| 摘要 |
A speed indicator for marine vehicles is mounted on the lower transom area of such a vehicle and includes an impeller. The impeller rotates at an angular velocity dependant on the speed of marine vehicle relative to the water. A mounting bracket secures the speed indicator to the marine vehicle in a manner to permit movement of speed indicator relative to the marine vehicle so that the axis of the impeller remains generally in line with the direction of travel of the marine vehicle. To try to ensure laminar flow across the impeller and to facilitate movement of the speed indicator, the speed indicator has a guide vane positioned upstream of the impeller. The mounting bracket also permits adjustment of the speed indicator so that the axis of the impeller is basically parallel to the plane of the bottom of the marine vehicle. A sensor including a magnetic conductor and a magnetic pick-up detects rotation of the impeller and generates output representative of the speed of the marine vehicle. In one embodiment, the magnetic pick-up is supported by the speed indicator above the water level.
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