Originally Posted by jaitch
Why not skip the ring altogether and just use a Prusik knot? Seems like it's essentially the same thing without the weight of the ring.
This has a mechanical advantages over a Prusik. Just like a whoopie sling, both ends of the outer line are under tension causing it to constrict on the adjustable buried line going through. The purpose of the ring is to keep the outer line from unwinding and forcing it to constrict when tensioned.
In a Prusik Knot, the line passing through the knot is under tension and the loops of the knot are wrapped around with tension on one end, but not constricting. The shape of the knot attempts to force a twisting action on the interior line assisting in it gripping the interior line so that it doesn't slip.
In the case of a suspension where the line is under high tension - resisting the twist - and the amsteel is very slippery a prusik just slips. Ditto for a taut-line hitch.