6:14 pitch. The ark (an ancient Hebrew word used also for the small box in which the infant Moses floated on the Nile) was made of a hard dense wood whose species has not yet been identified; it was made waterproof, not by a bituminous pitch (a different Hebrew word) but by some as-yet-unknown “covering.” The Hebrew word is kopher, equivalent to kaphar, frequently translated later as “atonement” (e.g., Leviticus 17:11). In providing a protective covering against the waters of judgment, it thus becomes a beautiful type of Christ.
6:15 three hundred cubits. The dimensions of the ark were ideally designed both for stability and capacity. It has been shown hydrodynamically that the ark would have been practically impossible to capsize and would have been reasonably comfortable, even during violent waves and winds. Assuming the ancient cubit to have been only 17.5 inches (the smallest suggested by any authority), the ark could have carried as many as 125,000 sheep-sized animals. Since there are not more than about 25,000 species of land animals known (that is, mammals, birds, reptiles, amphibians), either living or extinct, and since the average size of such animals is certainly much less than that of a sheep, it is obvious that all the animals could easily have been stored in less than half the capacity of Noah’s ark, each pair in appropriate “rooms” (literally “nests”).
6:16 window. The “window” was probably an opening for light and ventilation extending circumferentially around the ark, with a parapet to keep out the rain. The one large door in the side was to be closed only once (after the animals were in) and opened only once (to release them a year later).
6:16 third stories. The three decks may have been laid out as follows: large animals on the bottom; small animals and food storage on the middle deck; family quarters, possessions, records, etc., on the top deck. Water could have been stored in cisterns on the roof and piped throughout the ark where needed. Overhead water storage could also have provided fluid pressure for various other uses.