Soft Shackles

[John D]

I'm not talking about loupes or grommets, but a ropework loop formed from a line with an eye at one end and a knob at the other which you can "unbutton" to open and "button up" again to close. This doesn't use a toggle or a spool, just soft rope. In three strand this would be a spliced eye just bigger than the manrope knot at the other end.

A soft shackle in 12 strand has an eye made near the middle of the original line with the untapered bury emerging from the body at the desired length, the two legs are then tied together to form the knob. I've seen several variations made by sailors. Some use a simple square knot for the knob, others use a diamond knot or a doubled figure-8 . There seems to be two schools of thought about the best type of eye, fixed or sliding.

The fixed eye is usually a locked Brummel sized to fit over the knob knot.

The sliding eye just dives the bury straight into the body, leaving an eye just larger than the diameter of the body with the bury. To fit the knob through the eye you have to slide the bury out of the body to enlarge the eye and then milk the body back down to close the eye.

My question to the forum: If I'm going to be be making some Soft Shackles out of Amsteel (or some other UHMW 12 strand rope) which type of eye should I use? And what is the best knot to use to form the knob?

Thanks

John D.

[John D]

When I mentioned to a friend my questions about the best design for a soft shackle, he replied that I should simply duplicate the commercially available design. When I went "Huh? I don't know of anybody selling these" he muttered under his breath about "provincial Americans" and declared that innovations in sailing technology are born in Europe, and pointed me to the online catalog of a German chandlery. A close-up shows it in use.

The manufacturer is Liros (select English as your language and search on Shackle in their product list).

Their design looks to be a sliding eye with a diamond knot.

John D.

[tolachi]

I'm also interested in this and was hoping to find a little more discussion of the soft shackles topic on spartalk.

I've made a few of these and have used the button knot doubled for the knob. It looks great and I have a lot of confidence that it will never work out. However, it is a PITA to tie and really slows down production. I am curious about the diamond knot. Does anybody else have any feedback on how appropriate it would be? Seems much easier to tie.

For the loop I have been using a sliding eyesplice and locking it with a brummel just before I tie the knob. This helps me keep the lengths of either side of the loop the right length. My thought is the eye of the loop should just not close around the neck of the shackle, thus ensuring that both strands are carrying load.

Does anyone know what kind of breaking strength you get from a soft shackle? It seems that there is theoretically the potential to have 2x the breaking strength of the line. With 1/8" sk78 that comes to 5600 lbs, which seems ridiculous.

Any thoughts appreciated.

[Don Z.]

Give the guys at Rope Warehouse a call... They have something similar, and have load tested them.