I''ve tried using a swivel a couple of times when anchoring with two anchors: shackled the two rodes to the swivel and a stopper over the roller from the swivel; lowered the swivel to a depth well below the keel and cleated off. Hoped it would keep the rodes from winding about each other, but didn''t help. I haven''t tried putting a swivel at the anchor, but haven''t noticed a problem I could attribute to not having one.
I do think anchoring must be one of the most interesting cruising topics.
On another related topic: I have a bronze manual anchor windlass I''ll probably use on my next boat and would like to locate its manufacturer. It is marked "MORITZ Costa Mesa, California". Anyone know anything about it? No luck in the Yellow Pages.