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CD0057. Doppler log

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About this collection

The Seagull CBT bank is organised into modules covering safety, shipboard operations, maintenance and other topics. Original module names and codes are retained to help you find the topic you need.

“Seagull CBT — CD0057. Doppler log” contains 10 questions across 1 collection.

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Sample questions and answers

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Select, from the options given, six factors that are likely to affect a Doppler log system.

Multiple correct answers

  • Density differences in water✓ Correct answer
  • Loss of signal or weak signal✓ Correct answer
  • Aerated water✓ Correct answer
  • Loss of bottom track✓ Correct answer
  • Loss of water track✓ Correct answer
  • Orientation of the transducer✓ Correct answer
  • Clock error
  • DGPS-speed error
Aerated water can affect a Doppler log. Which one of the options is the most likely to produce aerated water?

One correct answer

  • Passage through a shoal of fish
  • Varying density layers caused by water temperature differences
  • The wake caused by the other ships’ propellers✓ Correct answer
  • The Doppler log losing “Bottom track”
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)?

One correct answer

  • Bottom track
  • Water track✓ Correct answer
  • Sailing mode
  • Docking mode
Which one of the options is the type of measurement used by the Doppler log?

One correct answer

  • Frequency measurement✓ Correct answer
  • Time measurement
  • Hyperbola measurement
  • NMEA-0183 measurement
Which mode is the most suitable to use if the primary function of the connected ARPA is traffic surveillance?

One correct answer

  • Bottom track
  • Water track✓ Correct answer
  • Track mode

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