An ultrasonic sonar transducer ( 10 ) for facilitating transmission and reception of sonar signals, particularly at high speeds. The sonar transducer includes a transducer element ( 12 ) and a transducer housing ( 14 ). The housing includes a bottom wall ( 34 ) that is continuously curved with no major portion thereof parallel to the bottom face of the element. The bottom wall has a recessed portion ( 40 ) that partially forms an acoustic window for facilitating the transmission and reception of acoustic energy, with the acoustic window having a thickness approximately equal to one half or an integer multiple of one half of the wavelength of the acoustic energy. The bottom is preferably bow-shaped to create a positive angle of attack relative to the oncoming water, thereby promoting a laminar flow that reduces turbulence and cavitation and therefore nearly eliminates undesirable attenuation and reflection of transmitted and received energy.