This is an appropriate concern given the usual low voltage at many marinas...you'll want to make sure you have adequate voltage or you'll end up damaging airconditioners, refrigerators, and ice makers over time. One 50 amp 125/250 volt shorepower cord (4 pin connector) should normally carry all the power you'll need, provided you have a 240 volt supply. Because the cost of wiring for 240 is prohibitive for many marinas, they use smaller gage wire designed to carry something less, about 220 volts. However the actual voltage delivered may be something even less, say 190 to 205! While most older components will run on this power, damage will occur below about 208 volts. Newer components often have built in drop outs if the voltage goes below a certain value for a few minutes to protect the component.)
If this is the case in your marina, you'll need to buy a smaller transformer for your slip, pluged into the dockside 50A shorepower recepticle, capable of boosting the voltage to 240 volts. Your shorepower cord can then be connected directly to the transformer. Note that amperage will drop as the voltage is increased, but again you'll seldom need all 50 amps simultaneously.
There is one other option, more expensive, and that is to upgrade the boats internal isolation transformers (located behind the generator) with a kit from Wards Electric. The Hatteras technical support line can give you Ward's number in Florida, and provide you more details. This isolation "boost" kit modifies your isolation transformers and will allow you to plug into low power at most any marina, and the boat will then produce it's own 240 volt supply from the 220 marina supply. There is some wiring to be done with the kit....I haven't any personal experience with this, but maybe someone here has and can speak to it...
