ANSWER:
Bathtmetric chart is an immersed equivalent of above water topographic map. It uses the lines and symbols to represent the land shapes and also gives information about its elevation. 
Step-by-step explanation:
- The greatest use of the bathymetric chart is done by the submarine navigation. 
- It helps to find out the locations and aids in the ocean signals. In the marine journey it provides all the information about the underwater topography. 
- Basically bathtmetry is nowadays used for the underwater communication.