Plus, i mentioned the hoist, couse the wire can rotate freely around its axis on the point where the hook is atached to the wire.
No experience of sling loading etc, but worked extensively with wire rope at sea. Whilst my experience was with using wire mainly for towing as opposed to lifting, I never found any swivel device that actually worked well under pressure. Most would rotate with the assistance of a bar but not on their own - those that did weren't under much strain and even then the movement was very jerky.
Seem to recall that as wire is wound onto a drum, as in a winch, the coiling will induce turns to the wire... IE. if you try to pull it off without any strain on it bights form... when pulled tight the wire will try to twist to straighten out the lay of the strands= spinning if you re dangling on the end of it!
PW