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Marinenavigation is the art and science of steering aship from a starting point (sailing) to a destination, efficiently and responsibly. It is anart because of theskill that the navigator must have to avoid the dangers of navigation, and it is ascience because it is based onphysical,mathematical,oceanographic,cartographic,astronomical, and other knowledge.
Marine navigation can be surface orsubmarine.
Navigation (from theLatin wordnavigatio) is the act of sailing or voyaging. Nautical (from Latinnautĭca, and this fromGreek ναυτική [τέχνη]nautikḗ [téjne] "[art of] sailing" and from ναύτηςnautes "sailor") is that pertaining to navigation and the science and art of sailing. Naval (from the Latin adjectivenavalis) is that relating to ships and navigation, or particularly to thenavy.[1]
InAncient Rome, thenavicularii conducted long-distance trade by sea.
Coastal navigation was practiced since the most ancient times.[2] The biblical account ofthe great flood, where theNoah's Ark appears, is based both on myths and on the navigational practice of theMesopotamian civilizations, who from theSumerians onwards navigated their two rivers (Tigris andEuphrates) and thePersian Gulf. Theancient Egyptians did not limit themselves toinland navigation of theNile either, and used theMediterranean sea routes existing since theNeolithic — through which cultural phenomena such asmegalithism or themetallurgy would havespread for millennia. TheCretans even established a truethalassocracy (government of the seas, attributed to KingMinos) until theMycenaean period (2nd millennium BC), when the events mythologized in theHomeric poems[Note 1] ought to be placed.
TheHittites, led by KingŠuppiluliuma II faced theCyprus in the first historically recordednaval battle (ca. 1210 BC); at the same time, all the civilizations of theEastern Mediterranean suffered from the incursions of the denominated "Sea Peoples".
ThePhoenicians — whom theGreeks considered their masters in navigation and who are also cited in the Bible —[Note 2][3] would have been the first Mediterranean civilization to sailthe high seas bysculling andsailing, guided by the sun during the day and by theNorth Star at night. It is recorded that, crossing theStrait of Gibraltar — the "Rock of Gibraltar", the so-called "Pillars of Hercules" in the Greek myths — they sailed across theAtlantic Ocean reaching the south to some point on the west coast of Africa and the north to theBritish Isles (or even beyond, to the place that the texts callThule), but it is unclear if they circumnavigated Africa or crossed the Atlantic reaching America, something most likely achieved bythe Norsemen in the 10th century.
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In theIndian andPacific oceans, the oceanic navigations made it possible to populate all the archipelagoes (Polynesian navigation). However, the possibility ofreaching South America is still a matter of debate — thesettlement of the Americas through theBering Strait would not have required navigation, or in any case, coastal navigation would have sufficed — as well as other possiblepre-Columbian transoceanic contacts. In the first quarter of the 15th century, the Chinese expeditions led byZheng He reached the African coasts of the Indian Ocean. It has beenproposed that they might have reached the South Atlantic and even America and Europe, but this proposal has not been accepted beyond mere speculation.
Mediterranean navigation, which the Romans had come to control (undisputedMare Nostrum since their victories over the Carthaginians in thePunic Wars [264-146 BC], the Egyptians during theBattle of Actium [31 BC], andpirates), was once again a contested environment in theMiddle Ages, from the moment theVandals managed to attack the Italian coasts from the sea. In the 6th century, theByzantines managed to regain control, and in the 7th century it was theArabs who ended up dividing theMediterranean area,[5] which even theVikings andNormans were able to access. Since the time of theCrusades,Venetian,[6]Genoese[7] andCrown of Aragon[8] navigators also had a strong presence. Knowledge of thecompass, transmitted to the Europeans by the Arabs (who in turn had obtained it from the Chinese), together with other improvements in astronomical techniques (astrolabe,Jacob's staff,sextant, cartographic techniques (portulan and shipbuilding (caravel,nau,galleon), made theAge of Discovery — initially led by thePortuguese andCastilians — possible, especially afterHenry the Navigator impulsed theschool of Sagres. In 1492, thefirst voyage of Christopher Columbus took place. In 1488,Bartolomeu Dias rounded theCape of Good Hope, whichopened the route to the Indian Ocean —Vasco de Gama reached Calicut (India) in 1498. Between 1519 and 1521, theMagellan-Elcano expedition circumnavigated the world — measuring thegeographical longitude with the method of its scientific organizer,Rui Faleiro. Until the 6th century, the Spanish-Portuguese hegemony in navigation was patent in fields such as geography andcosmography. Both English and French pilots learned to navigate from the texts ofPedro de Medina,Martín Fernández de Enciso andMartín Cortés, among others.[9][10] The conjunction of "cannons and sails" has been argued to have given European states the advantage to prevail over the rest,[11] launching the modern "world system".[12]
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Since the 18th century, England exercised maritime hegemony, a fact that was confirmed in the early 19th century with theBattle of Trafalgar (1805). Among the main English expeditions of the time wereCaptain Cook's (1768-1779), also the second expedition of theBeagle (1831-1836) — which was of great importance for the later development ofCharles Darwin'stheory of evolution. Already fully in the age ofsteam navigation, techniques and vessels continued to be perfected in transoceanic sailing (clipper), that did not become obsolete for commercial navigation until the 20th century — especially after the opening of thePanama Canal. Even then, the unbridled optimism that characterized the naval design of the time suffered a severe blow with the sinking of theTitanic (1912).
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![Sinking of an enemy ship by a German "U-boat" in 1917. In addition to submarine warfare, submersible vessels have had all sorts of uses, including mail,[14] the oceanography or polar exploration.[15]](/mt/?noimg=&dark=on&url=http%3a%2f%2fen.wikipedia.org%2fwiki%2fFile%3aSt%25C3%25B6wer_U-Boot_Truppentransporter.jpg)
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Contemporary shipping has massively ceased to perform one of its traditional functions and has been replaced by aviation, such aspassenger transport, although with two important exceptions: leisure travel (tourism bycruise ships) and irregular traffic of people (irregular immigration). Since theSecond Industrial Revolution, the main volume offreight transport has been hydrocarbons (oil tankers andgas tankers). Other raw materials are also transported inbulk oncargo ships, but from 1956 onward, a large part of goods of all kinds were adapted to standardizedcontainers that speed up loading and unloading, allowing a combination with land transport (hub). Highly technological navigation has reduced crews and increased the size of ships. For example, indeep-sea fishing, which locates its prey with sophisticated means and lasts indefinitely in time — freezer ships orfactory ships — which in some circumstances has made them vulnerable to new forms of piracy.
These are the methods used in maritime navigation to solve the three problems of the navigator:
Navigation and location of the ship by positioning techniques based on the observation ofbearings and distances to notable points on the coast (lighthouses,capes,buoys, etc.) by visual means (pelorus), observation of horizontal angles (sextant) or electronic methods (bearings fromradar toracons,transponders, etc.)
Navigation and location of the ship by analytical means, after considering the following elements: initial location,bearing(s) — whetherabsolute bearings, surface bearings, orrelative bearings. Alsovelocity as well as the external factors that have influenced the course either partially or entirely, such as thewind (leeway) and/or thecurrent (bearing of the current and hourly current intensity). The point obtained from the calculations is called the "Dead reckoning location", with its correspondinglatitude andlongitude. This point is also known as Fantasy point.
Navigation that follows arhumb line — that is, all meridians are cut at the same angle. On anautical chart following theMercator projection, a loxodromic is represented by a straight line.
This type of navigation is useful for not too long distances, as it allows the course to remain steady,[16] but it does not offer the shortest distance.
Navigation that follows the shortest distance between two points, i.e., that which follows agreat circle. Such routes yield the shortestdistance between two points on the globe.[16] To calculate the bearing and distance between two points it is necessary to solve aspherical triangle whose vertices are the origin, the destination, and the pole.[17]
Navigation and location of the ship bygeopositioning techniques based on the observation of thestars and othercelestial bodies. The variables measured to find the location are: the observed angular height of the stars above thehorizon, measured with thesextant (formerly with theastrolabe or other instrument), and thetime, measured with thechronometer.
Conceptually, the process is not complex to understand:
In practice, the mathematical process, called "reduction" of the observation, can be complex for the uninitiated. To the height observed with the sextant, it is necessary to apply a series of corrections to compensate for atmospheric refraction,parallax and other errors. Once this is done, it is necessary to solve aspherical triangle by mathematical and trigonometric methods.
There are many methods to do this. The manual methods use tables (trigonometric,logarithms, etc.) to facilitate the calculations. The introduction ofcalculators andelectronic computers at the end of the 20th century greatly facilitated the calculation, but the creation ofGPS made celestial navigation no longer important, relegating it to the background as an alternative method in case of failure of the on-board electronics or as a hobby of scientific interest.
Navigation and location of the ship by positioning techniques based on the aids provided by global positioning systems, such asGPS,GLONASS, orGALILEO. It is the system most widely spread and easiest to use, in spite of the errors that may arise.
Navigation and location of the ship by means of the analysis of the data provided byaccelerometers and/orgyroscopes located on board, which integrate the accelerations experienced in complex electronic systems, that converted into velocities (in the 3 possible axes of displacement) and according to the observed courses, make it possible to obtain the location of the ship.
The harbinger of a successful navigation was thedolphin, which is why its representation became the symbol carried by all ships.
More recently, navigation was represented as a woman crowned withship's sterns whose clothes are agitated by the winds. She rests one hand on a rudder and the other holds the instrument for measuring height. At her feet, theampoule, the compass, thetrident of Neptune and the riches of commerce, while the sea can be seen on the horizon, completed by a lighthouse and traversed by ships at full sail.[10]
