Contrary to popular belief, the Jaredites made barges on two separate occasions. Upon leaving the valley of Nimrod, they came to a body of water which was not the same as the ocean which is described as the great sea which divideth the lands (v. 13). They crossed this sea in barges, landed on the other side, and kept traveling. Hence Moroni’s statement, the Lord would not suffer that they should stop beyond the sea in the wilderness, but he would that they should come forth even unto the land of promise. In other words, they had crossed many waters but had not yet reached their final destination. Hugh Nibley explains that in ancient Asia Minor, there were many large bodies of water, “Now it is a fact that in ancient times the plains of Asia were covered with ‘many waters’, which have now disappeared but are recorded as existing well down into historic times; they were of course far more abundant in Jared’s time…The steady and continual drying up of the Asiatic ‘heartland’ since the end of the last ice age is one of the basic facts of history.” (Lehi in the Desert and the World of the Jaredites, pp. 178) “It [is] our guess that the Caspian was ‘the sea in the wilderness’ that the Jaredites had to cross (Ether 2:7).” (An Approach to the Book of Mormon, p. 330)
We get more evidence that they built barges on two separate occasions in verse 16. The Lord explicitly tells the brother of Jared, Go to work and build, after the manner of barges which ye have hitherto built