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NORTEK
8 Installation
8.1 Instrument orientation
When mounting the Signature sensor to the vessel it is important to note the orientation. As shown in the
figure, the ‘X’ is not pointing straight forward, but 45 degrees off the centre line. If mounted like this, the
heading offset as used by the software should be set to 45 degrees (See section 6 (Offsets) for details on
how enter the orientation)
Figure 31 Signature orientation relative to the vessel
8.2 Mounting Considerations
8.2.1 Bubbles
Try to avoid mounting the Signature sensor in areas where bubbles from the propeller or thrusters will pass
over the Signature sensor head. The system can tolerate some bubbles in front of the acoustic transducers
but when the bubble-cloud gets too dense, the acoustic energy will be blocked and the profiling range will be
greatly reduced. Also, bubbles on the sensor head will change the speed of sound and potentially lead to
erroneous results in the velocity measurements.
In order to avoid interference from bubbles, the best solution is to find an area under the hull where there
are fewer bubbles. It this is difficult, it can be a good idea to mount a V-shaped structure in front of the
Signature sensor that will deflect the bubbles. Another possibility, often used with commercial echo
sounders, is to mount the Signature sensor on a piston rod that can be moved as much as 0.5-1m below the
hull so the sensor head is located below the bubble layer.
8.2.2 Grounding
Fore
Aft
Bottom View
