According to scientists specializing in this area, its winds and currents, no theory, belief, or hope for anything else with these monsoon winds is possible, never has been changed, altered or abrogated since measurement and memory have existed.
Although Mariners have been aware of the existence of the Monsoon current for nearly a thousand years, a detailed understanding did not emerge until after the International Indian Ocean Expedition of the 1960s, and especially when the World Ocean Circulation Experiment of the mid 1990s permitted detailed measurement of these currents through an extensive field campaign (D. Shankar, P. N. Vinayachandran and A. S. Unnikrishnan, “The monsoon current in the north Indian Ocean,” Progress In Oceanography, Volume 52, Issue 1, 2002, p 63-120; and Friedrich A. Schott and Julian P. McCreary, Jr., “The monsoon circulation of the Indian Ocean,” Progress In Oceanography, Volume 51, Issue 1, 2001, p1-123).
As stated, there are two seasonal periods, the Summer Monsoon and the Winter Monsoon. They do not overlap, as one fades the other picks up, the Summer Monsoon winds, blowing inland, ends in the end of September, and the first of October, like clockwork, the Winter Monsoon winds begin to blow in the opposite direction.
The Summer season structure (summer monsoon), is located between 10º and 15º north latitude in the Arabian Sea. During the summer monsoon, this current bends around India and Sri Lanka, and enters the Bay of Bengal as the entire current flows northward toward the mainland across the width of the Sea of Arabia.
During the summer when the current flows toward the northeast, Ekman transport (to the right of the flow in the Northern Hemisphere) is offshore, transporting warmer waters deeper into the Arabian sea, and permitting upwelling of cooler waters along the coast. This sea surface temperature pattern (cooler waters west of warmer waters) reinforces the northward current through geostrophic flow. The Southwest Monsoon Current is eastward from April through September, and reaches a peak intensity of 30 cm s during the summer months (Stephen Marshak, Earth: Portrait of a Planet, New York: W.W. Norton & Company, 2001)
The Winter Season structure (Winter Monsoon), is located in this same general latitudinal area and extends from the Bay of Bengal, around India and Sri Lanka, and across the Arabian Sea at a latitude of approximately 8º north. Measurements of the strengths of these currents have been obtained from ship drift records. The Northeast Monsoon Current is westward only during the months of January through March, and is strongest in February when it reaches 50 cm s. Estimates of westward volume transport range from 7 to 14 Sverdrups.
The Somali Current, describes the flow along the Horn of Africa from the equator to around 9º north, also shifts direction seasonally with the monsoon winds. It eventually separates from the coastline, turning to the right as it enters the Arabian Sea ( W. Munk and C. Wunsch, 1998: “Abyssal recipes II: energetics of tidal and wind mixing,” Deep-Sea Research Part I, 1998, No 45, pp1977-2010). As part or adjacent to this current, off the coast of Somalia, is the Great Whirl, a gyre located around 10 N and 55 E, and is only present during the summer season. During a 1995 field campaign, the Somali current was measured to transport 37 +/- 5 Sv during mid-September (Lynn E. Talley, "Reading-Advection, transports, budgets,".SIO 210: Introduction to Physical Oceanography. [Fall 2013]. San Diego: Scripps Institute of Oceanography, University of California San Diego).
There are several currents in the Indian Ocean Sea of Arabia that are important to understand. First of all, (Green Arrow) Bountiful where Lehi launched his ship; Currents by color: Purple: Monsoon Drift; Brown: Somali Current; Lt. Blue: Mozambique through Madagascar Strait; Red: South Indian Current; Yellow: Antarctic Circumpolar Current, which is part of the (Dk. Blue) Southern Ocean, which travels unencumbered around the globe, cutting the distance across the equator by about 2/3rd. The two circles and line in maroon are the direction of the monsoon winds, from (top) northeast to (bottom) southwest
The Somali Current, is strongly linked to the Indian monsoon, and during the summer monsoon, the current flows eastward into the Bay of Bengal, which would be a dead end, because the winds coming off the South Pacific Gyre and through the Indonesia Archipelago flows from east to west, keeping any sailing ship like Nephi’s “driven forth before the wind” from passing into the massive island chain.
During the winter monsoon, the Somali Current, flows westward, at a reduced speed, bringing ships from Arabia toward the southwest and allowing them to breach the current, Great Whirl and Socotra gyre current on their path toward the Agulhas/Mozambique current and through the Madagascar Strait or to the east of the island where (see map for both courses, blue arrow in the straight and red arrow to the east of the island), in either case, the ship would be picked up by the South Indian Current and swung toward the southeast and the Southern Ocean.
The Agulhas current (like the Gulf Stream and the Kuroshio) is a very narrow current and despite its fast speed, would not likely capture any vessel sailing toward the southeast, which has its own very fasts speeds of the Southern Ocean and the high winds of the Prevailing Westerlies.
Thus, Nephi’s ship and Lehi’s course would have taken them into the Southern Ocean and headed across the Pacific in the highwinds and swift currents
As shown earlier, the course of Nephi’s ship would have had to sail at certain times to avoid changing wind and currents in the Sea of Arabia and the Indian Ocean, in order to reach the Western Hemisphere
The idea of sailing westward around the Cape of Africa is a foolish idea for a sailing ship “driven forth by the winds” for those very winds push the Agulhas current back upon itself and into the South Indian Current which is the current Lehi would have been on past Madagascar as it bent toward the southeast anyway. In the Age of Sailing, experienced sailors look toward sailing around the Cape with a fearful eye for this Cape of Storms, the Graveyard of Ships, has taken many a good ship captained by an experienced navigator/pilot, and manned by experienced crews, to the bottom for several centuries. It is both foolish and unconscionable for a man of the 21st century to suggest that Lehi, with a crew never having gone to sea before, would be sent around that Cape, for many a good sailor lost his life in such an attempt. The course being laid out by the map above is a simple, easy sailing direct course, with high winds and swift currents all the way and no obstructions or converse currents, and about only 1/3 the distance of crossing either the Atlantic or the Pacific around the equator.