Abstract: A rotary solenoid comprises a housing, a rotor rotatably mounted in the housing, the rotor and the housing being comprised of a magnetically permeable material, and a solenoid coil mounted in the housing about the longitudinal axis thereof. The housing has at least a first pole piece portion therein with the rotor further comprising at least a first permanent magnet means mounted therein for simultaneous rotation therewith. The first permanent magnet means has first and second null positions with respect to the first pole piece and is mounted in the plane of the first pole piece for rotation about the longitudinal axis and provides a reverse magnetic flux in the housing and rotor magnetically permeable material. The solenoid coil has an energized state and a deenergized state with the rotor rotating a predetermined angular amount about the longitudinal axis from an initial position in response to a predetermined potential applied to the coil in the energized state.

Abstract: Apparatus responsive to immersion in water to complete an electrical circuit through which a signalling means is energized from an electrical energy source includes a sensor which is salt or fresh water actuated depending on the sensitivity of the circuitry utilized in conjunction with the sensor. The sensor comprises an outer peripheral shield, such as an outer conductor, and an inner conductor, or pair of inner conductors, wherein air holes or slots are provided in the outer shield so as to enable the venting of air from within the interior of the outer shield at substantially any depth of immersion of the sensor in water less than total immersion while preventing the inadvertent entry of splash water prior to such immersion. The venting passageway extends substantially the full longitudinal extend of the outer electrical shield and also acts as a waveguide to restrict electromagnetic, RF and electrostatic interference from entering through the outer shield which could inadvertently turn on the sensor.