| 摘要 |
A transparent-overlay combined navigational computer and plotting sheet usable directly upon any map, chart or the like, or, when secured to a rigid support panel, forming a pocket to receive such chart for portable or open-cockpit use; removably pivoted to the underside of the cover sheet are discs providing a compass rose protractor, a grid of distance lines and a series of parallel locating lines, a novel arrangement for magnetic deviation corrections with its reading auxiliaries, a series of azimuth locators, and axial graduations for vector diagram construction, all facilitating course, distance and location estimation and plotting, with allowances for compass variation and deviation error, current vector construction, and the solving of standard coastwise navigating problems and the like, together with protection of the chart against weather abuse, and windblown loss. A pelorus arm with sighting vanes, pivot, and hairline coinciding with the compass rose protractor is also provided.
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