your swivel is an extraneous bit of metal .
i do not use one.
the swing of your boat on anchor is going to tewist chain with and without that swivel.
when i raise anchor i take that time to untwist the chain and to inspect my chain and clean it as it is raised onto my deck
and into the deck
hole for the chain locker.
i was anchored by one fluke of bruce in zihuatenejo for 2 months, very securely and comfortably--the rocks helped keep anchored well. we turned 360 every day with tide changes and winds....
there will be twist, and anchor and chain need minding while being raised. might as well inspect and clean that chain.