[dugout]

I think maybe you are referring to a buntline hitch? It's a good hitch but not a fixed loop knot like a bowline. Maybe try the "Locked" or "Yosemite Turn" Bowline. I've never seen one of these shake out. I see now you are talking about life support and reserve any recommendation. I, personally, use the scaffold hitch or the buntline hitch, both with stoppers in the tags.