In the Genesis account of Noah’s Ark, the vessel was ordered to be 300 cubits long. Genesis 6:15 gives the Ark’s dimensions as 300 cubits in length, 50 cubits in width, and 30 cubits in height.
A cubit was an ancient unit commonly related to the length of a forearm, although its exact value varied by culture and period. Using an approximate cubit of 45 centimetres would make the Ark about 135 metres long, but the biblical text itself gives the measurement only in cubits.
The dimensions describe a large rectangular vessel intended to preserve Noah, his family, and the animals during the Flood narrative. They are not presented as modern naval specifications. The Genesis account does not provide a precise modern conversion, so answers in metres can differ depending on the cubit used.