Simrad SC90, Installation Manual

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419050/B
Important considerations related to noise
The operational performance of all hydroacoustic systems depend on the noise
conditions. It is essential that the noise signature is as low as possible. Careful planning
of the SC90 installation may reduce the acoustic noise.
The installation trunk must be mounted so that it remains vertical during normal
operating conditions. The fairing around the installation trunk must be streamlined. The
transducer must be protruding far enough down to reach out of the boundary layer.
The primary sources of underwater disturbance (other than a vessel’s main propeller and
bow/stern thruster) that affect SC90 reception performance are:
1 Main or bilge keels
2 Zinc anodes
3 Cooling elements protruding from the hull
4 Equipment such as sonar transducers, echo sounder transducers and pilot tubes
5 Sea chests
6 Overboard discharges
7 Dents in the hull
Important
All appendages to the hull, indentations and pipe in/outlets are potential sources of
underwater noise. They may act as resonant cavities amplifying noise at certain
frequencies, create cavitation or turbulence. Transducers should not be located in the
vicinity of such objects and especially not immediately aft of them.
Simrad SC90 Installation Manual