Siman - Shabbos Daf 101
- Small boats of Meishan
Rav Huna said that in the small boats of Meishan, which was a small river that only small boats could go on, one may only carry four amos, because they have the status of a karmelis.
These boats were wide at the top but narrowed to a point like a canoe, and since the bottom was not four tefachim wide, its walls lose their status as legal partitions (מחיצות) and the walls above are considered a מחיצה תלויה, a suspended wall, which is not considered a legal partition. Therefore, the boat is considered a karmelis and not a reshus hayachid.
Rav Huna continues that the boat would have the status of a reshus hayachid if the four tefachim width of the walls was within three tefachim of the bottom of the boat, which would raise the base of the ship through the principle of lavud. Alternatively, says Rav Huna, one could fill the base of the boat with reeds and willow branches until the point where the boat widens to four tefachim.
- גוד אחית מחיצתא
Rav Nachman challenged Rav Huna, suggesting that the principle of גוד אחית מחיצתא (extending the walls downward) should apply, which legally extends the walls of the boat down to the ground below so that they are not legally considered suspended. Since the top of the boat’s width is four tefachim wide, the principle of גוד אחית would extend the walls down at that width, giving the boat a status of a reshus hayachid and not a karmelis.
- Making an eruv between two ships
Rav Safra clarifies that the Mishnah on Daf 100b that stated that it is permitted to carry between ships that are tied together, was referring to a case where the ships have different owners, and the Mishnah is coming to teach that it is permitted make an eruv.
The Gemara brings a Baraisa to support Rav Safra, that states that in a case of two ships tied together, their owners may make an eruv and carry between the boats. If the boats were to be separated, then the eruv would be negated. If they are once again tied together, whether inadvertently, deliberately, unwillingly, or accidentally, then the eruv is automatically reestablished, and it is permitted to carry between them.
