Simrad ES333-7CD - REV A, Руководство по установке, Страница: 10 / 32

Simrad ES333-7CD
the sound energy, and may in worst cases block the sound
transmission totally. Therefore, design the towed body so that it
can operate in deep water.
Caution
Observe the maximum operational depth of the
transducer. Do not exceed this limitation.
Do not allow the towed body to hit the sea bed. This
may inflict permanent damage to the transducer(s).
Noise from protruding objects on the body
Objects protruding from the towed body, such as zinc anodes,
sonar transducers or even a rudder or a keel, may generate
turbulence and flow noise. Holes and pipe outlets are also
possible noise sources, as these may act as resonant cavities
amplifying the flow noise at certain frequencies. Do not place
an echo sounder transducer in the vicinity of such objects, and
especially not close behind them. For the same reason, it is
very important that the body area adjacent to the transducer
face is as smooth and level as possible. Even traces of sealing
compound, sharp edges, protruding bolts or bolt holes without
filling compound will create noise.
Inclination of the transducer face
Ideally, the transducer face should be mounted in parallel with
the sea surface when the towed body is in normal trim, as this
will provide the most accurate echo information. However, it is
also very important that the water flow over the transducer face
is laminar. In order to ensure laminar flow, the transducer face
may be tilted slightly upwards in relation to the water flow. This
allows the flowing water to meet the face directly, and assures
laminar flow. The inclination angle must however be determined
carefully. The angle must be small on transducers with narrow
beam angles. As a rule of thumb, mount transducers with beam
angles smaller than seven degrees with minimum inclination
angle. The smaller beam angle your transducer has, the smaller
the inclination angle can be. Make sure that you do not mount
the transducer with a negative inclination angle. This may cause
turbulence under the transducer face, and reduced echo sounder
performance.
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