As a European (the Netherlands) engineer
living in the US I should have an answer, but the question was asked very 'loosely'.
A lot of equipment
does not care whether it is fed with 50 or 60Hz. A lot of PC- and other power supplies can even handle 100 to 240 Volts input. Pin configuration is of course different but that's easy to bridge.
Just be careful with transformers and converters to not use them over their power rating. E.g. do not run a 1,000 Watt hairdryer over a 100 Watt converter!!!!!
Power-eaters like hairdryers and ovens will be the biggest problem, but if you can afford a Euro boat, why not include some Euro equipment?
When dealing with all this it is handy to know what Volts, Amps, Watts and Hz mean so you can make good decisions before plugging something in........