Genesis 6:15

This is the fashion. The ship was to be built according to exact divine instructions. Its dimensions as given to Noah show the vessel to be of extraordinary size. Had it not been for these detailed instructions from God, Noah, a man of no previous experience in ship construction or sailing, could never have built it. The largest ancient vessel now known was an Egyptian ship up to 130 cubits long and 40 cubits wide. The ark of Noah was almost three times as long. If the cubit of 20.6 in. is meant (cf. Deut. 3:11), the length of the ark would have been 515 ft., its width 86 ft., and its height 52 ft. It has been generally assumed that the ark was in the form of a chest or box rather than that of a ship, but this is nowhere stated in the Sacred Text. Because of the lack of precise information in regard to the form of the ship, it seems futile to compute the exact cubical contents of Noah’s ark. It is clear, however, from the given description, that it was a vessel of formidable dimensions, with ample space for the animals housed within and for a year’s food for all.