How does a vessel's echo sounder assist in electronic navigation?

A vessel's echo sounder plays a crucial role in electronic navigation by measuring water depth, which is essential for detecting underwater hazards. This device operates by sending sound waves from the vessel's transducer down to the seabed. When these waves hit the bottom or any submerged object, they bounce back to the transducer. The echo sounder then calculates the depth of the water based on the time it took for the sound waves to return.

Knowing the water depth is vital for safe navigation, as it helps mariners avoid grounding on shallow areas or submerged dangers such as rocks or shipwrecks. Accurate depth measurements ensure that vessels can navigate safely in various conditions, especially in areas where charts may be outdated or unreliable.

Other choices, while relevant to navigation, do not pertain specifically to the functionality of an echo sounder. For instance, providing real-time video feeds is not a function of echo sounding technology. Plotting charts electronically is a task associated with Electronic Chart Display and Information Systems (ECDIS) rather than echo sounders. Similarly, recording the speed of the current involves different instruments like current meters, which measure water movement rather than depth. Thus, option B accurately captures the primary function of an echo sounder in the context of electronic navigation