Autopilot Troubles Robertson ap200dl

[Westiculo]

Currently on a cruise to Maine and having autopilot troubles. I have a two station Robertson ap200dl autopilot with an octopus 1012 linear drive linked directly to the rudder. The autopilot head has been working inconsistently, throwing an error that says it’s off course periodically. Initially I thought i didn’t have it in the right setting, but it keeps happening more frequently to the point that now i can tell something is wrong. Each time it does this the boat swings way off course. Checked the compass input in comp mode and it seems to get steady, continuous reads. Don’t think it’s the problem.

The error happens when using the autopilot from either station, which makes me think its not related to the computer. Gotta be the pump? I have never serviced the pump over the 3 years I’ve had the boat (do they need service?). After we anchored, I tried the autopilot in power steering mode and the pump seems to do what it’s supposed to.

Any ideas? Anything you think I should test to narrow in on the problem?

 

[caltexflanc]

Sounds like something metallic or electronic is interfering with the rate bearing compass.

Are you using the NAV function to steer to a waypoint or are you just doing a compass heading?

 

[boomerang]

Your symptoms are quite often as simple as a failing rudder feedback unit. If the pilot computer "sees" the rudders moving due to the erratic readings from the RF100 ,it will try to correct the heading even though the compass heading hasn't actually changed. You observed the compass heading & stated it remained steady. Look at the rudder position while moving the wheel hardover to hardover and see what the rudder position indicator on the DL display says. If it jumps instead of moving smoothly, thats your problem.