Made of transparent plastic,“Inoue" and “Kent" types are available. 1. Inoue Type: Nautical Triangles, a position finder for the navigator, consisting of a danger-angle triangle (A) and a protractor triangle (B) made of transparent plastic, 36 cm. 2. Kent Type: Two 45o triangles provide an easy method for plotting position and course and doing other chart work. Using protractor scales, the triangle is easily aligned in any direction with a chart meridian. Direction is maintained as one triangle is slid along the other to the desired position. Durable, clear, vinylite. Long side length 30 cm.

航海三角板分为INOUE-TYPE 360mm和KENT-TYPE 300mm,由透明塑料制成,船舶上都配有两只同规格的航海三角板。根据不同情况，可单独使用或两只配合使用。在应用中，航海三角板比平行尺方便、灵活。特别是在量取的方位线或航向线度数，但又与海图上的罗经花距离较远时，使用航海三角板量取方位线或航向线的度数就更为方便。具体操作时，用一只三角板的长边对准所要量取的方位线或航向线，然后与另一只三角板配合，将对准方位线或航向线的长边平行移到就近的经度线上，使圆弧的中心点与经度线相重合，最后从圆弧刻度尺上读取方位或航向度数。在这种情况下，使用平行尺，则需要平行移动较远的距离才能到罗经花上，操作不慎，静尺容易移位而产生误差。