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A sailor and a man on shore, both sounding the depth with a line. Depth sounding, often simply called sounding, is measuring the depth of a body of water. Data taken from soundings are used in bathymetry to make maps of the floor of a body of water, such as the seabed topography. Soundings were traditionally shown on nautical charts in fathoms ...
Bathymetry (/ b ə ˈ θ ɪ m ə t r i /; from Ancient Greek βαθύς (bathús) 'deep' and μέτρον (métron) 'measure') [1] [2] is the study of underwater depth of ocean floors (seabed topography), lake floors, or river floors.
The depth was determined (rather inaccurately) by the time it took to surface. [3] Jacob Perkins (1766–1849) proposed a bathometer based on the compressibility of water. [ 4 ] In this instrument the movement of a piston compressing a body of water enclosed in its cylinder is dependent on the pressure of the water outside the cylinder, and ...
Chip log and sand glass serve to measure the ship's speed through the water.; Sounding line used to measure the depth of the water and to pick up samples from the bottom.; Drift meter optically measures the effects of wind on an aircraft in flight.
The beams update many times per second (typically 0.1–50 Hz depending on water depth), allowing faster boat speed while maintaining 100% coverage of the seafloor. Attitude sensors allow for the correction of the boat's roll and pitch on the ocean surface, and a gyrocompass provides accurate heading information to correct for vessel yaw .
A deep-sea lead, the heaviest of sounding leads, was used in water exceeding 100 fathoms in depth. [21] This technique has been superseded by sonic depth finders for measuring mechanically the depth of water beneath a ship, one version of which is the Fathometer (trademark). [22] The record made by such a device is a fathogram. [23]
Tide tables give the height of the tide above a chart datum making it feasible to calculate the depth of water at a given point and at a given time by adding the charted depth to the height of the tide. One may calculate whether an area that dries is under water by subtracting the drying height from the [given] height calculated from the tide ...
Echo sounding or depth sounding is the use of sonar for ranging, normally to determine the depth of water . It involves transmitting acoustic waves into water and recording the time interval between emission and return of a pulse; the resulting time of flight , along with knowledge of the speed of sound in water, allows determining the distance ...