The recommendation from osirisail to basically move all of your onboard electrical
devices to 12VDC and power them from your batteries and a chargers is the best solution if you are starting from scratch. However you appear to have a fully equipped European yacht and swapping everything out at this point may not be a viable option. If much of your onboard electrical
equipment (frig, battery charger, water
heater, AC, etc., is 240VAC50HZ then your most viable option is to add a voltage transformer to boost the dock
voltage from 120 to 240.
You will find that many marinas
provide 240AC60HZ power at the dock
, but that is normally dual phase power (4 wire). You will need an adapter to turn that into 240AC single
So I think your best option may be a transformer.
Then you still have the problem of the 50hz motors and other electrical devices on board. Before running any of these devices I recommend you consult with the manufacturers. There, I hope you don't run into the usual CYA response (No). I ran my 120VAC60Hz refrigeration
on 120VAC/60Hz power from my Mastervolt transformer for 2 years in Europe
. It is still running fine on 120VAC60Hz power since I returned to the USA in 2007. I did run my AC for one night on 60Hz power. It sounded like a cement mixer and I shut it down after one night. It is still working tonight so there did not appear to be any lasting damage from the 50HZ power.
So, if you have a number of installed 240VAC devices, a transformer will likely be required. You may also luck out on the 50-60 Hz issue, but your equipment manufactures should be able to provide advice in this area.