I am not sure what you have tried, but I have many links on the Job Page of the main site, especially to most cruise companies. From my experience they do work, thats how I wound up working on cruise ships at differing companies.
The cruise lines' HR Dept are notorious for being a big black hole full of mystery on how the hell they make up their mind, and not letting you know anything until you get a call "can you be on the ship tomorrow". Generally it is one or two persons in charge of connecting you to a job on board. Getting your sharp looking and concise resume to that person is of paramount importance, best achieved by someone already working there.
I have about a 50% success rate when it come to referral to a cruise company I worked for. I am not sure why they took some not others, but generally speaking it is a business largely dependent on appearances. Young, smart looking (keyword "looking"), Caucasian, unattached, and adventurous (willing to settle for a low salary) certainly will have an easier time than most. ...and usually for lower ranks.
Thats my perspective...
Certified Marine Engineer and Webmaster
Martin's Marine Engineering Page