Is one allowed to be on a cruise on Shabbos or Yom tov? Does it make a difference if the boat is moving? Is there an issue of being in a boat? Of techum? Any other issues?
Please see the following post. https://dinonline.org/2016/12/13/cruises-and-shabbat/
Aside from that, todays cruise boatgs are definitely in water that is 10 tefachim deeper than the bottom of the boat, so tecumin will also not ba an issue. the only issue is that the crew that is running the nboat may not be Jewish, because they are doing melacha for you.