[?]vigator

[?]ter, the electronic [?]vigator

ter mariner Captain Vic Sanderson writes on a revolutionary electronic device, the so-called Digital Navigation Computer 17, which vastly simplifies the work of the navigator.

small transistor radio has only brought news, music entertainment into homes, s and boats - to the navi r it has brought accurate : signals, which are of the

nee when calculating longi-

For practical purposes, it made the chronometer su luous. gain, the small hand-held ette recorder makes it poss for the navigator of any el, however large or small, ;cord course changes, tran -3f landmarks, weather con

ins and everything that

ild be written in the ship’s at times when writing Id either be difficult or rfere with other duties, t a slightly more complex 1 is the pocket calculator :h has reduced the time re ed for solving complex cal tions, including the ility of the ship, to a frac of that required by other ms and with greater accu r than, say, with logarithmic es. he heart of the pocket cal itor is a tiny silicon chip, no >er than a little finger, ch contains many minute trical components and cir ries. Initially it cost millions lollars to complete the de i and set up the production , but once the output paid initial costs, they became liable for a very few dollars ti. hen we come to the most e-consuming task of all for

navigator, conservatively

mated at one and a half irs of calculation per day, ch is the daily ritual of

iblishing the ship’s position

m celestial observations fol

ed by sight reduction.

Vith the development of

;rocircuitry, as used in

inary pocket calculators, it

5 only a matter of time be e a calculator for sight uction was created. This s first achieved by the well )wn nautical instrument nufacturer C. Plath of Ham

burg. Now a slightly different but even more versatile instrument, at about one-fifth the price, has been produced by Tamaya of Japan. It is known as the Digital Navi gation Computer NC-77.

This computer, which is only a little larger than the average hand-held calculators, pro duces results for a multitude of

navigation problems, ranging

from running fix to distance off by vertical sextant angle. It in cludes dead reckoning by Mer

cator sailing; course planning

by great circle sailing, together

with distance, initial course and intermediate points on the great circle.

Other features are finding the height and tide for a se lected time and velocity of the tidal currents at any time re quired; also, finding the course

and speed made good through

a current and the course to steer and speed to maintain to make good to the intended

point.

Above all, the NC-77 will compute celestial navigation problems and solve these by

producing position lines and

fixes in less than 90 seconds.

The NC-77 is programmed with astronomical data for the sun up to the year 2000, and from this data can compute Greenwich hour angle by the sun, Aries, equation of time and declination for the sun without using a nautical alma nac with the latter only re quired for planets, stars and moon.

The instrument is supplied with an excellent handbook,

not only explaining step by step

how the available information is to be fed into it in order to get required results, but also explaining at great length the fundamentals of astronaviga tion.

In Australia at a price of around $3OO to the professional navigator, and, because of sales tax, slightly more to the yacht ing fraternity, it must be con sidered an absolute steal.