According to the Fred. Olsen brochure they have dual voltage 110 volts requiring US style flat two pin plug and 220 volts requiring a continental round 2-pin plug. On my cruises I have found that some cabins have been adapted to UK type plugs but others not. Why not visit the Fred. Olsen website and go to A-Z of cruising? To be certain contact Fred. Olsen Cruise Lines.
The plug sockets are the same as we use here in the UK, when I was on Boudicca last year I did not have to use any adapters. Enjoy your cruise. Ann.