From my experience....it is hit or miss on poker for cruise ships. Some ships you get a game going every night with a line waiting to play. Others...never saw a game. No interest. One thing is....I believe the rake is 10%. (Generally) so....it isn't in the players best interest to play. The longer you play the more the house takes off the table
Other people might have other opinions or more info. Best of luck on your cruise. You should have a great time.