Not much money....
http://www.cruisejobline.com/
Medical Center
Doctor: US$ 4,800 7,000 per month. Oversees the entire shipboard medical facilities, treatment mostly to passengers and sometimes crew. Current license, extensive experience with cardiac and primary care, trauma, internal, and emergency medicine required. Diploma from an accredited medical school and fluent English Language skills required.
Nurse: US$ 2,800 3,200 per month. Requires background in trauma care or accident and emergency treatment, preferably in an ER/ICU. Diploma from accredited nursing school with a minimum of two years recent hospital experience required. Certified nurse.
Dentist: US$ 4,800 7,000 per month. Qualified Dentist with diploma from accredited medical/dentistry school and minimum of two years recent experience required.