Civilline: Bathymetry survey equipments manual guide and method

Definition of bathymetry:

Paleobathymetry is the study of underwater depths in the past.The term “bathymetry” originally referred to the ocean’s depth relative to sea level, although it has come to mean “submarine topography,” or the depths and shapes of underwater terrain.

This technique measures the depth only a singular point at a time, and is therefore inefficient. It is also subject to movements of the ship and currents moving the line out of true and therefore is inaccurate.