Yes they mostly are. I went on one that boarded and 6pm left dock at 7and returned @ 12:30. Had all you can eat dinner also. They also have daytime cruises.
They do both a day cruise and a night cruise on the weekend
There are two a day. The a.m. leaves at 11:00 and the night time leaves at 7:00. There are buses that will pick you up and return you to the same place. Ala carte menu and buffets are available for both. Bon voyage
I think it's a 6 to 7 hours trip. I don't know whether they can make it a one entire day deal. But not lijely cause the ship has to go through cleaning stucking and immigration procedures
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