We expect that a sailing vessel would be driven before the wind, but that doesn’t mean that the winds are always blowing in the right direction. In fact, assuming a location for Bountiful on the east coast of the Arabian Peninsula, the winds are usually blowing in the wrong direction.
The exception is during an El Niño year. During that year, the winds change to be favorable to a Pacific crossing for the Lehite ship. While there were certainly various reasons that kept Lehi and his family 8 years in the wilderness, one of the reasons the Lord may have allowed that length of time was the necessity of having the ship finished near to the time that the appropriate winds were blowing.
Nephi uses the departure to set up the next story. As with the others, this is a story that will demonstrate that Jehovah favors Nephi over his older brothers. Most interesting is that this is set up by singing and dancing. It might appear that these two things are inherently dangerous, but that isn’t the intention here. Nephi continues to draw parallels to the Exodus story. As Moses returns to his people, he finds them singing and dancing (Exodus 32:18–19). The children of Israel were singing and dancing as part of a religious practice that harkened to their time in idolatry. Nephi uses that image to demonstrate that while Laman and Lemuel had times of repentance, they too were quick to forget.