This card is intended as an addition to a back-up nav kit or just as a quick reference to emergency techniques of navigation without conventional instruments. With it you can find your way across an ocean or across a desert. The card includes techniques of steering without a compass, finding boat speed without a knotmeter, and how to find latitude from sun and stars without sextant or watch. It also includes methods of enhancing your navigation with a watch that has lost the correct time.
It also includes a method of sight reduction devised for this card using the included almanac and low-angle “sextant sights” made with the scales on the edge of the card. Called the N(x) table, this is doubtless the world’s shorted sight reduction table. This reduction method takes more steps than conventional tables, but they will get the answers. It is much quicker, however, to use it for other purposes such as finding the bearing of the sun or a star at any time. It does this very nicely. This table and our long term almanac for sun along with key star data makes this card a complete navigation solution in an emergency.
For best use of the card, the methods it presents should be practiced before they are needed—an exercise that is rewarding in its own right.