Depends. How long will you be going? Are you going to be sleeping in a coffin-rack, or will you have a stateroom? Either way, you should probably bring your own twin bed sized sheets and your own pillow. Hospital ships are big enough that you shouldn't have to worry about seas sickness. People wearing khakis are in charge, people in blue do the actual work. Breakfast is the best meal of the day, but damn near anything can be made edible with Tapatio. Bring hot sauce, as gifts for the people you work with if nothing else. Ship coffee is like what Cypher described his Matrix rotgut as: Good for two things; waking you up and degreasing engines.