Underwater depth sounder with variable beam transducer

Claim 1

In combination in a sonic depth sounder which includes an electrical source of power, a directional electroacoustic transducer and a visual display means with a plurality of selectible range scales for reading the depth of a submerged reflecting target when it appears within the path of the radiated sound from the directional transducer, said transducer characterized in that the vibratile surface of the transducer is divided into a plurality of sections, a plurality of electrical conductors connected to said plurality of transducer sections, switching means connecting said plurality of electrical conductors in any specified combination, whereby a plurality of different specified beam widths are selectively available from said transducer, said visual display means including range selector means for selecting any one of said plurality of range scales on said display means, coupling means between said range selector means and said switching means, said coupling means characterized in that a particular beam width is selected for operation in combination with a particular range setting, said transducer further characterized in that said plurality of transducer beam widths are in approximate inverse proportion to the depth range scales with which the beam widths are selectively combined, whereby the area of the insonified target region at each different full-scale range is approximately the same.