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+--- Thread: Evolution wheel pilot heading variance (/showthread.php?tid=170)
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Evolution wheel pilot heading variance - kcford - 02-17-16 12:09 PM
New install on 30' sailboat. Using A67 chartplotter for control head. Dockside wizard completed successfully. Compass lock off. Went on 30 minute cruise at 6 kts with several 360 degree turns. Autopilot holds a heading very well, but reports the heading 57 degrees off from COG from A67. Set "goto" a waypoint. Autopilot responded and set a course 57 degrees from true BTW.
The EV-1 is mounted well away from motor and electronics. How do I resolve this discrepancy?
RE: Evolution wheel pilot heading variance - Steve - Raymarine - Moderator - 02-17-16 01:21 PM
What is being displayed as the Deviation in the system? To check press Menu>Setup>Diagnostics>About Display, then scroll to the bottom of the page to view the Deviation information at the very bottom.
Also make sure that the arrow on the EV-1 heading sensor is pointed toward the bow.
RE: Evolution wheel pilot heading variance - kcford - 02-17-16 02:04 PM
EV-1 sensor pointed to bow. Will the menu sequence be the same on the A67? I don't intend to install the P70.
RE: Evolution wheel pilot heading variance - Steve - Raymarine - Moderator - 02-18-16 11:49 AM
No, I apologize you said that in your initial inquiry. To check the Deviation with an MFD, from the Home Page, press Setup icon at the top right corner, then scroll to System Setup, then to External Devices, then Pilot Setup. The Deviation will be shown on this page.
RE: Evolution wheel pilot heading variance - Steve - Raymarine - Moderator - 02-23-16 10:19 AM
First, what is the heading on the autopilot, is this correct? Check that to COG that is coming from your GPS antenna.
Next press Auto does the autopilot hold the course?
RE: Evolution wheel pilot heading variance - kcford - 02-23-16 04:03 PM
Deviation reported as 5 degrees.
After issuing GoTo command to a waypoint, bearing to waypoint is 96 degrees per A67 GPS. This is accurate.
While navigating to waypoint, COG per A67 GPS is 66 degrees. This is the actual COG, but it should be 96 degrees. AP holds this 66 degree COG with precision.
AP reports heading as 120 degrees.
Attached pic confirms AP is in Track mode, navigating to a waypoint called "Point." You can clearly see all the specifics: BTW=96, COG=66, AP heading=120.
RE: Evolution wheel pilot heading variance - Steve - Raymarine - Moderator - 02-24-16 01:33 PM
Can you provide me with this picture?
I don't want you in Track Mode.
Just bring up a Data Page, with Heading and COG databoxes on the same page. While underway going around 5 knots, are they close?
This just might be an alignment issue with the autopilot.
RE: Evolution wheel pilot heading variance - kcford - 02-25-16 10:29 AM
The attached pics should make the situation clear:
Deviation = 5
Speed = 5-6 kts
Standby: COG=106, AP Heading=169
Auto: COG=78, AP Heading=176
Track: COG=66, AP Heading=122, BTW=94
RE: Evolution wheel pilot heading variance - Steve - Raymarine - Moderator - 02-25-16 02:54 PM
That is quite a difference between heading and COG, usually after completing the cruise to get the good deviation that you you've explained that you have 5 degrees, the difference is close, inside of 10 degrees. Not in your case here.
What I think the next step will be is to adjust the heading, in order to be within 1-2 degrees for COG. In your 3rd picture above, the Pilot Set-up page, you would press the Pilot Settings button then choose Vessel Settings, and Compass Offset. This section will allow to adjust the heading information.
RE: Evolution wheel pilot heading variance - kcford - 02-26-16 10:30 AM
The compass offset is limited to +-10 degrees. I made the 10 degree adjustment, but saw little improvement. I also tried the "Align heading to GPS" option, but saw no improvement. Manual says you must be within 10 degrees for this to work.