Noah's Ark was the largest ocean going vessel ever built until the building of the P&O Liner "the Himalaya." The Babylonian account which speaks of the Ark as a cube betrays complete ignorance. It was a cube that would spin around in the water and go no where! The Ark was the near-exact dimension of a modern ship, a ratio of 8.1 to 1.
The Ark was the sufficient dimensions to accomplish its intended purpose of saving alive thousands of kinds of air-breathing creatures that would otherwise not have survived the year-long flood waters. Assuming the length of the cubit to a have been at least 17.5 inches, the available floor space of this three-decked barge was over 95,000 square feet, and its total volume was 1,396,000 cubit feet.
Such figures are difficult to picture without comparisons. For the sake of realism, imagine waiting at a railroad crossing while ten freight trains, each pulling 52 boxcars, move slowly by, one after another. That is how much space was available in the Ark, for its capacity was equivalent to 520 modern railroad stock cars. A barge of such gigantic size, with its thousands of built-in compartments (Gen. 6:14) would have been sufficiently large to carry two of every species of air-breathing animal in the world today.
—Dr. Mal Couch (9/11)