In Genesis, Noah's Ark was 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. Because the ancient cubit did not have one universally fixed length, modern conversions vary. A common estimate of roughly 45 centimeters per cubit places the ark at about 135 meters long, 22.5 meters wide, and 13.5 meters high.
The measurements describe a long, rectangular, box-like vessel rather than a ship designed for navigation. Genesis says the ark had rooms, a door in its side, and a window, but it does not describe a mast, sails, or a rudder.
The proportions have attracted engineering comparisons, especially because a long hull can be stable. Such comparisons do not establish that the biblical ark was historically built; they simply examine how the stated dimensions would behave as a vessel.