Autopilot Hunts

[CHSBoater]

After working great for 3 years, my autopilot developed a world of problems.

Based on advice received in the old forum, I sent the SPX30 controller and fluxgate compass back to the factory for repair. After reinstalling, I discovered my Seastar Smart Stick was also faulty, so I replaced it. Now, after a factory head reset and performing and passing the dockside wizard tests, compass deviation test (3 degrees) and sea trail wizard tests, the autopilot hunts when used in the AUTO mode.

At low speed, it keeps a reasonably straight course but you and see the motors being turned to port and starboard constantly. At speed, it steers the boat in an S pattern, 5 - 8 degrees to starboard, 5 - 8 degrees to port, 5 - 8 degrees to starboard, and so on.

I lowered the response level to 2 without effect. I am sure there is some other setting that needs to be adjusted, but I am unaware of exactly what counter rudder, rudder damping, and such do.

Setup is e7 (data master), E120W, SPX30, ST70 Control Head, Seastar Smart Stick Rudder Reference, Seastar Hydraulic Pump. Software v 6.27

Pursuit 315 Offshore w 300 Yamahas.

Thanks for any and all suggestions
Tom Uffelman
Charleston, SC

[CHSBoater]

So, research said I should increase rudder dampening to end the hunting. I did the dockside test and it looked good at 6. On the water, it still hunted at speed. I've increased dampening all the way to 9 and it still hunts when running 30 knots.

Suggestions?

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Tom,

At what speed was the boat operating when the Auto Learn feature of the Sea Trial Calibration was executed? What is the Rudder Gain set to?

[CHSBoater]

Thanks for the response. Auto learn was done at about 10 knots. I was afraid to run fast with all the maneuvering it does in the crowded harbor. I'll have to get over to the boat to check rudder gain, probably on the weekend.

[CHSBoater]

So I worked on the drive/vessel settings over the weekend and got the thing running straight with only a very slight wobble. The settings are
Dampening - 6
Gain - 5
Counter - 5
Trim - 2
Response - 5
Offset - 0
Turn rate - 5

The only thing still bothersome is that hitting the +1 button a number of times does not alter course very quickly. Otherwise, I'm prepared to declare victory.

Thanks for the hint about rudder gain.

[Chuck - Raymarine - Moderator]

CHSBoater,

I'm glad to learn of your success. For planing hulls, Auto Learn should be performed at a speed which is sufficient to permit the vessel to stay on plane. Heading changes of +/- 1 degree would be expected to have the reported effect. Within my own system, I typically perform heading changes in +/-10 degree increments or +/- 5 degree increments (rapid presses of +/- 1 button).