The ship icon/course vector appears to be misoriented

Two of the most confused navigation concepts are heading and course over ground (COG). Heading is the angle that indicates the vessel's orientation relative to true or magnetic north; in short, it is the direction the vessel is pointing. This assumes that the magnetic heading sensor has been calibrated and adjusted correctly.

COG is the angle that indicates the direction in which the vessel is moving over the earth relative to magnetic or true north. By definition, COG requires the vessel to be in motion to express the direction of its movement. If you are stationary, you will get an invalid COG reading. Depending on the vessel's speed and drift (resulting from current and wind vectors), heading and COG can be very close or very different in value. Generally, heading and COG will be closer in value as the vessel's speed increases, reducing the effects of drift. Conversely, slower vessels will be more affected by drift and therefore slower vessels will typically show greater differences in the values reported for heading and COG.

You can determine if the Raymarine system has been connected to a source of heading data by configuring the Multifunction Display (MFD) to display "Heading" data within the MFD's Databar, Databox, or within one of the Data application's Datapanels. If the reported value for "Heading" data is ---, you can assume that the Raymarine system has not been connected to a source of heading data (e.g., an autopilot).

When the vessel is underway and making good speed, the chart application on an MFD running within a system lacking a source of heading data will:

• Orient the chart according to the chart orientation setting
• Offset the chart and vessel icon according to the boat position setting

Head-Up vs Course-Up chart orientation... Like the confusion between heading and COG, many operators of systems lacking a source of heading data mistakenly assume that the chart application should be configured to Course-Up orientation rather than Head-Up orientation when they want the system to orient the chart in the direction the vessel is moving. Head-Up chart orientation is most often used by those navigating in pilot waters and/or wanting all objects displayed within the chart application to be shown relative to the vessel's heading. In contrast, Course-Up is associated with the chart application's navigation functions (e.g., Go To Cursor/Waypoint and Follow Route). If the system is commanded to navigation mode by executing one of the mentioned commands and the chart application is then commanded to Course-Up, the displayed chart will be oriented to match the navigation course line to the waypoint/cursor position, which may not be the direction the vessel is moving over ground (COG) or pointing (heading).

It is not necessary to connect a source of heading data to the system, but it is highly recommended, because: if you want the vessel icon to be correctly oriented when the vessel is stationary or navigating at maneuvering speeds or if you want to use one of the system's heading-dependent or heading-enhanced features - e.g., MARPA tracking or radar overlay Raymarine recommends that accurate heading data at 10Hz or higher be provided to all systems using any of (but not limited to) the following radar and chart application features:

• MARPA
• AIS targets displayed within the radar application
• Waypoints displayed within the radar application
• North Up or Course Up orientation within the radar application
• Radar overlay within the chart application.. can be used with COG only.
• Heading vector within the chart application
• Vessel icon orientation within the chart application (will default to COG when no source of heading data is detected)
• Heading databar and data application data objects
• Other heading-dependent features.

If the MFD has been connected to a source of heading data and the vessel icon is misoriented and/or appears to crab when the vessel is making good speed, the system's heading data source would be considered to need calibration and adjustment or need servicing/replacement. If heading errors are detected, the vessel's heading data source must be calibrated for deviation and then adjusted to correct heading. The owner's manual for the heading data source should be consulted for information on how to calibrate it for deviation and then adjust the compass. After doing this, the heading should be tested against the vessel's correctly calibrated fluid-filled compass (if available) again. If heading errors continue to be detected, it is recommended that the heading data source be serviced/replaced.

Before performing any calibration and adjustment of a heading sensor, it is highly recommended that the area around the heading sensor be inspected to ensure that all sources of magnetism (e.g., iron materials, electric motors, high-current conductors have not been placed within at least 3' of the heading sensor. The most common source of heading data on board a vessel is an autopilot system. Other heading sources include the retired ST60+ instrument compass, Pathfinder Smart Heading System, and third-party NMEA 0183 and NMEA 2000 GPS compasses and magnetic heading sensors.

Image of Fluxgate compass heading sensor used on SPX, Smart Pilots etc.

Image of EV-1/EV-2 heading sensor used on Evolution pilots.