The interesting thing about Noah's ark its construction was on a 1:6 ratio. Naval architecture reveals that this is the most stable ratio for an ocean-going vessel. It could have easily survived even big ocean waves and would be next to impossible to capsize. The amount of water the ship would displace, given a draught of 15 cubits, exceeds 22,000 tons.
The total volume of Noah's Ark was roughly 1.5 million cubic feet, which is equal to the total capacity of more than 570 standard stock cars used on a typical railroad. The floor space would be above 100,000 sq. ft. (9,383 square meters). What God had Noah make would be nothing less than the BIGGEST ship of its kind for many, many years until man began to build even bigger ships in the late 1800's A.D.!
How many total animals did God want carried in the ark? Many who refuse to believe in what the Bible says state that the ship's capacity would be nowhere big enough to handle the millions of different animals it was supposedly required to carry. The truth, however, is far different from the rhetoric of those who are against God and his word!
How many clean and unclean animals would Noah's Ark have to take on board? What the Bible (Leviticus 11, Deuteronomy 14) considers clean (fit for human consumption) and unclean (not fit to eat) animals is easy to identify based on the characteristics of a particular creature. For example, warm-blooded mammals that have split hooves and chews the cud is clean to eat (e.g. Bison, Cattle, Deer, Goats, Sheep, etc.). Those that do not have these characteristics are not clean and good for man (e.g. Pigs, Lions, Tigers, Boars, etc.).
Those who are against God say that only SEVEN pairs of clean animals and SEVEN pairs of the birds (Genesis 7:2-3) were on the ark. Is this assumption true? The answer to the question is in Leviticus 11 and Deuteronomy 14. When properly understood, Noah took on seven (7) individual animals and birds (not seven pairs) of each kind that were clean. Since these types of animals would later be used for food, it would be important to have extra breeding stock. There was three pair of clean animals and clean birds plus a seventh. The seventh one was to be offered as a sacrifice at the end of the flood (Genesis 8:20). If an animal were unclean, which the vast majorities were, then only one pair came aboard the great ship.
Contrary to what many believe and what "documentaries" concerning the ark claim, the ship would have EASILY been big enough to carry all the required animals. Only air breathing, land dwelling animals would have to be placed on the ark itself (Genesis 7:22). In the book The Genesis Flood, it states that animals such as fish, starfishes, sea urchins, mussels, clams, corals, jellyfish, sponges, and many others could have survived outside Noah's ship.
Other aquatic mammals such as the dolphins, whales, porpoises, and so on could also easily live in water and survive the flood. Many aquatic reptiles would also not need to be saved from Noah's deluge. Still other animals that could survive the flood without needing to board the ark include shrimp, crabs, lobsters, insects, worms and others. Only a small percentage of the animals on earth would need saving on a ship.
The number of animals saved
Those who have written about Noah's ark have arrived at various estimates regarding the total amount of animals the ship would have to carry and transport. The Genesis Flood estimates that 35,000 or so animals were placed on the ship. In another book written on the subject, Noah's Ark - A Feasibility Study, it declares that only about 2,000 animals would have to be on it. A conservative number of 40,000 animals, which allows extra animals to represent those that have gone extinct, could easily travel on the ship.
Space needed for the animals
The average size of all animals, in general, is roughly that of a common sheep. One railroad stock car carries about 240 sheep. This would mean that all 40,000 animals (if we assume our conservative number needing to be saved) could fit in 167 railroad cars. The total capacity of the ark was 569 stock cars. These animals would require LESS THAN 30% of the total space available! In other words, all the animals could fit on one of the ship's three decks with PLENTY of room to spare for Noah's family, food, supplies, and baggage.