Genesis gives specifications. The vessel is of gopher wood, made with compartments, sealed with pitch inside and out, three hundred cubits long, fifty wide and thirty high, with three decks, a single door in the side, and an opening at the top whose Hebrew term is uncertain and is translated as a window or as a source of light. The proportions are those of a chest rather than a ship: it has no rudder, no sail and no means of steering, because it is not going anywhere but up. The Quran tells the same account in several places, adds the son who refused to embark and drowned, and names the resting place as al-Judi rather than the mountains of Ararat.
The Mesopotamian versions are older and are close enough that the relationship is not in dispute. Atrahasis and the eleventh tablet of the Gilgamesh epic both have a man warned by a god to build a vessel, load it with his family, his craftsmen and animals, ride out a flood sent by the gods, and send out birds to test for land. The vessels differ: Utnapishtim builds a cube, and a cuneiform tablet published in recent decades describes a large round coracle of coiled rope, waterproofed with bitumen, which is a real Mesopotamian boat type built at an unreal size.
The comparison of these accounts is where most scholarship on the subject actually happens.