The Sea and Civilization: A Maritime History of the World (73 page)

From a technological standpoint, literacy and improvements to navigation were accelerated by the invention of movable type, and the
first printed sailing directions were published in
Venice in 1490, only thirty-five years after
Gutenberg’s
Bible. The practice of compiling information about sailing routes was nothing new, but whereas earlier guides tended to emphasize the commercial opportunities in different places, there was now a distinction between merchants’ manuals with raw data about various commodities, their prices, and where to purchase them, and navigational instructions. Ancient works such as the
Periplus of the Erythraean Sea
sometimes combined this information in one text, but as new tools and methods for determining direction or fixing one’s position developed in the early modern period, navigational information was increasingly differentiated.

As to the actual practice of navigation, we can consider four distinct
approaches:
coastal piloting, dead reckoning, latitude sailing, and position fixing. Coastal piloting is in principle the easiest but in some respects the most dangerous type of navigation, for inshore hazards are more numerous than those encountered on the open sea. As the term suggests, the essence of coastal piloting is sailing more or less in sight of land and relying on a familiarity with its terrestrial and hydrographic features to get safely from place to place. Sailors everywhere learn from a young age the landmarks and seamarks of their own waters: the location of shoals, rock outcroppings, the best holding ground for anchors, the direction of the prevailing winds, the nature of tidal currents along the shore or in the approaches to a bay, harbor, or river mouth. Similarly, they have a familiarity with terrestrial features: bays, headlands, hills, stands of trees, or man-made structures. Knowing the depth of water is of great importance, but so, too, is a familiarity with the composition of the seabed, which differs from place to place. For this reason, sounding leads attached to long lines marked off at fixed intervals were fashioned with a hollow depression on the underside that could be smeared with tallow or wax; when the lead landed on the bottom, a sample stuck to the tallow. By gauging the depth and composition of the seabed—white sand in one place, crushed shells in another—one could approximate one’s location even when well out of sight of land.

Regional differences in
geography dictated distinctive approaches to navigation. The rivers that facilitate commerce between inner Europe and the
English Channel or
North Sea deposit tons of silt into shallow waters where powerful tides constantly reconfigure the seabed, so soundings and a knowledge of tides and tidal currents are crucial for sailing northern
European waters. The Mediterranean is generally too deep for taking soundings when out of sight of land; the major river
deltas are few, the most important being the Rhône near
Marseille, the Po south of Venice, and the Nile; and there is almost no tide to roil the shallows twice a day. The distinct concerns of Mediterranean and northern European sailors are reflected in the written instructions developed for the two regions. Whereas the mid-thirteenth-century
Lo Compasso da Navigare
gives directions by compass bearings and distances within the Mediterranean,
northern European instructions give compass directions and information on tides and soundings. Even the earliest written English sailing instructions, which date to the 1460s but may incorporate fourteenth-century material, do not bother with distances:

The spread of literacy and quantitative approaches to navigation made the dissemination of rutters—a guide to sea routes—and
portolani
increasingly common in the Renaissance. Yet some of the finer points of navigation are so changeable and require such an intimate familiarity with specific waterways that recording them is little more than a temporary expedient. This is still true, hence the periodic release of “notices to mariners” giving changes to published charts.

Medieval
laws governing pilots included severe penalties for negligence or fraudulent claims of ability.
Il Consolato del Mar
(the customs of the sea), a codification of some five centuries’ worth of maritime laws and customs published at Barcelona in the mid-fifteenth century, specifies that

Likewise, the fifteenth-century English
Black Book of the Admiralty
stipulates that “
if a ship is lost by default of the lodeman [leader, or pilot] the mariners may, if they please … cut off his head without the mariners being bound to answer before any judge because the lodeman has committed high treason against his undertaking of the pilotage.”

In addition to having a good feel for the features above and below water and the forces acting upon them, sailors had to know how to determine a ship’s direction and speed, and how to estimate leeway, a vessel’s sideways drift due to the wind or current. Drawing on this information enabled one to estimate one’s position by
dead reckoning. An observant mariner did not require sophisticated equipment to do this well. For instance, speed could be calculated by throwing a floating chip overboard and counting the seconds it
took to pass between two points on the ship’s hull. So the data that could be compiled in a portolan or rutter was useful but no substitute for experienced observation, especially when venturing into unknown waters of which no one had any prior knowledge.

One reason navigational guides became more common in this period is that the growing number of ports that mariners might visit made it harder to retain all the information one might need, especially after the compass came into use. The earliest written evidence that Europeans had discovered a navigational application of a magnetized needle comes from a work of about 1180 by the English polymath
Alexander Neckham:

There is no evidence of a Chinese origin for the western compass, but this echoes
Zhu Yu’s description of the south-pointing needle earlier in the century. At first, the “needle and stone” (lodestone, or magnetite) were used to locate
Polaris when a visual sighting was impossible.
^a
According to
Vincent of Beauvais, writing about 1250, “
When clouds prevent sailors from seeing Sun or star, they take a needle and press its point through a straw and place it in a basin of water. The stone is then moved round and round the basin, until the needle, which is following it, is whirling swiftly. At this point the stone is suddenly snatched away, and the needle turns its point to the Stella Maris.”

The notion that the needle was attracted to the North Star was soon abandoned, although the magnetic pole was not understood for centuries. Even so, the traditional star shape of the compass rose reflects this original belief that the compass had a celestial orientation. At the same time, sailors’ tradition of sailing “by the wind” is reflected in the division of the mariner’s compass into points. Although astronomers divided the circle into 360 degrees in antiquity, Mediterranean sailors thought of direction in terms of the eight winds: north, northeast, east, southeast, and so on. With the development of the compass,
these “winds” were further divided into eight “
half winds” (north-northeast, east-northeast, east-southeast…) and sixteen “quarter winds” (north-by-east, northeast-by-north, northeast-by-east, east-by-north, and so on), for a total of thirty-two points of 11.25 degrees.

The adoption of the compass for navigation contributed to the development of the medieval
portolan, or sea chart, by Mediterranean navigators. The Italian
portolano
originally referred to a collection of written sailing instructions, the oldest surviving of which is
Lo Compasso da Navigare
. In time these were accompanied by maps that showed with remarkable felicity the outline of the Mediterranean coast. This attempt at geographic realism was a sharp departure from the highly stylized—and useless for navigation—medieval T-O maps, the intent of which was to represent an ordered world with
Jerusalem at the intersection of the T, the arms of which represent the Danube, the Nile, and the Mediterranean. Between the arms lay Europe, Asia, and Africa, and the whole was encircled by
Oceanus, the O. In addition to their realism, portolans are characterized by the liberal incorporation of wind roses each with radiating rhumb lines extending to the edges of the map to create a bewildering tangle of intersecting lines. These were colored according to widely adopted convention: black or brown for the winds, green for the half winds, and red for the quarter winds. Ports were identified by name—always written on the landward side perpendicular to the coast—and occasionally by flags or other insignia. On
Angelino Dulcert’s map of 1339, for instance, Lanzarotto Malocello’s association with
Lanzarote is indicated by the cross of Saint George, tutelary saint of his native Genoa.

Compasses provide a sense of direction, but not of place. Being able to fix one’s position relative to one’s home port or destination, if the latter was known, was essential. The easiest way to do this was by reference to a stationary object on land, but absent landmarks on the horizon, one must look skyward. The relative constancy with which the moon, stars, and planets make their rounds over the course of the year makes it fairly easy to determine latitude—one’s position north or south of the
equator—by measuring the angle between the horizon and either the sun or, in the northern hemisphere, the
North Star. The oldest instrument for measuring altitude was the
astrolabe, the origins of which can be traced to classical antiquity. The astronomer’s astrolabe was too cumbersome and complex to be useful at sea (Chaucer’s unfinished
Treatise on the Astrolabe,
the oldest technical manual in English, runs to fifteen thousand words), but the Portuguese had a
mariner’s astrolabe by 1481. Use of this simpler instrument was widespread and it is mentioned in the accounts of voyages by
Bartolomeu Dias,
Vasco da Gama, and
Pedro Álvares Cabral. Developed somewhat before the mariners’ astrolabe was the mariner’s quadrant,
which appears in the written record around 1460. Other devices added to the navigator’s repertoire included the cross-staff (end of the fifteenth century),
Davis’s backstaff (end of the sixteenth century), octant (1730), and, ultimately, the sextant (1759), which remained the standard tool for navigators until the development of electronic navigation. A practical method of determining longitude—one’s position east or west of a given meridian—at sea would have to await the invention of an accurate timepiece in the eighteenth century.

Improvements in navigational practice were accompanied by advances in shipbuilding. The
medieval period had seen the maturing of two distinct traditions, the shell-first
cogs of the Atlantic coast and the Baltic and the frame-first round
ships of the Mediterranean, which could reach impressive size.
A Genoese contract of 1268 called for the construction of ships measuring thirty-seven by nine meters. The major drawback to sailing such large ships, however, was their unwieldy lateen rig. Although lateen-rigged vessels can sail closer to the wind than square-riggers, which work best with a following wind, they are more difficult to handle. It is impossible to shorten sail in a lateener by furling it on a yard or boom. Instead, the yards must be lowered, the larger sails removed, and smaller ones bent on. Even tacking is a laborious process that requires lowering the yard—which could be fifty meters long—from the mast, swinging the yard and sail to the vertical, and repositioning them on the leeward side of the mast, evolutions that required large crews.

Soon after Mediterranean shipwrights began building cogs modeled after northern
European prototypes they began experimenting with new sail configurations that incorporated both the fore-and-aft lateen of the Mediterranean and the square sail of the north, a change that yielded ships with three and four masts, square sails set forward and
lateen sails aft. Columbus’s
Santa María
set five sails: a single square sail on the foremast, a square mainsail and topsail on the main, a lateen sail on the mizzen, and a square sail set below the bowsprit called a spritsail. As time went on, Mediterranean sailors knew these vessels simply as
“ships”—
naves
in Italian,
não
in Portuguese, and
nao
in Spanish—while the English used the word “carrack.”