sonic depth finder
depth recorder

She joined in fleet maneuvers, cruises from Alaska to the Caribbean, development and tests of sonic depth finders, antiaircraft gunnery, aircraft rescue and plane guard rehearsals.

This technique has been superseded by sonic depth finders for measuring mechanically the depth of water beneath a ship, one version of which is the Fathometer (trademark).

On her voyage to the United States West Coast, she made history by becoming the first Coast and Geodetic Survey vessel to use a sonic depth finder to measure and record the depth of the sea at points along her course.