In Doppler speed log operation, the volume reverberation mode is also known as water track.

• A. Water track
• B. Bottom track
• C. Air track
• D. Surface track

Answer: (A)

In a Doppler speed log, the measurement can be tied to different references in the water or to boundaries. Volume reverberation means the transducer picks up Doppler shifts from scatterers spread throughout the water column, not from a single surface. The system then interprets those shifts to estimate the vessel’s speed through the water. That mode is called water track because it tracks movement relative to the water itself rather than to a boundary.

This approach is especially useful when the bottom is unreliable as a reference (deep water, soft or complex seabed) since it doesn’t depend on seabed reflections. In contrast, modes that reference the seabed or surface rely on reflections from a boundary and are chosen when those surfaces provide a stable reference.