Annotated History of the Gulf Stream Current

In actual observations of the Gulf Stream, or rather in the currents contributing to it, Columbus was the pioneer in Western recorded history.  Later related by Peter Martyr, in 1492 Columbus remarked about the strong currents of the Caribbean Sea.  However, the first record of satisfactory evidence of the discovery of the Gulf Stream current, comes from Ponce de Leon's expedition in 1513 to search for the fountain of youth.  Referring to the current in the ship's journal,  it seemed as if the ship was moving quickly through the water, but they soon recognized it was an illusion.  In fact that they were being driven back because the current was stronger than the wind.  Two vessels, which were somewhat nearer the coast, came to anchor; the third vessel, a brig, being in deeper water, could not anchor, and was soon "carried away by the current and lost from sight although it was a clear day."

In 1590 John White, the Governor of the colony at Roanoke, referred to the portion of the voyage from the Florida Keys to Virginia: "We lost sight of the coast and stood  to sea for to gaine the helpe of the current, which runneth much swifter farre off than in sight of the coast, for from the Cape of Florida to Virginia, all along the shore, are none but eddie currents setting to the south and southwest."  This is the first recorded knowledge of an approximate position of the Gulf Stream.

The influence of the Gulf Stream in the colonization of North America was great. In 1606 the English divided their claimed land into two parts, northern and southern territories prescribed by the routes the ships had to take to reach their destinations.  After the English and Dutch settlements became firmly established and crossing the Atlantic became common, the personal experience of navigators was no longer thought to be of sufficient importance to print, so their information was not widely shared.  Several people continued to offer descriptions and explanations for the current, but no maps or charts of the current seem to have been created or survived history.  

The lack of general knowledge of the Gulf Stream impacted early American ship travel.  For instance, there are several accounts of voyages from Boston, Massachusetts, traveling south to Charleston, South Carolina, taking three or four weeks, while a return trip would frequently be made in one week.  The whalemen, however, were gaining knowledge and experience regarding the Gulf Stream.  The whalers extended their search for the current as far south as the Bahamas and as far east as the Azores.  The interest in the current lay in the discovery that whales appeared to the north and to the south of the current and were but rarely seen within the Gulf Stream.  The whale fishery soon became the school for American navigators, so the knowledge of the Gulf Stream slowly was introduced into commercial shipping.  The American shipmasters, from their superior information on the subject of currents, inaugurated a change in the sailing route from Europe, by which they could save two weeks or more in the passage.  From England they crossed the Newfoundland Banks in about latitude 44 and 45 degrees, and set then a course along the coast, avoiding the Gulf Stream.   Throughout the colonial era, the Gulf Stream remained the principal ocean route along the southern coast of North America.  Trade in rum, sugar and spices was vital to the economic needs of the growing markets.  Although the current was a benefit to some ships, it proved detrimental to others, primarily the English, pushing west to the New England colonies from Britain.  (NOAA Gulf Stream History)

In 1768, when Benjamin Franklin, then-postmaster general for the American colonies, traveled to London, where he was questioned by British authorities about why letters took much longer to get to New York than to New England ports when the two locations were ‘‘scarcely a day's sail apart" and why westward mail from Europe to America took weeks longer than the east-bound ships from America.   Franklin could not offer an immediate answer but began an investigation.  His first piece of evidence was actually in his own journal.  Franklin recalled a curious occurrence in 1726 while sailing from London to Philadelphia.  After several weeks at sea, Franklin noted that the color of the ocean water began to change. There were "hot damp winds," along with "an abundance of grass" and other seaweed visible in the water.  To Franklin, the warmer air and warmer water suggested that the ship must be very near the coast, but the ship’s captain scoffed at that idea. And, indeed, after six days, the ocean water regained its former darker color, and the hot wind and abundant seaweed disappeared. The ship was nowhere near the coast.  Franklin had no explanation for the peculiar changes in the character of the ocean he had seen in the mid Atlantic, but later in 1769, that was about to change.  (Study Place: Ben Franklin and the Gulf Stream)

Franklin thought of another source of information.  His cousin, Timothy Folger, an American whaling captain.  Folger knew exactly why there was a delay in mail delivery.  Folger informed Franklin that American whalers were well-acquainted with the Gulf Stream. They knew whales could be found along its plankton-rich boundaries.  They also knew travel back to New England whaling ports could be hastened by sailing north of the powerful push of the current.  Folger said Americans had frequently told British captains about the futility of fighting the current (running against the current could cost a ship as much as 70 miles a day in westward progress) and how to avoid it, but that they had ignored the advice. ‘‘They were too wise to be counseled by simple American fishermen."   (The Atlantic Coastline: The Gulf Stream)

Franklin asked Folger to sketch the current on a map, which he then had printed and presented to the Lords of the Treasury, who in turn passed it along to their captains.   In the light of later research, including satellite observations in the late 20th century, the Franklin-Folger chart proved a remarkably accurate portrayal of the path taken by the Gulf Stream.  Unfortunately, most of the packet ship captains ignored the new charts, and mail service between Europe and America continued to lag.  All the original copies of the Franklin-Folger chart were soon lost (one was finally located in a French library in 1978), but subsequent versions were published in France in the early 1780s and in Philadelphia in 1785. (NOAA and Ships of Opportunity on the Northeastern Continental Shelf)

Franklin, being the scientist that he was, became intrigued by the idea of a "stream" existing in a large body of water such as the Atlantic ocean.  Therefore, in 1775 during his return voyage from England to the colonies, Franklin took temperature measurements of the ocean water from two to four times per day (Van Doren).  From his readings, he could determine whether a vessel was in or out of the stream, and even approximately how close or distant a ship was from America.  Franklin proposed that, "This Stream is probably generated by the accumulation of water on the eastern coast of America between the tropics, by the trade winds that constantly blow there . . ." He also recorded that the western bank of the stream is significantly cooler (shallower water) than the eastern bank.  He reasoned that the velocity of the stream gradually slowed as it flowed north, but could maintain its relative warmth to the colder North Atlantic.  Franklin is generally given credit for correctly explaining the stream's cause.  Franklin even suggested the name "Gulf Stream," even though it is a huge, circular motion in the Atlantic Ocean and has little to do with the Gulf of Mexico.

In 1776, the American Congress appointed three commissioners to travel to France in order to gain French support in the American Revolution. Franklin was chosen as one of the commissioners. On 26 October, Franklin left Philadelphia on board the Reprisal. "The indomitable old man, who was almost certain to be hanged for high treason if the Reprisal should be captured, noted the temperature of air and water every day, again studying the Gulf Stream" (Van Doren).   Franklin did not return to America until 1785. On this trip, he again took daily measurements of the water temperature and notes concerning the currents, water color and gulf weed content.  He also wrote Maritime Observations on this trip. This work included his notes on the Gulf Stream's causes and uses as well as a multitude of other information about sailing the oceans. (Van Doren).  (Benjamin Franklin and the Gulf Stream)

In the mid 1800's, Matthew Fontaine Maury and his contemporaries used equipment to measure water temperature, buoyancy and current speed information from around the world.  He distributed special logs, each with 12 blank pages in the back, to Navy and merchant captains to record data from their travels.  Maury and his staff analyzed the notes from the crossings and generated the first edition of ‘‘Wind and Current Charts’‘ in 1847.   Captains who were once reluctant to take part in Maury's study began to take notice when crossing times began to be dramatically reduced. One captain cut 35 days off a 110-day journey to Rio de Janeiro.  Maury offered the charts for free to anyone who would send in data.  His work was the foundation for much of the research over the next century.  Oceanographers poured over reports of derelict ships and floating debris, a peril to navigation and a treasure-trove of information.  As the location of the flotsam was plotted and the drifting debris was tracked, scientists gradually began to realize that currents formed oceans, not the other way around.

Scientists continue to study the Gulf Stream using increasingly sophisticated technology.