Abstract: An improved acoustic baffle for use with underwater hydrophone or acoustic transducer equipment on submarines and the like for attenuating acoustic energy of a noise character emanating from the submarine carrying the hydrophone equipment thereby rendering the hydrophone immune to undesired ambient noise conditions, incorporates a laminated assembly of compliant or spring like elements. One embodiment is characterized by a ribbed member for effecting a spacing of a plurality of rubber tubing type sound absorbing elements. An alternative embodiment incorporates a plurality of metallic springs for controlled compliancy of the baffle. The assembled elements are attached to a steel plate and before being placed in operation, a hydrophone or acoustic transducer is mounted on the opposite side of the steel plate.

Abstract: A deep water explosive echo ranging system capable of detecting high perfance submarines by using favorable acoustic paths available at deep depths. An umbrella hydrophone array is deployed from a sonobuoy to deep depths; an electrical subsystem transmits data from the hydrophone array to a transmitter housed in a surface float unit; a multichannel receiver and signal processing and display apparatus in an aircraft receives and processes radio data signals sent from sonobuoy transmitters; and an explosive underwater charge package is remotely triggered by a command generator in the aircraft.