As Rad has invited me here goes!
The standard European marina supply is 220v and the maximum current rating of the IEE connectors used (i.e. the plugs) is 16 amps. They are the blue ones as yellow is for 110V.
16 amps at 220 Volts equates to 3.5 KVA and usually more than covers the needs of a yacht. There are 32 amp supplies in some marinas for much larger yachts and these will provide 7KVA of power.
However all building sites ashore are run from temporary 110V supplies and all the power tools etc on sites are also 110V. This is achieved using a
site transformer. These step down the voltage to 110V and these start at about £60. They are heavy, but not excessively so and are either rated for intermittent use or continuous use. I just went and weighed mine and it was 60 lb.
See model N30-2 on
http://www.newmarket-transformers.co.uk/tool-transformers.asp as an example, and it weighs 16Kg = 35lb.
You will need to look at the labels on your on board mains powered appliances and total up their power consumptions in kilowatts, i.e. KW (or KVA which is almost the same number).
Remember you might not want to run everything at once so you can take a view on which appliances are necessary and which you might need to run together. Also note whether it will be continuous or short term. e.g. a kettle or coffee pot or microwave is regarded as intermittent but a fan heater or air-con would be continuous. Just add them up and this will be the transformer you need.
The question of 50 or 60Hz (cycles) should also be indicated on your appliance labels. Most equipment which is not made solely for the American market will run off either. Any heating appliances are normally okay and also many appliances which use brush motors, however items such as washing machines or dishwashers might run slowly or even overheat. For each you need advice from the manufacturers instruction book, or by e-mailing the maker direct.
Good luck and have a nice trip.
