Fishfinders

Fishfinders - fishing sonars for every situation from fishing tackle shop Riboco. Fishing sonar - fishing from a boat sonar, for ice fishing sonar, fishing from shore, portable sonar. Catch more and catch trophy fish. Now you can see underwater! Sonar (abbreviated from English SOund NAvigation and Ranging) is a technique and a tool that uses the laws of sound propagation to find objects underwater. There are two kinds of sonar - active (sending sounds and recording his echo that is needed transmitter, transmitter and receiver) and passive (listening to the noise, which need only receiver). 

history
In its original form primitive sonar was invented during the First World War. By 1948 in England called asdik (ASDIC, from Allied Submarine Detection Investigation Committee). Although underwent many modifications and refinements, the principle of action remains the same today.
use
Military sonar AN/AQS-13, suspended from a helicopter SH-3 Sea King
* In naval battles to find submarines and mines or Droopy objects on the bottom
* In fishing to find the fish
* Navigation and cartography for ustanovavane of water depth or relief of the seabed