We are beginning Klal 4, which discusses the issue of a person boarding a boat when they will end up on the boat over Shabbos. Although the practical contemporary applications of these halachos are uncommon, since the rishonim give multiple explanations of these halachos, it has many practical applications. In Maseches Shabbos, 19a, the Gemara quotes a braisa which states that it is assur to board a boat three days before Shabbos for a journey that will not end before Shabbos. We pasken that the three days include Shabbos, so the three days are Thursday, Friday and Shabbos. If a person leaves Wednesday afternoon, they can board, but one cannot board starting from Wednesday night. There are multiple explanations to understand the concern of Chazal.
- The Baal Hamaor writes that a person may have to perform chillul Shabbos, given the unsafe circumstances of a boat. It is not appropriate to put oneself in a potential situation of chillul Shabbos so close to Shabbos.
- The Ramban disagrees, and holds that the concern is not the Jew having to perform chillul Shabbos, but that the non-Jewish workers and captain will have to perform chillul Shabbos in order to protect the Jew (and other passengers). Although, once in the situation, they must do the melacha in order to save their lives, one should not lechatchilla place themselves in a situation in which they must perform amira l’achum.
- Rabbeinu Channanel understands that the issue is the boat may go beyond the techum on Shabbos.
- The Rif writes that there cannot be an issue of chillul Shabbos or techum, because if there was, it would be assur to board a boat even from the beginning of the week. (We will address why there is no issue of chillul Shabbos or techum in later shiurim.) Rather, he holds that the issue is causing a lack of oneg Shabbos. The Rif holds that it takes up to three days for a person to get used to boat travel and seasickness. Putting oneself in a situation which will cause them to be mevatel oneg Shabbos is not appropriate, so Chazal made this stringency that one cannot get into a boat within three days of Shabbos.
- Tosfos writes that we know that Chazal enacted a prohibition against swimming on Shabbos, out of concern that one may create a flotation device, which would be the issur deoraysa of boneh or makeh bepatish. Therefore, Chazal prohibited swimming. Included in the issur of swimming is the issur of boarding a boat, because it looks as though one is swimming in the water. There is a case later, in siman 339, about going into the water on Shabbos itself, which all agree is assur out of concern that one may create a flotation device. The added chiddush of Tosfos is that one cannot board a boat even before Shabbos out of concern that it appears like swimming.
- Chazal made a takana that one cannot board a boat from Wednesday night if the journey will not end before Shabbos. There are multiple understandings as to why Chazal made this takana. The Shulchan Aruch understands, based on the Rif, that the concern is a lack of oneg Shabbos