Raymarine C140w User Reference Handbook page 107

North Up (N-UP)
Note: If heading data becomes unavailable whilst in this mode,
a warning message will be shown, the status bar indicates
North-Up in brackets and the radar uses 0° heading in relative
motion. When heading data becomes available once more,
North-Up mode is reinstated.
Note: It is not possible to select Head Up mode when the motion
mode is set to True.
Using radar
Course Up (C-UP)
If you select a new course, the picture will reset to display the new
course upwards.
The reference used for Course-Up depends upon the information
available at a given time. The system always prioritizes this
information in the following order:
1. Bearing from origin to destination, that is, intended course.
2. Locked heading from an Autopilot.
3. Bearing to waypoint.
4. Instantaneous heading.
Note: If heading data becomes unavailable whilst in this mode,
a warning message will be shown, the status bar indicates the
Course Up in brackets and the radar uses 0° heading in relative
motion. When heading data becomes available once more,
Course-Up mode is reinstated.
Selecting the radar orientation mode
In the radar application:
107