Isn’t that what we learned in the mishna, with regard to which Rabbi Yoḥanan said: That liability is when it came to rest atop something, which means that the object must actually land in order for the one who threw it to be liable. Mareimar said to Ravina: Are you saying it is a case of rolling? One cannot cite proof from a rolling object because a rolling object will not ultimately come to rest. However, with regard to this object, which passed within three handbreadths of the ground, I would say: Since it will ultimately come to rest, even though it has not yet come to rest, it is considered as an object that came to rest. Therefore, Rava teaches us that even in that case one is not liable until it actually comes to rest upon something.

MISHNA: One who throws an object four cubits into the sea is exempt. If there was a swamp and the public domain passes through it, one who throws an object four cubits into it is liable like one who carried four cubits in the public domain. And how deep is this swamp? It is less than ten handbreadths deep. In the case of a swamp that the public domain passes through, one who throws an object four cubits into the swamp is liable.

GEMARA: One of the Sages said to Rava: Granted, passing passing is mentioned twice in the mishna; this teaches us that passage under duress is considered passage, but usage under duress is not considered usage. But why do I need it to mention swamp swamp twice? Rava answered him: One case is referring to the summer, and one case is referring to the winter. And both cases are necessary, as had the mishna taught only one mention of swamp, I would have said that these matters, i.e., cases indicating that passage under duress is considered passage, apply only in the summer because people commonly pass through the swamp to cool themselves; however, in the winter I would have thought that it would not be so. And had the mishna taught us only the case of winter, I would have said that since they are filthy from mud anyway, they do not mind walking through the swamp, but in the summer it would not be so.

Abaye said: It is possible to explain this other way. It was necessary for the mishna to state swamp twice because it would have entered your mind to say that these matters apply specifically where the swamp is not four cubits wide because then people walk through the swamp and do not circumvent it, but where the swamp is four cubits wide, people circumvent it. Therefore, it was necessary to teach that people walk through swamps that are both narrow and wide.

Rav Ashi said another explanation: It was necessary for the mishna to state swamp twice because it would have entered your mind to say that these matters apply specifically where the swamp is at least four handbreadths wide, but where the swamp is not four handbreadths wide, people step over it and do not walk through it. The Gemara comments: And Rav Ashi follows his own reasoning, as Rav Ashi said: One who threw an object and it came to rest on one of the beams of a bridge is liable. Even though the width of each beam is less than four handbreadths, it joins together with the other beams to form a single surface of the public domain because even though many people step over the beams, still many people step on it.

MISHNA: One who throws an object from the sea to dry land, or from dry land to the sea, or from the sea onto a boat, or from a boat into the sea, or from one boat to another is exempt because the sea has the legal status of a karmelit. If boats are tied together, one may carry an object from one to the other on Shabbat. However, if they are not tied, even though they are adjacent, one may not carry from one to the other.

GEMARA: It was stated that the Sages disagreed with regard to the manner in which one may draw seawater onto a boat on Shabbat. Rav Huna said: One extends a projection of any size from the side of the boat as a distinctive sign, and fills a receptacle with water from the sea. Rav Ḥisda and Rabba bar Rav Huna say: One creates an area, a frame of four by four handbreadths, and fills the water from inside it.

The Gemara explains: Rav Huna, who said that one extends a projection of any size and fills a receptacle with water, maintains that we measure the karmelit from the sea floor. Since the sea itself is deeper than ten handbreadths, the boat is considered to be floating in the air, and the air is an exempt domain, as it is above ten handbreadths from the ground of the karmelit. And by law one should not require a projection because he is drawing water from an exempt domain into a private domain, which is permitted ab initio. Rather, the reason a projection is required is so that he will have a distinctive sign and not come to draw water from a karmelit into a private domain.

Rav Ḥisda and Rabba bar Rav Huna say: One creates an area, a frame of four by four handbreadths, and fills a receptacle with water. They maintain that we measure the karmelit from the surface of the water, and the water in the sea has a legal status like that of solid land. Therefore, if one does not create an area of four by four, he will carry from a karmelit to the private domain.

Rav Naḥman said to Rabba bar Avuh: And according to Rav Huna, who said that one extends a projection of any size from the side of the boat and fills a receptacle with water, isn’t there room for concern that at times when the water is not ten handbreadths deep, he will carry from a karmelit into the private domain? He said to him: We learned through tradition that a boat does not travel in water that is less than ten handbreadths deep. He asks: Although a boat has a protrusion at its bow is more than ten handbreadths above the sea floor, the entire length of the boat is not necessarily that far above the bottom. Rav Safra said: Those people who measure the depth of the water with long poles proceed before the ship and ensure that that the water is at least ten handbreadths deep.

Rav Naḥman bar Yitzḥak said to Rav Ḥiyya bar Avin: According to Rav Ḥisda and Rabba bar Rav Huna, who say that in order to draw water onto a boat on Shabbat one creates an area of four by four handbreadths and fills a receptacle, how does he throw out his waste water? And if you say he pours it out in the same area from which he draws water, the water that he subsequently draws from there will be disgusting to him. Rav Ḥiyya bar Avin answered him: He pours it onto the side of the boat from which it runs into the sea, and he does not pour it directly into the sea. The Gemara asks: Even so, it is accomplished by means of his power. Although he did not pour it directly, he caused the waste water to enter the sea. The Gemara answers: The Sages did not issue a decree to prohibit an action performed by one’s power in a karmelit. They only prohibited throwing an object directly. And from where do you say that this is so? As it was taught in a baraita: With regard to a ship, one may neither carry from it into the sea, nor from the sea into it.