Headings and Bearings in True Rather Than Magnetic

This information applies only to a AISWatchMate 650. All other display models have built-in magnetic variation computations.

Check the setting "Course and heading mode" or "Bearing to target mode". If it is set to magnetic and the heading or target bearings are still in true, then it's because the GPS is not providing magnetic variation. Marine GPS units usually include this data in their RMC sentence, but embedded GPS modules, such as those used in transponders and other devices, do not provide magnetic variation.

If the vessel has a transponder and magnetic headings or bearings are wanted, then connect the AISWatchMate to another GPS. Do this by using the second port on the AISWatchMate and selecting GPS as the input device for that port.