Description

Last used in search for the Medusa. The two large posters are sonar recordings of Boston Harbor made with the pinger. The small poster is a sonar recording of the Vinyard Light Ship which went down near Buzzards Bay Light. The unique feature of the pinger is its ability to penetrate mud and other sediments.

Sonar works by bouncing a sound signal off something, measuring the time that it takes the signal to return, and then calculating the distance to the object. The Pinger Probe evolved from the pinger used to position deep-sea cameras in relation to the ocean floor. Doc adapted the probe for shallow water bottom penetration to depict submerged objects and layers of soft bottom sediments.

The complete Pinger Probe included this submersible transducer, which emitted an acoustic pulse as it was towed through the water; the high resolution recorder, that traced a continuous profile of the sediment layers; a marking amplifier for the record; and a transdriver, consisting of a power supply, storage capacitors, and triggering circuitry, that received the return signals.

For more information, see Reprint "Sediment Penetration with a Short-Pulse Sonar" in Journal of Gedology and Petrology, Dec. 1964.