In addition to the traditional methods of navigation a number of sophisticated electronic devices have been developed to help the navigator. These include the echo sounder, radar and various types ofradio navigation equipment.
The echo sounder sends a radio signal from the bottom of the ship to the sea-bed, from which it is reflected. The time taken to recive the reflected signal is a measureof the depth of water under the ship. The time taken to recive the reflected signal is a measure of the depth of water under the ship. The receive pulse is displayed on a chart by a pen recorder sothat the navigaton can see the outline of the bottom over which the vessel is passing. A similar device is the sonar system, which uses high frequency sound signals. In sonar the sound signal can be sentahead or sideways. The time for the echo to be sent back from an object, such as an underwater rock, is a measure of the onject's distance from the ship. The sonar system can also be used to measurethe speed of the ship over the seabed.
It is now common for ships, including traqlers, tugs and ferries, to be fitted with radar to help them navigatenear land. High-frecuency radio beams are sentout and recived by a rotating radar scanner on the ship. These signals are then converted into images on a screen. The ship is shown in the centre of the screen and nearby ships are shown in reltion toit. On the screen moving objects leave a short trail to indicate their direction and speed. But radar is only an aid to navigation. It is the correct interpretation of the picture on the screen whichensures the safe passage of the ship.
Además de los métodos tradicionales de la navegación varios dispositivos electrónicos sofisticados han sido desarrollados para ayudar al navegante. Éstosincluyen la sonda acústica, radar y diversos tipos del equipo de navegación de radio.
La sonda acústica envía una señal de radio del fondo del barco al fondo del mar, del cual es reflejado. El tiempo...
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