Sound Navigation Ranging. Electronic equipment which provides the means to search and detect submerged obstructions such as reefs or sunken ships that endanger sea routes. The basic sonar system consists of a display console, a transmitting/receiving unit, transducer unit, control unit, and power supply. A sonar transducer emits ultrasonic pulses horizontally around the ship. Echoes of targets are received and the picture is displayed on the screen.