Which Epic of Gilgamesh character built a flood-survival boat?

In the Epic of Gilgamesh, Utnapishtim built a boat to survive a great flood.

The flood story appears in Tablet XI of the Epic of Gilgamesh. The god Ea warns Utnapishtim to build a boat, preserve living creatures and craftsmen, and escape the coming flood. After the waters subside, Utnapishtim releases birds to test whether the land has emerged.

The episode has notable parallels with Genesis, including divine warning, a large survival vessel, preservation of animals, birds sent out after the flood, and a sacrifice after landing. The two narratives are not identical, however. Their characters, divine settings, boat descriptions, and endings differ.

Utnapishtim is sometimes called Atrahasis in related Mesopotamian traditions. That connection can cause confusion, but the specific character named in the Epic of Gilgamesh flood episode is Utnapishtim.