackle
Finished Button Knot.
Button Knot. In the form at lower right, with the ends cut off flush, you will have a decorative soft shackle; just pass the loop end around the objects you want to shackle together, then slide the loop open, slip it over the button, and slide the loop closed.
But if you want full strength, leave the ends long, and tuck them 10 rope diameters or so down into adjacent standing parts. (Finished shackle, above.)
Cut the ends off at an angle, so that they just barely draw inside when you smooth out the standing parts. Make a few stitches through the rope where the ends enter, under the button, so that they can’t crawl out when no load is on.
Congratulations, you have just completed an improved soft shackle, one that is 50% or more stronger than the “conventional” soft shackles that you can commonly find in today’s chandleries. Test results on absolute strength vary depending on the quality of fabrication, but it is reasonable to say that you can expect in the neighborhood of twice the rope’s strength from the finished shackle. So, for instance, the -inch rope shackle described here would have a breaking strength of 5 to 6 tons(!)
You can make soft shackles of any length. If for instance you want to hang a block from a boom, you will want a longer shackle than if you wanted to secure a block to a deck padeye or cleat. Soft shackles, improved or otherwise, replace steel shackles for many, many applications, afloat or ashore. They can be made in a few minutes, using scrap lengths of rope, they weigh almost nothing, and they can be easily inspected and replaced. Wonderful.
