After 150 years, Bowditch still a necessity for world mariners
By Carling Uhler, NGA Office of Corporate Communications

​Sailors, naval historians and maritime enthusiasts gathered in the National Geospatial-Intelligence Agency’s Museum Oct. 31, in Springfield, Virginia, to bask in the history of Nathaniel Bowditch’s American Practical Navigator, and to celebrate its legacy as the premier navigational reference book of the seas.

The NGA Bowditch event featured keynote speaker Michael Crawford, Ph.D., senior historian at the Naval History and Heritage Command, who honored Nathaniel Bowditch, “The American Practical Navigator,” and NGA’s contribution to keeping mariners safe.

Members of the Maritime Publications Branch, part of NGA’s Maritime Safety Office, attended the event. The Maritime Safety Office provides timely and accurate data, products, applications and services that are dynamically updated, easily discoverable and consumable, and delivers it to the warfighter, analyst - and, in this case, mariners.

NGA and its predecessor organizations have been responsible for updating The American Practical Navigator since the U.S. government purchased the rights for $25,000 in 1867.

The book often is called ”Bowditch” after its author, Nathaniel Bowditch, of Salem, Massachusetts. Bowditch was a 19th-century insurance actuary and a lover of numbers, said Crawford.

The reliability and accuracy of the book is anchored in Bowditch’s education and passion for mathematics, said Crawford.

Bowditch made four lengthy sea voyages in his effort to correct and revise information in J.H. Moore’s “The Practical Navigator,” according to Encyclopedia Britannica.

Bowditch’s “dogged determination and deep devotion to accuracy” resulted in the publication of “an epitome of navigation” and had a positive, significant effect on maritime trade, economics and business practices, said Crawford. 

“As a 19th-century mariner heading out on a whaleboat, you would grab the essential tools for sailing – compass, quadrant and ‘Bowditch,’” said Crawford.

Today, “The American Practical Navigator” in its 54th edition, remains a “most trusted tool,” helping mariners find their bearings and sail across the Earth’s waterways safely, said Crawford. 

“The immaculate Bowditch” as it’s also called, demonstrates its continual, practical use as an educational tool at the U.S. Naval Academy and U.S. Merchant Marine Academy, said Crawford. The Naval Academy used to require plebes to own a copy. Today, most choose to have one.

Gerard Clifford, Ph.D., a Merchant Marine Academy graduate and Bowditch 2017 editor in chief, shared a story of a Naval officer swearing an oath on “The American Practical Navigator,” an illustration of the importance of Bowditch to military service members.

“It [The American Practical Navigator] has lived because it has combined the technology of each generation,” Crawford stated.

Though with each new edition comes changes, Crawford emphasized the value of “The American Practical Navigator” lies in its reliability, not innovation.

“The errors in Moore’s tables, in ‘The Practical Navigator,’ led to navigational mishaps, sometimes fatal,” said Crawford. “But sailors found they could safely stake their lives on Bowditch.”


Michael Crawford, Ph.D., senior historian at the Naval History and Heritage Command, speaks at the National Geospatial-Intelligence Agency's Bowditch ceremony, honoring the legacy of "The American Practical Navigator."  

 More News