The following Halacha has ramifications in several areas which we shall, G-d-willing, discuss in the coming days.
Setting Sail on a Ship Close to Shabbat
The Baraita (Shabbat 19a) states: “Our Sages taught: One may not set sail on a ship within three days of Shabbat. Nevertheless, this only applies when one is travelling for a mundane purpose. However, if one is travelling for the purpose of a Mitzvah, one is permitted to do so (set sail within three days of Shabbat).” This means that the prohibition of setting sail on a ship within three days prior to Shabbat applies only when one is travelling for a mundane purpose, such as for a vacation and the like; however, if one is travelling for a Mitzvah, such as if one is travelling to Eretz Yisrael, one may indeed begin one’s sea voyage even within the three days prior to Shabbat. Most Rishonim quote this Baraita as Halacha as does Maran Ha’Shulchan Aruch (Chapter 248, Section 1).
The Reason for the Prohibition of Setting Sail Close to Shabbat
The Rishonim disagree regarding the reason why setting sail by ship is prohibited close to Shabbat. The
Rif writes that the primary reason for this prohibition (which is how we rule halachically) is because during the first three days of one’s voyage by sea, it is probable that one will suffer from sea sickness, as the verse (Tehillim 107) states, “They shall celebrate and swerve like a drunkard,” and one will not be able to fulfill the Mitzvah of enjoying Shabbat. This is why our Sages prohibited beginning one’s sea voyage so close to Shabbat unless one is travelling to perform a Mitzvah. However, when one is travelling to perform a Mitzvah, one is exempt from the Mitzvah of enjoying Shabbat, for “one who is involved with performing one Mitzvah is exempt from performing another Mitzvah” and our Sages thus did not forbid him to travelling close to Shabbat.
The student of the Rif, the great Rambam, writes likewise (Chapter 30 of Hilchot Shabbat) that one may not set sail on a ship within three days of Shabbat “so that one may relax and regain one’s composure before the onset of Shabbat so that one does not suffer too much.” Indeed Maran Ha’Shulchan Aruch writes: “This that one may not set sail by ship within three days of Shabbat is due to enjoyment of Shabbat, for one suffers and is disoriented during the first three days of a sea voyage.”
The Law Regarding a Salt-Water Sea and a Non-Salt-Water River
Since the primary reason for this prohibition is because of a lack of enjoyment of Shabbat, the Rishonim, as well as Maran Ha’Shulchan Aruch, write that this prohibition applies only when one is travelling by ship in a salt-water sea; however, if the ship is travelling through a sweet-water river, one may board the ship and set sail even on Erev Shabbat. This is because sea sickness results from the saltiness of the water along with the ship’s movement and in a river whose waters are sweet, there is not as much concern for this.
(There is another issue we must discuss regarding setting sail by ship close to Shabbat which is that one may only set sail on Erev Shabbat even in a sweet-water river only when there is over ten Tefachim or approximately 80 cm of space from the bottom of the ship until the sea bottom. However, if one is certain that there is not 80 cm of space from the bottom of the ship, one may not set sail on this vessel on Erev Shabbat due to the prohibition of traversing boundaries on Shabbat (see Chazon Ovadia-Shabbat, Part 1, page 108).
The Law Nowadays
We have already written in the past that one should not set sail on a ship which is operated by Jews or when most of the passengers are Jews when it is certain that the passengers will remain on board on Shabbat since experience has shown that Shabbat is desecrated needlessly for non-life-threatening purposes. Likewise, on many ships, the faucets and doors are electrically-operated in a way that a Torah-abiding individual would not be able to board such a vessel when he knows it will operate on Shabbat as well. Only if one is completely certain that the above concerns and other such issues do not exist, such as when the ship is steered by non-Jews and most of the passengers are non-Jewish, may one set sail on Sunday, Monday, Tuesday, or Wednesday (see Chazon Ovadia-Shabbat, Part 1, page 107).
We shall broaden this discussion in the following Halacha.