Abstract: A depthsounder for selectively measuring either bottom depth or the depth of any fish located beneath a vessel. When operating in a depth mode, the depthsounder automatically adjusts the gain of its receiver to minimize interference and provide a filtered display of bottom depth. When operating in a fish finding mode, the depthsounder likewise automatically adjusts the gain of its receiver to minimize interference in its detection of fish. In addition, the depthsounder suitably processes any return pulses to distinguish those produced by fish from those produced by other objects in the water. When fish are detected, the depthsounder provides a visual display of their depth and an aural alarm whose repetition rate is proportional to the number and size of the fish.

Abstract: An anemometer includes a rotor mounted to spin about a vertical axis in response to wind being directed against it, and a cage having a plurality of circumferentially spaced apart, vertically disposed vanes surrounding the rotor. The vanes deflect the normal flow of air to produce an asymmetrical airflow pattern across the face of the rotor to cause the rotor to spin about its axis. A transducer senses the rotational speed of the rotor and converts it into a signal proportional to airspeed. In one form of the invention, the cage is fixed, and in another embodiment the cage is attached to a windvane to rotate with the windvane relative to the rotor. The windvane senses the direction of the wind, and a second transducer converts the rotational motion of the windvane into a signal proportional to wind direction.