Inverter 6 kW from 220v/50Hz to 110v/60Hz

For my chief’s boat (Four wins 348 vista) I need this equipment:

Inverter from 220v/50Hz to 110v/60Hz, and power : 5 Kw (minim)
(It can be under 5 Kw, but not under 3 – real power).
When the boat is anchored, the engine isn’t work, and the boat is necessary to be powered
from national grid of electricity, which is for 220V/50Hz.
The boat need 110v/50Hz.

If you have it, tell as how much it cost.

Kind regards,