Colloquy: The epitome of navigation

March 18, 2013

COLLOQUY: Editor's Column

Earliest records of navigation as a science come from the Indus Valley civilization, along the Indus River, which flows from the Tibetan Plateau through India and Pakistan. Among the earliest navigation tools are the mariner’s astrolabe (possibly in use as early as 1295), reflecting quadrant, octant, and sextant, and the medieval Portolan charts, navigational maps based on compass directions and estimates of observed distances.

Modern navigation relies primarily on satellite positioning, or on crossing lines of position (LOP) identified on a nautical chart and by direct observation. LOPs include compass bearings, transits, leading lines, and can also be determined from leading and sector lights. The intersection of two LOPs is a single ‘fix,’ used to determine location.

Sadly, basic marine navigation skills fall outside most ordinary curricula. Mariner scouting programs began to train youth in England and moved to the US shortly thereafter; Sea Scouting in America was founded in 1912, and the Mariner Girl Scout program officially began in 1934. The Sea Scouts organization has been coed since 1971.

Maritime academies

The Royal Observatory at Greenwich was founded in 1675, and in 1767, began to publish The Nautical Almanac and Astronomical Ephemeris. It was the first almanac containing data for the convenient determination of longitude at sea. Since 1958, Her Majesty’s Nautical Almanac Office and the US Naval Observatory have jointly published a unified Nautical Almanac.

Training in advanced navigation is relegated to nautical study programs for merchant shipping and defensive navies, such as Britain’s Royal Naval College. Napoleon Bonaparte founded a maritime academy in Antwerp in 1814, which was ‘re-founded’ under the Belgian regime in 1834. The National Maritime College of Ireland (NMCI) is among the most recent; it opened to students in 2004 and offers Marine Engineering and Nautical Science degree courses.

SUNY Maritime College, Fort Schuyler, Bronx, New York was the first US college of its kind (federally approved, offering commercial nautical instruction), founded in 1874. There are only a handful of accredited maritime colleges in the country, including the US Naval Academy (Annapolis, MD), US Coast Guard Academy (New London, CT), US Merchant Marine Academy (Kings Point, NY), California Maritime Academy (part of the California State University system, Vallejo), Great Lakes Maritime Academy (a division of Northwestern Michigan College), Maine Maritime Academy (Castine), Massachusetts Maritime Academy (Buzzards Bay), Texas Maritime Academy (part of the Texas A&M University System, Galveston), and the private Maritime Institute Inc. (San Diego, CA).


It’s difficult to consider the life and accomplishments of Nathaniel Bowditch without a certain degree of awe. Born on 26 March 1773 – 240 years ago this month – he was inquisitive, gifted, and motivated to learn. He left school at age 10 to work in his family’s cooperage business in the port town of Salem, Massachusetts. He was employed at 12 as a bookkeeping apprentice to Ropes & Hodges, ship chandlers, working on the day-to-day financial transactions of supplies and equipment for ships. In the evenings, he studied in the library of Jonathan Hodges, and was encouraged by three local, Harvard-trained scholars. Over the course of his nine-year indenture, he read math, science, astronomy, and languages, learning algebra at 14, calculus at 16, Latin at 17, French at 19.

Bowditch built his own astronomical and surveying instruments and participated in a land survey of Salem in 1794. His accuracy and thoroughness resulted in an invitation from shipmaster John Gibaut to clerk on his first sea voyage in 1795. Bowditch studied sea journals and navigation techniques, and made five trips to the East Indies, from 1795 to 1803. While at sea he studied charts, took lunar measurements, and recorded his observations. Bowditch was also interested in the mathematics behind celestial navigation and his mastery of French later enabled him (beginning in 1812) to translate the five volumes of French mathematician and astronomer Pierre Laplace’s Traité de Méchanique Celeste into English: Treatise on Celestial Mechanics.

His practical sailing experience and astronomy scholarship made him one of the best navigators in America and secured his place in history. In the late 18th century, mariners relied on navigation tables prepared by John Hamilton Moore of the British Royal Navy, and others. Edmund March Blunt commissioned Bowditch to update and revise The American Coast Pilot, published in 1796, and Bowditch checked the data and recalculated the tables 1797-98.

Bowditch was elected to membership in the American Academy of Arts & Sciences in 1799, and was awarded an honorary LLD from Harvard College in 1802.

In the same year, Bowditch published The New American Practical Navigator, a completely new, comprehensive work that explained the principles of navigation, surveying directions, winds, currents, directions on how to calculate high tides, a dictionary of sea terms, an explanation of rigging, keeping a ship’s journal or log, and business topics such as contracts, insurance, and bills of exchange. It became known as ‘the seaman’s bible’ and went through 10 editions before Bowditch died in 1838. His son, J Ingersoll Bowditch, took over editorial responsibility for editions published over the following 30 years.

In June 1866, the United States Hydrographic Office was established as part of the Bureau of Navigation, Department of the Navy, and it purchased the copyright and plates for $25,000 from George Blunt (son of publisher Edmund M. Blunt).

The US government has published 52 editions since acquiring the copyright, the most recent being the 2002 bicentennial edition. The US National Geospatial-Intelligence Agency offers free digital files of The American Practical Navigator. The entire document or separate chapters and tables can be downloaded. Although online editions of Bowditch are constantly updated, a hardcover edition never crashes or has to be rebooted, and is never subject to the vagaries of battery failure.

Such is the appreciation of this time-tested volume that it has its own Facebook page: Bowditch’s American Practical Navigator.OE