On almost all ships there will be one 110V outlet and one 220V outlet. If you will need to charge more than one thing at a time then a power strip or mutliplug is a good idea.
I always carry a 220V plug adapter in my laptop case. The AC adapters for PC's and most other electronics work with either 110V or 220V current. You just need the correct plug. I just put the 220 plug adapter on my PC and use the 220V outlet.