The Medrash Rabbah (31:11) presents two views, Rabbi Yehuda and Rabbi Nechemyah, as to the layout of the three decks. Each Tanna’s design is identical for each of the three decks. Each Tanna agrees that the Torah designated the dimensions of the Ark as 300 amos length and width of 50 amos.
Rabbi Yehuda states that the Ark contained 360 rooms, each room measuring 10 amos by 10 amos each. Each deck thus held 120 rooms, built in four rows of thirty attached rooms. Between the four rows were two corridors of four amos, to allow access to each room. Further on each outer row, there as a one-amah corridor between the row and the side of the Ark. Please see the diagram below:
According to Rabbi Yehudah
OPEN SPACE OF ONE AMAH WIDTH
WALKWAY OF FOUR AMOS WIDTH
WALKWAY OF FOUR AMOS WIDTH
OPEN SPACE OF ONE AMAH WIDTH
Rabbi Nechemyah states that the Ark contained 900 rooms, each room measuring 6 amos by 6 amos each. Each deck thus held 300 rooms, built in six rows of fifty attached rooms. Between the six rows were three corridors of four amos, to allow access to each room. Further on each outer row, there as a one-amah corridor between the row and the side of the Ark. Please see the diagram below:
According to Rabbi Nechemyah
OPEN SPACE OF ONE AMAH WIDTH
WALKWAY OF FOUR AMOS WIDTH
WALKWAY OF FOUR AMOS WIDTH
WALKWAY OF FOUR AMOS WIDTH
OPEN SPACE OF ONE AMAH WIDTH
Another Medrash posits that one desk was for waste and thus, did not need rooms on that deck. Yefeh To’ar maintains that both Rabbi Yehdah and Rabbi Nechemyah disagree with that other Medrash and they held that there was no separate deck for waste.
The Torah states that the Ark was finished to an Amah (Bereshis 6,16). If the three decks were symmetrical, how does each Tanna explain this concept?
Rabbi Yehdah says the Torah means like the Ark’s amah on the lower deck, so was it amah on the upper deck. Thus, the instruction is to use the same measurement to finish the Ark from above, that is used below. Thus, the Ark would not be narrower at the top than the bottom, same measurement for the bottom would apply to the top. The Ark was like a cuboid.
Rabbi Nechemyah says the Torah means that the top of the Ark should be shaped like a tent slanting upwards until the top was only one cubit wide. This would enable the water could easily run off. Yefeh To’ar maintains the roof was slanted along the length of the ark but not it’s width. So, the at its peak, the Ark measured 300 amos by one amah.
