Loop Shackles/Connectors aka The Nacrabiner
My first contribution to this great forum.
I use a homemade version of these on sailboats using 1/8 spectra or vectran to replace a clevis or shackle. Spectra handles the chafe a little better than vectran, but I have a lot of 1/8" vectran on hand. Probably some good applications for ultralight folks or hammocks.
These could be used in suspension systems in place of biners, marlin spike hitches and other areas where two lines or eyes needs to be joined quickly.
These work by allowing one side of the loop to adjust opening the eye and when tension is applied the eye closes and secures the knot end. Very easy to make if you have any skills at all splicing 12 strand.
Any strong stopper knot will work on the end, I use a special knot (it's probably a lanyard knot) so that I can cut the tails very short, but it is complex knot to tie while balancing the lengths of the two "legs". A good stopper knot with a little extra tail is much simpler.
They are very strong, the applications are for racing sailboats, where weight and strength are at a premium.
I believe APS sells these as well as the Tylaska Spool Shackle, which is another great way to form a cow hitch when you don't have access to the end of the line.
MOD'S EDIT: See Post 71 for Schneiderlein's findings re: load testing the shackles:
- Use a diamond knot for loop shackles made from Amsteel.
- It is not critical to have the legs of the shackle perfectly balanced.
- The loop shackles have a failure load around 175% of the line's rating (190% for the 3mm Lash-It).
- The Ashley stopper knot and the overhand knot are not suitable for this application.
Pictures and Instructions posted in my gallery
I posted some pictures and instructions in my gallery. Pardon the fuzzy tails, vectran is tough to cut and I didn't have a razor handy. Also, it doesn't burn easily so I couldn't melt the ends.
Not sure how to put a link my gallery, but here is link to step one of making it.
I may have not been real clear in my orginal post. These don't do the same thing as the spool shackles or the holes in a coin trick for adjusting a line.
One example of a use of these is in place of a biner in a WBBB strap setup.