. A new treatise on the practice of navigation at sea : containing all the details necessary to enable the mariner to become a good practical navigator. . n the Chart a^Dace 4* PLANE SAILING. Plane Sailing is the Art of Navigating a Ship on ^lano surface, supposing the surface of the Earth M♦© an extended plane, and the meridians all parallel to each other. This supposition is nearly true foi•mall portions of the Earths surface, and for a considerable space on each side of the Equator. But as the Meridians contract in Sailing from the Equator towards the Poles, the sides of the Rightijogled Tr
. A new treatise on the practice of navigation at sea : containing all the details necessary to enable the mariner to become a good practical navigator. . n the Chart a^Dace 4* PLANE SAILING. Plane Sailing is the Art of Navigating a Ship on ^lano surface, supposing the surface of the Earth M♦© an extended plane, and the meridians all parallel to each other. This supposition is nearly true foi•mall portions of the Earths surface, and for a considerable space on each side of the Equator. But as the Meridians contract in Sailing from the Equator towards the Poles, the sides of the Rightijogled Triangle do not bear the same relation to each other on large portions of the Earths surface. Plane Sailing also supposes the parallels of Latitude to be at right angles to the Meridians, and thi»ngth of a degree on the Meridian, Equator, and parallels of Latitude, everywhere equal. CASE L , The Course and Distance given to find the Difference in Latitude and Departure. Example.—A Ship from Latitude 48° 30 N. Sails North-East by North 300 miles. Required he Latitudean and Departure from the Meridian. BY PROJECTION ON THE PLANE SCALE. Fig. Draw a horizontal line representing the parallel of Latitude sailed from; then with the Chord of 6P uthe dividers, and one foot on this line, describe a Semicircle; divide this Semicircle ,into equal parts of fOeach, (oi a Quadrant); divide the right hand Quadrant into 8 equal parts, which transfer to a line dravvTi aoroaithe , will give the line of Rhumbs. Divide the left hand Quadrant into 9 equal parts, and transferthem to a line drawn across the Quadrant in like manner, will give l^e line of Chords. Those figures ar«always drawn so that the upper part represents the North, and the ship is supposed to sail from the centre ona given course towards the circumference or horizon, the course North-East by North, 300 miles given. Taka3 points from the line of Rhumbs and lay it off from the North towards the East, and draw the
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectnavigat, bookyear1902
