Echo Sounder Control switch, Error, Maintenance of echo Sounder
On / off switch:
Range switch: 0-100 M
Gain switch: to get clear echoes
Draft setting switch: ship draft
Brilliance or dimmer switch
Paper speed control switch
Transducer changeover switch: if two or more transducer
Fix mark: to get depth at certain time
Error of echo Sounder
Velocity of propagation: velocity change with temperature and salinity. So depth changes. Consult table of velocity in NP-157
Stylus speed error: voltage fluctuation affect stylus Motor. So, incorrect depth. Monitor voltage.
Pythagoras error: when two transducer is used, one for transmitter and another for reception. So use only one transducer.
Multiple echo: strong echoes bounce back and forth between Ship’s hull and sea bed, results in multiple echo.
Density error: density change with temperature and salinity. So depth changes.
Cross noise: high amplification make this error. Gain control can remove this.
Aeration: echoes reflected back from air bubbles. During astern propulsion, pitching, course alternation.
Zero line adjustment error:
For large fish
For tidal stream
For Air bubbles
For Cross noise
Maintenance of echo Sounder
Check stylus Motor
Check transducer at dry dock
Don’t paint transducer
Lubricate Moving parts
Spare paper roll
SOLAS CH V / Regulation 19
Ships 300 gt and above and passenger ships of all size shall be fitted.