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Emergency Navigation Card (2016)
A handy card to have on board in case your sight reduction system, sextant, or almanac becomes lost. The card is loose-leaf sized. You can punch holes in it if desired for insertion in a binder. It is plastic laminated for weatherproofing and durability. A wealth of information is provided on it in addition to: an emergency almanac for the sun, and declination tables for the stars; several methods for accomplishing sight reduction, including one that requires only the card itself; and angular markings on the perimeter of the card that allows approximate altitude measurements of celestial bodies. It also includes a method of sight reduction called the N(x) table, which is, without doubt, the world's shortest sight reduction table. This reduction method takes more arithmetic than conventional tables, but they will get the answers. It is much quicker, SW 0.1 lb.
This card is intended as an addition to a back-up nav kit or just as a quick reference to emergency techniques. Davis Instruments and others have published a series of such cards on various topics, and if you have a set of these or have found individual ones useful, this would fit well into that category.
The card includes techniques of steering without a compass, finding boat speed without a knotmeter, how to find latitude from sun and stars without sextant or watch, and so forth.
It also includes a method of sight reduction we devised for this purpose, called the N(x) table, which is, without doubt, the world's shortest sight reduction table. This reduction method takes more arithmetic 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 and stars makes this card a "complete navigation resource" in an emergency, but it takes practice to learn to use these special features of the card. We include complete instructions with each card.
Other things like steering by the stars can be read right off of it without any reckoning. All info on it except the N(x) table and the long-term almanac are included in the Emergency Navigation book, which is the basis for the techniques and information printed on the card.
