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For centuries, sailors crossed oceans using charts, experience, and accumulated wisdom.
But in the 19th century, one naval officer realized that the logs of countless ships contained something far more valuable: data.
By studying winds, currents, and voyage times, he found ways to make ocean travel faster, safer, and more predictable, helping transform navigation into a science.
… and he did it not on board a ship, but sitting at a desk.
Learn more about Matthew Fontaine Maury and his revolution in ocean travel on this episode of Everything Everywhere Daily.
The evolution of sea transportation has taken thousands of years. At first, humans sailed only within sight of the shore to make navigation easier and to put sailors’ minds at ease.
Eventually, with the construction of larger ships, sailors were able to go into the open ocean. However, while there were improvements in navigation and ship design, for most of that time sailing was straightforward: determine the direction of your destination and sail straight towards it.
By the early nineteenth century, navigators had become quite good at determining a ship’s position. Latitude could be determined from accurate marine clocks that allowed navigators to calculate longitude. An innovation developed by British clockmaker John Harrison, which I covered on an early episode.
But knowing where you were did not necessarily tell you the fastest way to get where you were going.
Sailing ships depended completely on the atmosphere and ocean. A vessel might have a destination only a few thousand miles away in a straight line, but sailing directly toward it could lead into persistent headwinds, adverse currents, or large regions of calm. Another route that was hundreds or even thousands of miles longer could actually be much faster.
Experienced captains understood this. They accumulated personal knowledge about prevailing winds, currents, and seasonal conditions. But much of this information remained scattered among individual captains and navies.
There was no comprehensive system for combining all those observations.
Enter Matthew Fontaine Maury.
Maury was born in Virginia in 1806 and entered the U.S. Navy as a midshipman in 1825. During his early naval career, he became intensely interested in navigation.
One formative experience came in 1831, when he was assigned as sailing master aboard the USS Falmouth for a voyage to the Pacific. Maury searched for reliable information about winds, currents, and the best routes but found remarkably little organized material.
According to the Naval History and Heritage Command, this helped convince him that the accumulated experience of navigators ought to be systematically collected and made available to everyone.
A carriage accident in 1839 badly injured Maury’s leg and largely ended his active seagoing career. Unable to continue regular sea duty, he remained in the Navy but was relegated to a desk job.
It was that accident that indirectly changed maritime navigation and led to the creation of this episode.
In 1842, Maury was placed in charge of the U.S. Navy’s Depot of Charts and Instruments in Washington. When the U.S. Naval Observatory was formally organized, he became its first superintendent in 1844.
It gave him access to something enormously valuable.
Old ships’ logbooks.
Here I need to shift gears a bit and explain exactly what ship logbooks are and why they were kept.
A ship’s log in the age of sail was essentially the vessel’s official operational record. It combined the functions of a navigation record, weather record, work diary, and legal document.
The practice became increasingly important during the 16th and 17th centuries, as ocean voyages became longer and navigation became more systematic.
The term “log” comes from the “chip”, not ship, log that was used in ships to estimate speed. A chip log was a navigation tool that measured a ship’s speed by paying out a knotted line attached to a weighted wooden log and counting how many knots passed overboard during a timed interval. This is the origin of the term “knots” for measuring speed on water.
The ship’s speed was then recorded in a “log book.” So the etymology of a logbook literally comes from a wooden log.
The ship’s log eventually added information such as position, weather, sail and rigging repairs, and weapons exercises. Commercial vessels also recorded cargo transactions.
By the 1600s, European merchant companies and navies were keeping increasingly formal logs. The British East India Company has surviving official ship logs dating back to 1605, while the Royal Navy has surviving lieutenant’s logs from 1673 onward. By the 18th century, keeping a log was a thoroughly established part of professional seamanship.
The log served as a legal record of what happened on a ship, and when a voyage ended, unless something unusual happened, the log was filed away and never seen again.
Maury was one of the first people to realize that the plural of anecdote is data. An individual log told the story of a single voyage, but together they told the story of weather, wind, and current patterns across the sea and throughout the year.
Maury and his assistants began systematically extracting observations from thousands of logbooks.
They divided the ocean into geographic squares. For every square, they might record observations such as the direction and strength of the wind, the direction and estimated speed of currents, the month or season, sea temperature, air temperature, storms, calms, and other conditions.
With enough observations, patterns started to emerge.
Maury’s breakthrough was essentially statistical. He was not asking, “What happened to this ship?” He was asking, “What usually happens in this location during this season?”
That distinction was revolutionary.
By 1847, Maury’s research had progressed far enough that he produced his first major Wind and Current Chart of the North Atlantic. These charts represented something quite different from conventional nautical charts.
A traditional nautical chart told a sailor about geography: coastlines, harbors, islands, reefs, and water depth. Maury’s charts described the behavior of the ocean and atmosphere.
An 1852 Maury chart held by the Royal Museums Greenwich, for example, records wind and current directions along ship tracks, distinguishes observations by season, and includes magnetic variation and sea temperature.
This essentially added another dimension to navigation. Instead of seeing the ocean as empty space between continents, sailors could now visualize it as a dynamic system.
The creation of these maps was an enormous leap forward; however, it wasn’t the end of the story. Maury offered charts and sailing directions to captains who agreed to participate in his observational program.
They received standardized log forms and instructions explaining how observations should be recorded. Captains recorded information during their voyages and returned their observations to the Naval Observatory.
Maury’s staff analyzed the new information and incorporated it into future editions. Those improved charts were then distributed to more mariners, who collected still more observations.
It was a virtuous cycle.
The program eventually expanded beyond the United States. By 1851, more than 1,000 vessels operating worldwide were supplying Maury and his team with observations.
In modern terminology, Maury had created an international crowdsourced scientific database.
So, with all this data, what exactly did mariners learn?
One of Maury’s most important practical conclusions was that navigators should stop thinking primarily in terms of geographic distance.
The shortest line on the chart might take a ship directly into persistent headwinds. A longer route might take the vessel hundreds of miles out of its way but place it in strong favorable winds.
A sailing ship traveling steadily at eight or ten knots could easily outperform a vessel taking a shorter route that spent days in calm winds or sailing against headwinds.
Maury’s charts encouraged captains to think in terms of travel time rather than raw mileage.
This is essentially the same principle used in modern aviation and shipping today.
Also, Maury did not simply publish charts. He also produced extensive Sailing Directions that explained how captains should use the data. These works combined observations with recommended routes for particular voyages and seasons.
A captain sailing from New York to Rio de Janeiro, for example, could consult information about the trade winds, currents, and expected weather conditions along various routes.
The results were immediate. Together with the rise of the American Clipper ships, sail times were slashed. In 1851, the ship Flying Cloud sailed from New York to San Francisco around Cape Horn in approximately 89 days and 21 hours using Maury’s charts. This was when sailing times for that route averaged roughly 188 days.
On some of the world’s longest routes, Maury’s charts cut sailing times by a third, potentially shaving weeks or even months from a voyage around the world.
The importance of saving several days at sea is easy to underestimate.
For a merchant ship, every extra day meant wages, food, maintenance, insurance risk, and delayed cargo delivery.
Suppose a voyage could be reduced from 120 days to 100. That was not merely convenient. The ship could potentially complete more voyages in a year, perishable cargo arrived in better condition, passengers arrived sooner, and capital invested in cargo was tied up for less time.
Maury’s recommendations also helped formalize the idea that ships traveling between the same ports need not follow identical routes in opposite directions.
Because atmospheric circulation has preferred directions, the optimal outbound route might be completely different from the optimal return route.
This principle helped establish recognizable oceanic shipping lanes.
In August 1853, representatives of maritime nations met at Brussels for an international conference on marine meteorology. The conference sought to standardize the kinds of observations ships recorded and the methods used to record them.
Maury played a central role in promoting the conference and its objectives. Participants adopted standardized forms and instructions for meteorological observations aboard ships, and additional nations later joined the system.
As important as Maury’s work was for maritime navigation, he took it beyond that. In 1855, he published The Physical Geography of the Sea, building upon earlier editions of his work and describing the ocean as an interconnected physical system.
It is often regarded as a foundational text in the field of oceanography.
Maury’s work also became an early basis for the science of meteorology.
Maury’s research also contributed indirectly to another nineteenth-century innovation, submarine telegraph cables, another topic which I’ve covered on a previous episode.
Maury was one of the first people to conduct large-scale data analysis in an era before computers. He and his team had to do everything on paper.
I’d be remiss not to mention a major stain on his record. Maury was from Virginia. When the Civil War started in 1861, he resigned his commission in the US Navy and joined the Confederacy. He was anti-secession, but he felt he had to remain loyal to Virginia.
He served the Confederate government, including working on naval mines and traveling abroad in efforts related to Confederate naval procurement and diplomacy.
After the war, he eventually returned to the United States and became a professor at the Virginia Military Institute. He died in 1873 at the age of 67.
The name Matthew Fontaine Maury isn’t well known. He did not discover the winds and currents of the oceans, but he found a new way to understand and use them. By turning thousands of ship logs into organized data, he showed sailors that the fastest route was not always the shortest one and helped make ocean travel faster, safer, and more predictable.
Maury demonstrated something that remains just as important today: when enough observations are brought together, patterns can emerge that no single traveler could ever see on their own.