Making Waves On Shabbos
The Gemara in Shabbos makes an undisputed statement: Less than three days before Shabbos, one is not allowed to board a boat that will travel on Shabbos unless the travel is for the purpose of a mitzvah.
Travel
Taking a Cruise Over Shabbos in the Gemara
Whether one may stay on an engine-powered cruise ship over Shabbos when non-Jewish crew run it, depending on who the passengers are and whether it sails regardless.