By any estimation, the building of Noah’s Ark was a monumental task. Assuming an 18" cubit, the Ark was 450 feet long, 75 feet wide, and 45 feet high. Could Noah and his sons have accomplished it? By making reasonable assumptions, we can perhaps determine whether the task was too great.

First, the prophecy of coming judgment was given 120 years in advance of the Flood (Genesis 6:3). Let’s assume that Noah had the full 120 years warning. Next, consider that in the immediate post-Flood time, man probably had remarkable intelligence, because early civilizations built monumental structures like the pyramids. Tantalizing clues suggest humans explored and even mapped the entire globe back then, indicating they may have had shipbuilding skills from even earlier years. Perhaps Noah was a shipbuilder by trade.

Consider the workforce. Noah’s three sons began to be born 100 years before the Flood (cf. Genesis 5:32 with 7:6) and were able to help. There may have been other helpers, for Noah’s father, Lamech, and grandfather, Methuselah, were alive during almost the entire project. It may also have been that Noah hired construction workers, but again we have no knowledge of these details. All we know is that only eight people—Noah and his wife, their three sons and their wives—constituted the faithful still living when the Flood finally came (Genesis 7:13; 1 Peter 3:20).

Let’s assume the worst-case scenario, that only Noah and his three sons were available to build the ship. In Scripture, we are only told the gross dimensions and that the vessel was to have three decks and an 18-inch “window” on top (Genesis 6:15-16). Thus, the overall volume of the Ark was:

450' x 75' x 45' = 1.52 x 10⁶ ft.³ total volume

But any structure consists mostly of open space. Most houses are over 95 percent open, less so for large ships. But recognizing that this ship had to be structurally strong, let’s assume that 20 percent of the Ark’s volume was worked lumber, and that the four men had to gather that lumber, transport it to the construction site, and do the necessary shaping and installing.

1.52 x 10⁶ x .2 = .304 x 10⁶ ft.³ volume of worked lumber

Remember, the Ark didn’t have to win any beauty contests or speed races, it just had to be strong and float. It probably more resembled a rough barn in workmanship. The generations so soon after the “very good” (Genesis 1:31) creation, living in an ideal environment with long lifespans and less chance for harmful genetic mutations, were no doubt intelligent and capable. It hardly matters if the family was initially experienced in construction technique, for within a year or so they would have been true professionals. An experienced crew of four could have installed, we assume, an average of 15 cubic feet of wood per day. If anything, this estimate seems low, but this is the worst case!

15 ft. x 6 days x 52 wks. = 4,680 ft.³/year lumber installed

It’s now easy to calculate how long it would have taken.

.304 x 10⁶ ft.³ 
___________   =   65 years
4,680 ft.³/year

Sixty-five years under this worst-case scenario! A big job, yes, but Noah was a faithful man and accomplished the task. As we see, the Bible makes sense, and simple calculations can enhance our faith in God’s Word.

Adapted from The Global Flood by Dr. John Morris (Dallas, TX: Institute for Creation Research, 2012).

* Dr. Morris is President of the Institute for Creation Research.

Cite this article: Morris, J. 2012. An “Impossible” Task? Acts & Facts. 41 (12): 15.