When used as a trawling sonar, the Simrad SN90 can be provided with a hull unit. The hull unit allows you to retract the transducer when the SN90 is not in use, and thus protect it against ice and objects in the sea.
The transducer is mounted with a fixed 30 degrees tilt.
(A) Hand crank for manual hoisting and lowering
The Simrad SN90 sonar can be provided with one of the following hull units:
When placed on a hull unit, the transducer housing can be fitted with two hydrophones. A hydrophone is a vital part of a catch monitoring system. The hydrophone receives the acoustic communications from the catch sensors on the gear and converts these to electrical signals.
Both hydrophones point aft. The hydrophones are connected to a catch monitoring receiver or transceiver.