Yup Europe by boat does sound like a very interesting trip. Sort of a
Viking cruise where you get to decide where you go and how long you
stay.
It does beg the question, how would the electrical shore tie work at
220v 50HZ.
You might need to buy a big assed transformer. I imagine most of the
motors would tolerate the 50 hz but you need to read the nameplate
rating.
That "transformer" might need to be a VFD. (lighter but more
expensive)
===
All of my battery chargers are rated for 50/60 so that is not a
problem. What is an issue is 220 V non-center tapped. For that you
need an isolation transformer rated at 12 KVA/50 Hz. You can pick
them up on EBAY for a half reasonable price but you need to build a
weather proof enclosure and install some Euro style inlet connectors.
The isolation transformer also solves the GFI tripping issue which is
common on some Euro docks.