גזוזטרא (פירוש דף או בנין בולט מתוך הבתים חוצה) שהיא למעלה מן המים וחלון פתוח לה מן הבית אין ממלאין ממנו אלא אם כן עשה לה מחיצה כל סביבה או יעשה המחיצה סביב הנקב שדולים דרך שם והוא שיהא בו ארבעה על ארבעה ואין חילוק בין אם יעשנה למטה מחוברת לה בין אם יעשנה על גבה וכיון שעשה מחיצה מותרין גם לשפוך ממנה וכן ההולך בספינה אינו יכול למלאות אא"כ יעשה דף ארבעה על ארבעה ועושה בו נקב וממלא דרך שם ואינו צריך לעשות לו מחיצות אלא אמרינן כוף הצדדים וגוד אחית מחיצתא שהקילו בספינה מפני שאינו יכול לעשות שם מה שיעשה בבית והני מילי כשהוא בתוך י' טפחים אבל אם דופני הספינה גבוהים עשרה מעל המים מוציא זיז כל שהוא ועושה בו נקב וממלא דרך שם שהרי דרך אויר מקום פטור הוא ממלא וסגי בהיכר זיז ומימיו יכול לשפוך על דפני הספינה והם יורדים לים דכיון דלא זרק להו להדיא לים אלא מכחו הם באים כחו בכרמלית לא גזרו: הגה ועיין לקמן סוף סימן שנ"ז. שני ספינות זו אצל זו אסור לטלטל מזו לזו אלא א"כ קשורות זו בזו או אא"כ הם גבוהים מן המים י' וצריכים לערב ביחד אם הם של שני בני אדם (מרדכי פרק הזורק):

If a balcony (meaning a panel or a structure that protrudes from the house outwards) is above the water, and a window in the house opens up to the balcony, we do not collect water [to the balcony] unless it has a wall around it. Alternatively, one may make a wall just around the hole that he draws water through it, as long as it is four [tefachim] by four. There is no difference between making the wall under the balcony as an attachment or on top of the balcony. Since the wall is made, one may also pour water into it. Similarly, one traveling by boat cannot collect water unless he made a four by four panel, makes a hole in it, and draws water from there. He does not need to make walls, because we [imagine] bending the walls and then we can [adopt the legal fiction of] extending the walls down. This is because we are more lenient with a boat, because it is not possible to do things there that can be done at home. All of this is specifically when the [distance between the water and the top of the boat] is ten tefachim, but if the walls of the boat are higher than ten tefachim above the water, he should make a ledge, put a hole in it, and draw through there, because it will be through the air of the place of exemption, and the ledge is good enough. One is permitted to pour water on the walls of a boat such that it will fall into the sea because he is not explicitly throwing into the sea. Rather, the water continues through its own force, and there is no rabbinic decree against this in the karmelit. Rema: See below the end of chapter 357. If there are two boats adjacent to one another, it is forbidden to carry between them unless they are tied together or unless they are more than ten tefachim above the water. It is necessary to conjoin them [with an eruv] if they belong to two people (Mordechai Chapter HaZorek).

If a toilet is made above the water, it is permitted if there are walls suspended from it. These walls must be made to direct the waste, but if they are made for privacy, they do not make it allowed. If one makes a panel closer than three tefachim such that the feces will fall onto it before falling into the water, walls are not necessary, because the feces fall by their own force in the karmelit, and it is allowed. This is also the case for a toilet that is made such that the feces first fall onto a wall and then rolls and fall into the karmelit. If the panel breaks on Shabbat, it is still permitted, because of the importance of human dignity.

If the toilet protrudes outside of the wall of the city such that the feces fall into the pit that surrounds the city, and the pit is bigger than two se'ah and is thus a karmelit, it is not permitted to use a toilet with protruded walls, because this was only allowed with regards to water. However, using a panel is allowed, because something falling its own force is allowed in every karmelit. Rema: There are some who say that if the toilet is higher than ten tefachim, it is always permitted because he is moving something from the private domain to the karmelit through a place of exemption. (And see above chapter 346 that some disagree.) And there are some who say that if there were feces in it during the day on Friday, it is always allowed, because feces are a place of exemption as the masses do not walk in them (Mordechai Chapter HaZorek). And see above chapter 345 that some disagree and think that there is no place of exemption in the karmelit. And according to what was explained above in chapter 345 that all agree that there is no place of exemption in the private domain, if a toilet is between two houses, it is forbidden to use it if the houses are not conjoined (eruv) and nothing has been done during the day on Friday. If such had been done, as was explained in paragraph 2, it is permitted, but otherwise it is considered a non-enclosed yard, as will be explained below in chapter 357. And see below chapter 376 paragraph 4 (Rama's own opinion). All of this is initially, but afterwards if they forgot to make an eruv, this is allowed because of the importance of human dignity (Hagahot Mordechai and his own opinion). Those who use boats go to the bathroom from the paddle wheel to the sea. Because it is not ten tall, even though it is four wide, it is karmelit, and it is considered moving something from karmelit to karmelit (Beit Yosef in the name of Orchot Hayim).

If water is not ten tefachim deep, there is no leniency to allow the pouring of water into them with suspended walls. smalllRema: All the more so when the water dries up, even if it was ten deep (Mordechai).

If there are two balconies, one above the other, [or even] a bit offset but not four [horizontal] tefachim away from each other, whether they have ten [vertical] tefachim between them or more, if they jointly made walls for the top one [in order to be allowed to draw water from below the balcony], it is forbidden for either of them [to draw water] until they make an eruv. This is even more true if they jointly made walls for the bottom one. However, if one made walls for his balcony independently, the other does not render it forbidden, even if it doesn't have walls. Similarly, if they both jointly made walls for both, one balcony's existence does not render the other forbidden for use.