How do I choose a chartplotter for sailing?
I've bought a 31ft cruising yacht with older wind and depth instruments, and I want a chartplotter in the cockpit for coastal sailing. Would a tablet do the job, or should I buy a dedicated unit, and which sailing features are worth paying for?
Answer
Choose a sailing chartplotter by checking compatibility with your existing instruments, readability from the helm and chart coverage for your cruising area. For regular cruising, start by looking at a dedicated cockpit plotter with a 9-inch screen, backed up by a tablet for passage planning and independent navigation.
Check your existing equipment
Before comparing screens, list the make and model of your wind instruments, depth sounder, AIS, autopilot and radar. Photograph their connectors and identify the network. This often determines which plotter will give you the most useful installation for the least money.
NMEA 2000 carries instrument data over a powered backbone with a terminator at each end. Older boats commonly have NMEA 0183 or proprietary networks such as Raymarine SeaTalk, which may need a converter. A matching plug alone does not establish compatibility.
- Wind, heading and speed: check that the plotter can receive the data its sailing functions need.
- AIS: confirm that it displays targets and supports closest-point-of-approach alarms from your receiver or transponder.
- Autopilot: distinguish sending navigation information from full pilot control; compatibility varies by model and software.
- Radar: check the exact scanner model, because radar connections are usually manufacturer-specific.
A working depth display does not mean its transducer can plug directly into a new plotter. Keeping the existing instrument and sharing its depth data may be the simplest solution.
Size the screen for sailing
A 7-inch display can suit a small cockpit and straightforward coastal navigation. A 9-inch screen gives more room for charts alongside depth, wind and AIS. Consider 12 inches if you regularly split the display between charts and radar. Measure the complete casing, mounting bracket and cable clearance, as well as the screen diagonal.
Try the display from your normal steering position, including through polarised sunglasses. Check that you can read depth figures, distinguish nearby AIS targets and reach the controls while braced against the cockpit.
Touchscreens make panning and route editing quick. Physical buttons, a rotary controller or a compatible remote can be easier to use when spray, gloves and boat movement make accurate touches difficult. Before buying, test zooming, placing a waypoint and returning to your boat's position.
Think carefully about the mounting position. A companionway installation may be visible to everyone but awkward to reach from the helm. A pedestal display can obstruct instruments or the compass.