A SOUND-PROBE FOR REAL-TIME CHECKING OF PHYSICAL BOTTOM CHARACTERISTICS

A new, handy sound-probe for simple, real-time checking of physical bo ttom characteristics in; shallow waters is described. The device consi sts of an underwater sensor and an amplifier unit, connected by a stro ng cable. Observations are made by lowering the sensor, and listening to the sound generated when it touches the bottom, either by gentle lo wering, free-fall dropping or slow dragging. Barren rock and coarse el astic deposits, finer pebbles and sand, and mud, are three easily reco gnized bottom types. Mixed deposits can also be identified. We have us ed the instrument for several years as a means to map bottom character istics in coastal marine areas, with satisfactory: results.