Mishnah Zavim 3:3: [If] a Zav and a clean person sat [together] on a big boat, [but] what is a big boat? Rabbi Yehuda says, One that does not sway with a man's weight, [or if] they sat on a plank, bench or bed frame or a beam when they are firmly secure, [or] they went up into a tree that is strong, or in a branch that is strong [or they they were climbing] on a Tyrian ladder or an Egyptian [ladder] that was secured [to a wall] with a nail, [or] on a ramp or a rafter or on a door when clay was used [to secure them in the ground], even [only] on one side, they are clean. A clean person that hit an unclean person [he remains] clean. [If] an unclean person hits a clean person, [the clean person] becomes unclean, because if the clean person draws [back, as he is being hit], the unclean person would surely fall, thus it is as if the zav had actually leaned on the clean person and that renders him unclean].

הזב והטהור שישבו בספינה גדולה, איזו היא ספינה גדולה. רבי יהודה אומר, כל שאינה יכולה להמיט באדם. ישבו על הנסר, על הספסל, על הגשיש של מטה ועל האכלונס בזמן שאינן מחגירין, עלו באילן שכחו יפה, בסוכה שכחה יפה, ובסלם צורי או מצרי בזמן שהוא קבוע במסמר, על הכבש, על הקורה ועל הדלת בזמן שהן עשויין בטיט אפלו מצד אחד, טהורין. הטהור מכה את הטמא, טהור. הטמא מכה את הטהור, טמא, שאם ימשך הטהור, הרי הטמא נופל:

Mishnah Zavim 4:1: Rabbi Yehoshua says, [If] a niddah [a menstruant woman] sat with a clean woman on a bed, [even] the cap on her [the clean woman's] head are unclean due to [uncleanliness called] midras [treading contact]. [If] she [the menstruant woman] sat in a boat, [even] the vessels that are on top of the mast are unclean due to midras. [If] she took a tub of clothes, if their weight was heavy, they are unclean, [If] their weight was light, they are clean. [If] a zav knocks against a balcony, and [as a result] a loaf of terumah falls, it remains clean.

רַבִּי יְהוֹשֻׁעַ אוֹמֵר, נִדָּה שֶׁיָּשְׁבָה עִם הַטְּהוֹרָה בְּמִטָּה, כִּפָּה שֶׁבְּרֹאשָׁהּ טָמֵא מִדְרָס. יָשְׁבָה בִסְפִינָה, כֵּלִים שֶׁבְּרֹאשׁ הַנֵּס שֶׁבַּסְּפִינָה טְמֵאִין מִדְרָס. נוֹטֶלֶת עֲרֵבָה מְלֵאָה בְגָדִים, בִּזְמַן שֶׁמַּשָּׂאָן כָּבֵד, טְמֵאִין. בִּזְמַן שֶׁמַּשָּׂאָן קַל, טְהוֹרִין. זָב שֶׁהִקִּישׁ עַל כְּצוֹצְרָא, וְנָפַל כִּכָּר שֶׁל תְּרוּמָה, טָהוֹר: