The best solution in my mind is to go the AC->Batt Charger-> DC->Battery->Inverter route
. This allows you to use any shore power system as long as the battery
charger is multi-system. ( the good ones are). Decide on the main AC system on board ( ie 230 VAC or 110) but cable for 110VAC. If you want both voltages aboard. then use two invertors one for each voltage. If you want to bullet proof the system , then use N+1 invertors, and make the system out of 1Kw units , giving you redundancy ( since you depend on these).
If you want belt an braces put a isolating transformer before the battery charger, but in my view there no need as this is the only Main AC device directly connected. Note wherever possible get an isolated ground battery charger. In my opinion nothing good comes from tying AC neutral to DC ground.
Secondly ensure you have a 30ma RCD immediately after the shore power entry into the boat. Only take the shore power earth wire to the battery charger. Follow thw invertor wiring
for boat side earth wiring , usually the neutral and earth and joined at the invertor. Again use RCD's on the output of the invertor.
Both the 110VAC, 230VAC( if you have two onboard voltage systems) and DC system should be isolated from each other. ( which is not ABYC practice but is current
EU practice as RCB are required and these provide sufficient protection .
All three system need independant panels
etc. It can get quite complex
Note that in practice for these system to work , you will need big battery banks 1000amp/h or greater and a good big charger ( 100amps+) and engine
( with a smart regulator) and a good battery monitor
, but its a very flexible system. The charger should have a controllable limit to avoid tripping shore power systems
It will however in pratice be limited to 3-4Kw AC on board, fine for power tools, microwaves etc, but will rule
out on-board Air Conditioners.
The next stepis to add a AC Generator and use it to power heavy AC devices and run the charger , but in my mind its not needed. ( buy a little Honda
2000i for backup). A DC generator would be useful if you have a big batteyr bank, but they are expensive and fault prone ( I built my own).