Navigation and Seamanship

3.1.8.6. Recording unit

The recording unit is normally fixed in front of the Skipper’s position in the wheel house.

Maintenance of tranducer of echosounder

- Transmitter and receiver do not require routine maintenance

- Transducer should be inspected and its surface to be cleaned whenever possible

- Transducer face must be kept free from growth of seaweed or fouler in order to function properly.

- Scratching of surface with hard sharp instrument will damage the soft parts, so use only wood pieces for cleaning the surface of transducer.

- Do not paint the transducers face

Fish detection at depths greater than 500m requires high transmission power, a narrow beam and medium or low frequency. This will be the costlier and sophisticated instrument.

Points to be remembered while operating echosounders and sonars

1. Select high operating frequency of the sounder in shallow waters and low frequency in deeper waters
2. Short pulse length would give better vertical resolution of the echoes
3. For greater depth select long pulse length and narrow band width
4. For shallow waters short pulse length and wide beam width