Noah’s Ark and Naval Architecture

FOR more than 40 years, I have worked as a naval architect and marine engineer. My work has involved designing vessels of various shapes and sizes, along with the mechanical and other systems that propel them. In 1963, while I was living in British Columbia, Canada, one of Jehovah’s Witnesses showed me that the Bible book of Genesis describes Noah’s ark as a long box, or chest. This description intrigued me, and I decided to look into it further.

The Genesis account shows that God determined to cleanse the earth of wickedness by deluging the planet with water. He told Noah to construct an ark in order to preserve himself, his family, and representatives of the animal world through this great Flood. God told Noah to make the ark 300 cubits long, 50 cubits wide, and 30 cubits high. (Genesis 6:15) According to one conservative estimate, this would make the ark about 438 feet [134 m] long, 73 feet [22 m] wide, and 44 feet [13 m] high.* It thus had a gross volume of some 1,400,000 cubic feet [40,000 cu m].

The Ark’s Design

The ark was constructed with three decks, which gave it added strength and provided a total floor space of about 96,000 square feet [8,900 sq m]. It was built of resinous—and thus water-resistant—wood, possibly cypress, and was sealed inside and outside with tar. (Genesis 6:14-16) We are not told how Noah fastened the timbers together. But even before relating the Flood account, the Bible mentions forgers of copper and iron tools. (Genesis 4:22) In any case, to this day wooden drive pins known as treenails are used to build some wooden ships.

The ark had internal compartments, a door in its side, and a one-cubit-high tso′har, which may have been a gabled roof, possibly having openings below it for ventilation and light. The Genesis account makes no mention, however, of a keel or a prow or of any sails, oars, or rudders on the ark. In fact, the same Hebrew word for “ark” is used to describe the pitch-covered basket used by the mother of the infant Moses to keep him afloat in the waters of the Nile River.—Exodus 2:3, 10.

Good Seakeeping

The ark’s length was six times its width and ten times its height. Many modern ships have similar proportions, although for them the length-to-breadth ratio is chosen with regard to the power required to move them through the water. The ark, on the other hand, had only to float. How well would it have performed?

The manner in which vessels respond to wind and waves is called seakeeping behavior. This too is related to a vessel’s proportions. The Bible describes the tremendous downpour that produced the Flood and also says that God later caused a wind to blow. (Genesis 7:11, 12, 17-20; 8:1) The Scriptures do not say how strong the waves and wind were, but likely both wind and waves would have been powerful and changeable, even as they can be today. The longer and harder the wind blows, the higher and farther apart are the waves. In addition, any seismic action could have produced strong waves.

The ark’s proportions contributed to its stability, preventing it from capsizing. The ark was also designed to deal with the forces that could cause it to pitch lengthwise in heavy seas. Extreme pitching—when each wave lifts one end of the vessel and then allows it to plunge downward—would have been very uncomfortable for the people and animals on board. Pitching also puts heavy stresses on a vessel. The structure must be strong enough to resist the tendency to sag in the middle when large waves lift both ends of the vessel at the same time. Yet, when a large wave lifts the vessel at its midpoint, with nothing to support its ends, the bow and stern may bend downward. God told Noah to use a length-to-depth ratio of 10 to 1. Later shipbuilders would learn only by hard experience that such a ratio can accommodate these stresses.

Safe and Comfortable

Because of the ark’s chestlike shape, buoyancy—the force that makes a boat float—would have been uniform from end to end. Its weight too would have been uniform. Likely, Noah made sure that the cargo—including the animals and more than a year’s supply of food—was distributed evenly. Good weight distribution minimizes the additional stress that cargo places on a vessel’s structure. Thus, two main factors contributed to the ability of the ark and its passengers to ride out the global Flood safely—the ark’s divinely originated design and Jehovah’s protective care. God undoubtedly saw to it that the ark came to rest in a safe and suitable location.

My thorough examination of this subject led me to conclude that what the Bible says about Noah’s ark is realistic and consistent with modern shipbuilding practice. Of course, there are many details about the ark and the Flood that are not mentioned in the Genesis account. I hope one day, after the resurrection, to meet Noah here on earth, right among the families of humans and animals whose existence was made possible by the ark that he worked so long and hard to construct. (Acts 24:15; Hebrews 11:7) First, I will thank him and his family. Then I will ply him with many questions.—Contributed.


The cubit is an ancient unit of measurement corresponding approximately to the distance from the elbow to the fingertips. During Israelite times, the cubit seems generally to have been standardized at about 17.5 inches [44.5 cm].

[Box/Picture on page 22]


  You can make and test your own scale model of the ark using the accompanying pattern. (You may build a bigger model by proportionately enlarging the pattern shown below.) Ordinary paper can be made suitably waterproof by rubbing it all over with wax or crayon. The paper can then be folded and the corners secured with tape or glue. Attach ballast weights to the floor of your model—such as a few evenly spaced coins held in place with tape or glue—until it floats with between a third and a half of its height under water.

  To demonstrate the ark’s seaworthy behavior, place your finished model in the middle of a tub of water, such as a bathtub, and align it lengthwise. Try making small regular waves by holding a milk carton or similar object crosswise at the end of the tub and pushing it down into the water lightly and rhythmically.


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The ark’s proportions were similar to those of an oceangoing vessel

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Noah’s ark was about 438 feet long, nearly half as long as the “Titanic”

[Credit Lines]

Titanic plan: Courtesy Dr. Robert Hahn/; photo: Courtesy of The Mariners’ Museum, Newport News, VA