hello, I am looking for a specific knot. Something that has a loop and a tagline that I can connect together for a larger loop. Hopefully the picture explains it better. My intentions is mainly for quick attaching accessories, like a rescue ladder, at predetermined lengths, around the rails. And I intend it for rope like 3/8 anchor line or diamond braid poly. I guess I could tie a double surgeon loop with a long tag line; I've done that before when I kept my stink pot in a slip. But I was wondering if there was something more specific. I posted this in the sailing forum because- "who knows knots better?" The keychain hardware isn't necessary, just an idea.