Autopilot always deviates to starboard side of the route

[crck0848]

Can anybody suggest why my autopilot consistently tracks 10-15 yards to the starboard side of my route? In all other aspects, the system performs great, but it always runs to the right of where it should be. (I also replied to an older thread here: https://furunousaforum.com/threads/20382)

TZT16F chartplotters
SCX20 satellite compass
NavPilot 711C autopilot

My heading doesn't matter ... I'm always offset to the starboard side of the route. If I manually steer back to the route and reengage the AP, it always deviates back to starboard.

See attached screenshot: As I approach the waypoint, I'm offset to the right. The AP steers left to get back onto the route, goes directly over the waypoint, then steers right until it's 10-15 yards off the route again. It's particularly annoying when I'm in a narrow channel or canal. The frequent direction changes confuse nearby vessels.

Grateful for any suggestions.

 

[21Outrage]

I don’t know the answer to your question but venture it may be a deliberate setting, intended to keep you slightly outside of everyone else’s path. If that’s the case I’d wager you can adjust the setting.

 

[crck0848]

Interesting suggestion. But if that were the case, the AP would also leave the waypoints to port, rather than veering left to cross directly over the waypoint. I've dug pretty deep on this one, and can't find a setting anywhere.

 

[gtstang462002]

I have similar issues with mine always tracking to the port side if I am running any mode other than prescise.

 

[JJ Neutron]

Can anybody suggest why my autopilot consistently tracks 10-15 yards to the starboard side of my route? In all other aspects, the system performs great, but it always runs to the right of where it should be. (I also replied to an older thread here: https://furunousaforum.com/threads/20382)

TZT16F chartplotters
SCX20 satellite compass
NavPilot 711C autopilot

My heading doesn't matter ... I'm always offset to the starboard side of the route. If I manually steer back to the route and reengage the AP, it always deviates back to starboard.

See attached screenshot: As I approach the waypoint, I'm offset to the right. The AP steers left to get back onto the route, goes directly over the waypoint, then steers right until it's 10-15 yards off the route again. It's particularly annoying when I'm in a narrow channel or canal. The frequent direction changes confuse nearby vessels.

Grateful for any suggestions.

This could be due to a number of variables: Here are a few things to check... Possibly a faring block for a transducer or some other feature under the hull creating drag, or perhaps the RRU is having an issue, or perhaps something in the steering system linkage etc. or running one engine in a dual engine system while underway.

 

[crck0848]

The rudder signal behaves normally and says 0 when running straight ahead, so I doubt it's an RRU issue. Can't be a problem with the hull or running gear, as the boat runs straight and true under manual control. I've never run the boat on a single engine. The AP seems to know exactly where I am and how to control the boat, but it chooses to deviate to starboard. Keep the suggestions coming!

 

[21Outrage]

The rudder signal behaves normally and says 0 when running straight ahead, so I doubt it's an RRU issue. Can't be a problem with the hull or running gear, as the boat runs straight and true under manual control. I've never run the boat on a single engine. The AP seems to know exactly where I am and how to control the boat, but it chooses to deviate to starboard. Keep the suggestions coming!

Sorry, that must be very frustrating. Hoping for a relatively simple resolution

 

[JJ Neutron]

The rudder signal behaves normally and says 0 when running straight ahead, so I doubt it's an RRU issue. Can't be a problem with the hull or running gear, as the boat runs straight and true under manual control. I've never run the boat on a single engine. The AP seems to know exactly where I am and how to control the boat, but it chooses to deviate to starboard. Keep the suggestions coming!

Would it be possible for you to post some photos of the SCX20 as it is installed on the boat with any surrounding equipment in the photo, also an under hull photo if you have one from when the boat was out of the water last. Perhaps some photos of the steering system linkages and hydraulic lines too? Maybe having a look at these items may reveal something to help diagnose the root cause.

 

[crck0848]

The SCX20 has a great view of the sky -- highest point on the boat, well above the beam of the radar. Re: running gear and hydraulics, how could that be relevant given that everything acts perfectly normal under manual control? I don't want to assume anything ... just don't understand the question.