A transducer assembly (36, 56, 96, 236)comprising: a housing (50, 250) mountable to a water craft capable of traversing a surface of a body of water; a linear downscan transmit/receive transducer element (66, 66', 266) defining a substantially rectangular shape with a top surface, bottom surface, and opposing side surfaces (66b,66c) positioned within the housing (50,250) and aimed downwardly, and configured to transmit sonar pulses in the form of a fan-shaped beam in at least a direction substantially perpendicular to a plane corresponding to the surface of the body of water, wherein the linear downscan transmit/receive transducer element (66,66',266) is further configured to receive sonar returns from the sonar pulses and convert sound energy of the sonar returns into downscan sonar return data in the form of electrical signals representative of the sound energy; a sound attenuating material configured to substantially attenuate transmission of sonar pulses therethrough positioned proximate to the linear downscan transmit/receive transducer element (66, 66', 266) and at least one sidescan transducer element (62, 62', 64, 64', 262, 264) positioned within the housing (50,250) and aimed outwardly and downwardly, and configured to receive sonar returns from the sonar pulses and convert sound energy of the sonar returns into sidescan sonar return data in the form of electrical signals representative of the sound energy, characterised in that the at least one sidescan transducer element (62,62',64,64') is a receive-only transducer element; and in that the opposing sides (66b, 66c) and bottom surface of the linear downscan transmit/receive transducer element (66, 66', 266) are free of the sound-attenuating material such that the linear downscan transmit/receive transducer element (66,66', 266) is configured to transmit sonar pulses from the bottom surface and opposing side surfaces (66b, 66c) without transmitting sonar pulses from the top surface. a housing (50, 250) mountable to a water craft capable of traversing a surface of a body of water; a linear downscan transmit/receive transducer element (66, 66', 266) defining a substantially rectangular shape with a top surface, bottom surface, and opposing side surfaces (66b,66c) positioned within the housing (50,250) and aimed downwardly, and configured to transmit sonar pulses in the form of a fan-shaped beam in at least a direction substantially perpendicular to a plane corresponding to the surface of the body of water, wherein the linear downscan transmit/receive transducer element (66,66',266) is further configured to receive sonar returns from the sonar pulses and convert sound energy of the sonar returns into downscan sonar return data in the form of electrical signals representative of the sound energy; a sound attenuating material configured to substantially attenuate transmission of sonar pulses therethrough positioned proximate to the linear downscan transmit/receive transducer element (66, 66', 266) and at least one sidescan transducer element (62, 62', 64, 64', 262, 264) positioned within the housing (50,250) and aimed outwardly and downwardly, and configured to receive sonar returns from the sonar pulses and convert sound energy of the sonar returns into sidescan sonar return data in the form of electrical signals representative of the sound energy, characterised in that the at least one sidescan transducer element (62,62',64,64') is a receive-only transducer element; and in that the opposing sides (66b, 66c) and bottom surface of the linear downscan transmit/receive transducer element (66, 66', 266) are free of the sound-attenuating material such that the linear downscan transmit/receive transducer element (66,66', 266) is configured to transmit sonar pulses from the bottom surface and opposing side surfaces (66b, 66c) without transmitting sonar pulses from the top surface.