The first venture of man to use the aquatic element for his transportation took place when he observed that some objects could float on the water, and consequently could help him to achieve his purpose.

Thus, starting by the tree log and by joining more than one, he constructed the first raft that was gradually evolved into the oared boat, the triremes of the ancient era, the galleys of the Middle Ages and finally the contemporary vessels.

Since the first time man used the aquatic element for his transportation the need for new methods and instruments appeared, which would allow him to command his ship safely. Thereby navigation was born, the science that involves all the navigational methods that were gradually invented by the man.

At the beginning, navigation had the form of transportation near the shores, where man could command his vessels using for his guidance visible objects. Later, when he sailed far from the shores, he realized that he had to invent new methods in order to determine directions, to measure the distances, to find his position and to be able to define the actions that would lead him to reach the places he wanted.

Initially, because of the aforementioned needs, he used the celestial bodies in order to determine the course of the ships (when he could not see the shores), to estimate the covered distance in connection with the time –which the mariner could count by using clepsydras- and the velocity, which he used to estimate by counting the beats of the oars.

After visiting more places, and by describing his journeys, he produced the first sailing directions – like Stabo’s Geography- and the first maps that initially had the form of simple sketches. By using these rough means, and the empirical knowledge he had acquired, he achieved to sail at the known word of the era and, at the same time, to discover new routes – for example the voyage of Alexander the Great to India.

In the 20^th century navigation has already been evolved because of the invention of the gyrocompass, the release of the modern ephemeris and the data it presents about various celestial bodies, the maps that accurately depict the morphology of the shores and the seafloor, the pilots that describe clearly the shores, the harbours, the dangers etc and dictate instructions of voyage and, finally, because of the lighthouse catalogs that record the characteristics of the lighthouses.

However, the revolution was brought by the development of electronics, whose applications in navigation helped the mariner to sail safely in the globe. Such applications are: The emissions of hourly signals that contribute to the testing of the chronometers, the weather forecasting that predicts heavy weather in an area, the radio beacons that obtain the bearings far from the shores, the radiotelegraphy and radiotelephony for communicating with other vessels and offshore stations, the echo sounding instruments that determine the sea depth under the vessel, the radar that estimates the distances and obtains the bearings even in the denser fog, the various instruments of hyperbolic navigation that enable the mariner to determine accurately his position thousands of miles far from the emission stations, and finally the satellites that are the most modern means in position fixing.

However, the aim of the aforementioned developments was to give the mariner the more data possible in order to sail safely knowing every single moment his exact position on the globe, so as to be able to respond properly in the needs of the voyage.

Despite all these developments in the field of navigation, the nautical chart remains the most helpful aid for the mariner because it enables him: to observe both the representation of the terrestrial surface in a scale marked with the depths and the depth curves that depict the morphology of the seafloor, to be aware of the navigational perils and the exact position of the navigational aids (beacons, minor lights, radio beacons, curves of hyperbolic navigation) and thus to determine on the map his position and shape the course. Moreover, it enables him to register the information he receives.

Therefore, the nautical map is not a dead map but a live aid that can be updated continuously with new navigational information providing the required safety in navigation.

The demand for safety in navigation necessitated the foundation of various hydrographic services in national level, and the creation of large organizations through which International Regulations were decreed and new services were founded providing accommodations in national and global basis. Moreover, new methods and procedures were established aiming exclusively at the protection of human life at sea.

The most prevalent of the aforementioned international organizations are:

a. The International Hydrographic Organization (I.H.O) based in Monaco. Its main objective is the coordination of the Hydrographic Offices of the states and the establishment of International technical specifications for the construction of nautical maps and the edition of nautical publications. It was established in 1921.

b. The International Maritime Organization (I.M.O), based in London. Its main task is the protection of human life at sea. It publishes international regulations and resolutions that are decreed by the governments of the states and constitute inviolable rules that protect human life.

c. The International Association of Marine Aids to Navigation and Lighthouse Authorities (I.A.L.A), based in Parish. Its main task is the development of Lighthouse Networks and the coordination of all the National Lighthouse Services.

d. The International Telecommunication Union (I.T.U) based in Geneva. Its main task is the development of telecommunications in ships and the development of a radio aid network.

To conclude, Navigation has evolved in a great scale until today. However, it cannot be claimed that it has reached to the end of its development. The progress in navigation is going to continue until the point that man will be satisfied by the means he has acquired concerning the safety of the human life.