What was Noah’s ark? A boat? Not really. As Morales points out (The Tabernacle Prefigured, 157), the word used for ark (tabah) isn’t a normal term for a sailing vessel.
Some have suggested the word derives from Egyptian words meaning coffer, chest or palace, house. The Akkadian flood story uses ekallu, normally “palace,” and the odd babu (related to Babel) to describe the door of the ark, a term usually reserved for the gates of a city or a magnificent building.
Morales summarizes the evidence that the ark is to be understood as functioning like a temple, even if we can’t say that it is a temple: It is like the cosmic mountain that emerges from the waters; it is measured and set apart; it becomes a place of sacrifice; it is filled with animals. As Morales notes, the ark gradually ascends to heaven as the waters increase, life the ark above the highest mountains (159). There are multiple verbal connections between the ark-building project and the tabernacle-building later in the Pentateuch. The ark thus does what all temples are supposed to do—it joins heaven and earth.
Morales also finds some support in Ancient Near Eastern mythology. According to the flood story in Gilgamesh, the ark was like a palace or ziggurat temple. Morales quotes MEL Mallowan: “[The ark] was described in the Gilgamesh epic as rising in seven stages which were subdivided vertically into nine sections with sixty-three compartments: in one passage it was referred to as ekallu, a noun meaning temple or palace, and I therefore venture to suggest that the narrator had in mind a floating Ziggurat and that he imagined one—always a refuge in time of flood—as sailing over the vast inland sea” (149).
All of which nicely knits Genesis together. God forms a temple-mount at the beginning, and places Adam in it as the priest. Noah builds a floating temple that reaches up to heaven, a wooden mountain. After the flood, the men of Babel fall by trying to replicate Noah’s achievement in the plains of Shinar—building a ziggurat to pierce the sky. After that, another great cycle begins as Yahweh calls Abram to be the father of a new Noachic nation that will build a refuge for the creation, a tent reaching to heaven.