I have come up with what might be a new way to connect a line such as Amsteel to something without having to use a separate soft shackle. It is very fast to use, much faster than a soft shackle and may even be faster that a regular snap shackle. It is based on a soft shackle but with the eye as part of the line and the diamond knot permanently connected to the target, such as the head of a sail. I have used it on my boat in several places and it really works well.
I am not completely sure if it is new and if it is, not sure what to call it. I have been calling it a soft halyard shackle but it has way more uses than just halyards. I would appreciate some feedback.
I completed some strength testing and find it very strong. I pulled it to destruction using a sample made from 1/8 Amsteel. It breaks just like a soft shackle -- at the diamond knot. Tests on a soft shackle show it has about 170% of line strength so I conclude that this shackle is 80-90% of line strength based on the fact that the knot in a soft shackle carries half the load. From previous tests, I felt I was near the line strength when the knot finally let go. It took a lot of force to break it. For example, I observed about 10% stretch on the 7/16 XLS anchor line from from the initial condition of being pulled as tight as a Barient 22 could pull to where the knot broke being pulled by a hydraulic jack.
I have written an article explaining it in detail.
http://l-36.com/halyard_shackle.php
Allen