220v 2 wire 50hz to 220 3 wire usa transformer

Why "But"? I didn't say that Pascal was wrong in saying that inverters convert DC into AC.
I was just trying to explain why a boat where "Dock power goes to the inverters then out to the boat systems", which Pascal said can't happen, actually is not unusual at all.
So, it stands to reason that RossC saw such setup.

Ref. "new generation" of inverter/chargers, define "new".
I installed a Victron Quattro on my old boat at least 10 years ago, and I did that after having seen similar installations on other boats...

I was really referring to typical inverters. Indeed some shore power systems include an inverter module, like our Atlas ShorPower. It does not pull power from any battery though.

The other side of that Atlas might be 480Vac 3ϕ