| 摘要 |
A generally spherical compass for mounting on a boat has a transparent grid which is superimposed over a compass card with navigational markings. The grid has radial arms extending from a central hub to the outer rim of the grid upon which a heading line, a reciprocal line and two bearing lines are inscribed. Each bearing line is offset 45 DEG from a side of the course line, which is aligned with the longitudinal axis of the boat, in order that the boat may be navigated from either side of the helm. In an alternate embodiment, a transparent disc with a heading line, a reciprocal line and offset bearing lines inscribed on it is superimposed over the compass card. The transparent disc is supported over the compass card by a set of pins whose vertical axis is substantially offset form corresponding holes positioned about the periphery of the disc. An apparent disappearance of the transparent members, leaving only the lines visible, results from the damping fluid having approximately the same index of refraction as the transparent members.
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