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Sound Velocity Profiler
The sound velocity profiler is a self-contained, semi-autonomous device, which collects oceanographic data while the vessel is underway.   The sound velocity profiler system includes a computer controlled winch and deployment system for a variety of the free-fall sensor systems. For hydrographic surveys, this tool is used to obtain sound velocity data.

Currently, the Office of Coast Survey (OCS) owns and operates the sound velocity profiler aboard two survey vessels. The two OCS sound velocity profilers have a velocimeter that operate on the “sing-around” sound principlel*, and contain a transducer head and a reflective plate a known distance apart. The free-fall and retrieval interval are set by the operator for optimal data acquisition.   Sound velocity profilers are capable of measuring continuous sound velocity data which increase the accuracy of hydrographic soundings.

*What is the "sing-around" sound principle?
The "sing-around" sound principle refers to the use of a transducer and reflective-plate pair that is a known distance apart.  The device calculates the speed of sound in water by effectively dividing this known distance by one-half  the time required for a signal to be transmitted by the transducer, reflected by the reflective plate and received  by the transducer. 

 Sample path of a sound velocity profiler in the water column.

Sample path of a sound velocity profiler in the water column, including the deployment/freefall path,
maximum depth and recovery path.


 

This shows an artists rendition of the principal parts of a velocimeter including the transducer and a reflective plate which are a known distance apart.     This is an example of a velocimeter.

 Principal parts of a velocimeter.

 Example of a velocimeter.



This is an example of the computer controlled winch and deployment system on the deck of a ship.   This is an example of a sound velocity profiler on the deck of a ship.  
 Example of the computer controlled winch and deployment system.                 Example of a sound velocity profiler.
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