sentences:  While off Oregon that year, she successfully employed the technique at a distance of 206 nautical miles (382 km) between the ranging explosion and the remote hydrophones detecting its sound and in the process achieved the first observed indication of the ocean sound layer that was later called the sound fixing and ranging (SOFAR) channel or deep sound channel (DSC).Based at San Diego and conducting hydrographic surveys off the U.S. West Coast, "Guide" performed Coast and Geodetic Survey duties for over 17 years.In company with "Pioneer", she conducted many early bathymetric surveys on the U.S. West Coast.