"William Andersen" wrote in
news:U1fBe.13258$HV1.495@fed1read07:

What is a yeoman plotter?


It's a scanned piece of PC board (usually mounted in either a foam holder
in the portable model, or attached to the bottom of a chart table top in
permanent installations. The scanning produces a magnetic signal that
scans across the board in lines, then down the board, much like the
scanning your television does to make a picture.

The pickup for this signal is a "puck", just like the ones used for
electronic drafting tables, but with buttons specialized for navigation.
The computer that generates the signals also reads the data from the puck's
electronics. By comparing the two signals, the Yeoman's computer knows
within a pencil lead thickness where the puck's pickup coil center is in
relation to the scanning board whenever the puck is near the board...within
about 6 inches on ours.

Now, programmed into the permanent memory of the computer, are reference
points that match the Yeoman reference points on Maptech's chart books.
Each chart page in each volume has 3 reference points that make a right
angle. You select the volume number, then page number on the puck's LCD
display. Then, you put the chart book on top of the scanning board so it
can't move and screw up the calibration. (We put it against two fiddles on
our chart table which give it the reference place.) Now you point the
puck's little target hole over each (marked A, B and C) and press the enter
button as the LCD asks you to show it A, B and C points on the chart. As
soon as you enter the points, the display switches to Lat/Long and starts
reading the exact latitude and longitude, nicely calibrated to the chart.
As you move the puck over the surface of the chart, the display shows the
puck's target position in Lat/Long on the LCD display.

If you chose not to use the Maptech charts, ANY chart in ANY scale will
work. YOU put 3 reference points on your chart, two on a line of latitude
and one on a line of longitude common with one of the latitude points
making a right angle. YOU tell the Yeoman puck the lat/long of each point
you chose on your chart and it stores this data for future use in its user
memory bank. All you do is make a notation on the paper chart of each
point (mark them A, B and C) and make a note in the margin of the chart as
to which user memory this particular chart's data is programmed into so you
can easily recall it later. Do three points on all your charts and you can
use them all with the Yeoman, any place on the planet. It even works on
common aeronautical charts, if you like.

Around the target area are four LED lights that make arrows away from the
target. These arrows tell you which direction to move the puck to put it
over your present position, unless you've clicked a specific point for a
waypoint, for instance, then it shows you the way back to that point. When
you get over your GPS' current position, the arrows all go out, easily
showing you your exact position (within the width of a pencil point) on the
chart....no drafting by hand to do. To plot your course on the paper
chart, simply move the puck until the arrows go out and mark your position
with a pencil through the puck's target hole made for this purpose.

There's another little handy button on the puck that changes the display
from Lat/Long to azimuth and distance. When you click the button, the
display shows you how far you are from either your current position or from
a reference point you've clicked up. "How far are we from the harbor
entrance bouy?", you ask. Click this button and simply put the puck target
over the bouy on the chart. Read the course and distance right off the LCD
display on the puck. It's that simple.

Yeoman will also transmit to your NMEA network, too. Lionheart has two
chart plotters at the helm, a Raymarine RL-70CRC radar/chart plotter
display and an old trusty Garmin 185 chart plotter/sonar. She also uses a
Dell Latitude notebook running The Cap'n nav software, which IS her primary
navigation system. Because the Yeoman's data output is connected to a port
on our NMEA network multiplexer, the network is fed NMEA data from the
Yeoman, like waypoints near that bouy if you like. When you click up a new
waypoint on the Yeoman, it shows up on all the other charts in the system.
We don't use the Yeoman for this because of the computer charts being much
more comprehensive, but it's a great backup system.

Aboard Lionheart, Yeoman provides us with hard copy course plotting every
hour just in case the whole electronic suite goes down. The line we keep
on a plastic overlay on the paper chart insures we know where we are if the
whole boat's dead. In a simple system, a GPS receiver, even a handheld
with data output, and the Yeoman plotter will give you great navigation
without all the old mechanical measurement problems rocking about....

Works great.....easy to use.

http://www.yeomanuk.co.uk/
http://www.marinews.com/electronics/electronics/GPS's/e_silvagps.htm
http://www.yeoman.net/

B&G bought Yeoman:
"Central to establishing Precision Navigation has been the acquisition from
Brookes & Gatehouse, of the manufacturing, marketing and distribution
rights of the Yeoman Plotter - which both men feel is a hugely underrated
piece of marine navigation technology.

Cole commented, "The Yeoman plotter already has thousands of dedicated
users throughout the world. It has a unique place on the navigators chart
table either as a stand-alone plotter or as a compliment to even the most
sophisticated navigation package."
Hatfield added, " It is the perfect link between paper charts and
electronic positioning devices, as it marks your precise position right
where you need it - on the paper chart!"

Richard Acland, Managing Director at B&G believes Precision Navigation is
the perfect home for the Yeoman Plotter. "Though it doesn't integrate with
our current product portfolio, the Yeoman Plotter is a great system and we
wish Precision Navigation every success for the future," says Richard.

The Yeoman Plotter will form the core business of Precision Navigation and
join a considered portfolio of navigation products - from chart work tools
to computerised chart plotting systems. Precision Navigation will, of
course be offering expert advise on all navigation matters.

Precision Navigation are based at 12, Court Farm, Brantham, Essex, CO11 1PW
close to the Orwell and Stour estuaries and can be contacted by telephone
on 01473 327813, fax on 01473 326859 or by email on
. A website is currently under construction
at www.precisionnavigation.co.uk."

which should insure its production for more years to come.....

http://www.waypoints.com/yeoman.html
http://www.carolinamapdistributors.c...echchartkitacc
essories.htm
http://www.benmeadows.com/refinfo/ezfacts/ezf1036.htm


--
Larry