Aerated water can affect a Doppler log. Which one of the options is the most likely to produce aerated water?
Passage through a shoal of fish.
Varying density layers caused by water temperature differences.
The wake caused by the other ships propellers.
The Doppler log loses “Bottom track”.
Select the option, which correctly completes the following statement: “If undisturbed reverberation measurement in shallow water is not possible, the system automatically switches to…”:
Water track.
Heading mode.
Docking mode.
Bottom track.
Select from the options given six factors, that are likely to affect a Doppler log system:
Density differences in water.
Loss of signal or weak signal.
Aerated water.
Loss of bottom track.
Loss of water track.
Orientation of the transducer.
回答
Which mode is the most suitable to use if the primary function of the connected ARPA is traffic surveillance?
Bottom track.
Water track.
Track mode.
Which one of the following statement depends on the “Janus configuration”?
Small errors due to sound velocity.
Small errors due to salinity and density.
Small errors due to trim, roll and pitch.
High sound energy.
Which one of the modes given in the options should be used when the Doppler log is connected to an ARPA-radar, which is primarily used for traffic surveillance (according to IMO-rules)?
Bottom track.
Sailing mode.
Water track.
Docking mode.
Which one of the modes given in the options should be used, when the Doppler log is connected to an autopilot with track keeping functions?
Bottom track.
Sailing mode.
Water track.
Docking mode.
Which one of the options identifies when the Doppler log would normally be switched off?
The Doppler log should never be switched off.
At sea, during daylight hours.
During dry-docking.
When loading cargo.
Which one of the options is the most likely reason, that a Doppler log’s operation might be disturbed during docking operations?
Due to aerated water from the backwash from own propeller.
Due to interference from the GPS-speed.
Due to the orientation of the transducer.
Due to weak signal (normal in harbour areas).
Which one of the options is the type of measurement used by the Doppler log?
Frequency measurement.
Time measurement.
Hyperbola measurement.
NMEA-0183 measurement.
Этот тест предназначен для оценки знаний и навыков, связанных с использованием доплеровского лага для измерения скорости судна, что важно для точного управления судном и планирования маршрута.
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