Well, Hive account@benjaminrushmd, there are several companies that run "concessions" on cruise ships; of these, Image and Cruise Ship Photographer are perhaps the most prominent. Best way would be to drop by their websites and submit a CV/resume. If you have a link to a portfolio of your photos online, that would also be helpful.

As with any job, there are advantages and disadvantages. You'll have to decide for yourself ;)