Techniques are disclosed for systems and methods to provide accurate and compact three dimensional (3D) capable multichannel sonar systems for mobile structures. A 3D capable multichannel sonar system includes a multichannel transducer and associated processing and control electronics and optionally orientation and/or position sensors disposed substantially within the housing of a sonar transducer assembly. The multichannel transducer includes multiple transmission and/or receive channels/transducer elements. The transducer assembly is configured to support and protect the multichannel transducer and associated electronics and sensors, to physically and/or adjustably couple to a mobile structure, and/or to provide a simplified interface to other systems coupled to the mobile structure. Resulting sonar data and/or imagery may be displayed to a user and/or used to adjust a steering actuator, a propulsion system thrust, and/or other operational systems of the mobile structure.