Abstract: An apparatus for activating and deactivating a bilge pump in a marine vessel in response to the presence or absence of water or other fluid in the bilge area wherein a pair of acoustic transducers are mounted in proximate and opposed relationship to one another such that a first transducer, the generator transducer, transmits acoustic waves to a second transducer, the receiver transducer, across a designated narrow channel. The apparatus operates on the principle that acoustic waves transmit greater energy in a dense transmission medium such as water or other liquid. The sensitivity of the transducer pair and its associated electronic circuitry is adjusted such that the transmitted acoustic signal is detected at the receiver transducer when the signal is transmitted through liquid and the signal fails to reach a detectable level at the receiver transducer when the signal is transmitted through air. The detected signal triggers electronic circuitry operating a relay coil which switches power to the bilge pump.

Abstract: The swivelled knob provides an exterior grip portion and a laterally opening finger defined by a thin walled flange. These characteristics provide optimum characteristics for three modes of reel operation: power retrieval for bringing in a catch; fast retrieve of a line and lure by a finger twirling operation; and sensitive lure retrieve or play by engagement of the thin walled flange by the opposed thumb and forefinger.