That marina with just a single amp service does not want live boards or anybody on the docks for sure. Single 30 will just keep a battery charger, fridge and de-humidifier running fine. There is not much you can do with a single 30a rather than go to another dock. In the states, a single 30A outlet is only 115Vac, period. A step up transformer to 230Vac will only offer 14Amps. Nothing is for free and usually cost some in the conversions.