According to the Hiltons, although LDS literature is full of discussions of ocean currents and wind patterns in the Pacific, such discussions of drifting with the currents rather than purposefully steering and sailing directly "eastward" (1 Nephi 17:1) should be of lesser importance, because Nephi specifically said he "sailed" (1 Nephi 18:22) and "steered" (1 Nephi 18:13) his ship. He did not just allow it to coast along with the natural current. Remember, it is the "set of the sails and not the gales" that tell you where to go.
Moreover, mariners and even desert travelers in ancient Arabia used a simple device, composed of a small board and a knotted leather thong, to measure the angle of Polaris above the horizon, to navigate due east or due west. They achieved surprising accuracy with this device. With such a device, as well as the Liahona, Nephi could easily have navigated eastward. [Lynn M. and Hope A. Hilton, Discovering Lehi, p. 173]
“They Knew Not Whither They Should Steer the Ship”
Although Nephi had received inspiration and direction from the Lord, when the "compass which had been prepared of the Lord did cease to work," he notes that "they" (apparently Laman and Lemuel) "knew not whither they should steer the ship" (1 Nephi 18:13). This brings up the question of ancient navigation techniques. The following excerpts from Tim Severin's book The Sindbad Voyage might provide some interesting cultural background:
The navigation of Sohar was an essential element in the whole Sindbad Voyage. One of the objectives of the project was to find out how the early Arab navigators had succeeded in finding their way to China. It was a stupendous achievement: they had sailed nearly a quarter of the way round the world at a time when the average European ship was having navigational problems in crossing the English Channel, and the Arabs had steered their routes, not by luck, but by careful calculation. The earliest Arab texts gave a few hints as to how they had managed this feat. They stressed that they used the stars, not the sun, to fix their position; and there were a number of vague references to charts and pilot books which seem to have been carried on board, and which had been compiled from the experience of senior navigators. But no early Arab sea charts have survived, and not until the fifteenth century did a book appear which began to lift the edges of the veil of mystery which surrounded Arab navigation. Suitably, the book was written by an Omani. He was master navigator from Sur, by the name of Ahmed Ibn Majid, and he was one of the most renowned seafarers of his time. Fortunately his writings had been translated and painstakingly annotated by an English scholar, Gerald Tibbetts. I had taken a copy of Tibbett's edition of Ibn Majid's book with me aboard Sohar, and now it became my manual in trying to test out the methods of early Arab navigation. . . . [It] offered a great deal of astronomical theory, explaining how the stars moved in the heavens at different times of the year and how to identify different constellations, and so forth. What interested me were the practical details. Just how did an early Arab navigator measure his position? How did he lay off his course? The instrument he used was no more than a wooden tablet about 3 inches wide with a hole in the middle of it; through this hole ran a piece of string with a knot in it. The navigator placed the knot between his teeth, stretched out the string until it was taut, and closing one eye held the tablet so that one edge of it touched the horizon. He then checked the height of the Pole Star against the side or the upper edge of the tablet. It seemed devastatingly simple.
I cut a sample tablet out of a piece of cardboard, pierced a central hole, rigged the knotted string, and went on deck to try out the Majid's instructions. . . . The best time to take an observation, he said, was when there was a clear horizon. The moonlit night was perfect, and after a few moments of waving the tablet unsteadily I got the knack and found I could measure the height of the Pole Star. Then I took a star sight with a modern sextant, worked out Sohar's position, and made a note of the result. The following night I repeated the experiment, and saw how the position of the Pole Star had altered against the side of the cardboard tablet. I consulted my copy of Ibn Majid's manual, and compared his data with a set of modern navigation tables. The relationship was obvious, though Ibn Majid did not use degrees and minutes for his measurements, but calculated the height of the Pole Star in finger widths, which he called isba. By the third night I was able to judge the height of the Pole Star accurately enough to plot the ship's latitude position to within a variance of 30 miles, using only a bit of cardboard and a string with a knot in it! I was only a beginner, yet already I could have navigated Sohar to any selected point on the Indian coast a good 500 miles away from Sohar's present position. All I needed to know was the height of the Pole Star in finger breadths at that location, sail south until I counted the same number of finger breadths aboard Sohar, turn east and keep the Pole Star at the same height until I made my landfall.
It is a technique now known as "latitude sailing", but what made Ibn Majid's achievement much more impressive was that he claimed to know how to calculate his latitude not just by the Pole Star, but by a whole series of other stars which he used when the Pole Star was invisible. He produced lists of stars whose altitude, if measured at the right time, could be substituted for Pole Star altitudes. Some of these stars were easy enough--he used the stars in the Southern Cross, for example--but others had to be measured in pairs, when they were in a particular relation to one another, and in a certain lunar month. Thus Ibn Majid's knowledge of the constellations and their movement had to be encyclopedic. He also explained how to allow for variations in the height of the Pole Star, how to set a course to take account of wind drift, what signs to look out for when approaching land after an ocean passage, and so forth. He did not know how to calculate the longitude of a place, that is its east-west position, but that did not matter. On the voyage to China the coasts mostly lie north and south across the track of the ship;, and to know one's latitude position would have been enough. . . . he gave a whole list of the isba positions of the most important ports. Little wonder that Ibn Majid had been considered a mu'allim, the highest grade of navigator. . . .
The star-reading tablet and string, known usually as a kamal, worked for me, but would it work for other members of the crew? Several of them tried holding the piece of cardboard at the end of the string and measuring the Pole Star. We found that the piece of cardboard worked best for someone of my own size. Other people produced different readings. I consulted Ibn Majid's writings and he had an answer for that problem too. In the constellation of Capella are two distinct stars. The distance between the two stars is exactly four isba. So if a man made his own kamal, he should check it against the two stars of Capella, and that way he would know whether his kamal was correct. (pp. 91-92)
[Quoted from Tim Severin, The Sindbad Voyage, New York: G. P. Putnam's Sons, 1982] [For more excerpts see the commentaries on 1 Nephi 17:8; 18:6; 18:8; 18:12]
1 Nephi 18:13 They knew not whither they should steer the ship ([Illustration]): Tim Severin shows Khamees Navy how to use a kamal, the medieval Arab navigation instrument. The kamal, a wooden tablet held out at the end of a string, measured the height of a selected star. With very little practice it was possible to obtain a latitude position accurate to within 30 miles.
1 Nephi 18:13 They knew not whither they should steer the ship ([Illustration]): Steering by Polaris, the North Star, Arab seafarers of old used a kamal, a kind of sextant, to measure latitude. At dusk, Severin demonstrates the technique to one of the Omani crew members. In his left hand he holds the kamal, a wooden rectangle, with its bottom edge on the horizon. A knotted string held in his teeth, each knot representing the latitude of a known port, tethers the kamal at the proper distance. The position of Polaris in reference to the kamal helps determine the ship's course (see diagrams). Photographs by Richard Greenhill. [Tim Severin, "In the Wake of Sindbad," in National Geographic, Vol. 162, no. 1, July 1982, p. 22]