A system for measuring acoustic signature of a target object in water includes a plurality of rigid segments connected to each other to form a longitudinal member and a plurality of floats connected to the longitudinal member. Two buoys are connected at two ends of the longitudinal member and two weights are suspended from the buoys, thus making the longitudinal member neutrally buoyant when suspended in water. A plurality of hydrophones and an acoustic projector of a known source level are connected to the longitudinal member. The system further includes a data acquisition system for receiving signals from hydrophones and a signal processing means for processing signals received by data acquisition and determining acoustic signature of the target object. A depth/pressure sensor may be included. A pinger is located on the target object to measure range of target object to hydrophones. Range to target object is displayed in real time.