**This reply is not intended as a Psak Halacha but rather as an exploration of possible Halachic solutions to the question posed.**

(a) First, we have to make sure that the owner and crew of the boat are non-Jews. The crew must be non-Jews because we cannot have a Jew doing work for us on Shabbos. The owner must be a non-Jew because a Jew is not allowed to hire non-Jews to work for him on Shabbos, and by us traveling on his boat, we would be aiding and abetting his wrongdoing. With large companies, and especially publicly owned companies, it may be difficult to find out who the owner and the crew are.

Assuming the owner and the crew are not Jewish, the next issue is: who are the passengers? If most of the passengers are non-Jews then we say that the crew is doing its work on Shabbos primarily for them and not for the Jewish passengers. If half or more of the passengers are Jewish we may have a problem. Normally we would say that it is forbidden. However, if the boat runs on a fixed schedule, whether or not there are passengers, then there are Poskim that allow traveling on the boat even if most of the passengers are Jewish because we don't say in this case that the crew is working for them - they would have done the same work without them (See Shmiras Shabbos ke'Hilchasa 30:55). Determining ahead of time precisely who the passengers will be is next to impossible. They are not going to provide you with a passenger list and even if they did, you wouldn't know with certainty who is Jewish and who is not. It is probably safe to assume that the make-up of the passengers is similar to that of the general population - that is, mostly non-Jewish - but this requires more investigation.

(b) Now let's deal with the actual issue of traveling on Shabbos. Assuming that your cruise is traveling on the open sea and not on a river, the major issue is how long before Shabbos the cruise leaves. If the cruise leaves three days before Shabbos (before Wednesday), then you may certainly go on the cruise (Shulchan Aruch OC 248:1). If not, then you may still go but you will have to ask the crew not to sail on Shabbos - i.e. to pull into a port for Shabbos. If they don't agree to your request (which is likely to happen, unless it is your own private cruise) then you may still go but you must go through this formality (Mishnah Berurah there, 3). The reason for the distinction between before three days and within three days, is that it takes a person three days to "get his sea legs", and if he is still adjusting to sea travel on Shabbos, it wont be a very enjoyable Shabbos. (This rule doesn't apply if you are on a river cruise because there is no motion sickness there. It is possible that in today's large cruise ships one is more isolated from the wave motion of the sea and therefore this distinction wouldn't apply. This requires further investigation.)

(c) Regarding disembarking on Shabbos: even if the boat docks on Shabbos, you may leave the boat and walk about the port city (Shulchan Aruch OC 404:1). The problem is getting back on the boat on Shabbos. The Beis Yosef rules that one may not enter a boat on Shabbos because it appears like he is going for a swim which is forbidden on Shabbos (Shulchan Aruch 248:3). The Remah (there) rules that if one was already on the boat when Shabbos arrived and then left the boat, he may get back onboard on Shabbos. Ashkenazim may follow the ruling of the Remah. Even if you are allowed to leave the boat, however, in most cases you will not be able to carry anything with you because you are going from one type of Shabbos domain to another.

(d) Another issue is whether you are allowed to carry objects on the boat on Shabbos. The boat is considered a Reshus ha'Yachid (private domain) because the walls of the boat are more than ten Tefachim (approximately one yard) high, and therefore by Torah law you may carry on the boat. However, since everyone has their own private cabin, an Eruv Chatzeros may be required to allow carrying between your cabin and the rest of the boat (Shulchan Aruch 366:2). If an Eruv is required, then an arrangement will have to be made with the owner of the boat to rent from him the public areas of the boat. This is all very complicated and is probably not an issue because the passengers eat in a communal dining hall and therefore the boat is considered like a single house and doesn't need an Eruv (Mishnah Berurah OC 382 note 75).

(See also Insights to the Daf to Eruvin 43 and Shabbos 19)

Y. Sigler