[CA] [CA11] ST 8001 with smart pilot

[Scotttiara]

My pilot all of a sudden has started just counting up or down in degrees on the display screen. It will engage but steers all over the place.
Pilot has been perfect since 2006.
What’s the next step? New compass?

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Scott,

What model of autopilot course computer has the ST8001 autopilot control head been interfaced to?

[Scotttiara]

Looks like S36 AST

[Chuck - Raymarine - Moderator]

Scott,

Should you have meant to specify that the model of course computer is a S3G or S3 autopilot course computer, then please click here to view a FAQ addressing how the autopilot's fluxgate compass may be tested. As indicated within the referenced FAQ, should the measured resistances be within +/-2 ohms of the specified value then the measured values would be in spec. Also indicated within the fluxgate compass test FAQ, was an indication that binding within the fluxgate compass's moving parts could be responsible for the reported issue. If this is a S3G course computer, then it would be recommended that the S3G autopilot course computer's gyro cable be unplugged from the circuit board and that the autopilot's compass be re-calibrated and aligned. Should the problem persist, then it would be recommended that the fluxgate compass be replaced to address the reported issue. Should the problem appear to abate, then it would be recommended that the gyro be plugged back in and that the system be tested again. Should the problem persist, then the autopilot's rate gyro would be deemed to have suffered a failure and should be unplugged to permit the autopilot to function as a S3 course computer (non-gyro assisted) rather than a S3G course computer. Replacement gyros are no longer available for the S1G/S2G/S3G autopilot course computers. This will also reduce the heading data output rate from 10Hz to 1Hz. With regard to location of the fluxgate compass, it mounting location should yield a maximum deviation value which is less than 10 degrees. Should the reported maximum deviation value exceed 10 degrees, then another location may need to be sought for the fluxgate compass. Should none of the above address the reported issue, then it would indeed appear that the autopilot course computer has suffered a failure. Unfortunately, Raymarine's Product Repair Center can no longer service S1/S1G/S2/S2G/S3/S3G autopilot course computers, necessitating that an operational second hand S3G/S3 autopilot course computer be sought or that the autopilot (minus the drive unit) be replaced. Alternatively, the autopilot may be replace with an Evolution autopilot system pack and if operational, the currently installed drive unit may be retained for use with the Evolution autopilot.