The time of the journey is one of the reasons Allen gives for preferring the Pacific crossing for the Jaredites. He notes:
“The Book of Ether reports that the Jaredites took 344 days, almost one year, to travel from the point of departure to the Promised Land. If the Jaredites left from the Atlantic side, near Morocco, they would have traveled in circles for 8 or 9 months. Thor Heyerdahl made the trip on a raft from morocco to the Caribbean in two months. The scripture says, “…the wind did never cease to blow towards the promised land…” (Ether 6:8) We would not expect the Jaredites to travel in circles. The distance from the Pacific by China to the gulf of Tehuantepec is Mesoamerica is more than twice the Atlantic’s crossing distance, thus placing us closer to the required time for the Jaredites to travel from the Old to the New World.” (Joseph L. Allen. Exploring the Lands of the Book of Mormon. S. A. Publishers, Inc. 1989, p. 260.)
Certainly when stated in that way, it makes it appear that there is way too much time required for an Atlantic crossing. There are two important points that Allen misses, however. The first is that they simply could not have carried enough food and fresh water for themselves and their livestock. A journey of nearly a year would force them to land somewhere to restock. Since the last time they temporarily stopped it was for four years, we cannot assume that their stops to replenish supplies would have been short. Had the Jaredites gone the Pacific route, they would have needed to stop, and that would have added to the required travel time.
The second point is that while Allen is correct in citing Ether 6:8, he does not cite all of the important information in that verse. What we really need to know is that “the wind did never cease to blow towards the promised land while they were upon the waters” (italics added). Allen is presuming a continuous journey with no stopping. The text actually says that the winds blew while they were upon the waters, allowing for at least one time when they could stop for provisions. Of course we do not know where they stopped, nor for how long. However, stopping for provisions could easily add the extra time of travel.