Construction of the ark

The ark was a commercial river barge that hauled cargo between cities on the Euphrates River. It was built using the technology of Noah's time, about 2900 BC and was not designed for a stormy ocean; it was designed for the calm water of the river.

The ark is usually pictured much larger than would be practical for a wooden boat. The dimensions given in Genesis 6:15 are 300 cubits long, 50 cubits wide, and 30 cubits high. How long was the unit of length that was later translated into Hebrew as cubit? It has long been assumed that this unit was the length of a man's forearm or about one and a half feet. A barge 300 cubits long would have had a length of about 450 feet, or more than half the length of the Titanic. That would be longer than any modern ocean vessel built before 1858 and more than twice as long as the longest barges used in Egypt to transport obelisks. Wood boats much longer than 200 feet leak excessively. It is therefore very unlikely that Noah's barge was 450 feet long.

If the meaning of cubit changed or was mistranslated or if cubits was an editorial gloss, the size of Noah's barge could have been much smaller. Noah's barge was 30 "cubits" high and had 3 decks according to Genesis 6:15-16b, suggesting 10 "cubits" or 15 feet from deck to deck. Doesn't 15 feet seem excessive? If you were building a barge to transport animals would you make the stalls 15 feet high? Of course not. To minimize your construction costs you would build the stalls just high enough to clear the height of standing animals and adult workers. Wooden barges used on the Mississippi River in the early 19th century had an inside clearance of about 6 feet.

Assuming 6 feet for each of the three decks in Noah's barge plus another 2 feet for decking, bottom planking, and dunnage, the estimated total height would be about 20 feet. Hence, the unit of measurement would be about 8 to 9 inches (20 to 23 cm). This is the span of a man's hand, i.e. the distance between the tips of thumb and little finger when the fingers are spread apart. The Genesis 6:15 unit of measurement probably should have been hand span (zereth in Hebrew) in this instance or less than half a cubit (ammah in Hebrew). The source text used by an editor of Genesis 6:15 may have omitted the unit of measurement, just as we omit inches in the expression "two by four." A story teller or editor may have added cubits to the story. Alternatively, an archaic sign or pictograph for hand spans may have been used that was unfamiliar to an ancient translator who assumed it meant cubits. A barge measuring 300 hand spans in length would be about 200 feet (61 m) long.

In Gilgamesh XI,58 the length of the barge is given as ten ninda and a ninda was a dozen cubits. Hence the barge was 120 cubits long. The Sumerian cubit (kùsh) was about 20 inches, which again yields a calculated length of 200 feet. This confirms that the Genesis 6:15 dimensions were in hand spans rather than cubits.

In Gilgamesh XI, line 57 does not give the height of the walls. It literally reads "120 cubits each I raised its walls". There is no additional indication of whether the 120 cubits was height or length and therefore the text is ambiguous. The 120 cubits was probably a measurement of wall length rather than wall height, because a boat as high as its length would roll over in the water, if anyone were foolish enough to build such a boat. Other texts that specify wall measurements often omit an indication of whether the number means length or height, but length is implied.

Likewise, line 58 literally reads "120 cubits each equal-size [were the] edges [of] its-upper-part". This may be saying that the left edge and the right edge of the upper part of the boat had equal lengths of 120 cubits. In other words, the superstructure was symmetrical and ran the full length of the barge.

Repeating the length but not giving dimensions for the width or height is not how an architect or carpenter would describe a boat. But the author of Gilgamesh XI was a poet not a carpenter. We should be happy that at least he remembered to mention the length. The width and height are not given in Gilgamesh, but are given in Genesis.

The dimensions of a barge measuring 300 x 50 x 30 spans would be about 200 feet long, 33 feet wide, and 20 feet high, a large vessel by ancient standards but quite within the limits imposed by a wood structure. Barges with a length of 150-200 feet were used in the Old Kingdom of Egypt. It is not unreasonable to imagine that Sumerian merchants in 2900 BC might transport a few hundred animals and other cargo on a 200 foot barge.

Modern artists traditionally draw Noah's ark as a rounded-hull seagoing ship with a projecting keel. But deep keels and rounded hulls are required only on sailboats. Noah's barge had no sails because the prevailing wind in the Tigris-Euphrates valley is toward the southeast, the same general direction as the river current, thus making tacking upriver against both the wind and current impractical. Noah's barge was a flatboat, not a keelboat.

Ancient barges had a nearly rectangular cross section to maximize clear space for the cargo. Noah's barge was designed for transporting cargo in the calm, slowly moving water of the lower Euphrates river. Whatever the construction method used, Noah's barge used the technology of 2900 BC and was probably constructed in the same manner as river boats built hundreds of years later in Mesopotamia and Egypt. The construction details and several illustrations of how Noah's barge may have been constructed using 2900 BC technology are explained in Chapter 6 of the Noah's Ark book.

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