An Improved Instrument for use in Correcting a Course, Taking Bearings, and the like on Board Vessels.

摘要

5105. Bohm, J. E. March 17. Bearings and courses, determining, indicating, correcting. - A n i n - strument for use i n correcting a c o u r s e, taking bearings, and the like on board vessels is shown in Fig. 1 and in section in Fig. 2. The diagram card shows the compass line d, divided both into degrees and points, and the deviation curve e, and is fixed in the bottom groove c. The upper grooves a and b receive movable frames A and B, which can be locked in various positions. The frame A has reading-wires i and j, while the frame b has a wire k with scale l inclined as shown. In using the instrument, the frame A has its wire placed above the course on the compass-line ; the lower frame B is then moved till the reading-wire k intersects the wire j above the deviation curve, and the course to be set is given by the intersection of the compass line with the wire k. In taking a bearing, the reading-scale l is placed so as to intersect the compass-line above the course, and the deviation is read off to the right or left, according to the side on which the deviation curve falls.