In Genesis, Noah was told to coat the Ark with pitch to keep water out.
Genesis 6:14 instructs Noah to cover the vessel inside and outside with pitch. In the ancient setting, pitch refers to a waterproofing substance such as bitumen or another resinous material. The instruction is practical: a wooden vessel would need its seams and surfaces sealed against water.
The Hebrew wording is related to terms for covering or atonement, and translations vary in how they render the substance. “Pitch” is the traditional English answer, while some translations use “bitumen” or “tar.” These words describe the waterproofing function but do not establish a modern commercial product.
This detail is separate from the Ark’s building material. Genesis names gopher wood for construction and pitch for sealing. Confusing those two instructions produces an answer that combines different parts of the same verse.