In the Genesis flood story, Noah was told to use pitch to make the ark waterproof.
Genesis 6:14 instructs Noah to build the ark from gopher wood and to cover it with pitch inside and outside. Pitch is a tar-like, waterproofing substance, so the instruction addresses how the large wooden vessel could keep water from entering through its joints.
The passage does not identify gopher wood with a securely known modern tree species. The Hebrew term appears only in this verse, and translations differ in how they render it. Pitch, by contrast, is a more transparent description of the coating material, even though the exact ancient formulation is not specified.
Genesis also gives the ark three decks, a window, and a door. These details belong to the literary and religious account rather than to a verified archaeological design. No archaeological discovery has been accepted as proof that Noah’s ark has been found.