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Electronics

Back To The Future

Electronics May 2001
By Tim Clark


Back To The Future
An electronic plotter for paper charts combines today’s technology with the tried and true.
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Strolling down an aisle smack in the center of the electronics hall at the Miami International Boat Show in February, I caught sight of a paper chart flat on the counter of a notably uncluttered booth. How odd it seemed, there in the sea of parti-colored LCD monitors and logo-festooned dome antennas. As I left the main current of show-goers and neared the booth, I noticed a gentleman skating an oblong disk this way and that across the chart’s surface. He looked like a virtuoso psychic soloing on a Ouija board. Closer by, I saw an LED readout framed at the center of the device and noticed that every time it came to a halt anywhere on the chart, it indicated a precise latitude and longitude. I wanted to know more.

The man behind the counter was Robin Myerscough, UK-based Yeoman Group’s export sales executive, and his magic gadget, which he called a “mouse for maps,” was part of the Yeoman Navigator Pro paper chartplotter. Although Yeoman plotters have been available in the States for about four years, they have not been aggressively marketed. In fact, this was the first time one had been taken to the Miami show. As he stood opposite me manipulating the mouse like, it now seemed, someone running a shell game, Myerscough—rather than take me for a 20—kindly spilled the beans about the Nav Pro. The device’s other main component, out of sight under the chart, was a 281/2"x 21" x 2" chart board with an embedded circuit system. At the end of the mouse was a circle of transparent plastic about 1 1/2 inches in diameter with a small hole at its center for marking positions, waypoints, and such. This plotting circle is framed by a coil of copper wire that’s alive with a low-level alternating current. As the mouse moves over the chart board, its current is discerned by the board’s embedded grid.

Of course, for this interplay to be of any use, the mouse’s position must be relative in two-dimensional space. That is, its orientation on the flat surface must be established. You can do this on any chart in just a couple of minutes by entering any three positions into the mouse so long as the first two share the same latitudinal line and the third position is on the same longitudinal line as the second. In other words, you input a right triangle.

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This article originally appeared in the May 2003 issue of Power & Motoryacht magazine.

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