A History of Technology, vol. 5, Oxford Univ. Press, p. 355, states the
problem: There was an upper limit of around 300 ft. on the length of a wooden
ship because wood couldn't provide a rigid bow-to-stern connection, and tension
from wave-action increased as the length grew. The British Shipbuilding
Industry From 1870 to 1914, pp. 13-4, said pretty much the same thing, while
Alexander Laing's American Ships, pp. 409, quoted a shipwright as to the
opinion that the six-master clipper ships (region of 330 ft. in length) were
too long.
My response to this critique is to say that yes, there is some upper limit on
wood-hull construction boats, but that the 300 feet citations above are guesses
and opinions based on the observation that few attempts were made to build
wooden ships over 300 feet. The reason why not was that by the time that
expanding commerce in the second half of the 19th century would have demanded
larger vessels, iron was becoming a cost-effective material to use in hull
construction. So, the necessity to build larger wood vessels and/or improve
wood-hull design was not present.
However, there were some wood-hull ships built over 300 feet: from Famous
American Ships, by Frank O. Braynard, 1956, p. 75, the Hudson river steamer
"New World" (1848) was 371 feet long. This early steamer probably did not have
iron bar supports in the frame, since the text appears to say in the third
paragraph that "Metropolis" (345' long, 1854) was the first steamer to have
them [the page from Original American Lloyd's Registry implies that iron bar
supports were required for long wood vessels after the mid-1850's].
Also in the above Lloyd's are specifications for other American wood-hull
steamers (though all probably with iron bar strapping): "Dean Richmond" (348',
1865), "Adriatic" (ocean-going, 350', 1856), "Golden City" (ocean-going, 340',
1863), and the "Great Republic" (ocean-going, 334', 1853). The "Wyoming"
(Laing, p. 408) was the last of the six-master clipper ships, and was 330'
long, built in 1909. Laing's quote of the shipwright Rockwell shows that the
criticism of the six-masters was something other than that they wouldn't float.
Page 23 of Ancient Ships, by Cecil Torr, 1964, says that Callixenos reported a
40-banked (oar banks) ship that was 420' long and 57' wide. There is no proof
that this ship existed, however.
Of course, the issue of construction is not a very strong argument for the
atheist, since it is by definition an argument from the negative. Also,
"practical" commercial construction was expected to last 20 years or more,
while Noah's ark had to last only 1 year, and did not need to support any masts
or handle engine vibration. Finally, the correct proportionality of the ark
for stability is an argument in favor of its historicity (unlike the ark in the
Gilgamesh epic, which was 120 cubits by 120 by 120). I.e., did the Bible guess
the dimensions needed by a ship of this size? (I included a page with the
illustration of the iron-hulled "Preussen" that was close to the dimensions of
the ark.)
A footnote to this discussion is that there is some disagreement over how long the ancient cubit was. I would suggest being careful not to lightly assume the longer definition so as to allow enough space in the ark for all the animals, else the durability problem becomes too big.