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Navigation
 The
Iberian Peninsula lies between the Atlantic and the
Mediterranean Seas. Muslim rule in Al-Andalus after 711 CE
gave the peninsula links to the eastern maritime world
beyond the Mediterranean, through trade on the Red Sea, the
Persian Gulf, and the Indian Ocean with its link to
Indonesia and East Asia through the Strait of Malacca.
With
the rapid expansion of territory under Muslim rule in the
7th century, and the expansion of trade and urbanization in
the succeeding centuries, the Muslim lands acted as a hinge
between east and west, linking the waterways and
intercontinental land routes across Afroeurasia, and
bringing them to Europe’s doorstep.
Across
these routes, a wealth of knowledge concerning maritime
travel flowed.
Navigation is a term that describes
shipbuilding and sailing techniques, as well as knowledge of
plotting a course at sea, reaching the destination, and
passing on the knowledge of the routes. As in many other
 fields, Arabs and Muslims of the eighth century to the 15th
century CE had access to the pre-Islamic knowledge of many
civilizations, and accumulated knowledge and technology
during the Islamic era. Their constantly renewed contact
with mariners in the Mediterranean region and the Indian
Ocean provided the opportunity to stay abreast of new
inventions.
Knowledge and technology needed for maritime travel belonged
to several categories. The first requirement was knowledge
that there were lands to which mariners could sail. This is
not a minor matter in an age when some thought ships going
over the horizon would sail over the edge of an abyss, or
into the maw of sea monsters.
Knowing
the topography of the lands, their inhabitants (not
creatures with dog-like faces in their stomachs, for
example, but ordinary human beings), and most important for
the motivation to go there -- what natural resources and
manufactured products could be gained by sailing there.
Surveys of geography fulfilled this requirement -- detailing
the mountain ranges, coastlines, harbors, cities and towns,
and products, as well as the languages and customs of the
people.
Geographic surveys were compiled by prominent writers from
the ancients whose work was translated into Arabic, from the
pre-Islamic Arabs of Yemen, Oman and the Persian Gulf lands
whose maritime experience was already centuries old, and
then early Muslim geographers such as Yaqut, al-Mas’udi, and
others picked up the thread with their own, wider
exploration.
 Early
explorers of the Muslim lands also laid the groundwork for
determining the location of places. Navigation is about
getting from one specific location on the globe to another,
by determining where the ship is at any given time. The most
important technique for determining location is latitude and
longitude. Muslims inherited this skill of reckoning using
the stars and the sun in conjunction with fixed points on
earth from the Greeks and other ancient peoples. The Arabs
had relied on astronomical reckoning even traveling through
the trackless deserts. Basic techniques, from fingers held
up to the horizon to a simple card and string, could
determine latitude with fair accuracy, combined with other
knowledge of currents and landmarks.
 More
sophisticated instruments used to triangulate position based
on the sun, stars, and horizon were the quadrant, a quarter
circle marked with gradations and a dial, and the astrolabe.
The Greeks invented the astrolabe, and historians of science
agree that the Arabs perfected it, from the 8th
century CE on. Advances in astronomy and in mathematics made
it possible, including use of Arabic, or Hindi, numerals to
represent digits, and trigonometry, formulas dealing with
the mathematical relationships of the sides and angles of
triangles.
The
craft of instrument-making also contributed, as most
astrolabes and other instruments are made of brass inscribed
with great accuracy. Islamic Spain was the pathway by which
astrolabe technology entered Europe from the 12th
century, and it became so famous that the French scholar and
translator Abelard of Bath named his child Astrolabe! The
English writer Chaucer also wrote a treatise on the
astrolabe. The astrolabe could be used for navigation at sea
and surveying on land, determining depth or height of
distant objects.
The
magnetic compass is an invention whose origin is uncertain,
but which seems to have moved from China along the land and
sea routes toward the west. It was originally a lodestone or
magnetized metal floating in a bowl of liquid used to show
direction. The Chinese oriented it toward the south, and
Indian Ocean accounts describe a magnetized iron fish
floated in a bowl, whose head would point south to show
direction at sea. Dry-mounted compasses in which the needle
rotates on a pin over a paper or inscribed compass rose to
show direction may have originated in Europe, in Spain,
Italy, or elsewhere. Historians today must base their ideas
on written descriptions, which leave many gaps.
 Another
important aspect of finding location involved recording
places in detail using their coordinates. Mathematical
geography also used such instruments to plot locations and
so to be able to make more accurate maps. Islamic practice
required mosques to be oriented toward Makkah (qibla).
This led to a science of determining direction on land with
great accuracy. There were books written detailing the
coordinates of cities, and charts showing the orientation
toward the
qibla.
Just as Muslim scientists made it a priority to determine
accurate time for religious observances, direction was
equally important. Determining longitude at sea was much
more difficult, and awaited the use of mechanical clocks
combined with astronomical readings during the 18th
century.
 Portolan charts and pilot charts contained valuable
knowledge that allowed mariners to navigate to and from
their destinations. Pilots, or sea captains, traditionally
passed down orally the knowledge of directions needed to get
from one place to another by sea. Muslim mariners collected
and published this information in nautical manuals called
rahmani that
scholars study in detail today to identify earlier place
names visited and sea routes used to get there. Pilots had
knowledge of currents, depths of water, shoals and rocks,
and the shape of headlands from sea, very much like Mapquest®
driving directions today. This is an example from the 10th
century text of mariner Sulaiman ibn Ahmad al-Mahri (ca. 917
CE):
“The
journey from Sundib and Farandib to Shati Jam is [made in
the direction] ESE; from Shati Jam to the island of
Zanjiliya is due south and from Zanjiliya to Najirashi, SSE.
From Najirashi to Martaban is ESE. And from Martaban to
Tawahi, SSE; and from Martaban also to the island of Fali,
due south. From Fali to the island of Buttum is due south
and from Buttum to the islands of Pulau Sanbilan Malacca,
SSE… and from Malacca to Singapur, and this is the end of
Siam to the South, and there the Little Bear is 5 degrees
[above the horizon]… and from Ayam to Bab-i-Sin on the coast
at 17 ½ P.S. it is NE and from Bab-i-Sin the land turns
around to the south as they have told us.”
Another
famous navigator of a later period was Ahmad ibn Majid (b.
1432 CE), who wrote the
Book of Useful Information on the Principles and Rules of
Navigation in 1490 CE, whom some writers have
associated with personally piloting Vasco da Gama from east
Africa to India. What surely accompanied the Portuguese
mariner, however, was knowledge of the seas, directions, and
navigation that was current in the Indian Ocean, and in the
libraries of the Iberian Peninsula where interested Spanish
and Portuguese like Henry the Navigator could access it.
They had been preceded in the Indian Ocean by the Ming
admiral Zheng He, and by generations of indigenous (native)
mariners.
 Ship
design and sailing technology was another important aspect
of navigation. This included the design of the hull, the
masts and rigging (sails and their control with ropes), and
the steering devices. Among the earliest innovations to
reach the Mediterranean Sea from the Indian Ocean was the
lateen, or triangular sail. Before its introduction to
Europe, ships on the Atlantic and Mediterranean used square
sails that needed wind directly behind the ship. Lateen
sails allowed tacking, or sailing back and forth with the
wind at an angle to the ship.
Combining triangular with square sails
was one of the
innovations that characterized the Spanish and Portuguese
 explorers’ ships of the 15th century CE and
beyond. Another innovation that came from China by way of
Muslim mariners
was the stern rudder, a hinged steering
board at the stern of a ship (shown in the image at right),
which replaced an awkward oar lashed to the ship. The system
is still used on ships today. Hull design was another
innovation introduced through the Muslims’ connection with
hemispheric waterways. It may have been modeled on the Arab
“dhow,” a word of Swahili origin that lumps together many
different types of seagoing Arab and Indian ships of the
Medieval Indian Ocean.
What
came to be called “carvel-built” hulls, in which the boards
of the hull were attached side-by-side to the ribs instead
of being “clinker-built,” or overlapping like the shingles
on a roof, made ships sleeker, lighter and more
maneuverable. Early modern shipbuilding, like navigation
arts as a whole, did not spring fully formed from the minds
of any one group, but evolved over centuries and millennia
as the achievement of many peoples and many seas, just as
the waters of the world were gradually knit together by the
human desire to trade, explore, and travel over time.
Further Reading:
Gerard
Tibbetts.
A Study of the
Arabic Texts Containing Material on South-East Asia.
Leiden: E.J. Brill, 1979.
Syed
Sulaiman Nadvi.
The Arab
Navigation. Sh. Muhammad Ashraf: Lahore, 1966.
Ancient Navigation and Sailing,
at Nabataea.net (Canbooks, 2002), retrieved at
http://nabataea.net/sailing.html
Paul
Lunde. “The Indian Ocean and Global Trade,”
Saudi Aramco World,
56:4 (July/August 2005).
Citation:
Quotation of mariner’s directions from Sulaiman ibn Ahmad
al-Mahri (ca. 917 CE)
in
al-‘Umdat al Mahriyah
fi Dabt al-Ulum al-Najmiyah, MSS 2559, f. 21r, l.
13-f.
22r.,
l. 1, quoted in Tibbetts, pp. 211-212.
Images:
Hispano-Islamic Astrolabe ca.1230 CE, (the “Caird
Astrolabe”), National Maritime Museum, London, Nicolas
Landau Collection, retrieved at
http://www.nmm.ac.uk/collections/explore/object.cfm?ID=AST0570
Kamal
(string and card) navigation system, ancient Chinese spoon
compass, and Arabic compass chart at “Ancient Navigation and
Sailing,” Nabataea.net at
http://nabataea.net/sailing.html
Ship
with stern rudder, anchor in a Persian miniature of 1240 CE
at “Travelers,” Nick Bartel, Horace Mann Middle School, 3351
23rd Street, San Francisco, CA, retrieved at
http://www.sfusd.k12.ca.us/schwww/sch618/Travelers/Transportation.html
Dhow
from “History of Dhows at
http://library.thinkquest.org/C007541F/the_hashemi's_uses.htm
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