Abstract: An acoustic sensor and projector module for sonar applications includes a first acoustic transducer element operating as a projector to generate an acoustic beam, and a second acoustic transducer element acting as a hydrophone to sense pressure wave returns. When the second acoustic transducer element operates in a sensing mode, the first acoustic transducer element serves in conjunction with a baffle structure to baffle acoustic signals presented to the hydrophone. Similarly, when the first transducer element operates in a projecting mode to generate an acoustic beam, the second transducer element acts in combination with a baffle structure to baffle acoustic signals emitted by the projector.

Abstract: An electrical ground connection having two members, one of which may be connected to a system ground and the other of which may be for a connection to an electrical apparatus to be grounded. Each member includes a circular cavity which faces the cavity of the other member when the two are assembled together. An electrically conducting insert in the form of a multi-faceted rod is provided for insertion into the cavities, and wherein the rod has a slightly greater lateral dimension than that of the cavities, so that when the members are clamped together, the rod will be shaved, thereby exposing bare metal for better electrical contact and reduced resistance.

Abstract: An electrical ground connection having two members which are clamped together with each member having a cavity which faces the cavity of the other member when assembled. In one embodiment the cavities include a series of sharp projections and a disk of relatively soft metal such as copper is inserted into one of the cavities and when the members are brought together, the projections from both members penetrate into the disk to form a low impedance electrical connection which may be disassembled and reassembled with relative ease. An O-ring seal and a waterproof gel within the cavities may be utilized for underwater applications of the connector. In another embodiment a single projection in each cavity is used, in conjunction with a disk having a central aperture which fits over the projections, with edge portions of the projections digging into the central wall surface of the apertured disk.