We have two 30Kg Anchors that were gifts from the swivel breaking demon, ie. Other people lost
these anchors and we found them with half a swivel attached.
We have all chain, no swivel, and the chain has never jumped the gypsy
, therefore no twist. I am wondering if you have a horizontal shaft windlass
or vertical. A horizontal one only has about 100 degrees of wrap angle, a vertical shaft has about 270 degrees and almost impossible for the chain to jump it.
I also urge you to make sure that the last link on your chain is sized to fit the shackle pin perfectly ie 180 degrees of contact. You can hammer a tapered pin into it to size it correctly.
I have seen rope-chain rodes twist up like crazy...