Whatever else a plotter might do, its ultimate value is what you see on the screen. A chart plotter places greater demands on the acuity, contrast, brightness and size of the display screen than any other shipboard electronic equipment, including radar and sonar. Thus, you would do well to put down this magazine and go see a Northstar 962 for yourself.
If you can't, bear with me. I'll draw you the big picture.
The 962's screen is big enough (10.4-inch diagonal) to be really useful. Colors are vivid, and detail is more than acceptable. A non-glare filter and effective backlighting make the screen usable in any condition, including direct tropical sunlight. An ambient light sensor controls screen brightness manually or automatically.
The 962 uses raster charts, which fail to offer some vector chart capabilities. Raster chart data is not layered, so it's impossible to remove clutter by turning off sets of unnecessary data. However, the 962's MapTech (U.S. NOAA) or ARCS (British Admiralty) raster charts offer the significant advantage of being official Hydrographic Office products, ensuring they are accurate and complete.
Also important is that weekly electronic updates are available for NOAA digital raster nautical charts (NOAA, 301-713-2770; chartmaker.ncd.noaa.gov. MapTech, 978-933-3000; www.maptech.com). Although great strides are being made in improving available vector charts, experienced navigators likely will agree with Northstar's choice of raster format charts for this professional-level product. However, it's surprising the 962 does not support the aerial photos and other information included in MapTech ChartKits. The company is considering adding those features, according to Northstar's Mark Reedenauer.
The 962's ancillary database contains tide and current predictions for more than 3,000 NOAA and NOS tide stations covering the entire U.S. coastline, including Alaska and Hawaii, plus much of the western Canadian coastline.
The 962 can operate as a GPS/DGPS navigator, as a chart plotter and, when equipped with the optional model 490 Echo Sounder, as a sounder and fishfinder. The built-in 12-channel GPS receiver supplies position information for the 962X. The 962 XD version adds differential GPS accuracy with use of a two-channel, fully automatic low-frequency differential receiver. Fishermen or others who have valuable libraries of loran C TDs will be pleased by the system's ability to use real-time loran C information or phantom loran TDs created from GPS data. The GPS/DGPS mode provides either a steer to waypoint screen or a pseudo 3-D screen. Both screens present all the expected information: waypoint name, SOG, COG, distance, BRG, XTE, ETA and ETE. The large display makes both screens easy to use.
Chart plotter displays include vessel position data, waypoints, routes, avoidance points and multiple voyage tracks. Navigation management is quick, using the cursor in a point-and-shoot mode. The chart can be automatically centered on the vessel or on the cursor. Range rings, similar to those used with radar displays, help in finding the vessel's position on the screen. An adjustable prediction time vessel position vector simplifies some navigating tasks.
DISPLAY: 10.4" diagonal; 1,600 nits; sunlight readable; 640 x 480 pixel; controllable backlight with automatic/ manual brightness control and screen-saver dimming
CONTROLS: 11 single-function keys; four direction cursor controls; 12-button keypad; six soft keys; on-screen program dependent identification
GPS/DGPS: 12-channel parallel receiver; update rate of once per second; two-channel auto-tune low-frequency beacon receiver for differential correction signals; optional "E" or "H" field antennas
INTERFACE: Three bidirectional NMEA 0183 I/O ports; one bidirectional RS- 232/RS 422 port; VGA output; 200 ppm speed output; external MOB input; SAVE input; external alarm output
PROCESSOR: 233 MHz Pentium processor; 4.3 GB hard drive; CD-ROM and 1.4 GB floppy drive inputs; 100 MB Zip drive optional; DOS operating system
ECHO SOUNDER: Model 490; dual frequency; 50 and 200 KHz; 100W, 600W optional; 0.1-1 msec pulse lengths; 30-600 pulses/minute
SYSTEM POWER: 10-36 volts DC @100 watts, plus 8 watts for echo sounder system
The system provides a useful capability: instant access to two separate charts or two views of the same chart, without time-consuming memory access or screen redraw. System memory can store as many as 2,000 waypoints, 1,000 routes and multiple tracks. Extra navigation, vessel and chart reference information can be shown in addition to the navigation picture on one or two simultaneously displayed screen areas.
Depth sounder and fishfinder functions can be added with the optional 490 Echo Sounder Module. Stand alone sounder screen choices are full screen, split screen-dual frequency, split screen-A-scope and bottom lock/zoom. Sonar data can be combined with the chart plotter on split-screen displays. The sounder-fishfinder system stores up to three minutes of echo data for review and annotation.
The 962's control access and operation is quick and intuitive. There are 11 single-function buttons, a cursor control, a 12-button keypad and six soft keys. Most key functions operate as toggles. Charts can be shown course up, north up, leg up or chart up. The OverZoom feature is great when viewing a large chart area during voyage planning.
Although the 962 can exchange data with other devices, including an autopilot, its radar interface is limited to on-screen display of an operator-designated target on the radar screen. The system communicates with the outside world via three bidirectional NMEA input/output ports and an auxiliary bidirectional port that can be used to communicate with a personal computer. The VGA port simplifies interconnection to a remote display. A second 962 control-display module is optional.
The 962's overall design and performance are impressive, but the unit is a power hog. Even without the echo sounder option, the 962 consumes about 100 watts, more than 8 amperes on a 12-volt bus. This will not faze powerboaters, but sailors may find the energy consumption a bit much.
Overall, the system consists of a waterproof control and display unit, a remote-mounted computer box and a remote-mounted echo sounder module. The computer box appears larger than needed, and it's woefully short of environmental protection. One drop of salt water in the wrong place will make nasty things happen.
The system's suggested operating temperature limit of 55 degrees C (122 degrees F) may also be a concern, particularly if the display unit is exposed directly to tropical sunlight. Maximum screen backlighting will be needed under such conditions, further increasing the environmental stress. An over-temp sensor automatically dims the screen if things get too hot, but providing a bit of shade will be a worthwhile precaution. Suggested retail price: 962X, $10,195 plus $1,595 for the 490 Echo Sounder.
Contact: Northstar Technologies, (800) 628-4487; www.northstarcmc.com.