Installation manual

Trawl hydrophone installation
91
851-165187 / Rev.A
Coverage area, orientation and tilt
Once the fore-and-aft placement of the hydrophone is decided, it
is equally important to carefully consider its horizontal and
vertical orientation. Hydrophone orientation can have a large
influence on system performance.
Hydrophones must be configured so that they overlap one an
other i n the horizontal plane. Tilt is decided by the actual depth
of the gear. If fishing operations are to be conducted in both
deep and shallow water the hydrophones can be tilted
differently.
Horizontal coverage area
The hydrophone’s beam sensitivity is concentrated within a 50
degrees horizontal and -30 degrees vertical sector. By off-setting
hyprophones by 20 degrees each from the vessel’s centre line an
overlapping coverage area of 20 degrees is provided with a total
coverage area of 90 degrees.
Horizontal coverage area
(A) = Starboard hydrophone
(B) = Port hydrophone
This “rule-of-thumb” is for normal trawling operations. For
pair-trawling or when fishing with Danish seines, the horizontal
position of the hydrophones should be configured with regard to
the operation i n question.