[CA] [CA11] Aligning compass to GPS

[Captain reid]

I have an Es 128 MFD with an EV 1 course computer purchased in 2018. My autopilot heading reading continues to be off 10 Degrees west from my MFD GPS COG heading. The autopilot heading is the correct one as it alignes with both shipboard and handheld compass indiccators. I have performed a linearization with a full 360 deg turn without an effect.
Likewise. I have attempted through pilot setup/commissioning rmenu to alogn the compass and GPS headings but this feature aborts everytime despite steadt heading. I finally reverted to adjusting the compass offset to 10 deg. This seems like a big difference. Am i missing something?
Reid Lyon

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Reid,

Focus needs to be paid back to the vessel's autopilot installation, software level, and commissioning. The indexing arrow atop the EV-1 CCU must be pointing forward and parallel to the vessel's center line ... this should be verified. Please verify that the software levels of autopilot components (EV-1 CCU, p70RS Autopilot Control Head, ACUxxx) all be determined and that they, as well as the MFD's software be updated if any are found to be not to be operating with the latest available Raymarine product software update. Whether or not any of the autopilot components are found to have old software, it is recommended that a Pilot Factory Reset be perform, that the Dockside Wizard be executed again, and that the cruise to determine deviation be performed again ... the latter is not accomplished by turning in a circle. More detailed information concerning these steps may be found within the FAQ found here. The autopilot must complete "Detecting Magnetics" to perform properly and as indicated within the FAQ referenced therein, attention must be paid to the maximum deviation sensed by the EV-1 CCU and that the EV-1 be relocated if the maximum deviation is greater than 10 degrees. Ensure that the MFD's units set-up has been configured to report magnetic bearings. This preference will be communicated to the autopilot components via the system's SeaTalkng / NMEA 2000 network. Should the vessel have a properly calibrated compass, then I would typically recommend that the vessel be tied to the dock and then that the autopilot's heading be configured to match the compass's heading.

[Ken Tappert]

I am having a similar issue with EV-1 installed 2 years ago. When in my slip the autopilot display shows heading that is within 2 degrees of binnacle compass and heading on GPS. While sailing today in an easterly direction autopilot display showed a heading 50 degrees lower (more north) than binnacle compass and GPS were indicating. Returning to the west the autopilot showed a heading 30 degrees higher (more north) than the other sources. When back in slip it was again aligned with the other sources. I have had other instances of autopilot heading readings varying from other proven sources. Thanks for your help.

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum reid ,

The same recommendations provided to Ken should be applied to your system as well. I would add that the installation location of the EV-1 CCU should be inspected for objects located within 3' of the EV-1 CCU which are capable of producing magnetic fields. Please click here to view a FAQ addressing this subject.