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• There must be no other vessels in the vicinity.
• As much machinery as possible must be turned off. It is particularly important to
turn off electrical motors, as well as cooling systems and hydraulic pumps that may
cause electric noise.
• To prevent interference, all other hydroacoustic instruments must be turned off.
If you do this tests in a busy harbour, or with noise sources present, the sensitive
receivers will detect all the noise in the nearby waters.
Context
To measure the noise, observe the noise values provided on the
dialog box. Since the noise will vary with each ping, you must make five
Diagnostics
measurements for each vessel speed, and then calculate the average noise.
Tip
If you record all the raw data during the noise test, you can repeat the test later using
the replay file.
You may wish to make the noise/speed curve under realistic conditions. This means that
all relevant vessels systems are in normal use. If you experience very high noise levels,
you may wish to repeat the test with "silent ship" settings. To isolate noise sources, turn
individual vessel systems off, and check for any changes in the noise level.
Note
A hull unit may be provided as an option. It allows you to lower and hoist the transducer.
When the transducer is fully lowered, the speed of the vessel must not exceed the
maximum speed permitted for the hull unit. This maximum speed depends on the physical
size of the transducer, the mechanical construction of the hull unit, and how far down the
transducer has been lowered. The
that triggers an alarm if the maximum speed is exceeded. The
is located in the
Installation
381294/E
System Protection
dialog box.
Maintenance procedures
page in the
Noise
page allows you to define a limit
System Protection
page
261
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