How Could Noah Build the Ark?
The Bible does not tell us that Noah and his sons built the Ark by themselves. Noah could have hired skilled laborers or had relatives, such as Methuselah and Lamech, help build the vessel. However, nothing indicates that they could not—or that they did not—build the Ark themselves in the time allotted. The physical strength and mental processes of men in Noah’s day was at least as great (quite likely, even superior) to our own.2 They certainly would have had efficient means for harvesting and cutting timber, as well as for shaping, transporting, and erecting the massive beams and boards required.
If one or two men today can erect a large house in just 12 weeks, how much more could three or four men do in a few years? Adam’s descendants were making complex musical instruments, forging metal, and building cities—their tools, machines, and techniques were not primitive.
it's not even a foot a day