Hi Schnappi. We recently returned from a cruise in Europe. Not wanting to carry a lot of cash with us, we exchanged our USD for Euro prior to leaving home. We spent a few days in Amsterdam pre-cruise, and used an ATM to withdraw more as the cruise approached. (Just check with your bank before you go...they will give you numbers to call if you run into problems overseas, and advice regarding your PIN). As f-mattox indicated, many places will take MasterCard or Visa...some will take American Express, as well.
Enjoy your cruise!