What does a Doppler log in the bottom return...

Question 1 of 2707066636ee928f7522a1c5195f1

What does a Doppler log in the bottom return mode indicate?

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Question 1 of 27070

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What does a Doppler log in the bottom return mode indicate?

🔍 Key Concepts

• Doppler log basic function – what quantity does it primarily measure on a vessel? • Difference between speed through the water and speed over the ground • What changes when the log is using bottom return (bottom track) instead of water-mass return

💭 Think About

• Ask yourself: when the Doppler log is in bottom track mode, what is it bouncing sound waves off of, and what motion is it comparing that to? • Think about which of the choices depends on time plus distance moved relative to the seabed, and which are completely different types of measurements. • Which option would be most useful for navigation and position fixing when near shore or in shallow to moderate depths?

✅ Before You Answer

• Make sure you distinguish between speed vs. depth vs. current – they’re not the same physical quantity. • Check which option describes a rate (something per unit time), since a log is a speed‑measuring instrument. • Verify that bottom return mode requires the seabed to be within effective range; consider which of the answers would logically depend on being able to “see” the bottom.