Simrad CA/50 Chart Plotter

A serious chart plotter system that's a true navigation center.

October 4, 2007

Many manufacturers overstate the capability of their products, but Danish marine electronics manufacturer Simrad has understated the capability of its CA/50 and CA/40 chart plotter systems. The systems, like competing products, offer a multitude of chart, radar and sonar display screen options, including dual displays of chart and radar data. The operating manual collectively calls the features DGPS ChartRadar with Echosounder, but the installation manual is more accurate, identifying the CA/50 and CA/40 as navigation centers. When connected to external data sources that provide magnetic or true heading, hull speed, water temperature and wind velocity, these products provide valuable information beyond the GPS/chart/ radar/sonar constellation.

The system’s wired cables make it simple to install the display, radar power supply box, radar scanner, DGPS antenna and sonar transducer. The DGPS sensor incorporates an H-field antenna for receiving signals from low-frequency differential correction stations. This type of antenna also eliminates the need for a separate whip antenna and for grounding the antenna unit’s base. The DGPS can monitor as many as 14 channels and will be compatible with future, external, GPS-quality surveillance systems. We cobbled together the world’s worst-looking mast mount for the radar scanner and had the whole system up and running in about one hour. Simrad says the color LCD displays are not suitable for use in direct sunlight and warns against possible overheating if the display is exposed to direct tropical sunlight, so we placed the unit at the chart table-a normal position for equipment with TFT color LCD screens.

The CA units provide two set display colors: one for daylight, the other for night. You also may enter and store as many as seven additional color/contrast combinations. Doing so will be simple for anyone familiar with today’s chart plotters and GPS navigators, but despite the CA’s ease of use, you should spend some time with the 159-page operating manual. Unlike some systems, the program logic provides a graceful escape from whatever mode you may blunder into.


All the controls are grouped vertically to the right of the display screen. Two C-map cards can be inserted into watertight drawers at the control panel’s bottom. System control is via 26 push-button keys and a four-way cursor control pad. The key arrangement is excellent, with the most often used and most urgent controls (menu, enter and man overboard) across the top row. Zoom in and zoom out keys are immediately below, near the cursor pad. Three immediate action keys are arranged vertically in the center column: echo/a-scp, radar Tx and chart goto. This arrangement, with the plus-and-minus gain keys to the left and the window and page keys to the right, makes for facile system management. The 10 alphanumeric keys at the panel’s bottom provide immediate radar-scale or chart-scale change.

A series of pull-down menus similar to those on most computers provides the interface. The cursor keypad or numerical keys select the menu items. Overall, the system is well designed. When you name waypoints, you have to manually advance the cursor from one letter or number to the next, and the characters advance automatically when you enter numeric position information. One desirable improvement would be automatic advance for waypoint identification.

The LCD has five display typography choices: a full-size screen, a vertically split screen, a four-panel screen and two three-panel screens (with a full-height left or right half and the remainder divided horizontally). The CA/50’s large screen is an obvious advantage when using multiple screen options. Screen selection is via the window button. Each window arrangement may be programmed with as many as four stored data display choices, allowing rapid cross-checking among navigation data presentations. The programmed pages may be automatically sequenced with user-adjustable dwell times.


A three-panel display-half radar data with quarter-screen displays of chart and DGPS navigation data-is useful for overall situation awareness, especially in harbors with heavy traffic and complex buoy systems. Offshore, we found the dual radar display particularly useful with half the screen showing radar data out to eight miles while the other half displayed information on the half-mile scale. The current radar/chart design suffers from one shortcoming: It can’t superimpose radar information on a chart display.

Additional data inputs via the NMEA 0183 bus greatly enhance the system’s navigation value. Supplying wind velocity enables a wind speed/direction display, showing true and relative wind angle and wind speed. Connected to a heading sensor input (magnetic or true) and a hull speed transducer, the system can display an analog current set and drift presentation with the current’s relative direction, true direction and speed. An analog dual-speed display depicts average and instantaneous speed, plus normal navigation data. The speed diagram display depicts speed over the ground, speed through the water and velocity toward the waypoint vs. time, all while displaying the instantaneous digital values for these variables, plus wind speed.

All the system’s chart information is from the built-in world chart or either of two C-map vector format chart cartridges. As with any electronic charting system, the screen’s re-draw speed when you change chart scales or move beyond a display boundary can influence your level of satisfaction. This chart system provides a choice of large, medium or small areas, but screen re-draw is fastest with the small chart area.


Waypoints, tracks, routes, lines and targets are normally entered from the on-screen chart by positioning the cursor on a geographic point on the chart. Entering waypoints using lat/lon data is less convenient and requires a number of steps. First, you place the cursor on any point on the chart and select the plot mode. Second, you select plot-waypoint-with-name from the on-screen dialog box. The data representing the cursor’s position is then overwritten with the name and geographic position of the waypoint, which may be outside the boundaries of the C-map chart in use. An alternate approach lets you use the lat/lon readout at the chart display’s top to position the cursor at a location, then select the plot mode. (The latter process may have less precision, but the waypoint information may be edited after it’s entered.) Waypoints and other points on-screen are identified by any of 18 symbols. Lines and targets may be plotted on-screen and saved. Memory capacity is not stated in the manual, but it appears to be substantial.

Although the C-map data source is acceptable for many users and benefits from the layering inherent in the vector system, a device with the CA/50’s capability should be able to accept data from other chart sources, including raster scan charts. Using the vector chart, information about buoys and other navigation aids is available, but access requires multiple steps.

You can choose one of three Anritsu radar sensors: an 18″ radome with 24 nm range and a 2kW transmitter; a 26″ radome with 36 nm range and a 4kW transmitter; or a 4kW transmitter open-array unit with 3′ or 4′ slotted wave guide antenna that offers ranges up to 48 nm. An extensive on-screen setup menu manages the radar’s performance, and you can make operating adjustments by pressing the adjust key. All the normal upscale radar features are present, but having to use the multipurpose keypad controls may make radar control somewhat less facile than with stand-alone radars.


The echosounder can operate on frequencies of 38, 50 and 200 kHz, depending on transducer choice. Display ranges extend from three to 3,000 meters with a variable output power of up to 1kW rms. per channel. Two transducers may be connected to the system simultaneously, with one incorporating hull speed and water temperature sensors. Four types of echosounder display are available: standard, bottom zoom, marker zoom and A-scope. Display options include a time- or distance-based depth and temperature diagram (histogram) that can be especially useful when navigating uncharted or inadequately charted areas. With a bit of programming and an associated computer, you could prepare area charts (based on DGPS position data) that would have spot soundings and contour lines.

The CA/50 is big: 18″ wide and 12″ high. It weighs almost 11 lb. It may be mounted using the supplied bracket or in a bulkhead. The TFT color LCD measures 8″ by 11″and has a 640-by-480 pixel resolution. Visibility in subdued light or total darkness is excellent.

This unit has a suggested retail price of nearly $15,000. It’s money well spent.

Contact: Simrad USA, (425) 778-8821;


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